Hobart 90CU24 Operation And Maintenance Manual

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OM-2084

112797 Revised 10/98

Operation and Maintenance Manual

Model 90CU24 Generator Sets

Series 500392

Hobart Brothers Company

Ground Power Division

Troy, OH 45373

U.S.A.

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WARRANTY

HOBART BROTHERS COMPANY, TROY, OHIO, U.S.A.

GROUND POWER DIVISION

1. Hobart Brothers Company (hereinafter called HOBART) warrants that each new and unused Hobart Ground

Power Equipment, (hereinafter called the PRODUCT) is of good workmanship and is free from mechanical defects, provided that (1) the PRODUCT is installed and operated in accordance with the printed instructions of HOBART, (2) the PRODUCT is used under the normal operating conditions for which it is designed, (3) the PRODUCT is not subjected to misuse, negligence or accident, and (4) the PRODUCT receives proper care,

lubrication, protection, and maintenance under the supervision of trained personnel.

2. This warranty expires 15 months after shipment by HOBART to the first user, or 12 months after installation,

whichever first occurs.

3. This warranty does not apply to: primary and secondary switch contacts, cable connectors, carbon brushes, fuses,

bulbs, and filters unless found to be defective prior to use.

4. Hobart DOES NOT WARRANT THE FOLLOWING COMPONENTS: Engines (gasoline or diesel),storage

batteries, engine starters generators, alternators, regulators, governors, tires, axles,transmissions,and cable retrieving devices. Many of the foregoingcomponents are warranted directly by the manufacturer to the first user and serviced by a worldwide network of distributors and others authorized to handle claims for component manufacturers. A first user’s claim should be presented directly to such an authorized component service outlet. In the event any component manufacturerhas warranted its component to HOBART and will not deal directly with a first user then HOBART will cooperate with the first user in the presentation of a claim to such manufacturer. Under NO circumstances does HOBART assume any liability for any warranty claim against or warranty work done by or in behalf of any manufacturer of the foregoing components.

5. This warranty is extended by HOBART only to the purchaser of new PRODUCTS from HOBART or one of its

authorized distributors. The PRODUCTS purchased under this warranty are intended for use exclusively by the buyer and his employees and by no other persons and, therefore, there shall be no third party beneficiary to this warranty.

6. A claim of defects in any PRODUCT covered by this warranty is subject to HOBART factory inspection and

judgment. HOBART’S liability is limited to repair of any defects found by HOBART to exist, or at HOBART’S option the replacement of the defective product, F.O.B.factory, after the defective product has been returned by the purchaser at its expense to HOBART’S shipping place. Replacement and exchange parts will be warranted for the remainder of the original Warranty, orfor a period of ninety (90) days, whichever is greater.

7. UNDER NO CIRCUMSTANCES whatsoever shall HOBART and its authorized distributors be liable for any special

or consequential damages, whether based on lost goodwill, lost resale profits, work stoppage impairment of other goods or otherwise, and whether arising out of breach of any express or implied warranty, breach of contract, negligence or otherwise, except only in the case of personal injury as may be required by applicable law.

8. Continued use of the PRODUCT(S) after discovery of a defect VOIDS ALL WARRANTIES.

9. Except as authorized in writing, this warranty does not cover any equipment that has been altered by any party

other than HOBART.

10. THERE ARE NO WARRANTIES WHICH EXTEND BEYOND THE DESCRIPTION ON THE FACE HERE OF.

HOBART MAKES NO WARRANTIES, EXPRESSED OR IMPLIED, OF ERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

11. HOBART neither assumes nor authorizes any person to assume for HOBART any liability in connection with the

PRODUCTS sold, and there are no oral agreements or warranties collateral to or affecting this written Warranty.

This warranty and all undertakings of HOBART thereunder shall be governed by the laws of the State of Ohio, United States of America.

AT ALL TIMES, SAFETY MUST BE CONSIDERED AN IMPORTANT FACTOR IN THE INSTALLATION,

WARNING

SERVICING AND OPERATION OF THE PRODUCT, AND SKILLED, TECHNICALLY QUALIFIED PERSONNEL

SHOULD ALWAYS BE EMPLOYED FOR SUCH TASKS.

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Safety Warnings and Cautions

WARNING

IMPORTANT

General

Equipment that supplies electrical power can cause serious injury or death, or damage to other equipment or property. The operator must strictly observe all safety rules and take precautionary actions. Safe practices have been developed from past experience in the use of power source equipment. While certain practices below apply only to electrically-powered equipment, other practices apply to engine-driven equipment, and some practices to both.

Shock Prevention

Bare conductors, or terminals in the output circuit, or ungrounded, electrically-live equipment can fatally shock a person. Have a certified electrician verify that the equipment is adequately grounded and learn what terminals and parts are electrically HOT. Avoid hot spots on machine. Use proper safety clothing, procedures, and test equipment.

The electrical resistance of the body is decreased when wet, permitting dangerous currents to flow through it. When inspecting or servicing equipment, do not work in damp areas. Stand on a dry rubber mat or dry wood, use insulating gloves when dampness or sweat cannot be avoided. Keep clothing dry, and never work alone

CALIFORNIA PROPOSITION 65 - DIESEL ENGINES. Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer, birth defects and other reproductive harm.

ELECTRIC SHOCK can KILL. Do not touch live electrical parts. ELECTRIC ARC FLASH can injure eyes, burn skin, cause equipment damage,

and ignite combustible material. DO NOT use power cables to break load and prevent tools from causing short circuits.

IMPROPER PHASE CONNECTION, PARALLELING, OR USE can damage this and attached equipment.

Protect all operating personnel. Read, understand, and follow all instructions in the Operating/Instruction Manual before installing, operating, or servicing the equipment. Keep the manual available for future use by all operators.

a. Installation and Grounding of Electrically Powered Equipment

Equipment driven by electric motors and maintained in accordance with the National Electrical Code, ANSI/NFPA 70, or other applicable codes. A power disconnect switch or circuit breaker must be located at the equipment. Check the nameplate for voltage, frequency, and phase requirements. If only 3-phase power is available, connect any single-phase rated equipment to only two wires of the 3-phase line. DO NOT CONNECT the equipment grounding conductor (lead) to the third live wire of the 3-phase line, as this makes the equipment frame electrically HOT, which can cause a fatal shock.

November 27/1997 Safety Warnings

(rather than by diesel or gasoline engines)

must be installed

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Always connect the grounding lead, if supplied in a power line cable, to the grounded switch box or building ground. If not provided, use a separate grounding lead. Ensure that the current capacity of the grounding lead will be adequate for the worst fault current situation. Refer to the National Electrical Code ANSI/NFPA 70 for details. Do not remove plug ground prongs. Use correctly mating receptacles.

b. Output Cables and Terminals

Inspect cables frequently for damage to the insulation and the connectors. Replace or repair cracked or worn cables immediately. Do not overload cables. Do not touch output terminal while equipment is energized.

Service and Maintenance

This equipment must be maintained in good electrical and mechanical condition to avoid hazards stemming from disrepair. Report any equipment defect or safety hazard to the supervisor and discontinue use of the equipment until its safety has been assured. Repairs should be made by qualified personnel only.

Before inspecting or servicing electrically-powered equipment, take the following precautions:

a. Shut OFF all power at the disconnecting switch or line breaker before inspecting or servicing

the equipment.

(amperage)

b. Lock switch OPEN c. Disconnect power to equipment if it is out of service. d. If troubleshooting must be done with the unit energized, have another person present who is

trained in turning off the equipment and providing or calling for first aid.

Fire And Explosion Prevention

Fire and explosion are caused by electrical short circuits, combustible material near engine exhaust piping, misuse of batteries and fuel, or unsafe operating or fueling conditions.

a. Electrical Short Circuits and Overloads

Overloaded or shorted equipment can become hot enough to cause fires by self destruction or by causing nearby combustibles to ignite. For electrically-powered equipment, provide primary input protection to remove short circuited or heavily overloaded equipment from the line.

b. Batteries

Batteries may explode and/or give off flammable hydrogen gas. Acid and arcing from a ruptured battery can cause fires and additional failures. When servicing, do not smoke, cause sparking, or use open flame near the battery.

c. Engine Fuel

Use only approved fuel container or fueling system. Fires and explosions can occur if the fuel tank is not grounded prior to or during fuel transfer. Shut unit DOWN before removing fuel tank cap. DO NOT completely fill tank, because heat from the equipment may cause fuel expansion overflow. Remove all spilled fuel IMMEDIATELY, including any that penetrates the unit. After clean-up, open equipment doors and blow fumes away with compressed air.

Toxic Fume Prevention

Carbon monoxide - Engine exhaust fumes can kill and cause health problems. Pipe or vent the exhaust fumes to a suitable exhaust duct or outdoors. Never locate engine exhausts near intake ducts of air conditioners.

Bodily Injury Prevention

Serious injury can result from contact with fans inside some equipment. Shut DOWN such equipment for inspection and routine maintenance. When equipment is in operation, use extreme care in doing necessary trouble-shooting and adjustment. Do not remove guards while equipment is operating.

(or remove line fuses)

so that power cannot be turned on accidentally.

Safety Warnings November 27/1997 Page 2

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

7. Medical and First Aid Treatment

First aid facilities and a qualified first aid person should be available for each shift for immediate treatment of all injury victims. Electric shock victims should be checked by a physician and taken to a hospital immediately if any abnormal signs are observed.

EMERGENCY

FIRST AID

Equipment Precautionary Labels

Inspect all precautionary labels on the equipment monthly. Order and inspect all labels that cannot be easily read.

Call physician immediately. Seek additional assistance. Use First Aid techniques recommended by American Red Cross until medical help arrives.

IF BREATHING IS DIFFICULT, give oxygen, if available, and have victim lie down. FOR ELECTRICAL SHOCK, turn off power. Remove victim; if not breathing, begin artificial respiration, preferably mouth-to-mouth. If no detectable pulse, begin external heart massage. CALL EMERGENCY RESCUE SQUAD IMMEDIATELY.

November 27/1997 Safety Warnings

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Introduction

This manual contains operation and maintenance information for a Hobart generator set manufactured by Hobart Brothers Company, Ground Power Division, Troy, Ohio 45373.

This manual is not intended to be a textbook on electricity or electronics. Its primary purpose is to provide information and instructions to experienced operators, electricians, and mechanics who have never operated this equipment. It is the intent of this manual to guide and assist operators and maintenance people in the proper use and care of the equipment.

Use of the manual should not be put off until a trouble or need for help develops. Read the instructions before starting the unit. Learn to use the manual and to locate information contained in it. Its style and arrangement are very similar to commercial aircraft manuals. The manual is divided into five chapters. Each chapter is divided into as many sections as required. Each new section starts with page 1. Each page is identified by chapter, section and page number, which are located in the lower, outside corner. When information located in another portion of the manual is referred to, its location is identified by a chapter, section, and paragraph or figure number.

For example: “ Paragraph 1.a. If a chapter and section are not indicated in a reference, the referenced material is located in the same section as the reference, for example: “

In addition to operation and maintenance instructions, the manual contains an illustrated parts list in Chapter 4, and a collection of manufacturer’s literature and supplemental information in Chapter 5.

Appendix A contains a list of options and corresponding TO documents. If the machine purchased contains one of these options, the corresponding TO will be inserted in this section.

Content of the manual is arranged as follows:

Chapter 1. Description/Operation Chapter 2. Servicing/Troubleshooting Chapter 3. Overhaul/Major Repair Chapter 4. Illustrated Parts List Chapter 5. Manufacturer’s Literature Appendix A. Options / Features

(see Section 2-3, Paragraph 1.a.)

” refers to information located in Chapter 2, Section 3,

(see Paragraph 1.a.).

”

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Table of Contents

Chapter-Section Page

Chapter 1. Description / Operation

Section 1. Description 1-1 1

General 1-1 1 Orientation 1-1 1 Optional Equipment 1-1 1 Special Features 1-1 1

Protective Monitor 1-1 1 Voltage Regulator 1-1 1 Electric Governor 1-1 1

Canopy 1-1 1 Engine, Generator, and Control Box 1-1 4

Basic Engine 1-1 4 Engine Manufacturer’s Equipment 1-1 4 Engine Cooling Fan 1-1 6 Occasional Engine Faults 1-1 6 Hobart Installed Engine Equipment 1-1 7 Generator 1-1 8

Control Box Assembly 1-1 9

Power Module Panel Assembly 1-1 18

Section 2. Preparation for Use, Storage or Shipping 1-2 1

Preparation for Use 1-2 1

Inspection/Check 1-2 1 Installing Three-phase AC Output Cables 1-2 2

Preparation for Storage 1-2 3

General 1-2 3 Temporary Storage 1-2 3 Long Time Storage (Over 30 Days) 1-2 3 Preparation for Shipment 1-2 4

November 27/1997 Table of Contents

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Section 3. Operation 1-3 1

General 1-3 1 Operating the Unit 1-3 1

Pre-start inspection 1-3 1 Normal Engine Starting Procedures 1-3 1 Failed Starting Procedures 1-3 4 Power Delivery 1-3 4 Discontinue Power Delivery with Unit Shutdown 1-3 5

Chapter 2. Servicing

Section 1. Maintenance Inspection/Check 2-1 1

General 2-1 1 Maintenance Schedule 2-1 1

General 2-1 1 Maintenance Schedule Check Sheet 2-1 1 Time Intervals 2-1 1 Identification of Interval Periods 2-1 1

Inspection/Check 2-1 4

General 2-1 4 “AR” Checks and Operations (As Required) 2-1 4 “BR” Checks and Operations (Break-In Period) 2-1 4 “A” Checks and Operations (10 Hours or Daily) 2-1 5 “B” Check and Operations (250 Hours or 3 Months) 2-1 7 “C” Checks and Operations (500 Hours or 6 Months) 2-1 7 “D” Checks and Operations (1000 Hours or 1 Year) 2-1 8 “E” Checks and Operations (1500 Hours or 1 ½ Years) 2-1 8 “F” Checks and Operations (2000 Hours or 2 Years) 2-1 10 Seasonal Maintenance Checks (Engine) 2-1 11 Lamps and Circuit Breakers 2-1 12

Section 2. Maintenance Procedures 2-2 1

General 2-2 1 Lubrication 2-2 1

General 2-2 1 AC Generator 2-2 1 Generator Controls 2-2 1 Engine 2-2 1 Engine Accessories Lubrication 2-2 5

Servicing the Air Cleaner 2-2 6

Inspecting the Air Cleaner 2-2 6 Changing the Air Filter 2-2 6 Disposal 2-2 6

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Engine Fuel 2-2 7

How to Select Fuel—Quality 2-2 7 Cold Weather Operation 2-2 7

Engine Fuel System 2-2 7

Fuel Tank 2-2 8 Fuel Pre-Filter/Separator 2-2 8 Fuel Pump 2-2 9 Fuel Filter and Pre-filter Straining Screen 2-2 9 Fuel Return 2-2 11 Priming Fuel System 2-2 11

Engine Cooling System 2-2 14

General 2-2 14 Radiator Cap 2-2 14 Coolant 2-2 14 Draining the Cooling System 2-2 15 Flushing the Cooling System 2-2 15 Cleaning the Radiator Core 2-2 15 Filling the Cooling System 2-2 16 Thermostat 2-2 16 Coolant Filter Removal 2-2 16

Drive Belts 2-2 17

General 2-2 17 Preparation for Belt Check and Adjustment 2-2 17 Check Fan Belt Tension 2-2 17

Generator Maintenance 2-2 18 Cleaning 2-2 18

Adjustment 2-2 18

Section 3. Adjustment/Test 2-3 1

General 2-3 1 Testing the Generator Set 2-3 1

Pre-operational Test Procedures 2-3 1 Operational Test Procedures 2-3 4 Testing the No. 1 output circuit 2-3 5

November 27/1997 Table of Contents

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Testing the No. 2 output circuit 2-3 6 Testing and checking meters, switches,

relays, and indicating lights 2-3 7

Re-checking the entire unit after testing 2-3 9

Generator Set Adjustment 2-3 10

Generator Adjustment 2-3 10 Adjust 400 Hz voltage regulator 2-3 10 Basic Engine Adjustments 2-3 11 Engine Accessories Adjustment 2-3 11 Electric Governor System Adjustment 2-3 12

Generator and Exciter Test 2-3 18 Diode Test 2-3 18

Section 4. Troubleshooting Procedures 2-4 1

General 2-4 1 Equipment for Troubleshooting 2-4 1 Parts Replacement 2-4 1 Test Values 2-4 2 Check Connections and Leads 2-4 2 Electric Governor Troubleshooting 2-4 2 Engine Troubleshooting 2-4 3 Illustrations 2-4 3 Connection and Schematic Diagrams 2-4 3 Engine Controls 2-4 7 Generator Excitation Circuits 2-4 13 No. 1 Load Contactor Operating Circuit 2-4 15 No. 2 Load Contactor Operating Circuit 2-4 18 Protective Circuit 2-4 20 Generator 2-4 23

Chapter 3. Overhaul/Major Repair

Section 1. Exciter Armature 3-1 1

General 3-1 1 Exciter Armature 3-1 2 Exciter Armature Replacement 3-1 2

General 3-1 2 Tools Needed for Exciter Armature

Removal and Installation 3-1 3 Conditions for Exciter Removal 3-1 3 Preparation for Exciter Armature Removal 3-1 4 Exciter Armature Removal 3-1 4

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Installing the Exciter Armature 3-1 6

Preparation for Exciter Armature Installation 3-1 6 Exciter Armature Installation 3-1 6

Section 2. Dual Bearing Flexible Coupling

General 3-2 1

Coupling Bolts 3-2 1

Disassembly 3-2 1

Separate Engine and Generator 3-2 1 Remove Coupling Assembly 3-2 2

Coupling Service 3-2 3

Coupling Kit 3-2 4 Bushing Kits 3-2 4 Bushing Replacement 3-2 4

Coupling Installation 3-2 5

Cleaning 3-2 5 Assembly 3-2 5

Reassemble Engine and Generator 3-2 10 Run-in and Periodic Check 3-2 10

Section 3. Generator Assembly 3-3 1

General 3-3 1 Procedure for Generator Assembly Removal 3-3 1

Procedure for Gaining Access to the Generator 3-3 1 Removing the generator Assembly 3-3 3

Installing a Generator Assembly 3-3 4

Remounting the Generator Assembly 3-3 4 Remounting the Previously Removed Assemblies 3-3 4

November 27/1997 Table of Contents

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Chapter 4. Illustrated Parts List 4-1 1

Section 1. Introduction 4-1 1

General 4-1 1 Purpose 4-1 1 Arrangement 4-1 1 Explanation of Parts List 4-1 1

Contents 4-1 1 Parts List Form 4-1 1

Section 2. Manufacturer’s Codes 4-2 1

Explanation of Manufacturer’s (Vendor) Code List 4-2 1

Section 3. Illustrated Parts List 4-3 1

Explanation of Parts List Arrangement 4-3 1 Symbols and Abbreviations 4-3 1

Section 4. Numerical Index 4-4 1

Explanation of Numerical Index 4-4 1 Numerical Index 4-4 1

Chapter 5. Manufacturer’s Literature 5-1 1 Appendix A. Options/Features Appendix A 1 Unusual Service Conditions Wet Stacking

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Chapter 1. Description / Operation

Section 1. Description

1. General

The basic generator set covered in this manual is manufactured by Hobart Brothers Company, Ground Power Division, in Troy, Ohio. It is rated at 90 KVA and is designed to produce and deliver 115/200-volt, 400 Hz, 3-phase AC power to a parked aircraft or to Hobart approved test banks only. Series 500392 consists of the following part numbers:

Part Number 500392-001 identifies a single output unit structured* for trailer mounting. Part Number 500392-002 identifies a dual output unit structured* for trailer mounting. Part Number 500392-003 identifies a single output unit structured* for fixed/truck mounting. Part Number 500392-004 identifies a dual output unit structured* for fixed/truck mounting. Part Number 500392-005 identifies a single output trailer mounted unit similar to 500392-001. A

list of other features that make the 500392-005 unique is located with the Appendix in the back of this manual.

*In this manual, part numbers 500392-001 and 500392-003 are identical (single output) units. Part numbers 500392-002 and 500392-004 are identical (dual output) units. The difference between the units are the options available for them. For example, a fixed/truck mounting kit is not available for part numbers 500392-001 or 500392-002. See Appendix A.

Orientation

For purpose of orientation, the radiator is considered to be at the REAR of the unit. The generator and controls are at the FRONT. RIGHT and LEFT are determined by standing at the REAR end facing the machine. Thus, the control box is mounted on the LEFT side at the FRONT of the unit.

Optional Equipment

Chapters 1 through 5 of this Operation and Maintenance Manual identifies only the “strip down” version of the 90CU24 generator set. A list of optional equipment which make this manual unique to the generator set that you have purchased, appears in Appendix A. A few items included in Appendix A are cable trays, trailers, 28-volt DC power transformer-rectifiers, etc.

Special Features

The generator set has special features in which are described more fully under assemblies in which they appear. Three features, protective monitor, voltage regulator, and electric governor are mentioned here and described briefly.

a. Protective Monitor

The protective monitoring system receives signals from the fault sensing units in the generator output circuit and functions to cause the load to be disconnected from the generator if an abnormal condition of voltage, frequency, or load develops.

b. Voltage Regulator

A microprocessor-type, adjustable voltage regulator provides automatic voltage regulation at the aircraft. The regulator is also adjustable for a variety of output cable sizes and lengths.

November 27/1997 Chapter 1-1

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

1. Control Panel

2. Output Cable Clamps

3. Frame

4. Emergency Stop Switch

5. Canopy

6. Radiator Access Door

Generator Set

Figure 1

Chapter 1-1 November 27/1997 Page 2

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

c. Electric Governor

The engine is equipped with an electric governor kit and other special equipment more fully described under the engine description.

Canopy

A sheet metal enclosure, identified as a canopy, provides protection for the engine, generator, and electrical controls. The canopy is designed to reduce the operational noise level in the immediate area of the machine.

Physical Basic Unit

Length 100 in. (2540 mm) 148 in. (3759 mm) Width 45 in. (1143 mm) 77 in. (1956 mm) Height 47.5 in. (1203 mm) 61 in. (1549mm) Weight with T-R 6700 lb. (3039 kg) Weight of optional T-R 300 lb. (136 kg) Not applicable

Generator

Output power rating (kVA) Output Voltage 115/200 Volts Rated load capacity (Amps) 260 Amps Frequency (Hz) 400 Hz Output kilowatts 72 Power factor 0.8 Duty cycle 100% Operating speed (RPM) 2400 RPM Overload capacity, both outputs:

125% rated load (Amps) Output cable size 2/0

Over voltage Trips at 126 volts after a 1-second time delay

Under voltage Trips at any voltage below 100 volts after 7 seconds. Over frequency Trips at any value between 426-Hz and 480-Hz after a 5-second

Under frequency Trips at 375-Hz or less after a 5-second time delay. Overload time delay Trips in approximately 5 minutes at 125% load on either or both

90 kVA

325

Generator Protective System

Trips at 140 volts in 160 milliseconds. Trips at 180 volts in 50 milliseconds.

time delay. Trips immediately at any frequency exceeding 480-Hz.

outputs.

With Trailer

Specifications and Capabilities

Figure 2

November 27/1997 Chapter 1-1

(Sheet 1 of 2)

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Manufacturer Cummins Engine Company, Inc.

Model No. 6BT5.9C165 Type In-line 6 cylinder 4 Cycle Diesel Bore and Stroke 4.02 x 4.72 inches (10.2 x 11.9 cm) Displacement 359 c.i. (5.9 liters) Compression Ratio 17.5 : 1 Horsepower 165 Idle speed 850+/-50 RPM High speed limiting Approx. 2750 +/-75 RPM Normal governed speed 2400 RPM Electrical system 12-V DC Ground Negative Firing order (RH rotation) 1-5-3-6-2-4 Lubricating oil capacity (w/filter) 16 quarts (15.1 liters) Coolant capacity system 38 quarts (36 liters)

Engine

Columbus, Ohio 47201

Specifications and Capabilities

Figure 2 (Sheet 2 of 2)

Engine and Generator

The engine and generator comprise the principal components of the generator set. They are mounted on the welded steel frame of the chassis. The engine coolant radiator is also mounted on the frame just forward of the engine-generator combination. Figure 3 is an illustration showing the location of all major components and sub-assemblies.

a. Basic Engine.

The basic engine is an in-line 6-cylinder diesel rated at 165 horsepower. See Fig. 2 for general specifications.

b. Engine Manufacturer’s Equipment

As received from the engine manufacturer, the engine includes the following equipment which is more fully described in the Cummins Operation and Maintenance Manual.

(1)

Electrical System The 12-V DC electrical generating and starting system includes an alternator, voltage regulator,

and starter with solenoid switch.

(2)

Fuel Filter The fuel filter is a spin-on disposable, vacuum type connected between the fuel lift pump and

injector pump

(3)

Oil Filter The engine oil filter is a spin-on, full-flow type. It is mounted on the right side of the engine.

Chapter 1-1 November 27/1997 Page 4

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

1. Radiator

2. Engine

3. Generator

4. Air Cleaner

5. Control Box

Generator Set Components

Figure 3

November 27/1997 Chapter 1-1

6. Output Module Panel

7. Engine-Generator Control Panel

8. Mounting Frame

9. Muffler

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

(4)

Engine over-speed protection The engine is protected against over-speed by a speed-limiting mechanism in the mechanical

governor.

c. Engine-cooling fan

The engine fan is designed to blow air inward as a conventional fan does.

Refer to the engine Operation and Maintenance Manual in Chapter 5 for more engine details.

d. Engine faults

The following is a table listing faults which may occasionally occur. Column two of the table explains what happens in the engine’s circuitry when the fault occurs, and column three tells how to return the generator set to service.

outward through the radiator, rather than pull the air

ENGINE FAULTS

Engine Fault Condition What This Fault Condition Does

Over temperature or low oil pressure

Low fuel Turns on the low fuel indicating

Clogged air cleaner or other restriction in the combustion air inlet.

Automatically removes power from the electric governor controller, shuts down the engine, and turns on the applicable indicating light.

light (27, Fig. 5). Depending on the position of JP2 and JP3 on the control PC board, a low fuel fault may cause the engine to idle, shut down, or continue to run at rated speed.

Turns on the air cleaner restriction indicating light (6, Fig. 5)

To Put the Generator Set Back

into Service:

a) Press the engine stop button (20, Fig. 5) to turn off the indicating light and reset the protective system. b) Or use E-STOP (4, fig. 1)

button for immediate reset.

a) The low fuel fault indicating function must be reset by

pressing the engine stop button (20, Fig. 5). Fuel must be

added prior to attempting

another engine start.

b) Or use E-STOP (4, fig. 1)

button for immediate reset.

a) Press the engine stop button

(20, Fig. 5). The restriction must be removed prior to attempting another engine start.

b) Or use E-STOP (4, fig. 1) ]

button for immediate reset.

Chapter 1-1 November 27/1997 Page 6

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e. Hobart Installed Equipment

This generator set is modified at Hobart Brothers by the addition of the following equipment:

(1)

Shut Down/Reset device In addition to the other devices provided by the engine manufacturer, an engine shutdown/reset

feature is added by Hobart Brothers.

EMERGENCY SHUTDOWN/RESET SWITCH (mushroom button). The emergency shutdown switch has two purposes. One is to Reset the starting circuit

following a failed starting sequence. The other is to provide instant shut off of the generator set by disconnecting power to the governor circuit through the control box. It is located on the left side of the generator set on the door near the control box.

To operate the EMERGENCY SHUTDOWN/RESET SWITCH:

• Push button in until engine stops or until button travel stops

• Pull the button back out to reset

(2)

Engine Safety Devices In addition to the safety devices provided by the engine manufacturer, other engine shutdown

features are added by Hobart Brothers

Coolant high temperature shutdown system The coolant temperature shutdown system consists of a Detroit Diesel supplied temperature

switch. This switch controls a relay in the control box, which is in series with the governor system. This relay will stop the engine if the temperature reaches 220º F (96º C).

Oil pressure shutdown system The oil pressure shutdown system consists of a Hobart supplied oil pressure switch. This

switch is diaphragm operated and held is closed position by any normal oil pressure above 12 PSI (83 kPA). It is connected in series with the fuel shutoff valve and will open the holding circuit if the oil pressure drops to 12 PSI (83 kPA) or below.

(3)

Electric governor system

An electric governor kit is installed on the engine to replace a conventional mechanical type. The electric governor was selected for control of engine speed (and generator output frequency) because it provides faster engine response to changes in load conditions. This fast response results in very close frequency control. A brief description is given below:

The governor system consists of the following main components:

Magnetic pickup The magnetic pickup is a device for detecting the speed of the engine. It is mounted in the

flywheel housing directly over the ring gear. It produces an AC signal to the control unit when the ferrous flywheel teeth pass through the magnetic field at the end of the pickup.

Control unit The control unit is a box containing a compact assembly of solid state components. It

receives an AC signal from the magnetic pickup and senses speed changes in the engine. It provides a voltage signal to the actuator which causes the actuator to move the fuel control lever as required to maintain a predetermined engine speed. Its power is received from the 12-V DC battery system.

Actuator The actuator supplies the force needed to move and position the fuel lever as required to

maintain a constant engine speed. The actuator is operated by a DC signal from the control unit.

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

(4)

Radiator

The radiator is a one-piece type designed for long periods of operation without servicing. Refer to Section 2-1 for servicing procedure.

(5)

Air cleaner The diesel-engine air cleaner (fig. 4) is so constructed that air enters through its cylindrical body,

and then is filtered in the process before being passed onto the engine turbo-charge assembly. An air cleaner service indicator device is mounted on the air cleaner assembly to monitor air flow

in the air cleaner. As the air cleaner becomes filled with dust, dirt, and carbon, the intake system air flow becomes increasingly restricted. This restriction causes a diaphragm inside the indicator to move toward an electrical contact. When the maximum allowable restriction level is reached, the circuit closes and the air cleaner indicator light (6, Fig. 5) on the engine-generator control panel is illuminated to warn the operator that the air cleaner must be changed. The electrical indicator automatically resets after a new air cleaner is installed.

Service Indicator

Air Cleaner

Air Cleaner and

Service Indicator

Figure 4

f. Generator

The 400 Hz generator is a brushless, revolving field, three-phase, alternating current type. The generator set covered by this manual is a dual-bearing type. The front end of the rotor shaft extends forward beyond the front bearing and is attached to the engine flywheel by a flexible coupling assembly. The rear end of the rotor shaft extends rearward beyond the rear bearing and into the exciter stator housing. The exciter rotor is mounted on this shaft extension with a key and is secured by a washer and 1/2"-13 thread cap screw. A rectifier with three diodes is mounted on the exciter rotor and converts exciter AC output to DC for excitation of the generator revolving fields. The exciter DC output to the generator fields, and consequently the generator output, is controlled by the amount of DC voltage supplied to exciter fields by the voltage regulator. A centrifugal, radial-blade fan which is part of the flexible coupling assembly, draws cooling air over all internal windings. Air enters at the exciter end and is discharged at the drive end. The complete generator is bolted to the engine flywheel housing.

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

7. Control Box Assembly

The control box is a sheet metal enclosure which houses and provides mounting facilities for engine and generator controls and monitoring equipment.

a. Control Panel (Fig. 5)

On the door of this control box is the control panel. The control panel is divided into three sections. On the left side of the control panel, as one faces it, are engine meters and indicating lights. On the right side of the control panel are generator meters and indicating lights. At the bottom of the control panel are push-button switches for operating the engine and generator.

(1)

Panel lights and panel light push-button switch Meters are lighted from inside the control panel. They are controlled by a push-button switch (28)

at the bottom left on the control panel.

(2)

Engine hour meter The hour meter (5) is electrically driven from the 12-V DC battery system. The hour meter

measures and records engine running time and will record up to 9999.9 hours on five revolving drums. It is only functional when when the engine is running and the oil pressure safety shutdown switch, mounted on the engine block, is closed.

(3)

Engine oil pressure gage The oil pressure gage (7) is an electrical type which is connected by a wire to an oil pressure

sensor installed in the engine lubricating system. The range is 0 to 125 PSI (0 to 862 KPA).

(4)

Engine ON indicating light When the engine control push-button switch (26) is pressed to start the engine, a green

indicating light within the push-button switch glows.

(5)

Engine coolant temperature gage The temperature gage (3) is an electrical type which is connected by a wire to a water

temperature sensor installed in the engine cooling system. The gage indicates engine coolant temperature in the range of 100 to 240 º F (38 to 116º C).

(6)

Engine start push-button switch

This push-button switch (26) which actuates the solenoid switch to connect power to the engine starting motor. 12-V DC power is supplied directly to the governor controller and the oil pressure safety shutdown switch is bypassed. This bypass is necessary for engine starting because the low oil pressure switch is CLOSED until the engine is running normally.

When pressed a second time, this push-button switch provides a 12-V DC signal to the speed adjust PC board on the governor controller, which causes the governor actuator to adjust the engine speed to 2400 RPM. At the same time, a ground signal is provided to the regulator, enabling the generator to build up voltage for 400-Hz generator output.

Pressing the push-button switch once more removes these signals and the engine reverts to idle speed.

(7)

Engine stop push-button switch When the engine stop push-button switch (20) is pressed once, the indicator within the switch

will glow (red). Then a 3 - 5 minute delay will occur to permit the turbo and other engine components to cool evenly. After the delay, power is disconnected from the governor controller. This governor actuator will then close and shut off fuel to the engine so the engine can shut down.

when pressed, connects 12-V DC power to the starter solenoid coil

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

1. Fuel Gage

2. Front Panel

3. Engine Coolant Temperature Meter

4. Over Temperature Indicator Light (Red)

5. Engine Hour Meter

6. Indicating Light, Air Cleaner Restriction (Red)

7. Oil Pressure Gage

8. Engine Ammeter

9. Frequency Meter

10. Control Box Label

11. Strip Lights (3)

12. Generator Ammeter

13. Voltmeter

14. Overload Indicator Light

Engine Generator Control Panel

(Dual Output Shown)

Figure 5

Chapter 1-1 November 27/1997 Page 10

15. Over Voltage Indicator Light

16. Adjustable Grip Latch

17. Under Voltage Indicator Light (Red)

18. Meter Selector Switch

19. Test-Reset Push-Button Switch (Red)

20. Engine Stop Push-Button Switch

21. Under Frequency Indicator Light (Red)

22. No. 2 Contactor Push-Button Switch (Orange)

23. Over Frequency Indicator Light (Red)

24. No. 1 Contactor Push-Button Switch (Yellow)

25. Low Oil Pressure Indicator Light (Red)

26. Engine Start Push-Button Switch (Green)

27. Low Fuel Indicator Light (Red)

28. Panel Light Push-Button Switch (Yellow)

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

(8)

Engine ammeter The ammeter (8) indicates the direction and value of current flow from or to the 12-V DC battery.

Its graduated range is from -60 A through O A to + 60 A.

(9)

Engine fuel gage An electric fuel gauge (1) receives its controlling signal from a sending unit in the fuel tank.

Twelve volt DC operating power is supplied to the fuel gauge when the green engine start push-button switch (26) is pressed. The fuel level can be checked when the unit isn’t running by pressing the yellow lamps push-button switch (28)

(10)

Protective system Indicating lights, test and reset push-button switches The function of this set of five lights (14, 15, 17, 21 and 23)

abnormal condition of over voltage, under frequency, etc., which caused the protective monitor system to function. Each of the five lights is connected to an actuating circuit within the memory and time delay module. When one of the circuits is activated, it turns on the applicable indicating light. The light will remain on until the test/reset push-button switch (19) is pushed. All lamps in indicating lights may be tested by pressing the test/reset push-button switch. A lamps test should be performed only when disconnected from a load, as the contactor(s) will open during the test cycle.

(11)

Engine systems warning lights (red) Four red indicator lights are illuminated to warn the operator of abnormal engine operations

which must be corrected. These indicators are: The over temperature indicator light (4), air cleaner restriction indicator (27). The function of the air cleaner indicator circuit is explained in detail in Para. 6, E, (4).

(6)

, low oil pressure indicator light (25),and low fuel indicator light

is to indicate, to the operator, the

(12)

Generator output monitors The generator output is monitored by three instruments; a frequency meter (9),a voltmeter (13)

and an ammeter (12). The frequency meter is an analog type, and indicates the frequency of the generator output alternating current in the range of 360 to 440 Hz voltmeter indicates the generator output voltage in each phase-to-neutral (A-N, B-N and C-N) or phase-to-phase (A-B, B-C and C-A) as selected by the meter selector swit ch (18) has a 3-1/2-inch face and the scale is graduated 0 to 300 V. The ammeter is also 3-1/2-inch size and is graduated 0 to 500 A. The amperage value in each of the three phases may be read on the ammeter by selecting the desired phase with meter selector switch (18) current transformers, located on the output module (Fig. 9), lower the output load current to a lesser value, of definite ratio, which will operate the ammeter movement without damage. The ammeter dial scale is graduated and numbered so that the pointer will indicate the true load current value rather than the meter movement current.

(13)

Voltmeter-ammeter selector switch This switch provides a means of selecting and determining which phase of voltage and current is

indicated on the voltmeter and ammeter and whether the voltage is line-to-neutral or line-to-line. The meter switch (18) is a six-position, rotary type. A nameplate, located under the switch knob, is marked and lettered to indicate the six functional positions of the meter switch.

(14)

Load contactor indicating lights Indicating lights within the respective contactor control push-button switches (22 orange and 24

yellow) glow when the circuit is energized, indicating that power is available at the plug. When the load contactor opens for any reason, the light is turned OFF.

(meters)

(cycles per second)

The voltmeter

Three ammeter

. The

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

1. Control Box Wrapper

2. Control Box Top

3. Receptacles (4)

4. Memory and Time Delay PC Board

5. Over-Under Frequency PC Board

6. Over-Under Voltage PC Board

7. Voltage Regulator PC Board

8. Terminal Blocks (2)

9. Switch Mounting Bracket

11. Panel Lights (2)

12. Engine Circuit Breaker (10A)

13. Controls Circuit Breaker (5A)

14. Marker Light Circuit Breaker (10A)

15. Contactors Circuit Breaker (5A)

16. Test Bank / Aircraft Switch, No. 2 Output

17. Test Bank / Aircraft Switch, No. 1 Output

18. Regulated / Diagnostic Switch

19. Generator Set Control PC Board

10. Label, Switch Mounting Bracket

Control Box Interior Components (Dual Output Shown)

Figure 6

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

b. Control Box Interior Components (Fig. 6)

(1)

Test bank aircraft switches For each load contactor circuit, a single-pole, single-throw toggle switch (16 or 17) provides a

means of bypassing the interlock circuit for that contactor when supplying power to a load bank or to an aircraft not equipped with a plug interlock system.

(2)

Regulated-diagnostic switch When the regulated-diagnostic switch

output voltage is regulated by the solid state voltage regulator (7,Fig. 6, and Fig. 8) for 115/200 V-AC output to an aircraft. When this switch is placed in the DIAGNOSTIC (up) position, battery voltage (12-V DC) is applied to the generator exciter with the engine running at rated RPM, in order to check the operation of the generator. By applying this 12 V-DC battery voltage to the exciter and observing generator output voltage, it can be determined if a particular power output malfunction is caused by a defective generator or by a defective voltage regulator. When this switch is in the MAINTENANCE position, no current is supplied to the generator exciter. However, a low-level, unregulated voltage of approximately 30-V AC will be produced at the generator output terminals due to the residual magnetism of the exciter.

(3)

Circuit breakers A 10-ampere circuit breaker (12), protects the 12-V DC engine governor and fault circuits, and

another 10-ampere circuit breaker (14) breaker (13) protects the 12-V DC control system, and another 5-ampere circuit breaker (15) protects the circuits of the load contactors.

(18)

is in the REGULATED (down) position, generator

protects the 12-V DC lighting system. A 5-ampere circuit

(4)

Memory-time delay module The memory and time delay module (4) is sometimes called the protective monitor module. It is

a solid-state device with a hermetically-sealed, reed-type circuit. The printed circuit board includes five memory circuits and a time delay circuit. Each circuit is connected to a corresponding sensing circuit in the sensing modules. All memory circuits are connected to the module circuit relay coil, and any one of the circuits can energize the coil to open the circuit relay contacts. Thus, when a sensing device energizes any one of the module circuits, the module circuit is also energized to break the load contactor holding circuit and allow the load contactor to open. A time delay system is designed into the under voltage circuit to prevent nuisance opening of the contactor under conditions of momentary under voltage in the generator output. An under voltage condition which continues uninterrupted for a period of 4 to 12 seconds (adjustable) will cause the time delay circuit to open the load contactor. Each of the five circuits is connected to a corresponding indicating light (Fig. 5; 14, 15, 17, 21 or 23) occurs. The module circuit will remain energized (OPEN) and the light will remain ON until the reset push-button switch (19, Fig. 5) is pushed to break the module 12-V circuit, and allow the circuit to return to normal, CLOSED position.

(5)

Sensing modules The voltage sensing module (6) and frequency sensing module (5) are connected to generator

output leads between the generator and load contactor. These solid-state modules sense any abnormal condition of voltage or frequency and signal the solid-state circuitry of the memory and time delay module (4) to open the load contactor and disconnect output to the aircraft. Trip values are adjustable; however, adjustments should be made ONLY under laboratory conditions.

On the 400-Hz output module, one solid-state overload signaling device (1, Fig. 9), is also connected to the protective monitor module. Its function is similar to the voltage and frequency sensing modules.

which is turned on when a fault

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Trip values for protective circuits are as follows:

Over voltage relay Trips at 126 volts after 1-second time delay.

Under voltage relay Trips at 100 volts after 7 seconds. Over frequency relay Trips at any value between 420-Hz and 480-Hz

Under frequency Trips at 380-Hz or less after a 7-second time

Overload time delay Trips in approximately 5 minutes at 125% load

(6)

Generator Set Control PC Board The generator set control PC board (19, Fig. 6 and Figure 7) is a central location for the various

plug-in relays used for generator operation. Troubleshooting is thus easier for technicians working on the generator set. This PC board contains the following relays and associated circuitry.

Trips at 140 volts in 160 milliseconds. Trips at 180 volts in 50 milliseconds.

after a 5-second time delay. Trips immediately at any frequency exceeding 480-Hz.

delay.

on either output or both outputs.

• Master relay, K69, routes 12-V DC power to all circuits, except panel and clearance lights. This relay is operated upon pressing the START push-button switch remains in the OPERATE condition until it is RESET by the STOP push-button switch

(26, Fig. 5)

, and

(20,

Fig. 5).

• Bypass relay, K73, is also activated by pressing the START push-button switch. Relay K73 enables the start signal to the starter solenoid for 5 seconds after it is initially activated. K73 also disables the low oil pressure fault circuit during this 5 second period.

• Idle-excitation relay, K68, controls engine speed and generator excitation. K68 activates to idle the engine and remove excitation from the generator. In the RESET state, K68 provides a 12-V DC signal to the governor controller, causing the engine to attain rated speed (2400 RPM). At the same time, K68 provides a ground signal to voltage regulator, which enables excitation current to the generator. When the engine is running, K68 changes from OPERATE to RESET, or vice-versa, with each closure of the START push-button switch. Auxiliary circuit also controls the idle-excitation relay. This auxiliary circuit causes the relay to operate when: (1) Engine is at rest and the start push-button switch (26, Fig. 5) is pressed, (2) Any engine fault, except the air filter restriction, occurs.

• The circuit which controls K68 also drives a flasher circuit that controls the lamp within the START push-button switch (26, Fig. 5).

• Relay K72 controls the No. 1 contactor. When the engine is at rated speed, and voltage has built up, K72 changes from OPERATE to RESET, or vice-versa, with each closure of the No. 1 contactor push-button switch. An auxiliary circuit will reset K72 when the No. 1 plug is removed from the aircraft. The No. 2 contactor control relay, K272 operates in the same manner.

• Relay K70 controls panel and clearance lights. This relay changes from OPERATE to RESET, or vice-versa, with each closure of the LAMPS push-button switch (28, Fig. 5)

The fuel gage is also powered by K70 when the engine is at rest. K70 is reset, turning off all lights, when the engine STOP push-button switch is pressed.

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

1. Master Relay (K69)

2. Idle-Excitation Relay (K68)

3. Over Temperature Fault Relay (K67)

4. Low Oil Pressure Fault Relay (K71)

5. No. 2 Contactor Control Relay (K272)

6. Panel and Clearance Lights Relay (K70)

Generator Set Control PC Board

November 27/1997 Chapter 1-1

7. No. 2 Plug-Interlock Relay (K202)

8. No. 1 Plug-Interlock Relay (K2)

9. Bypass Relay (K73))

10. Low Fuel Fault Relay (K65)

11. Air Filter Fault Relay (K66)

12. No. 1 Contactor Control Relay (K72)

Figure 7

Page 15

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

• Relays K65, K66, K67 and K71 are fault relays. Each receives a signal from engine sensors, and illuminate panel lights to indicate the presence of a fault. Activation of the over temperature relay, K67, or low oil pressure relay, K71, result in interruption of 12-V DC power to the governor controller, causing the engine to shut down. Activation of low fuel relay K65 may result in the engine reverting to idle speed or shut-down, depending on the condition set by jumpers JP2 and JP3. The only result of an air filter fault, is that relay K66 causes illumination of the panel light. All engine fault relays remain activated until power is removed by pressing the STOP push-button switch (20, Fig. 5) or the emergency stop switch.

• The plug-interlock relays (K2 and K202) on the control PC board cause the respective output load contactors to open in the event the cable plug connector becomes accidentally disconnected from the aircraft during power delivery, or if an attempt is made to deliver power when the output cable is not connected to the aircraft. Twenty-eight volt direct current for operation of the circuit is supplied from the aircraft either through an on-board transformer- rectifier, or from a twenty-eight volt electrical system. Connection from aircraft to the interlock circuit is made through terminals E and F on the output cable plug

(7)

Voltage regulator PC board This voltage regulator (7, Fig. 6 and Fig. 8) is designed to provide 1% voltage regulation for all

loads up to 100% of rated load on a three-phase, four-wire, 115/200-volt, 400-Hz brushless alternator. This regulator provides field excitation power as required to meet varying alternator load conditions to hold the alternator voltage constant. In addition, the voltage regulator PC board circuitry provides line drop compensation. Any deviation of the alternator voltage from its set, regulated level is sensed at the voltage regulator PC board. The sensing signal is compared to a reference signal, and, with associated circuitry, varies the field power supplied to the rotary exciter.

• When the machine is started, and the engine is at rated speed, the rotary exciter is excited from alternator residual magnetism through the half-wave rectifier bridge, located on the voltage regulator PC board assembly. As the rotary exciter voltage increases, alternator excitation increases and the alternator voltage builds up. The sensing circuit of the voltage regulator PC board then compares the input voltage to a reference voltage and adjusts the field power of the rotary exciter to bring the voltage into regulation limits.

• When the alternator is loaded, its terminal voltage decreases, lowering the rectified three-phase voltage of the voltage sensing circuit. The sensing voltage is low in respect to its reference voltage, causing the voltage regulator PC circuitry to increase the power to the field of the rotary exciter. The alternator voltage increases until the voltage returns to its regulated value.

• When a load is removed from the alternator, the alternator voltage rises. The rectified three-phase voltage sensing signal increases, causing this signal to be higher than the reference signal. The associated voltage regulator circuitry causes the field power of the rotary exciter to decrease, lowering the alternator voltage until the voltage returns to regulated value. The line drop voltage compensation circuit consists of: (1) A current transformer on each phase of the load circuit, and (2) A fixed resistance in parallel with each current transformer. The current transformers detect the magnitude of current flowing through the power cables from the alternator to its load and feed a signal into the voltage regulator PC board. The PC board processes this signal to change the output voltage proportional to the current draw. The regulator output increases slightly so that the alternator output voltage is equal to the regulated voltage plus the voltage drop in the lines. The line drop compensation potentiometer may be adjusted to match exactly the voltage drop of the power cables carrying the load current.

• A receptacle connector at the bottom of the voltage regulator PC board provides a quick connect-disconnect facility for interconnecting wire leads.

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

1. Output Voltage Adjustment (Course)

2. Output Voltage Adjustment (Fine)

Voltage Regulator PC Board

Figure 8

November 27/1997 Chapter 1-1

3. Line Drop Compensation Adjustment

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

8. 400 Hz. Output Module Panel Assembly Single Output 500392-001 (See Fig. 9)

The output module panel assembly, sometimes referred to as the contactor panel, is located at the left front of the machine under the control box. It is accessible by opening the left front door and then removing the clear lexan and steel panels below the control panel. The panel assembly provides sensing and overload protection for the output circuit and provides a means of connecting and disconnecting generator output to and from the load (aircraft).

a. Load contactors

The load contacts (5) contains a magnetic operating coil and four sets of contacts. The three larger conduct three-phase AC generator output. A small contact set is connected in the protective monitor circuit and supplies 12-V DC power used by sensing relays to signal the protective monitor when a fault occurs. Three-phase, 400-Hz generator output power is conducted to the load contactor by 2/0 cables which pass through two sets of current transformers

b. Current transformers

(1)

Line-drop current transformers Items 2 and 3 (Fig. 9) are line-drop current transformer-burden resistor combinations. They work

in conjunction with one another to detect the magnitude of current flowing from generator to load. They feed a signal to the voltage regulator which interprets the signal and alters the exciter field current as required to maintain a constant predetermined voltage at the load.

(2)

Generator ammeter and overload current transformers Three overload current transformer-burden resistor combinations (4 and 6) work in conjunction

with one another, to convert a current signal to a voltage signal which is sent to the ammeter and to the overload sensing board. The ammeter is really a voltmeter graduated and numbered in amperes to show current proportional to the voltage signal received. This ammeter is so graduated and numbered that, when cables running through the current transformers carry a current of 260 amperes (rated load), 6.67 volts is sent to the ammeter. The ammeter will indicate it as 260 amperes.

c. Overload Conditions

When an overload condition develops, wherein load exceeds 325 amperes (125% of rated load) the overload sensing board (1) sends a signal to the memory and time delay PC board (4, Fig. 6). This signal, which is the same one used in the ammeter circuit, interrupts the load contactor circuit to open the load contactor.

(1)

Generator overload module When there is load on the generator set, and an overload condition exists which exceeds 125%

of the generator’s rated load) generator overload current transformers (3) and sends a signal to the memory and time delay PC board (4, Fig. 6).

To do this, the overload module is equipped with a hermetically-sealed, reed-type relay. Relay contacts are normally open. The solid-state circuitry is designed to close relay contacts when output current reaches 125% of normal rated output capacity. The closed relay sends a signal to the protective monitor. This signal gates the overload SCR (silicon-controlled rectifier) in the protective monitor and opens the contactor(s) (5).

this solid-state overload module (1) interprets a signal from the

The following is a list of overload module characteristics:

• At 125% load the module will function in 5 minutes.

• At 150% load the module will function in 16 seconds.

• AT 200% load the module will function in 4 seconds.

NOTE: The overload protective system will function when any phase carries 123% to 127% of rated

load. All times are plus or minus 25% and are adjustable.

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

4 2 4

6 3 6 36

1. Overload PC Board

2. Resistor, 50 ohm, 20 watt (R16, R17, R18)

3. Line Drop Current Transformer (T4, T5, T6)

4. Resistor, 16.6 ohm, 20 watt (R33, R34, R35)

5. Load Contactor

Single Output Power Module

d. Rectifier

A diode-bridge rectifier (9) receives 400-Hz AC from phase C of the generator output and converts it to a pulsating, direct current for energization of the load contactor holding coil only. This DC coil-holding circuit is controlled indirectly by controlling the 400-Hz AC to the rectifier. The ground circuit for the rectifier’s AC supply must pass through the relay contacts in the protective monitor module to ground cable N. Therefore, any time a protective device functions to open the protective monitor relay, the rectifier’s AC circuit is opened. No DC is then available for the load contactor holding coil, hence, the load contactor opens.

Figure 9

6. Overload Current Transformer (T30, T31, T32)

7. Flyback Diode, Exciter

8. Resistor, 100 ohm, 25 watt, No. 1 Contactor

9. Rectifier, No. 1 Contactor (CR6)

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

9. 400 Hz. Output Module Panel Assembly, Dual Output 500392-2

The dual output generator set (500392-2) can provide 400 Hz. service on two output cables simultaneously. To make this possible, certain components are added to single output module panel (Fig. 9), to make up the Dual Output Module Panel Assembly. These components are identified in Fig

10.

1. Load Contactor NO. 2

2. Rectifier, No. 2 Contactor (CR206)

Dual Output Power Module

Cold Weather Starting System

10.

This cold weather starting system is used for starting the engine of a generator set engine at very cold temperatures.

This cold weather starting system is a fully automatic Engine Starting Fluid System designed to spray a controlled amount of starting fluid into the air intake system of an engine during and immediately after cranking.

The system’s Engine Temperature Sensor (ETS) switch determines when the System should function. When needed, the solenoid valve is activated automatically during engine cranking. Once activated, starting fluid is released from the pressurized cylinder, through a flow metering orifice fitting at the bottom of the valve through the nylon tubing, and out of an injector nozzle located in the engine’s air intake system. A reservoir in the valve maintains a flow of starting fluid after cranking to prevent the just started engine from faltering or dying.

Whenever the engine does not start within a normal period of cranking, the starting fluid cylinder may be empty. Refer to “Servicing and Troubleshooting.”

3. Resistor, 100 ohm, 25 watt, No. 2 Contactor

Figure 10

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 / Generator Set

Section 2. Preparation for Use, Storage or Shipping

1. Preparation for Use

a. Inspection/Check

Inspect the unit thoroughly prior to operation.

(1)

Remove blocking, banding, ties, and other securing material.

(2)

Inspect exterior for shipping damage such as broken lights, damaged sheet metal, etc.

(3)

Open all canopy doors and inspect interior for foreign material such as rags, tools, shipping papers, etc.

(4)

Check fuel, coolant, and oil hoses and connections for visible leaks. Visually inspect the compartment floor and ground surface under the unit for signs of leakage. If leaks are found, correct by tightening hose clamps, tube fitting, etc., as required.

(5)

Check security of generator set retaining components.

(6)

Check the following for sufficient quantity:

Fuel Press lamps button to energize fuel gage when engine is stopped. Fuel is supplied from a

customer-furnished source.

NOTE: For recommended fuel specifications refer to the Cummins Operation and Maintenance Manual

provided with this Hobart manual (OM-2084).

Engine coolant Remove radiator cap to check coolant level. Coolant level should be at the bottom of the filler

neck. See figure 2 for coolant capacities.

CAUTION

NOTE: For antifreeze protection, use a solution of 50% permanent antifreeze (Ethylene glycol) and

50% clean water.

Engine lubricating oil level The oil gage rod (See Fig 1) has “H” high mark and “L” low level marks to indicate the

operating lubrication oil supply. Oil level should be kept as near the high mark as possible, without going over it. See figure 2 for oil capacity specifications.

BE SURE the cooling system antifreeze solution is adequate to protect below lowest temperature expected.

CAUTION

NEVER operate the engine with oil level below the “L” level mark or above the ”H” level mark.

See the Cummins Operation Maintenance Manual for oil recommendations.

Check Batteries Inspect the batteries for proper connection of the terminals and also check the electrolyte

level (if possible). Service or replace if necessary.

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 / Generator Set

Oil Level Gauge

Oil Fill

Oil Fill and Check Location

Figure 1

Lubricating oil capacity with filter 24 Quarts (22.7 liters) Coolant capacity including radiator 38 Quarts (36 liters)

Figure 2

Capacity

b. Installing Three-phase AC Output Cables

The generator set may be shipped without aircraft cables. The load contactors, to which cables must be connected, are located on the left side of the unit beneath the engine control panel.

The conductor size recommended for AC output cables is 2/0 AWG. Use No. 12 size for control (E and F) terminals. Large cables (A, B, C, N) should be equipped with terminals having at least a 3/8-inch diameter mounting hole. Mounting hole in small leads (E and F) should be at least 1/4-inch diameter.

To install AC output cables proceed as follows:

(1)

Open the left front canopy door of the generator set.

(2)

Remove plexiglass.

(3)

Remove upper panel below door.

(4)

Loosen screws on cable clamps located on the side panel beneath the left rear canopy door.

(5)

Route cables through cable clamp, and up to the load sides (bottoms) of the load contactors.

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 / Generator Set

(6)

Connect the phase cable terminal lugs to the appropriate terminal studs on the contactors: cable lug “A” to terminal stud “A”, “B” to “B”, and “C” to “C”.

(7)

Connect the cable’s neutral terminal lug securely to the neutral (ground) stud on the power module.

(8)

Connect the “E” and “F” cables to the “E” and “F” studs on the power module.

(9)

Tighten clamp screws securely on the side panel, but avoid damage to cable insulation.

(10)

Replace upper panel and plexiglass.

Tips on Cold Weather Starting

2. a. Battery and Cables

To start in cold weather, a diesel engine must crank at a fairly high speed. Worn out batteries, partially discharged batteries, and poor or loose cable connections will reduce cranking speed. Batteries, cables, and connections should be cleaned and tightened regularly.

b. Fuel

For an engine to start and continue running, fuel must flow through the injection system. Unblended #2 diesel fuel “clouds”, forming filter-clogging waste at temperatures around + 15º F (- 10º C) making starting and running impossible. Most engine manufactures recommend that fuel have a cloud point at least 10º F (5º C) below the coldest anticipated temperature.

c. Lube Oil

Engine lubricating oil gets thicker at lower temperatures. Many oils that flow freely at 70º F (21º C) are extremely thick at 0º F (-18º C). Follow your engine manufacturer’s recommendations regarding oil viscosity for the coldest temperatures you expect your engine to encounter.

Preparation for Storage

When a generator set is to be stored or removed from operation, special precautions should be taken to protect the internal and external parts from rust, corrosion, and gumming in the engine fuel system.

a. General

Pull all circuit breakers and/or disconnect battery negative terminal.

(1)

The unit should be prepared for storage as soon as possible after being removed from service.

(2)

The unit should be stored in a building which is dry and which may be heated during winter months.

(3)

Moisture absorbing chemicals (Hobart Brothers Part No. 76A-1354-001) are available for use where excessive dampness is a problem; however, the unit must be completely packaged and sealed if moisture absorbing chemicals are to be effective.

b. Temporary Storage

When storing the unit for 30 days or less, prepare as follows:

(1)

Lubricate the unit completely in accordance with instructions in Section 2-2. This will include changing engine oil, and all filter elements.

(2)

Start the engine and operate for about two minutes so that all internal engine components will be coated with new oil.

NOTE: Do not drain the fuel system or crankcase after this run.

(3)

Make certain the cooling system antifreeze solution is adequate to protect below the lowest temperatures expected during the storage period. See 2-2; Para 6. Be sure the solution is thoroughly mixed.

(4)

Clean the exterior of the engine. Dry with clean rags and compressed air.

November 27/1997 Chapter 1-2

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 / Generator Set

(5)

Seal all engine openings. Use a waterproof, vapor proof material which is strong enough to resist puncture damage from air pressures.

c. Long Time Storage (Over 30 Days)

To protect the generator and other electrical components, the complete unit should be packaged using moisture proof packaging material and sealing material. Place containers of moisture absorbing chemicals, Hobart Brothers Part No. 76A-1354-001, in the unit before packaging. The unit may be stored for long periods with no special preparation if it is possible to operate the engine once each week. When starting once a week proceed as follows:

(1)

Make certain the cooling system is adequately protected.

WARNING

ENSURE adequate ventilation before starting the engine.

(2)

Start the engine and operate under full load until coolant temperature has reached at least 176ºF (80ºC).

(3)

While the engine is running, ensure that normal operating controls are in good working condition before shutdown and storage.

If weekly operation is not possible, contact the nearest Cummins Engine Company distributor for instructions.

d. Preparation for Shipment

(1)

Disconnect battery negative terminal before shipping.

(2)

During long shipments, the generator set retaining hardware may become loosened by vibration, jolting, etc.

WARNING

NOTE: It is suggested that strong banding be used to secure the generator set, or a strong steel bar

may be welded or bolted across the front of the generator set frame.

When shipping the unit, provide sufficient retaining materials to ensure the generator set cannot roll out of the vehicle in which it is being transported.

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Section 3. Operation

1. General

This section contains information and instructions for the safe and efficient operation of the equipment. Operating instructions are presented in step-by-step sequence of procedures to be followed in supplying 400-Hz power.

NOTE: Read ALL of the Operating Instructions before attempting to operate the equipment.

WARNING

Ear protection equipment may be necessary when working close to this equipment.

Operating the Unit

a. Pre-start inspection

(1)

Be sure the fuel shutoff valve on the unit is open.

(2)

Ensure 12-V DC power is available to the engine starting system.

(3)

Check the engine and generator compartments to make certain they are free of rags or other foreign materials.

(4)

Make certain there is sufficient lubricating oil and coolant in the engine.

(5)

Check that all circuit breakers are reset.

b. Normal Engine Starting Procedures

Engine starting procedures are outlined below. Engine operating controls and monitoring instruments are illustrated in Fig. 1.

CAUTION

NOTE: The Cummins Operation Manual is provided with this Hobart manual (OM-2084)

Refer to Operating Instructions in the Cummins Operation Manual, when starting engine for the first time.

(1)

If illumination is required, press lamps push-button switch (28) one time. Pressing this button switch also activates the fuel gage. (1, Fig. 1).

(2)

Press the green engine start push-button switch (26) and hold until engine starts. The engine will start at IDLE speed, and the green light in the engine start push-button switch will flash to indicate that power is available to the engine protective circuit and electric governor.

CAUTION

November 27, 1997 Chapter 1-3

Do not attempt to bring to rated speed for at least 5 seconds after engine starts. Damage to the starter and flywheel will result.

Page 1

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

1. Fuel gage

2. Front panel

3. Engine coolant temperature meter 4 . Over temperature indicator light (red)

5. Engine hour meter

6. Indicating light, air cleaner restriction

7. Oil pressure gage

8. Engine ammeter

9. Frequency meter

10. Control Box label

11. Strip lights (3)

12. Generator ammeter

13. Voltmeter

14. Overload indicator light (red)

Operating Controls and Instruments

(Dual Output Shown)

Figure 1 (Sheet 1 of 2)

Chapter 1-3 November 27, 1997 Page 2

15. Overvoltage indicator light (red)

16. Adjustable grip latch

17. Undervoltage indicator light (red)

18. Meter Selector switch

19. Test-reset push button switch (red)

20. Engine stop push button switch (red)

21. Underfreqency indicator light (red)

22. No. 2 contactor push button switch (orange)

23. Overfreqency indicator light (red)

24. No. 1 contactor push button switch (yellow)

25. Low Oil Pressure indicator light (red)

26. Engine start push button switch (green)

27. Low Fuel indicator light (red)

28. Panel light push button switch (yellow)

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

29. Regulated-diagnostic switch

30. Test bank-aircraft switch No. 1 output

31. Test bank-aircraft switch, No. 2 output

32. Circuit Breaker, contactors (5-amp) 33 Circuit Breaker, marker lights (10-amp)

34. Circuit Breaker, control (5-amp)

35. Engine circuit breaker (10-amp)

36. Output voltage adjustment (coarse)

37. Output voltage adjustment (fine)

38. Line drop compensation adjustment

Operating Controls and Instruments

(Dual Output Shown)

Figure 1 (Sheet 2 of 2)

November 27, 1997 Chapter 1-3

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

CAUTION

If the engine fails to start within 5 seconds, the control system will automatically disable the starting motor and indicate a low oil pressure fault. The emergency stop switch must be pressed to reset the control system and allow another starting attempt. If the engine fails to start after four attempts, an inspection should be made to determine the cause.

If the engine fires sufficiently to disengage the starter gear, but does not start, allow the starting motor to come to a complete stop before attempting to engage the starter again, then press the start push button switch.

(3)

Check oil pressure to make certain that it is normal, and observe all other engine instruments for normal operation.

(4)

Allow engine to idle and warm for 3 - 5 minutes before bringing it up to rated speed.

CAUTION

DO NOT allow the engine to idle for long periods of time.

c. Failed Starting Procedure

In the event that the engine fails to start. The circuitry must be reset before the next attempt. To do this:

(1)

Push the red EMERGENCY STOP/RESET BUTTON on the left side door of the generator set.

(2)

Pull the red EMERGENCY STOP/RESET BUTTON back out before the next attempt of starting the generator set.

d. Power Delivery

(1)

Press engine start push button switch (26, Fig. 1) a second time to bring engine from idle speed to rated speed. The electric governor will immediately increase engine speed to 2400 RPM and maintain it. The voltage build-up will occur automatically. Also the green indicating light in the engine start push-button (26) switch will glow continuously.

(2)

Observe generator instruments. The frequency meter (9, Fig. 1) should indicate exactly 400 Hz. With voltmeter-ammeter selector switch (18) in any line-to-neutral position, (A-N, B-N, or C-N), the voltmeter (13) should read 115 volts. With voltmeter-ammeter selector switch in any line-to-line position, (A-B, B-C, or C-A), the voltmeter should read 200 volts.

The final step in delivering power is closing one or both of the load contactors. When satisfactory frequency and voltage values are indicated by the instruments, close either load contactor (or both load contactors) by momentarily pressing the load contactor control push button switch (22 and/or 24,). The yellow or orange indicating light of the push button switch that is pressed will glow at once, to indicate that the load contactor is closed and power is available at the aircraft. As soon as the light glows, release the push button switch.

(3)

Early in the power delivery run it is recommended that the operator check output voltage and current in each of the three phases. Use the meter switch (18, Fig. 1) to select the phase and line-to-line or line-to-neutral voltage. If the load is changing, it is good operating practice to observe the instruments until load conditions stabilize.

CAUTION

NEVER press the test/reset push button switch while power is being delivered. The contactors will open and power to the aircraft will be suddenly interrupted.

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

(4)

A condition of overvoltage, undervoltage, underfrequency, overfrequency, or overload in the output circuit will automatically open the load contactor and turn on the applicable indicating light to signal the operator which of the above faults caused the protective monitor system to operate. After the fault has been corrected, press the test/reset push button switch (19, Fig. 1) to turn off the indicating light and reset the protective relay system. Proceed with power delivery by operating the load contactor push button switch.

CAUTION

e. Failed Power Delivery (See Fig. 1)

CAUTION

If the indicating light should go out as soon as the push button switch is released, and the no fault lights are ON, it indicates that 28.5-V DC holding current is not being supplied from the aircraft to the plug-interlock relay. Correct the condition and again operate load contactor control push button switch (22 or 24).

The regulated/diagnostic switch (29) must be set to REGULATED for power delivery. This switch is located inside the control box behind the control panel.

The No. 1 and/or No. 2 output switch (30 or 31) must be set to AIRCRAFT position. These switches are located inside the control box behind the control panel.

See section 2-4 for other No. 1 and/or No. 2 Load Contactor Operating Circuit troubleshooting procedures.

f. Discontinue Power Delivery with Unit Shutdown (See Fig. 1)

(1)

Normal conditions

NEVER disconnect the output cable while power is being delivered. Output contactors must be open prior to removal of the cable from the aircraft.

The generator set must be shut down so that the failed power delivery problems can be diagnosed. Only licensed technicians should work on this generator set.

Push the load contactor push button switch (22 or 24) to open the contactor. The indicating light (yellow or orange depending on the contactor used) on that switch will go OFF immediately to indicate that the load contactor has opened and power is no longer being delivered to the aircraft. The engine will remain at rated speed.

Push the red engine stop push-button switch (20) once to bring the engine down to idle speed. This will begin the automatic shutdown sequence to shut off the engine, gauges, lights, etc., after approximately 3 - 5 minutes.

Disconnect output cable from aircraft after engine is at idle speed only.

(2)

Emergency conditions

Depress the EMERGENCY STOP BUTTON (sect. 1-1; 4, fig.1) located on the left front side of the generator set canopy. When pushed, this button instantly shuts the generator set off and must be pulled back to reset itself for restarting the generator set.

November 27, 1997 Chapter 1-3

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Chapter 1-3 November 27, 1997 Page 6

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Chapter 2. Servicing/Troubleshooting

Section 1. Maintenance Inspection/Check

1. General

To make certain the generator set is always ready for operation, it must be inspected and maintained regularly and systematically so that defects may be discovered and corrected before they result in serious damage to components, or failure of the equipment.

WARNING

STOP operations at once if a serious or possibly dangerous fault is discovered.

Maintenance Schedule

2. a. General

A periodic maintenance schedule should be established and maintained. A suggested schedule is provided in Fig. 1 on the following pages. It may be modified, as required to meet varying operating and environmental conditions. It is suggested that generator set and vehicle inspections be coordinated as much as possible.

b. Maintenance Schedule Check Sheet

It is strongly recommended that the customer use a maintenance schedule check sheet such as the one in Cummins Operation Manual. The check sheet will provide a record and serve as a guide for establishment of a schedule to meet the customer’s maintenance requirements for his specific operation.

c. Time Intervals (See Fig. 1 and 2)

The schedule is based on both hours of operation and calendar intervals. These two intervals are not necessarily the same. For example, in normal operation the oil change period, based on hours of operation, will be reached long before the three months calendar period. The calendar period is included to make certain services are performed regularly when the equipment is stored, or being operated infrequently. Lubricating oil standing in engines that are stored, or used very little, may tend to oxidize and may require changing although it is not dirty. Perform all services on whichever-comes-first basis.

d. Identification of Interval Periods (See Fig. 1 and 2)

Each interval period is identified by a letter A, B, C, etc., (See Fig. 2). For example, services under B schedule should be performed at the end of each 250 hours of operation, or every three months period, BR service is performed during the BREAK IN period (first 50-150 hours). AR service is performed AS REQUIRED.

Chapter 2-1

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

HOURLY INTERVAL CALENDAR INTERVAL

SYMBOL AR BR A B C D E F

ENGINE

Change Air Cleaner Cartridge X Tighten Manifold Hardware X Check Crankcase Oil Level X Drain Fuel PreFilter Elements X Check Coolant Level X Check for Leaks and Correct X X Check Air Cleaner Indicator X Check Exhaust System X Check and Record Oil Pressure X Change Fuel Filter Elements X X Clean Radiator Core (external) X

Req.

Once

after

150

Daily

250

Mo.

500

6Mo.

1000

or 1 Year

1500

1-1/2

Years

2000 or 2 Years

Check Governor Linkage X Change Crankcase Oil X X Change Oil Filter Element X X Check/Adjust Drive Belt(s) Tension X Check Engine and Generator Mounts X X Check Coolant, Additive-Concentration X Check Fan Hub and Drive Pulley X Check Fuel Prefilter Cartridge X X Check Hose Clamps on Air Intake Side X Service Fuel Cooler X Steam Clean Engine X X Clean fuel system X Check Vibration Damper X Check Injectors and Valve Clearance

(adjust if necessary) Check Fuel Manifold Pressure X Check Water Pump X

Check Alternator Check Cranking Motor

X X

Chapter 2-1 Page 2

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

HOURLY INTERVAL CALENDAR INTERVAL

SYMBOL AR BR A B C D E F

ENGINE

Clean/Calibrate/Replace Injectors Check Fuel Pump Calibration Change Coolant Inspect Cylinder Heads Inspect Pistons and Piston Rings Inspect Bearings and Journals Clean fuel cooler Spring & Fall Check Fan Mounting Spring & Fall Clean Cooling System Spring & Fall Check Hoses Spring & Fall Clean Electrical Connections Spring & Fall

Req.

Once after

150

Daily

250

Mo.

500

6Mo.

1000

or 1 Year

1500

1-1/2

Years

2000 or 2 Years

X X X X X X

Check Thermostats and Seals Fall

ELECTRICAL (12-V DC System)

Check All Lights Check Charging Rate Check Battery and Fluid Level Clean Battery Terminals Check Wiring and Connections

ELECTRICAL (400-Hz System)

Check Output Cable and Connectors Check Volt, Amp & Frequency Meters Check Protective Relays Inspect Wiring and Connectors Clean and Inspect Generally

X X

X X X

Chapter 2-1

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Symbols

BR 50-150 None AR As Required None

A 10 Hours Daily B 250 Hours 3 Months C 500 Hours 6 Months D 1000 Hours 1 Year E 1500 Hours 1-½ Years F 2000 Hours 2 Years S Seasonally Spring and/or Fall

Symbols and Time Intervals

Inspection/Check

Time Intervals

Hours Calendar

Figure 2

a. General

Inspections, checks, and maintenance are described in general here. More specific and detailed information contained in 2-2 and 2-3, will be referenced when applicable.

b. “AR” Checks and Operations (As Required)

(1)

Engine

Change air cleaner. A definite time schedule for changing the air cleaner cannot be established. This filter should

not be washed more then six times or retained for more than one year’s service, which ever comes first.

Tighten manifold, muffler, and exhaust pipe attaching hardware as required.

(2)

Electrical System (12-V DC)

Check battery terminals

• Anytime the battery compartment doors are opened for any reason, visually check battery cable connectors and battery posts. If corrosion is observed, disconnect cables and clean battery posts and connectors with a wire brush or special battery post-and-connector cleaning tool. Coat posts and connectors with a light film of petroleum lubricant before reconnecting cables.

c. “BR” Checks and Operations (Break-In Period, Once After 50-150 hrs.)

The following procedures are precautionary measures taken on most new engines. If a problem occurs with any of the following issues be sure to recheck it after the next 50-150 hours.

(1)

Check for leaks and correct. This involves an overall inspection of the engine and may require some maintenance if leaks are found. Refer to the Cummins Operations Manual for assistance.

(2)

Change fuel filter elements. Metal shavings from the new fuel tank can clog the filter. See 2-2, Para. 4 for details.

(3)

Change crankcase oil. New engines often release metal shavings more frequently. Therefore the crankcase oil must be changed as a precautionary measure. See 2-2, Para. 2, d, (4) for instructions.

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

(4)

Change oil filter element. The oil filter should be changed with the oil. See 2-2, Para 2, d, (4) for details.

(5)

Check engine mounts to ensure they are properly installed and that they have not worked loose. (Torque is set at 285 Nm, 210 ft-lb).

(6)

Check fuel prefilter cartridges for foreign substances which could have come in from the new fuel tank or possibly the fuel.

(7)

Steam clean the engine to free it of oil and dirt to prevent uneven engine cooling “hot spots.” The oil and dirt can also fall into the engine and fuel system when covers are removed during repair work.

(8)

Check Injectors and Valve clearances and adjust if necessary. Refer to Cummins Operations manual for details.

d. “A” Checks and Operations (10 Hours or Daily)

(1)

Check crankcase oil level

CAUTION

DO NOT overfill. DO NOT operate the engine with oil level below the lower bar

or above the upper bar on the dipstick.

Fuel Pre-Filter

Figure 4

Drain Valve

Chapter 2-1

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Check oil level daily with oil gage dipstick (see 1-2, Fig. 1).

Oil level should not be checked until 3 to 5 minutes after engine shutdown. Keep oil level as near the upper bar as possible.

(2)

Drain fuel prefilter (see fig. 3) The life of the fuel pump and injectors can be extended if the operator drains about a cup of fuel

from the fuel prefilter element to remove water and sediment before starting the engine each day.

CAUTION

BE SURE to prime and bleed the fuel system after draining the filters, replacing any element in the system, or if the fuel tank has run empty. Failure to do so can cause engine starting problems.

Provide a container for catching drained fuel.

Open the drain valve on the fuel/water filter by turning it counterclockwise.

Drain the filter until clear fuel is visible.

Tighten the drain valve.

Safely dispose of drained fuel.

(3)

(4)

(5)

(6)

WARNING

(7)

Purge air from fuel system if necessary.

Check coolant level

Check coolant level daily or at each fuel fill interval. Investigate for cause of any coolant loss.

Check for leaks and correct

At each daily start-up, check for coolant, fuel, and oil leaks. Coolant leaks may be more noticeable when components are cold. Observe pumps, hoses, fittings, gasket connections, etc., for signs of leakage. Correct as required.

Check air cleaner indicator

At each daily start-up, observe the air cleaner indicator light (1-3; 6, Fig. 1). If this light comes ON, it indicates that the air cleaner should be changed.

Check exhaust system

Visually inspect muffler and exhaust pipes for rust and signs of approaching failure. Listen for any gasket or joint leaks.

A leaking and defective exhaust system could be a fire hazard.

Electrical (Engine)

Check all lights Check all indicating lights to be sure they will operate when they should. If any light fails to

operate, check both the lamp and its protective circuit breaker. Figure 5 lists all lamps with their location and part number. Figure 6 lists all circuit breakers.

(8)

Chapter 2-1 Page 6

Check alternator charging rate Observe the 12-V DC ammeter each time the engine is started. A zero amperage reading or

extremely high reading for any length of time indicates trouble in the alternator, regulator, battery, or interconnecting wiring.

Electrical (Generator)

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Output cable plug connector Check the output cable plug connection for damaged insulation and contacts each time the

connector is attached to an aircraft.

Monitoring instruments Check operation of voltmeter, ammeter and frequency meter each time the unit is started.

e. “B” Check and Operations (250 Hours or 3 Months)

(1)

Engine

Check and record oil pressure After each oil change, check and record oil pressure at idle speed after oil has warmed to

approximately 140º F (60º C). Record oil pressure under identical conditions at each oil change interval. A comparison of pressure at idle speed with previous readings will give an indication of progressive wear of oil pump, bearings, shafts, etc. Investigate any abnormal change in pressure readings.

Change fuel filters. Refer to 2-2; Para. 4.

Clean radiator core. See 2-2; Para. 6, F for instructions.

Check governor linkage Check all attaching hardware. Check ball joints for wear and looseness. Check linkage for

free movement throughout its complete travel range.

(2)

Electrical (12-V DC system)

NOTE: The battery furnished with this generator set is MAINTENANCE FREE.

Battery electrolyte level (if applicable) Battery electrolyte level must be maintained above top of plates. Add distilled water as

required.

CAUTION

DO NOT overfill.

Check battery If battery requires water frequently, or is low in charge, the reason for the condition must be

found and corrected.

Battery terminals Check battery terminals and clean if necessary in accordance with Para. 3, B, (2) (a) above.

f. “C” Checks and Operations (500 Hours or 6 Months)

(1)

Engine

Change crankcase oil. See 2-2, Para. 2, D, (4) for details.

Change oil filter element each time crankcase oil is changed. See 2-2, Para. 2, D, (4) for details.

(2)

Check and adjust drive belts

See 2-2; Para. 7 for tension check and adjustment instructions.

Chapter 2-1

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

(3)

Check engine mounts

WARNING

(4)

(5)

(6)

An unstable or loosely mounted engine can create hazardous environment and may also damage equipment.

Engine mount bolts must be torqued to 285 Nm (210 ft-lb.).

Check coolant additive concentration The cooling system protective liquid (nitrite-, amine- and phosphate free) provides effective

protection against corrosion, cavitation, and freezing. See Cummins Owners and Operations Manual for ordering and mixture details.

Electrical (12-V DC system)

Wiring Inspect all cables and leads for worn or damaged insulation.

Connections Inspect connectors for security and damaged or corroded condition.

Electrical Generator

Protective relays Check operation of all protective relays to make certain they will function if a fault should

occur in the output circuit. Procedures for testing these relays are contained in the Adjustment/Test section of this manual.

Wiring and connections Check all cables, leads, and wiring for broken, worn and damaged insulation. Check all connections for tightness.

Clean and inspect generally

g. “D” Checks and Operations (1000 Hours or 1 Year)

(1)

Engine

Change the water coolant filter (See 2-2; 6, i).

Check fan hub and drive pulley. Inspect for loose bolts or worn features. Tighten bolts and replace parts if necessary

Check fuel prefilter cartridge (See 2-2; 5, B). Prefilter may accumulate foreign substances that may cause damage to fuel system if not

removed. Inspected prefilter thoroughly.

Check hose/clamps on air intake side. Be sure that all clamps are properly secured to prevent leaks.

Chapter 2-1 Page 8

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h. “E” Checks and Operations (1500 Hours or 1.5 Year)

(1)

Engine

Steam clean engine There are several reasons why the engine exterior should be kept clean. Dirt on the outside

will enter fuel and oil filter cases and rocker housings when covers are removed, unless dirt is removed first. A clean engine will run cooler and develop fewer hot-spots.

Steam cleaning is one of the most satisfactory methods of cleaning and engine; however, there are some CAUTIONS to be observed:

WARNING

Exercise care to avoid injury and damage to eyes and skin

CAUTION

1. If a cleaning compound is used, select one which is free from acid and which will not remove paint.

2. Protect (or remove) all electrical accessories, such as voltage regulator, alternator, and electrical wiring.

3. Seal all openings. DO NOT use a flammable solvent.

4. DO NOT use mineral spirits or solvents on a hot engine.

5. Remove or protect bottom panel of unit (belly pan) to protect insulation.

Clean fuel system See Owner and Operations Manual for instructions.

Check vibration damper. (Fig. 4) Check vibration damper for looseness or wobble, verifying the hub bolts are tightened to the

Cummins specifications.

Check adjustment of injectors and valves Injectors and valves must be in correct adjustment at all times for best engine performance.

Refer to Cummins Operation Manual for injector and valve adjusting instructions.

Check fuel manifold pressure This check is necessary only if there is an apparent or suspected loss of power. Refer to

Cummins Operation Manual for tools required and test instructions.

Check water pump (Fig. 4) Check water pump for signs of leaking and lubricant loss. Replace with new prelubricated

pump if lubricant is being lost.

Check fan hub (Fig. 4) Check fan hub for signs of lubricant loss. Replace with new prepacked hub if lubricant is

leaking.

Check alternator and cranking motor (Fig. 4). The alternator and cranking motor on this particular engine require no periodic lubrication.

Chapter 2-1

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OM-2084 / Operation and Maintenance Manual 90CU24 / Series 500392 Generator Sets

Alternator

Fan Hub

Water Pump

Vibration Damper

Cranking Motor

Engine Accessories

Figure 5

i. “F” Checks and Operations (2000 Hours or 2 Years)

(1)

Engine These checks should determine whether the engine requires a complete overhaul or whether it

may be operated for another service period. High oil consumption, low oil pressure at idle speed, oil dilution and other signs of wear must be considered.

Disassemble the engine sufficiently to perform the following inspections and services. Complete overhaul facilities should be available. If the user performs this operation in his own shop, a shop manual should be procured from Cummins Engine Company.

Clean/Calibrate/Replace injectors Injectors must be cleaned and calibrated regularly to insure proper fuel delivery to

combustion chambers. Special tools are required. It is suggested that the Cummins Distributor be consulted for this operation.

Check fuel pump calibration This operation may be performed on an as required basis. Pump calibration also requires

special tools and testing equipment. Consult a Cummins Distributor for information.

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Change coolant

Inspect cylinder heads for the possibility of overhaul

Inspect pistons and piston rings

Inspect bearings and Journals

j. Seasonal Maintenance Checks Spring/Fall (Engine)

(1)

Inspect engine cooling fan each spring and fall.

Check fan to be sure it is securely mounted.

Check for fan wobble and/or broken/cracked blades.

Check fan hub and crankshaft pulley for secure mounting.

(2)

Check cooling system each spring and fall. Clean if necessary. See 2-2, Para. 5, for cooling system maintenance.

(3)

Check all hoses. In addition to daily checks of hoses for leaks, inspect hoses thoroughly each time the cooling

system is cleaned and serviced. Inspect for signs of deterioration and collapse.

Inspect for cracks and cuts

Inspect for cutting and deformation caused by hose clamps.

Replace hoses as required.

(4)

Check and adjust V belts each time the cooling system is cleaned, or on an as required basis. See 2-2, Para. 6.

(5)

Check thermostat and seals each fall when cooling system is serviced.

k. Lamps and Circuit breakers

(1)

Check all lamps daily and check circuit breakers as required.

(2)

A lamp chart (Fig. 5) lists all lamps with their location and identifying trade number in table below.

(3)

The circuit breaker chart (Fig. 6) lists all circuit breakers with their location, size, and type.

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Light Identification Location

Instrument Panel Lights Control box Interior

(1-1; Figure 6, Item 11)

Engine Start Indicator Engine-Generator Control Panel

(1-1; Figure 5, Item 26)

No. 2 Load Contactor Switch Engine-Generator Control Panel

(1-1; Figure 5, Item 22)

No. 1 Load Contactor Switch Engine-Generator Control Panel

(1-1; Figure 5, Item 24)

FAULT Indicators (9) Engine-Generator

Control Panel

Clearance (Marker) Lights (4)

Engine Gauge Lights Oil pressure, Engine Temp.,

Canopy

ammeter, and fuel gauge on control box

Lamp (Bulb): as per

Lamp Industry Trade Number

1815

Lamp Identification Chart

Figure 5

Item Protected Location Illustration Size and Type

Engine Circuit and Instrument Panel

Controls Control box Interior 1-1; Figure 6, Item 13 Marker Lights Control box Interior 1-1; Figure 6, Item 14 Load Contactor Circuit Control box Interior 1-1; Figure 6, Item 15

Cold Weather Start Servicing and Troubleshooting

Many vehicle components can affect cold weather starting. The following guide is limited to general troubleshooting of the Dieselmatic System. Further details can be found in the Dieselmatic installation and maintenance manual, and should be read prior to operating. The two most common problems are an empty fluid cylinder and a clogging metering orifice.

a. Check Fluid Cylinder Contents and Valve Gasket

(1)

Clean all dirt from neck of cylinder and top of valve before removing the fluid cylinder. Protect top of valve from dirt when cylinder is removed.

(2)

Check that fluid cylinder has pressure.

(3)

Check valve gasket. If gasket inside valve is damaged or worn, replace with a new gasket. Make sure only one gasket is used.

Control box Interior 1-1; Figure 6, Item 12

Circuit Breaker Identification Chart

Figure 6

10A Circuit

Breaker

5A Circuit

Breaker

10A Circuit

Breaker

5A Circuit

Breaker

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(4)

Cylinder, or its replacement, should be reinstalled by turning cylinder clockwise until the o-ring contacts the valve. Tighten an additional 1-1/2 turns. DO NOT OVER TIGHTEN CYLINDER!

b. Check of electrical system.

(1)

Check to see if fuse is blown. Check all wiring for loose connections, shorts, and broken wires.

(2)

Check that the dieselmatic system is wired correctly (See Figure 2).

NOTE: To check system for proper operation, the Engine Temperature Sensor (ETS) must be below

40º F (4º C) or be bypassed by connecting the valve’s black lead directly to a good ground. After checking be sure to reconnect the black lead as it was originally connected.

(3)

Test valve by removing fluid cylinder and momentarily engaging cranking motor. Valve plunger should move up and remain up while cranking motor is engaged. If valve operates, proceed to step (5).

(4)

If valve plunger did not function, check valve by disconnecting leads from cranking motor and ground. Momentarily touch leads directly across battery across battery terminals. The valve plunger should move up and remain up until the leads are disconnected. If the valve does not activate when connected across the battery it is faulty and should be replaced.

(5)

Check Engine Temperature Sensors (ETS) switch by chilling to sub-freezing temperatures. At cold temperatures, the ETS Switch should close (i.e. show continuity when checked with a DC powered test light or ohmmeter.) The closing and opening temperature should be about 40º F (4º C). If either continuity test fails, the ETS Switch should be replaced.

c. Check for clogging of flow metering orifice fitting.

The Dieselmatic’s fluid flow rate is controlled by serviceable filtered metering orifice inside the fitting at the bottom of the valve assembly. See Figure 7. The following procedure is recommended when checking for clogging

(1)

Remove system’s nozzle from engine.

(2)

If starting fluid does not spray from nozzle when the system is activated, disconnect tubing from valve fitting. If starting fluid sprays from the fitting when the system is activated, check tubing for kinks, burns, cuts, clogs, or check for a clogged nozzle. When performing these two operations, be sure to spray fluid into and appropriate container.

(3)

If starting fluid does not spray from valve fitting, it should be removed from valve and cleaned. Remember, left hand threads.

(4)

The filter may be removed from the fitting, and the o-ring removed from the filter. It can be washed in clean solvent and blown with compressed air. For best results, replace filter with a new one KBI Part Number 240005. Reassemble filter with o-ring into fitting.

(5)

It is suggested before cleaned filter assembly is reinserted into valve, that valve be flushed by activating the system. When performing this operation, be sure to spray fluid into an appropriate container.

(6)

Reinsert clean filtered fitting assembly into valve. Remember: left hand threads. Reinstall system’s nozzle into engine. Reconnect tubing to valve fitting and nozzle.

(7)

Check all fitting and tubing connections for leaks.

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Section 2. Maintenance Procedures

1. General

A suggested Maintenance Schedule was provided in Section 1, of this Servicing Chapter. Each step of the schedule was also covered in general in Section 1. This Section covers maintenance in more details where necessary.

WARNING

Lubrication

2. a. General

Proper lubrication is one of the most important steps in good maintenance procedure. Proper lubrication means the use of correct lubricants and adherence to a proper time schedule. Lubrication points, frequency of lubrication, and recommended lubricants are indicated in Figures 1 thru 4.

b. AC Generator

The 400 Hz generator requires NO lubrication.

c. Generator Controls

Generator controls and instruments require no periodic lubrication. A few drops of oil may be required on door hinges occasionally to insure free and quiet operation.

d. Engine

Although the engine and its accessories require no more attention than any other similar installation, they still inherently require a major portion of the generator set lubrication and maintenance. Recommendations regarding engine lubrication have been taken from the engine manufacturer’s “Operation and Maintenance Manual” and incorporated here to make them more readily available to operators and maintenance personnel.

(1)

Lubrication schedule Time schedules indicated on the Lubrication Chart, Fig. 4, are approximate. They are based on

average operating conditions. It may be necessary to lubricate more frequently under severe operating conditions such as: low engine temperatures, high oil temperatures, or intermittent operation. However, time intervals should not exceed those indicated in the chart without careful evaluation.

Stop operation immediately if a serious or possibly dangerous fault is discovered.

(2)

Oil specification Engine lubricating oil, recommended by the engine manufacturer, is identified by an API

(American Petroleum Institute) classification designation. The use of quality lubricating oil, combined with appropriate lubricating oil drain and filter change

intervals are important factors in extending engine life. Oil recommended for the diesel engines in this application is API Class CE/SG. Use a high

quality 15W-40 multi-viscosity lubricating oil, such as Cummins Premium Blue, or its equivalent in Cummins engines. Choose the correct lubricating oil for your operating climate.

Lubricating oil is discussed in detail in the Cummins Operation and Maintenance Manual.

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ITEM MAINTENANCE REQUIRED

Lube Oil

Check oil level daily or after every 10 hours of use. Change oil and the oil filter after the first 50 to 150 hours of use, then at 500 hour or 6 month intervals there after. Use oil that conforms to API specification CE/SG.

Capacity Oil Filter Replacement

Engine lube oil capacity with filter: 16 quarts (15.1 liters) Oil Filter Replacement Hobart Brothers Part No. 286987-006

Oil Filter Replacement Cummins Part No. 3908615

VISCOSITY AMBIENT TEMPERATURE CONDITIONS Lube Oil Viscosity Required as per Ambient Temperatures

SAE 15W40 13ºF (-11ºC) and above for all seasons

SAE 10W30 -10ºF to +68ºF (-23ºC to +20ºC) Winter conditions

SAE 5W30 -20ºF to +50ºF (-29ºC to +10ºC) Arctic Conditions Synthetic Oils See the Cummins Operator’s Manual for usable synthetic oils and instructions. Fuel Prefilter Drain Filter Daily. Change filter element every 250 hours or 3 months of use. Coolant Check coolant level daily. Service and maintain coolant system according to

sect. 2-2, para. 6. Engine coolant capacity (system): 28 quarts (26.4 liters) Coolant hoses and

Check coolant hoses and connections daily for leaks. connections

Air Cleaner Change air cleaner filter as required when air cleaner indicator (on engine

control panel) shows that it should be changed. Fan Belt Check fan belt condition and tension every 500 hours or 6 months of use. AC Generator AC generator bearings are sealed and require no periodic lubrication. Alternator Alternator bearings are sealed and require no periodic lubrication. Starter Motor Starter motor bearings are sealed and require no periodic lubrication. Water Pump The water pump is packed at assembly and requires no periodic lubrication. Fan Hub The fan hub is lubricated at assembly and requires no periodic lubrication.

Lubrication and Maintenance Chart

Figure 1

Symbol

Name Specification Notes

Grease, General Purpose MIL-G-3545 Excludes those of sodium or

soda soap thickeners

Oil, Engine, Heavy Duty API Class CC Must contain ash but not more

than 1.85%

Dry Graphite Lubricant (for trailer brake cables)

MIL-T-5544, or equivalent

Use on brake cables. DO NOT use general purpose grease.

Lubricants

Figure 2

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Ambient Temperature SAE Viscosity

-13ºF to +95°F (-25 to +20°C) 10W-30

+14°F and above (0°C and above) 15W-40

-40°F to 68°F (-40°C to 20°C) 5W-40

Temperature and Viscosity Chart

(3)

Oil viscosity A temperature and oil viscosity index chart is shown above. For operation at temperatures

consistently below -13º F (-25º C), refer to Arctic Oil Recommendations in the Cummins Operation and Maintenance Manual.

(4)

Changing engine oil Oil should be changed after each 200 hours of engine operation. The generator set is equipped

with an hourmeter to record actual engine operating time. The ideal time to change engine oil is soon after a power delivery run, when the engine is at operating temperature.

Change the oil filter element each time the oil is changed.

Figure 3

Time Intervals

Symbols

AR As Required None

A 10 Hours Daily B 200 Hours 3 Months C 400 Hours 6 Months D 800 Hours 1 Year E 1200 Hours 1 Year F 6000 Hours 5 Years S Seasonally Spring and/or Fall

Symbols and Time Intervals

NOTE: If lubricating oil is drained immediately after the unit has been run for some time, most of the

CAUTION

sediment will be in suspension and will drain readily.

Do not use solvents as flushing oils in running engines.

Oil Capacity (including filter) 16 quarts (15.1 liters) Oil Capacity (oil pan) 15 quarts (14.2 liters)

Hours Calendar

Figure 4

Coolant Capacity 29 quarts (27.4 liters)

Oil and Coolant Capacities

Figure 5

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Change oil as follows:

Provide a container for catching used oil. Capacity must be greater than 24 quarts.

Remove drain plug located in oil pan.

While oil is draining, change the oil filter element. See instructions below.

Clean the drain plug and install when engine oil has drained. Torque the drain plug to 35 to 40 foot-pounds (47 to 54 Nm).

Remove oil filler cap by turning screw handle counter-clockwise to loosen cap and lift straight up.

Refill the crankcase with new, clean oil which meets engine manufacturer’s recommendations. (See Para. 2, D, (2) above, or Cummins Operation and Maintenance Manual).

CAUTION

1. Always use clean containers, funnels, etc.

2. Don’t forget to drain old oil, reinstall drain plug and install new oil before

starting engine.

Install filler cap and check oil level on gage rod (Sect. 1-2, Fig. 1).

Start engine and check oil pressure at once. Allow engine to idle for 5 minutes, then stop.

After the engine has been stopped for about 5 minutes, recheck the oil level. Add oil, if required, to bring the level up to the H mark on the gage rod.

(5)

Changing oil filter element

Provide a container for catching oil.

Remove the filter and inspect it.

NOTE: The o-ring can stick to the filter head. Make sure it is removed before installing a new filter.

CAUTION

If bearing metal particles are found on the element or in the shell, the source should be determined before a failure results.

CAUTION

Determine source of moisture, internal leaks; defective seals, gaskets, etc.

Fill the new filter with clean lubricating oil before installation.

Apply a light coating of lubricating oil to the gasket sealing surface and install the filter. DO NOT over tighten the filter.

Check crankcase oil level.

Start engine and check oil filter for leaks.

Stop engine, and after allowing sufficient time for oil to drain to crankcase, recheck oillevel. Add oil as required.

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Oil Filter

Left Side of Unit

Oil Fill Location

Changing Oil Filter

Figure 6

Right Side of Unit

Oil Level Gauge

Water Pump

Cranking Motor

Engine Accessories

Figure 7

Alternator

Fan Hub

Vibration Damper

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e. Engine Accessories Lubrication (Fig. 7)

(1)

Alternator Most alternators contain sealed bearings and require no periodic lubrication, however, CHECK to

make certain there are no lubrication points on your particular alternator.

(2)

Starter Most starting motors are lubricated at assembly and should be relubricated only when the starter

is removed and disassembled, however, INSPECT the starter to make certain it has no lubrication points.

(3)

Water Pump The water pump is packed at assembly and requires no periodic lubrication. Replace pump if

signs of lubricant leakage are found.

(4)

Fan Hub The fan hub is also lubricated at assembly and requires no periodic lubrication. Replace hub if

lubricant is leaking.

Servicing the Air Cleaner

This air cleaner is a dry type which may be cleaned as many as six times before replacing it with a new air cleaner. A definite time schedule for cleaning or changing the air cleaner cannot be determined because of varying operating conditions. However, since this air cleaner can be removed and replaced without difficulty on this generator set (simply by loosening three metal clamps on each end of the air

cleaner)

it may be inspected either at prescribed service intervals or at any time deemed necessary.

a. Inspecting the Air Cleaner

(1)

Make periodic checks of air cleaner inlet screen for obstructions. If any obstructions are present, remove them.

(2)

Check outlet connection for proper seal.

NOTE: DO NOT judge the element’s life just by looking at it, IT SHOULD LOOK DIRTY, or it’s not

doing its job.

b. Cleaning Instructions

CAUTION

(1) Do not tap the air cleaner on a hard surface to clean it, and (2) Never leave the air inlet ducting open longer than necessary during the

service procedure.

(1)

Pressurized air cleaning After removing the air cleaner from the generator set, blow air into the outlet neck, causing dust

to flow off the air cleaner filter media.

CAUTION

(1) Do not use compressed air higher in pressure than 100 psi, and

(2) Do not use compressed air cleaning when the filter media is wet.

(2)

Low pressure water flush

Flow low pressure water, warm or cold, into the air cleaner outlet neck, causing dirt to flow off

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the filter media. Always be sure not to let any contaminated water back into the outlet neck.

A mild detergent may also be used. However, the filter must then be flushed thoroughly with clean water. This cleaning method is recommended by the manufacturer.

Always allow filter media to dry before use.

c. Disposal

Normal trash pick-up is acceptable. NEVER burn the air filter for disposal.

Engine Fuel

a. Quality

The quality of fuel oil used in the diesel engine is a major factor in engine performance and life. Fuel oil must be clean, completely distilled, stable and non-corrosive.

The Cummins engine has been developed to take advantage of the high energy content and generally lower cost of No. 2 Diesel Fuel. The engine will also operate satisfactorily on No. 1 fuel. If other fuels are being considered, refer to the Cummins Operation and Maintenance Manual for fuel specifications and recommended fuel oil properties.

CAUTION

Use ASTM No.2D fuel with a minimum Cetane number of 40. No. 2 diesel fuel gives the best economy and performance under most operating conditions. Fuels with Cetane numbers higher than 40 may be needed in high altitudes or extremely low ambient temperatures to prevent misfires and excessive smoke.

At operating temperatures below 32º F (0º C), use a blend of No. 1D and No. 2D fuels, also known as “winterized” No. 2D.

NOTE: No. 1D fuels can be used, but fuel economy will be reduced.

b. Fuel Filter (Fig. 8)

A double element fuel filter is located between the fuel source and the pump. Its function is to remove foreign material from the fuel before it enters the fuel pump. The filter operates under vacuum. Elements are the throwaway type, in which the case and element are made as one disposable part.

(1)

Check fuel filter restriction The most accurate method of determining filter change requirement is by measuring the fuel

pressure drop across filters. The measurement of pressure drop across filters is 5 psi (9 kPA).

Due to the precise tolerances of diesel injection systems, it is extremely important that the fuel be kept clean and free of dirt or water. Dirt or water in the system can cause severe damage to both the injection pump and the injection nozzles.

(2)

Changing fuel filter elements Change elements after each 200 hours of operation unless a restriction test indicates the time

period should be extended.

• Replacement primary fuel filter elements are Hobart No. 286897-004.

• Replacement secondary fuel filter elements are Hobart No. 286897-005.

Unscrew element and discard.

NOTE: The elements should be removable by hand. If not, there are several types of filter element

removal tools.

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Fill NEW element with CLEAN fuel.

CAUTION

When installing new element, do not over tighten it. Tightening it with mechanical tools may distort or crack filter head.

Install new element and tighten by hand until seal touches filter head. Tighten an additional one-half to three-fourths turn.

Fuel Filter

(Left Side of Unit)

Figure 8

Fuel Filter

Engine Cooling System

a. General

Cooling system service requires more than maintaining the proper coolant level in the radiator and protecting the system against freezing. Water should by clean and free of any corrosive chemicals such as chloride, sulphate, and acids. It should be kept slightly alkaline with a pH value in the range of 8.0 to 9.5. Any water which is suitable for drinking can be used in the engine when properly treated as described in Cummins Operation and Maintenance Manual. The Cummins Distributor should be consulted regarding the selection of satisfactory brand, permanent-type antifreeze for use in the cooling system.

b. Radiator Cap

(1)

General A pressure relief valve is built into the radiator cap. It is designed to open at a pressure of

approximately seven psi.

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CAUTION

(2)

Removal To remove, turn the cap to the left (counterclockwise) to the safety stop. When all pressure is

released, press down on the cap and continue to turn until the cap is free to be removed.

When removing cap from a very hot radiator, do not turn cap past safety stop until all pressure or steam has escaped.

CAUTION

Allow engine to cool before adding coolant.

NOTE: Do not attempt to repair the valve in a radiator cap. Replace with a new cap.

(3)

Installation When installing the cap, be sure it is turned clockwise as far as it will go so that the pressure

retaining valve will be functional.

c. Coolant

Anti-freeze is essential in any climate. It broadens the operating temperature range by lowering

the coolant freezing point and by raising its boiling point. Do NOT use more than 50 percent anti-freeze in the mixture unless additional freeze protection is required. NEVER use more than 68 percent antifreeze under any condition. Never use soluble oil in the cooling system.

For complete information regarding coolant specifications, temperature ranges. testing equipment, antifreeze, etc., refer to Cummins Operation and Maintenance Manual.

(1)

General A permanent type antifreeze is recommended for use in the cooling system in any climate

CAUTION

(2)

Selecting antifreeze

Select a permanent type antifreeze know to be satisfactory for use with chromate corrosion resistor.

When it is not known if the antifreeze is satisfactory for use with chromate resistor, check with local Cummins Distributor for a list of compatible antifreezes.

1.Do not use methanol or alcohol as an antifreeze.

2.Do no mix brands or type of antifreeze. A solution containing two or more types of antifreeze is impossible to test accurately.

CAUTION

Do not use soluble oil in the cooling system

(3)

Checking antifreeze solution Check the solution with a reliable tester when in doubt about antifreeze protection.

NOTE: When testing, be sure coolant is at operating temperature. Follow manufacturer’s instructions on

tester.

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d. Draining the Cooling System

To drain the cooling system, proceed as follows:

WARNING

Check temperature gage; coolant temperature must be no higher than 120º F (50º C) before removal of radiator cap.

(1)

Remove radiator cap.

(2)

Open the radiator drain valve.

(3)

Allow the system to drain completely.

NOTE: Be sure the drain valve does not clog during draining.

(4)

When the system is completely drained, close the drain valve.

e. Cleaning the Cooling System

There may be need for cooling system internal cleaning. If chemical cleaning becomes necessary, refer to instructions in the Cummins Operation and Maintenance Manual.

f. Cleaning the Radiator Core

Blow out accumulated dirt from the radiator core air passages, using compressed air. Engine overheating is often caused by bent or clogged radiator fins. When straightening bent fins, be careful not to injure the tubes or to break the bond between fins and tubes.

NOTE: Direct the air in a reverse direction to normal air flow. Normal flow on this installation is from the

engine compartment outward.

g. Filling the Cooling System

(1)

Inspection/Check

Check system for evidence of leaks.

Inspect all hoses. Install new hoses as necessary. Tighten hose clamps as required.

Check the condition of fan and water pump belts. Replace belts if necessary.

(2)

Install coolant

Remove radiator cap. Be sure the drain valve is closed. Make sure the vent in the water manifold is open to allow air to escape when filling.

Pour coolant(anti-freeze/water) into radiator very slowly until it reaches level of top drain valve. Close valve and continue filling until coolant reaches a level approximately 1 inch below top of tank. Allow for a 5% expansion when coolant reaches operating temperature.

NOTE: A safety feature built into the tank consists of a pipe attached to the filler neck which extends

into the tank approximately 1 inch. If coolant is added after the liquid reaches the bottom of the safety tube, it will immediately overflow.

Start the engine and allow to idle. Add coolant as trapped air escapes from the system and the coolant level falls.

Continue to check coolant level until all trapped air escapes. Add coolant, if needed, to fill to the required level, 1 inch below top of tank. Install radiator cap and close the vent valve.

NOTE: It is good practice to attach a card, indicating the cooling system contents and dateserviced, to

the radiator filler neck.

h. Thermostat

The thermostat should be checked each fall, or as required. Refer to Cummins Operation and Maintenance Manual for recommended test instructions.

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6. Drive Belts

a. General

The engine cooling fan, alternator, fuel pump, and water pump are driven by a timing belt which must be replaced if it becomes worn or damaged.

b. Preparation for Belt Check and Adjustment

All driven assemblies must be securely mounted in operating position before checking belt tension.

c. Checking Belt Tension (fig. 9)

Check belt tension every 1000 hours, or once a year, whichever comes first. A belt which is too tight is destructive to bearings of the driven part. A loose belt will slip and cause inefficient operation of the part being driven as well as wear to the belt.

Belt tension may be checked either with a gage or manually. Use Cummins Belt Tension Gage no. ST-1293, or equivalent. Gage should indicate 90 to 110 pounds. If a gage is not available, tension may be checked manually by depressing the belt with the index finger to determine the amount of belt deflection obtained when force of approximately at a point halfway between pulleys on the longest span of the belt.

d. Check Fan Belt (fig. 10)

(1)

Check belt tension (see above).

(2)

Remove the drive belt by lifting on the belt tensioner with a 1/2 square drive. The belt can then be slid off the water pump pulley and worked off the other pulleys and around the fan.

(3)

Inspect the belt for damage.

Traverse (across the belt width) cracks are acceptable.

Longitudinal (direction of belt length) cracks that intersect with transverse cracks are unacceptable.

(4)

Replace the belt if it has unacceptable cracks, is frayed or has pieces of material missing.

(5)

Check the belt tensioner while the belt is removed. It should spin freely without any wobble or excessive (0.006") end play.

(6)

Install the drive belt.

Generator Maintenance

The 400 Hz generator required no maintenance or service other than periodic cleaning. The unit is brushless, and bearing(s) are permanently lubricated and sealed.

a. Cleaning

The generator may be cleaned by careful use of compressed air and/or a good, SAFE commercial cleaner. Steam cleaning of the generator is not recommended because the use of steam and harsh chemical compounds may result in damage to insulation and other generator components.

CAUTION

Do not use a flammable solvent. Be sure the unit is completely dry before operating.

b. Adjustment

The generator itself requires no adjustment. Adjustment procedures for generator controls are covered in 2-3.

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Checking Belt Tension

Figure 9

Removing and Inspecting

Drive Belts

Figure 10

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8. Voltage Regulator Maintenance/Repair

When the voltage regulator is working properly, no maintenance is necessary. However, if the generator set is used in a dusty environment, the regulator should be periodically cleaned with compressed air.

The voltage regulator, which is in fact a PC board, does not lend itself to field repair. For the convenience of maintenance personnel, this voltage regulator is designed to be trouble-free and simple to put back into service once it has malfunctioned or if it is not functioning properly. Most malfunctions of the voltage regulator will be corrected by (1) removing and replacing the PC board, and (2) making voltage and line-drop adjustments after installing the new board. To remove and replace voltage regulator PC board, proceed as follows:

a. Disconnect the 16-pin connector. b. Remove the nuts and washers which attach the voltage regulator to the four shock mounts which

are attached to the inside right panel of the control box. Exercise care to avoid breaking or dropping the PC board.

c. Place the new voltage regulator PC board on the four shock mounts from which the defective PC

board was removed, and fasten the new PC board securely in place with the nuts and washers which were previously used.

d. Re-connect the 16-pin connector, and make certain that this connection is securely made.

Cold Weather Starting Aid Servicing and Troubleshooting

WARNING

Many vehicle components can affect cold weather starting. The following instructions are limited to troubleshooting of the Dieselmatic System. The most common problems are (1) an empty fluid cylinder, and (2) a clogging metering orifice.

a. Check Fluid Cylinder Contents And Valve Gasket.

(1)

Clean all dirt from neck of cylinder and top of valve before removing the fluid cylinder. Protect top of valve from dirt when cylinder is removed.

(2)

An empty net weight 21 oz. fluid cylinder weighs 16 oz. (454 gr.), and a full fluid cylinder weighs 37 oz. (1049 gr.).

(3)

Check that fluid cylinder has pressure.

(4)

Check valve gasket. If gasket inside valve is damaged or worn, replace with a new gasket, KBI Part Number 300012. Make sure only one gasket is used, as two gaskets would prevent valve from operating.

(5)

Cylinder, or its replacement, should be reinstalled hand tight. Coupling Dirt Eliminator may be transferred from old cylinder to new cylinder or replaced with a new one, KBI Part Number

300830.

b. Check of electrical system.

When servicing or troubleshooting the cold weather starting kit, make certain that this work is done in a well ventilated area. Goggles should be worn to protect eyes when servicing this kit.

WARNING

Electrical shock can kill. Do not touch live electrical parts.

(1)

Check to see if fuse is blown. Check all wiring for loose connections, shorts, and broken wires.

(2)

Check that the Dieselmatic System is wired correctly.

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NOTE: To check system for proper operation, the Engine Temperature Sensor (ETS) must be below

40º F (4º C) or be bypassed by connecting the valve’s black lead directly to a good ground. After checking, be sure to reconnect the black lead in accordance with Connection Diagram.

(3)

Test valve by removing fluid cylinder and momentarily engaging cranking motor. Valve plunger should move up and remain up while cranking motor is engaged. If valve operates, proceed to step (5).

(4)

If valve plunger did not function, check valve by disconnecting leads from cranking motor and ground. Momentarily touch leads directly across battery terminals. The valve plunger should move up and remain up until the leads are disconnected. If the valve does not activate when connected across the battery it is faulty and should be replaced.

(5)

Check Engine Temperature Sensors (ETS) switch by chilling to sub-freezing temperatures. At cold temperatures, the ETS switch should close (i.e. show continuity). Check with a DC powered test light or ohmmeter. At warm temperatures, the ETS switch should open (i.e. not show continuity). The closing and opening temperature should be about 40º F (4º C). If either continuity test fails, ETS switch should be replaced.

c. Check for Clogging of Flow Metering Orifice Fitting

WARNING

The Dieselmatic’s fluid flow rate is controlled by serviceable filtered metering orifice inside the fitting at the bottom of the valve assembly. See Figure 2. The following procedure is recommended when checking for clogging:

(1)

Remove system’s nozzle from engine.

(2)

If starting fluid does not spray from nozzle when the system is activated, disconnect tubing from valve fitting. If starting fluid sprays from the fitting when the system is activated, check tubing for kinks, burns, cuts, clogs, or for a clogged nozzle. When performing these two operations, be sure to spray fluid into an appropriate container.

(3)

If starting fluid does not spray from valve fitting, it should be removed from valve and cleaned.

NOTE: Fitting end installed in valve has left hand threads.

The filter may be removed from the fitting. It can be washed in clean solvent and blown with compressed air. For best results, replace filter with a new one, KBI Part Number 300813. Reassemble filter with “O” ring into fitting.

(4)

It is suggested before clean filtered assembly is reinserted into valve, that valve be flushed by activating the system. When performing this operation, be sure to spray fluid into an appropriate container.

(5)

Reinsert clean filtered fitting assembly into valve. Remember: left hand threads. Reinstall system’s nozzle into engine. Reconnect tubing to valve fitting and nozzle.

(6)

Check all fitting and tubing connections for leaks.

When servicing or troubleshooting the cold weather starting kit, make certain that this work is done in a well ventilated area. Goggles should be worn to protect eyes when servicing this kit.

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Section 3. Adjustment/Test

1. General

These adjustment and test procedures are applicable to testing and adjusting the generator set after major repair, major parts replacements, or overhaul.

Testing the Generator Set

2. a. Pre-operational Test Procedures

(1)

Connect cables from the generator output terminals to a load bank. Use cables of the same size and length as those to be used in service. Be sure the generator output N cable is grounded.

(2)

Check engine oil level. Oil should be at high bar on the dipstick.

(3)

Check radiator coolant level (See 2-2, Para. 5).

(4)

Check tension of drive belt (See 2-2, Para. 6)

(5)

If governor throttle linkage was disturbed, check all linkage to make certain engine speed may be controlled when the engine is started. Refer to Paragraph 3, e, (1) and see Figure 3.

(6)

Inspect for oil, fuel and coolant leaks.

(7)

If the setting of the output voltage coarse adjustment potentiometer (36, Fig.1) on the voltage regulator has been disturbed, set it at CENTER position (halfway between full clockwise position and full counterclockwise position).

(8)

Check marker lights circuit breaker (33, Fig. 1) by pressing panel light push button switch (28).If panel lights (11, Fig. 1) operate, the circuit breaker, switch, and lamps are good.

(9)

Check fault indicating lights by pressing test/reset push button switch (19, Fig. 1).If lights glow, the control circuit breaker (34) and indicating lamps are good.

(10)

Make a general inspection of all wiring, and terminals. Inspect the equipment to be certain no damage will result from starting the engine.

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1. Fuel gage

2. Front panel

3. Engine coolant temperature meter 4 . Over temperature indicator light (red)

5. Engine hour meter

6. Indicating light, air cleaner restriction

7. Oil pressure gage

8. Engine ammeter

9. Frequency meter

10. Control Box label

11. Strip lights (3)

12. Generator ammeter

13. Voltmeter

14. Overload indicator light (red)

Operating Controls and Instruments

(Dual Output Shown)

Figure 1 (Sheet 1 of 2)

Chapter 2-3 November 27/1997 Page 2

15. Overvoltage indicator light (red)

16. Adjustable grip latch

17. Undervoltage indicator light (red)

18. Meter Selector switch

19. Test-reset push button switch (red)

20. Engine stop push button switch (red)

21. Underfreqency indicator light (red)

22. No. 2 contactor push button switch (orange)

23. Overfreqency indicator light (red)

24. No. 1 contactor push button switch (yellow)

25. Low Oil Pressure indicator light (red)

26. Engine start push button switch (green)

27. Low Fuel indicator light (red)

28. Panel light push button switch (yellow)

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29. Regulated-diagnostic switch

30. Test bank-aircraft switch No. 1 output

31. Test bank-aircraft switch, No. 2 output

32. Circuit Breaker, contactors (5-amp) 33 Circuit Breaker, marker lights (10-amp)

34. Circuit Breaker, control (5-amp)

35. Engine circuit breaker (10-amp)

36. Output voltage adjustment (coarse)

37. Output voltage adjustment (fine)

38. Line drop compensation adjustment

Operating Controls and Instruments

(Dual Output Shown)

Figure 1 (Sheet 2 of 2)

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b. Operational Test Procedures

(1)

Start the engine in accordance with instructions in 1-3, Para. 2, A thru C.

(2)

Check operation of engine instruments; DC ammeter (8, Fig. 1),coolant temperature indicator

(3)

, oil pressure gage (7) and hourmeter (5).

(3)

Check engine idle speed. Should be 850 +/- 50 RPM. If adjustment is necessary, adjust the idle speed potentiometer on the governor control box.

NOTE: A stroboscope is required for this check.

(4)

Again check for oil, fuel, and coolant leaks and correct any leaking condition.

(5)

Position switches and controls for automatic voltage regulation and power delivery as follows:

Place regulated-diagnostic switch (29, Fig. 1) in REGULATED position.

Place test-bank switches (30 and 31) in AIRCRAFT position.

If the of the output voltage coarse adjustment potentiometer (36) on the voltage regulator regulator has been disturbed, place the knob at mid-range position.

(6)

Bring the engine up to governed speed and also energize the generator by pressing the engine start push button switch (26) a second time. If the engine comes up to governed speed and a voltage value appears on the voltmeter (13) functioning.

(7)

After generator overhaul or repair, the Regulated/Diagnostic switch (29, Fig. 1) must be placed in the DIAGNOSTIC position for 3 to 5 seconds to remagnetize the exciter. Then return the switch to the REGULATED position after voltage has built-up.

(8)

Observe frequency meter (9). If engine speed is properly adjusted, frequency will be exactly 400 Hz. If not, adjust engine governed speed in accordance with Para. 3, E, (3). See Fig. 6.

(9)

Observe voltmeter voltage to 115 V AC.

(10)

Measure governor actuator input signal. See Para. 3, e.

(11)

Measure governor magnetic pickup signal. See Para. 3, e.

(12)

Check high-speed limiting governor. Engine limiting speed governor should limit engine speed to approximately 2750 +/- 75 RPM.

(13)

. Use output voltage coarse adjustment potentiometer (36) to adjust

the electric governor and excitation circuits are

(13)

Check adjustable voltage range.

Observe voltmeter (13) and turn output voltage coarse adjustment potentiometer (36) to full CLOCKWISE position. Maximum voltage should be 134 volts or higher.

NOTE: If voltage should decrease when regulator potentiometer is turned clockwise, it indicates that

internal wiring in the voltage regulator is incorrect. Replace complete voltage regulator assembly.

Observe voltmeter and turn regulator potentiometer knob to full COUNTERCLOCKWISE position. The minimum voltage should be 95 volts or lower.

(14)

Position load bank switches, etc., to apply a light load to the generator.

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c. Testing the No. 1 Output Circuit (See Fig. 1)

(1)

Make certain that the orange No. 2 contactor on-off push button switch (22, Fig. 1) is in the OFF position, which is indicated when its internal indicating light doesn’t glow. Then press the yellow No. 1 load contactor push button switch (24, Fig. 1). The No. 1 contactor power ON indicating light within the push button switch should glow, and an amperage value should appear on the AC ammeter (12). Hold in this position momentarily.

(2)

Release the No. 1 load contactor push button switch. The No. 1 load contactor should open immediately, and the No. 1 ON indicating light within the push button switch should go OFF. This is because the interlock circuit of the control PC board is not receiving power from an outside source of 28 V DC. It indicates that the No. 1 interlock circuit is OPEN as it should be when the interlock circuit is not receiving 28 V DC power.

(3)

Open the control panel door and place the No. 1 test bank switch (30) in TEST BANK position.

(4)

Press the No. 1 load contactor push button switch (24). The No. 1 contactor power ON indicating light within the push button switch should glow and remain ON when the push button switch is released. This indicates that the No. 1 test bank switch is functioning to bypass the plug interlock circuit.

(5)

Return the No. 1 test bank switch to AIRCRAFT position. The No. 1 load contactor should open at once and the yellow indicating light within the No. 1 load contactor push button switch should go OFF.

(6)

Connect a source of 24 V-DC power (two twelve-volt batteries connected in series) to terminals N and F (or E) at the output terminal panel. Connection polarity is important. Connect plus (+) to terminals E or F, and minus (-) to terminal N.

(7)

With test-bank switch in AIRCRAFT position, press the No. 1 contactor operating push button switch (24) . The No. 1 contactor power ON indicating light, within the push button switch, should glow and remain on when the push button switch is released. This indicates that the load contactor is closed and the plug interlock circuit is functioning properly.

(8)

Apply 1/3 to 1/2 load (30 to 45-KVA) at the load bank and allow the unit to run for 15 to 30 minutes. Observe operation of all monitoring instruments.

(9)

Increase load at the load bank to 90-KVA.

(10)

Check operation of the governor by observing the frequency meter (9, Fig. 1) when generator is switched from no load to full load. and vice versa. Use the No. 1 contactor control push button switch to apply and remove load several times. Steady-state frequency droop should be no more than 1 Hz. Adjust governor if necessary [see Para. 3, E, (3)].

(11)

Follow instructions in Para. 3, B, (2) (b) to set voltage regulator line drop compensation for the length and size of cable being used.

(12)

Check voltage regulator, at intervals, from no load to full load and on up to 125% load. Observe and note voltage at various loads. Steady-state voltages should vary no more than +/- 1% from normal output voltage.

(13)

Operate the No. 1 output circuit of the unit not less than 10 minutes under full 90-KVA load. The overload device (Ref. 1-1; 1, Fig. 9) MUST NOT trip.

(14)

Operate the No. 1 output circuit of the unit at 125% load (325 amperes) for 5 minutes immediately following the full load run. The overload device MUST trip within 5 minutes, and the overload indicating light on the engine generator control panel must come ON to indicate an overload condition.

(15)

Reduce load to normal. Turn off overload indicating light by pressing reset push button switch (19, Fig. 1).

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d. Testing the No. 2 output circuit (See Fig. 1) (500392-002 and -004 Only)

(1)

Make certain that the No. 1 contactor on-off push button switch (24, Fig. 1) is in the OFF position, which is indicated when its internal indicating light doesn’t glow. Then press the orange No. 2 load contactor push button switch (22). The No. 2 contactor power ON indicating light within the push button switch should glow, and an amperage value should appear on the AC ammeter (12). Hold in this position momentarily.

(2)

Release the No. 2 load contactor push button switch. The No. 2 load contactor should open immediately, and the No. 2 ON indicating light within the push button switch should go OFF. This is because the interlock circuit of the control PC board is not receiving power from an outside source of 28 V DC. It indicates that the No. 2 interlock circuit is OPEN as it should be when the interlock circuit is not receiving 28 V DC power.

(3)

Open the control panel door and place the No. 2 test bank switch (31) in TEST BANK position.

(4)

Press the No. 2 load contactor push button switch. The No. 2 contactor power ON indicating light within the push button switch should glow and remain ON when the push button switch is released. This indicates that the No. 2 test bank push button switch (31) is functioning to bypass the plug interlock circuit.

(5)

Return the No. 2 test bank switch (31) to AIRCRAFT position. The No. 2 load contactor should open at once and the orange indicating light within the No. 2 load contactor push button switch (22) should go OFF.

(6)

(7)

With test-bank switch in AIRCRAFT position, press the No. 2 contactor operating push button switch. The No. 2 contactor power ON indicating light, within the push button switch, should glow and remain on when the switch is released. This indicates that the load contactor is closed and the plug interlock circuit is functioning properly.

(8)

Operate the No. 2 output circuit of the unit not less than 10 minutes under full 90-KVA load. The overload device (Ref. 1-1; 1, Fig. 9) MUST NOT trip.

(9)

Operate the No. 2 output circuit of the unit at 125% load (325 amperes) for 5 minutes immediately following the full load run. The overload device MUST trip within 5 minutes, and the overload indicating light on the engine generator control panel must come ON to indicate an overload condition.

(10)

Reduce load to normal. Turn off overload indicating light by pressing reset push button switch (19).

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e. Testing and checking meters, switches, circuits, and indicating lights (See Fig. 1)

(1)

Check accuracy of voltmeter

Open door of control box and connect a master voltmeter of known accuracy to terminals of the voltmeter (13).

Compare the unit’s voltmeter reading with master meter. Error must not exceed 2% of full scale.

(2)

Check accuracy of AC ammeter

Connect a master ammeter of known accuracy to the AC ammeter (12).

Compare the unit’s ammeter reading with master meter under various loads. Error must not exceed 4% of full scale.

(3)

Check operation of meter selector switch (18). A voltage value should be shown in each switch position.

In any LINE-TO-NEUTRAL position, voltmeter reading should be 115 volts.

In any LINE-TO-LINE position, voltmeter reading should be 200 volts.

(4)

Check accuracy of frequency meter

Connect a master frequency meter of known accuracy to the terminals of the frequency meter (9).

Compare meter readings. Error must not exceed 1% of full scale.

NOTE: Make all protective system tests with the unit operating under load.

(5)

Check operation of over voltage circuit and indicating light.

With the unit running at normal load, adjust the coarse adjustment potentiometer (36, fig. 1) of the voltage regulator CLOCKWISE to increase voltage until the over voltage sensing circuit actuates the protective monitor to open the load contactor and turn on the over voltage indicating light. At 126 volts, the circuit will trip after a 1-second time delay. At higher values of voltage, time delays for over voltage trips are as follow:

• At 140 volts, the circuit will trip within 160 milliseconds.

• At 180 volts, the circuit will trip within 50 milliseconds.

If the load contactor does not open under the conditions described in step (a), refer to the Troubleshooting Chart in Section 2-4.

Return unit to normal operating conditions by adjusting coarse adjustment potentiometer (turning it counterclockwise) and pressing reset push button switch (19).

(6)

This step checks operation of the under voltage sensing circuit, indicating light, and time delay circuit.

When the voltage is reduced to a predetermined value, the under voltage sensing circuit activates the under voltage time delay circuit. If the under voltage condition continues for approximately 7 seconds, the time delay circuitry will activate the protective monitor’s under voltage circuit, which in turn opens the load contactor to stop power delivery and turns on the red under voltage indicating light (17).

A stopwatch is required for this check.

With the unit running at normal load, use the output voltage coarse adjustment potentiometer (36) on the voltage regulator to reduce the voltage to 104 volts. The load contactor should NOT open.

Reduce voltage in steps of 1 volt, with a time delay of 7 seconds between steps. At a setting of 100 volts, the load contactor will open and the under voltage light will glow after a

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sevensecond time delay.

If the load contactor does not open under the conditions described in step (b), refer to the Troubleshooting Chart in Section 2-4.

If the under voltage circuit performs satisfactorily, return unit to normal operation by adjusting output voltage coarse adjustment potentiometer for normal output voltage, pressing the reset push button switch, and closing the load contactor.

(7)

Check under frequency sensing circuit, protective monitor, and indicating light. At some frequency value from 380 Hz or less, after 7 seconds, the under frequency condition should signal the under frequency circuit in the protective monitor module to OPEN the load contactor holding circuit, thus OPENING the load contactor. To check the under frequency protective components, proceed as follows:

While the unit is operating normally under load, reduce generator output frequency by reducing engine speed. Use the governed speed setting potentiometer (Fig. 5). Turn adjusting screw gradually COUNTERCLOCKWISE to reduce engine speed until frequency meter indicates 385 Hz. Under frequency protective circuit should not open the load contactor at this frequency.

Reduce frequency in steps of 1 Hz, with a time delay of 7 seconds between steps.

If the protective circuit opens the load contactor and turns on the under frequency light after 7 seconds at 380 Hz, all components of the system are functioning properly.

If the load contactor is not opened at 380 Hz after 7 seconds, refer to Troubleshooting Chart to determine which component is defective.

Return unit to normal operating condition.

(8)

Check over frequency sensing circuit, protective monitor, and indicating light. At some frequency value from 420 Hz to 480 Hz, after 7 seconds, the over frequency sensing

circuit should signal the over frequency circuit in the protective monitor module to OPEN the load contactor holding circuit, thus OPENING the load contactor.

At any frequency value exceeding 480-Hz, the over frequency sensing circuit should immediately signal the over frequency circuit in the protective monitor module to OPEN the load contactor holding circuit, thus OPENING the load contactor.

To check the over frequency protective components, proceed as follows:

While the unit is operating normally under load, increase generator output frequency by increasing engine speed. Use the governed speed setting potentiometer (Ref. Fig. 5). Turn adjusting screw CLOCKWISE gradually to increase engine speed until frequency meter indicates 415 Hz. Over frequency protective circuit should not open the load contactor at this frequency.

Increase frequency in steps of 1 Hz, with a time delay of 5 seconds between steps.

If the protective system opens the load contactor and turns on the over frequency light after 5 seconds at 426 Hz, all components of the system are functioning properly.

If the load contactor is not opened at 426 Hz after 5 seconds, refer to Troubleshooting Chart to determine which component is defective.

Return unit to normal operating condition.

(9)

If the generator is operating under load at this point, place the contactor control switch(s) (22 and 24, Fig. 1) in OFF position to open load contactors and disconnect load. There will be no further need for the load bank in the following check.

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f. Re-checking the entire unit after testing

(1)

With the engine running at normal governed speed, check the entire unit for vibration and for any parts which may have become loosened during the above checks. Tighten any loose attaching hardware as required.

(2)

Check engine oil pressure at rated speed (2400 RPM). The oil pressure gage should indicate at least 45 psi (310 kPa) when engine is hot. Also at rated speed, check engine coolant temperature. The needle in the temperature gage should indicate in the range of 180° F to 200° F (82.2º C to 94º C), depending upon ambient temperature.

WARNING

If a metal sounding rod is used to detect bearing noises, exercise extreme care to avoid injury.

(3)

Check 400 Hz generator bearings. Use a stethoscope or metal sounding rod to listen for unusual noises. If using a metal rod, place on end on the generator housing and hold the other end near the ear. Hold the rod with three fingers and use the index finger and thumb to form a sounding chamber between the rod and the ear. Do NOT allow the rod to touch the ear. Listen for grinding or pounding sounds which would indicate a defective bearing. An engine noise may be telegraphed to the generator and misinterpreted as a generator noise. Send the unit to overhaul if in doubt of bearing serviceability.

Generator Set Adjustment

a. Generator Adjustment

The 400 Hz generator is a brushless type requiring no adjustments of any kind.

b. Adjust 400 Hz voltage regulator.

When a voltage regulator is first put into service, or when output (generator-to-aircraft) cables are changed, the regulator may require adjustments of output voltage value and line-drop compensation.

For making these adjustments, the voltage regulator has three potentiometers:

• Coarse output voltage potentiometer

• Fine output voltage potentiometer

• Line-drop compensation potentiometer. See Figure 1, Sheet 2 for identification of

components used for regulator adjustment.

For regulator adjustment, the generator set must be running at rated RPM, under no-load conditions.

(1)

Adjustment

Adjust Voltage Control The output voltage at which the generator is regulated is adjustable by the PC board fine

output voltage adjustment potentiometer (36, Fig. 1). Turn the potentiometer adjustment clockwise (cw) to increase generator output voltage, and counterclockwise (ccw) to decrease voltage.

Observe the output voltage as indicated by the voltmeter which is located on the control panel of the generator set. Set output voltage at 115-V AC line-to-neutral (200-V AC line-to-line).

Adjust Line Drop Compensation Adjustment of line drop compensation is made with the line drop compensation potentiometer

(38, Fig. 1). Turning the potentiometer knob clockwise increases the magnitude of the compensation, and turning the potentiometer knob counterclockwise decreases the magnitude. To adjust the line drop compensation, proceed as follows:

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• Connect the generator set output cables to a load. Load the generator set with the largest available three-phase load of rated power factor not exceeding the maximum rating of the generator set.

• Measure output voltage at the load end of the cables. If the load voltage rises or drops more than 1% at the load end of the cables, decrease or increase the line drop compensation until the regulation is flat (115-V AC line-to-neutral and 200-V AC line-to-line).

• If the line drop compensation adjustments have affected the no-load voltage output, adjust the fine output voltage control potentiometer (37, Fig. 1) to the desired value.

(2)

Test the Voltage Regulator After necessary adjustments have been completed, re-test the voltage regulator as follows:

Connect a voltmeter at the load end of the generator output cables.

Operate the generator set at no-load and observe voltage reading.

Operate the generator set under load and observe voltage reading.

Voltage under load should vary no more than 1% at the load end of the cables from voltage under no-load.

c. Basic Engine Adjustments

Adjustment procedures applicable to the diesel engine are included in the Cummins Operation Manual, which is located in Chapter 5. Specific information for these engines is listed in Figure 2. Refer to the Cummins Operation and Manual for detailed information on the following engine adjustments.

(1)

Exhaust valve adjustment

(2)

Fuel injector timing adjustment

(3)

Engine idle speed adjustment Engine idle speed is set at the factory. The adjustment is then sealed to discourage tampering.

Idle speed should not be changed by the user. If adjustment is required, contact the local Cummins Distributor. The recommended idle speed is 750 +/- RPM.

NOTE: A stroboscope is required for engine idle speed checks.

(4)

Engine speed limiting adjustment The speed limiting adjustment is also set and sealed at the factory. Speed should be limited to

2750 +/- 75 RPM. If adjustment is required, contact your local Cummins Distributor.

d. Engine Accessories Adjustment

(1)

Alternator and fan belt adjustment Refer to 2-2, Par. 6 for belt adjustment instruction.

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Manufacturer Cummins Type engine In-line 6 cylinder, 4 cycle diesel Model 6BT5.9C165 Engine governed speed 2400 RPM Idle speed 850 +/- 50 RPM Speed limiting governor approximately 2750 +/- 75 RPM Firing order 1-5-3-6-2-4 Fuel pump speed limiting governor automotive type Lubricating oil pressure at 2400 RPM 45 to 50 PSI (310.3 to 620.5 kPA Engine coolant temperature 160º F to 200º F

(71º C to 93º C)

Engine Specifications

Figure 2

e. Electric Governor System Adjustment

Two of the electric governor system main components, namely the magnetic pickup and electric control box, have critical adjustments which can affect engine performance and, therefore, generator output. Actuator-to-fuel control lever adjustment can also affect engine performance.

NOTE: When servicing the actuator linkage DO NOT lubricate the ball joints, as they are self

lubricating. DO NOT lubricate them as damage will occur.

When the complete system is to be checked, and/or adjusted, a definite sequence of procedures should be followed:

First - Check or adjust actuator linkage Second - Check or adjust magnetic pickup Third - Check or adjust electronic control box.

NOTE: When making governor system adjustments, an important factor in such adjustments is the type

of fuel used in the generator set. For the engine of this generator set, carefully follow the engine fuel guidelines referenced in 2-2, 4, (a).

(1)

Actuator linkage adjustment (See Fig. 3) The proper adjustment of the mechanical linkage between the electric actuator and engine

speed control lever is important to the satisfactory operation of the complete system. The engine run lever and the engine stop lever are two Cummins supplied pieces that control the engine speed.

The engine run lever (6) is a factory preset throttle control that should not be tampered with. It is set to run wide open.

The engine stop control lever (3) linkage along with the hobart installed governor actuator (1) is used to control the engine speed only. These two items (1 and 3) should be used for governor adjustment only.

Two definite rules must be followed in making the adjustment:

• Adjust linkage to use the full travel of the threaded rod (2) and the engine stop lever (3).

• Linkage must move engine stop lever (7) from no fuel to maximum speed (2750 rpm)

position, or very close to maximum speed position to allow engine to pull 125% load.

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1. Actuator

2. Stop Lever

3. Stop Lever Bracket

4. Ball Joint

5. Nuts

6. Actuator Rod

Governor Actuator Linkage

Figure 3

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Refer to figure 3 while making linkage adjustments. with engine stopped, check and adjust linkage as follows:

Before making adjustment, observe and note the hole that the engine stop lever (3) uses to

mount the ball joint (4) ball joint (4) to rest.

Loosen the ball joint nut (7) that fastens the ball joint loosen the nut (5) that fastens the ball joint to the threaded rod (2), and remove the ball joint (4) from the engine stop lever (3)

NOTE: Do not remove the ball joint from the threaded rod.

Be sure that the engine stop lever (3) has not slipped on its shaft. If it has slipped, position it correctly and tighten securely.

Place both levers (2 and 3) in NO FUEL position and hold in place. Attempt to position the ball joint (4) in the oval hole of the engine stop lever (3), that will allow for a maximum range of travel of both levers. To do this:

• Loosen nuts (5) and rotate the ball joint - inward or outward on the threaded rod - as necessary for making the placement.

• Hold the removed ball joint in its correct position in the mounting hole of the engine stop lever (3), and tighten the ball joint nut.

• Then fasten down the nuts (5) snug in order to inspect linkage travel.

It is oval shaped therefore it will allow for a variety of positions for the

(4)

to the stop engine lever. Then

Then manually operate the threaded rod (2) back and forth between no fuel and full speed to compare its travel with the travel of the engine stop lever (3). If adjustment is unsatisfactory, try another place in the oval hole in the engine stop lever and readjust the rod length.

When proper adjustment has been completed, tighten the jam nut (5) on the threaded rod (2) firmly against the ball joint (4).

Check governor linkage for freedom of travel. Move the rod assembly manually to see that there isn’t any binding or lost motion in linkage. Make corrections if andas required. At NO FUEL position, the engine stop lever should be pulled all the way forward. For maximum RPM, the actuator shaft should move far enough to force the engine stop lever to use all its travel as it moves backward.

Start the engine, and set idle speed to 850 RPM +/- 50 RPM. (Refer to Par. 3, (e) (3) for procedure for setting idle speed). Operate engine at idle speed until it is warmed to operating temperature.

(2)

Magnetic pickup adjustment The strength of the magnetic pickup signal to the control box can be weakened if the tip of the

pickup is too far from the flywheel ring gear or if it becomes damaged. If the pickup is removed for any reason, or if the signal is weak, as indicated by test in Par. 3, e, (3), adjust the pickup as follows:

Disconnect magnetic pick-up wires at the terminal strip on the governor controller (terminals 3 and 4).

Loosen the jam nut (2, Fig. 4)and remove magnetic pickup (1)

Inspect to make certain the tip is not damaged from contact with the ring gear teeth. Replace pickup if it is damaged. If it isn’t, clean the tip of it and re-install it.

CAUTION

The pickup tip must be directly over a tooth and not between teeth when adjustment is made.

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Magnetic Pick-Up Adjustment

Figure 4

Rotate the engine as required to locate a ring gear tooth directly below the tapped, pickup mounting hole. Continue turning pick-up CLOCKWISE until it bottoms out (hits a ring gear tooth).

Back the magnetic pick-up outward 1/4 to 3/4 of a turn COUNTERCLOCKWISE. This creates a gap between the magnetic pick-up and the ring gear.

Re-connect pick-up wires to terminals 10 and 11 of the governor controller.

Start the engine and run it at idle speed.

Check voltage at terminals 10 and 11. The signal should read about 10 V-AC.

If the signal is weaker than 4-V AC, check connections. If necessary, check magnetic pick-up continuity with an ohmmeter.

Tighten the jam nut when the pick-up is properly adjusted.

NOTE: A minimum of 2.5-V AC is required during engine cranking. This minimum voltageisnecessary to energize the electronics of the control box. At rated speed, the magnetic pick-up voltage could go as high as 25-30-V AC without damage to the internal electronics of the control box.

(3)

Governor control box adjustment (See fig. 5) The control box has three control potentiometers (pot) for setting the response characteristics of

the governor system. They are: “I”, “D”, and “GAIN.” There is a forth potentiometer named “DROOP”, which is not used in this installation. It is set to zero of minimum. There are two potentiometers for controlling speed. The “SPEED” potentiometer in the control box is for setting IDLE speed. The potentiometer on the external printed circuit board is for setting the RATED speed. These are both multi-turn controls. They are also interactive with each other.

Make the controller settings as follows:

Preliminary controller settings Turn the engine OFF

• Set the “I” potentiometer (pot) (2) to the FORTH increment mark from zero.

• Set the “D” potentiometer (3) to the THIRD increment mark from 0 (zero).

• Set the “GAIN” potentiometer (4) to the THIRD increment mark from 0 (zero).

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Electric Governor

Control Box

Figure 5

• Set the “DROOP” potentiometer (1) COUNTER CLOCKWISE to minimum 0 (zero).

• Turn the rated speed potentiometer (5) all the way COUNTER CLOCKWISE. Then count

twelve full turns CLOCKWISE.

• Start the engine, leave at IDLE speed and adjust the IDLE speed potentiometer in the control box until the engine is operating at 850 RPM. Turning the potentiometer CLOCKWISE increases engine RPM.

• Checking No-Load Operation of Controller (See fig. 5)

• Press engine start switch (26, Fig. 1) a second time to increase engine RPMs to

approximately the rated speed (2400 RPM).

• Turn the “GAIN” potentiometer (4) full CLOCKWISE. The frequency meter gage and governor should become unstable and oscillate. If it does not, manually bump the linkage to cause it to oscillate.

• Slowly turn the “GAIN” potentiometer (3) COUNTER CLOCKWISE until the oscillations stop. Turn the “GAIN” potentiometer ½ an increment past a point where the oscillations stop.

• Turn the “D” potentiometer full CLOCKWISE. The frequency meter gage and governor should become unstable and oscillate. If it does not, manually bump the linkage to cause it to oscillate.

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• Slowly turn the “D” potentiometer COUNTER CLOCKWISE until the oscillations stop. Turn the “D” potentiometer ½ an increment past a point where the oscillations stop.

• Turn the “I” potentiometer (2) full CLOCKWISE. The frequency meter gage and governor should become unstable and oscillate. If it does not, manually bump the linkage to cause it to oscillate.

• Slowly turn the “I” potentiometer COUNTER CLOCKWISE until the oscillations stop.

NOTE:If the frequency meter gage and/or governor should still oscillate after the adjustment of these

potentiometers,the typeof oscillationmight givean indicationof which(”GAIN” or“I”) mightneed further adjustment. If the oscillation is fast andjagged, the “I”needs to be reduced by½ to 1increment. If the oscillation is slower and not as sharp, the “GAIN” needs to be reduced by ½ to 1 increment.

• Use the start switch to toggle between the rated and idle speed. Run the engine from rated speed to idle speed. The governor should regain control after a short delay, there should only be between 2 to 4 oscillations (bounces) in the frequency meter. If this does not happen, the “GAIN” or “I” might need to be further adjusted. Again, the type of oscillation in the meter will tell which potentiometer to adjust (see above note). Repeat this procedure several times to assure consistency.

• Using the engine start switch, run the engine up to rated speed. After a short delay, there should be only 2 to 4 oscillations in the frequency meter. If there is more oscillations than that, then further adjustment is needed. If the oscillations are 2 to 4 or less, then the controls are set.

NOTE:The “GAIN’ and “I” controls interact with each other. That is to say that when one of them is adjusted,

it affects the other. So it might be necessary to adjust back and forth between the two potentiometers several times to optimize performance.

Adjust for RATED speed operation (fig. 5) The function of the speed adjust p.c. board is to set the rated engine speed. To check for

proper adjustment, proceed with the following steps:

• With the engine running and properly adjusted for IDLE speed, press engine start switch (26) to increase RPMs to RATED SPEED. The engine should be running at 2400 RPM and have an output frequency of 400 Hertz.

• If the frequency reading is high or low (from 400 Hertz), operate the generator set at RATED speed, turn the adjustment pot on the speed adjust P.C. board in the CLOCKWISE direction to increase RPM’s or COUNTERCLOCKWISE direction to decrease RPM’s.

• After making any adjustments, switch to IDLE speed, allow the engine to stabilize, then switch back to RATED speed.

Checking the Actuator The actuator does not require any adjustments. An actuator malfunction, when it occurs, will

result in the actuator being totally inoperative, either due to the actuator coil being open or shorted to the actuator case. Resistance measurements will reveal either of these conditions.

Checking Operation of Controller Under Load Apply a load to the generator set, then remove the load and observe the length of time

required for engine speed to stabilize. Engine speed should stabilize within 3 to 5 diminishing oscillations on the frequency meter. If this does not happen, proceed as follows:

• With the generator set operating at no load, turn the GAIN setting slightly in the COUNTERCLOCKWISE direction.

• Apply a load again to the generator set. Then remove the load again and observe the length of time required for engine speed to stabilize. It should now stabilize in 3 to 5 diminishing oscillations on the frequency meter.

NOTE: If engine speed STILL doesn’t stabilize, recheck governor linkage. If the linkage is set properly,

the governor controller is probably defective.

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Checking Magnetic Pick-up Signal Connect a high impedance voltmeter to magnetic pick-up input terminals (terminals 10 and

11, Fig. 5) on controller terminal board. The voltage value at no load, governed speed should be 4-V AC MINIMUM.

NOTE: A signal as low as 2.5-V is sufficient to operate the control unit satisfactorily. If a no-voltage

condition is indicated, the magnetic pick-up is too far away from flywheel teeth, or it is defective.

Generator and Exciter Test

The generator fields and exciter stators may be tested with a Kelvin bridge. This is a double-bridge type instrument required for the very low resistance’s encountered in this test. It is understood that 0 resistance indicates a SHORT CIRCUITED condition. An infinite resistance reading indicates an OPEN CIRCUITED condition. See Fig. 6 for resistance values.

a. Disconnect generator stator leads at the output module panel. b. Disconnect the two black exciter field leads from terminal block mounted on output module panel. c. Check resistance and compare to values given in Figure 6.

Test Connection Resistance (Ohms) Generator Stator Phase A to N (G1)* 0.00235 Generator Stator Phase B to N (G1)* 0.00235 Generator Stator Phase C to N (G1)* 0.00235 Exciter Stator Field (L2) 26.5 A - B, B - C, C - A Exciter Armature (G2) 0.1 Generator Revolving Field (L1) 2.1

*NOTE:The two leads of a phase must be connected when test is made. Take readings when unit is

cold and in an ambient temperature of 70º F (21º C).

Generator and Exciter Stator Tests

Figure 6

Diode Test

Test values for diodes are not given here because they could be misleading. Test values may vary even between diodes of the same part number, rating, and manufacturer. General instructions for testing diodes follow:

a. Disconnect exciter windings from diode lead(s). b. Use a good quality ohmmeter. An instrument which indicates 50 ohms at the center of the scale is

preferable.

NOTE: Make certain the battery is in good condition and the pointer is adjusted to zero when the test

lead points are shorted together. Set the scale selector to RX1.

c. Hold one ohmmeter lead point on the threaded end of the diode. Hold the other lead point on the

wire terminal end. Observe and note the indicated resistance. Now reverse the lead connection on the diode. Again observe and note the ohmmeter indicated resistance. Generally speaking, if an infinite or very high resistance was indicated with the leads connected one way and a low, readable resistance was indicated with the leads connected the opposite way, the diode may be considered good.

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Section 4. Troubleshooting Procedures

1. General

The Troubleshooting Chart, beginning on Page 6, covers the common malfunctions which you may find during operation or maintenance of this equipment. It cannot list all malfunctions that may occur. If a malfunction is not listed in the chart, start looking for the cause at the source of power in the affected circuit. Refer to the schematic and connection diagrams in Chapter 5 and test the circuit, step by step, until the source of the malfunction is isolated.

The Troubleshooting Chart is arranged under 3 headings: Trouble Symtom and Condition, Probable Cause, and Test Check and/or Remedy. Trouble(s), Symtom(s), and Condition(s) are described and numbered. Probable Cause(s) are indented to the right and listed in numbered steps below Probable Cause. Test Check and/or Remedy provides instructions for correcting the malfunction, and is listed below each Test or Inspection procedure. Tests and inspections called for in the Troubleshooting Chart are to be performed as described in section 2-3 of this manual.

Equipment for Troubleshooting

WARNING

Exercise extreme care to avoid contact with high voltage leads and components. High voltage can kill!

CAUTION

A good quality multi-scale volt ohmmeter is the only instrument required for troubleshooting. At least two jumper leads with alligator, or similar clips, will be required. The engine electrical system may be used as a 12-V DC power source.

Parts Replacement

To lessen end item down time and to get a faulty machine back on line as quickly as possible, the black-box concept of parts replacement is reflected in the Troubleshooting Chart. For example, if a component in the governor control box is defective, the quickest way to remedy the situation is to replace the complete control box and send the old box to stock. Assemblies which lend themselves to this concept are:

Electric governor control box Electric governor actuator

Maintenance personnel must be very careful when performing terminal-toterminal checks to be certain the proper terminals are being used, especially when using jumper leads. Damage to electrical components may result from the application of improper voltage and current.

Protective monitor PC board

Over-Under frequency PC board Voltage regulator Over-Under voltage PC board

November 27/1997 Chapter 2-4

Overload PC boards

Generator Set Contol PC Board

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4. Test Values

Although test values are provided throughout the troubleshooting chart , additional information and values are given here.

Generator output voltage at maximum voltage regulator potentiometer setting: 134 volts or higher. Generator output voltage at minimum voltage regulator potentiometer setting: 108 volts or lower. Over voltage relay Trips at 126 volts after a 1-second time delay.

Trips at 140 volts in 160 milliseconds.

Trips at 180 volts in 50 milliseconds. Under voltage relay Trips at 100 volts after 7 seconds. Over frequency relay Trips at any value between 426-Hz and 480-Hz after a

5-second time delay. Trips immediately at any frequency

exceeding 480-Hz. Under frequency relay Trips at 375 Hz or less after a 5-second time delay. Overload time delay Trips in approximately 5 minutes at 125% load on either output

or on both outputs+ Frequency at rated speed of 2400 RPM is 400 +/- 2 Hz at no load and rated load. Engine oil pressure (warm and at rated speed 2400 RPM) 45 to 90 PSI (445 to 621 kPa). Engine coolant temperature (normal operation) 160 to 200º F (71 to 93º C).

Check Connections and Leads

ALWAYS make a check of connections and leads to a component suspected of being faulty. With the exception of a few instances, we will assume that connections and wiring have always been checked first and that power has not been lost as a result of defective wiring or connections.

Electric Governor Troubleshooting

The following facts concerning the operation of the electric governor may be helpful in understanding the system and in determining which unit in the system is faulty in case of troubles.

(1)

The system requires two sources of power to operate normally.

12 V DC input power (from engine electrical system)

4 V AC input voltage normal, the actuator will go to, or remain in STOP position under the following conditions:

• No 12 V DC power

• No voltage from control box to actuator

• Inadequate magnetic pickup voltage

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(2)

The actuator will surge under the following conditions:

Stability or gain adjustment set too high

Actuator linkage loose

Actuator linkage binding

Engine Troubleshooting

The ability of the engine to start and run properly depends upon a number of things.

(1)

An adequate supply of 12 V DC power reaching a good starter (1, fig. 1) and starter button.

(2)

Sufficient 12 V DC power reaching the fuel.

(3)

An adequate supply of air, compressed to a sufficiently high pressure.

(4)

The injection of the correct amount of clean fuel at the proper time

NOTE:When troubleshooting the engine, keep the above requirements in mind.

Illustrations

Illustrations, Figures 1, 2, and 3 are referred to throughout the Troubleshooting Chart.

Connection and Schematic Diagrams

All connection and schematic diagrams for generator, engine, lights, and all controls are located in chapter 5.

1. Starter

2. Starter Terminal

3. Switch to starter terminal

4. Starter solenoid

5. Solenoid switch input terminal

Starter and Solenoid Switch

Figure 1

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1. Fuel gage 15. Overvoltage indicator light (red)

2. Front panel 16. Adjustable grip latch

3. Engine coolant temperature meter 17. Undervoltage indicator light (red) 4 . Overtemperature indicator light (red) 18. Meter Selector switch

5. Engine hour meter 19. Test-reset push button switch (red)

6. Indicating light, air cleaner restriction 20. Engine stop push button switch (red)

7. Oil pressure gage 21. Underfreqency indicator light (red)

8. Engine ammeter 22. No. 2 contactor push button switch (orange)

9. Frequency meter 23. Overfreqency indicator light (red)

10. Control Box label 24. No. 1 contactor push button switch (yellow)

11. Strip lights (3) 25. Low Oil Pressure indicator light (red)

12. Generator ammeter 26. Engine start push button switch (green)

13. Voltmeter 27. Low Fuel indicator light (red)

14. Overload indicator light (red) 28. Panel light push button switch (yellow)

Operating Controls and Instruments

(Dual Output Shown)

Figure 2 (Sheet 1 of 2)

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29. Regulated-diagnostic switch 34. Circuit Breaker, control (5-amp)

30. Test bank-aircraft switch, 35. Engine circuit breaker (10-amp) No. 1 output 36. Output voltage adjustment (coarse)

31. Test bank-aircraft switch, No. 2 37. Output voltage adjustment (fine)

32. Circuit Breaker, contactors (5-amp) 38. Line drop compensation adjustment

33 Circuit Breaker, marker lights (10-amp)

Operating Controls and Instruments

(Dual Output Shown)

Figure 2 (Sheet 2 of 2)

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1. Master Relay (K69)

2. Idle-Excitation Relay (K68)

3. Over Temperature Fault Relay (K67)

4. Low Oil Pressure Fault Relay (K71)

5. No. 2 Contactor Control Relay (K272)

6. Panel and Clearance Lights Relay (K70)

Generator Set Control PC Board

Chapter 2-4 November 27/1997 Page 6

7. No. 2 Plug-Interlock Relay (K202)

8. No. 1 Plug-Interlock Relay (K2)

9. Bypass Relay (K73))

10. Low Fuel Fault Relay (K65)

11. Air Filter Fault Relay (K66)

12. No. 1 Contactor Control Relay (K72)

Figure 3

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Engine Controls

Trouble, Symptom Test, Check, And/or and Condition Probable Cause Remedy

NOTE: Diesel engine trouble shooting is covered in Cummins Operation Manual.

1. Engine will not start. Starter

will NOT crank engine. (See Fig. 1)

a. Battery discharged, or

loose battery or ground connection.

b.Electrical defect in starter.

See fig. 1.

c. Mechanical defect in starter.

See fig. 1.

d.Internal seizure.

Check voltage across batteries. Voltage should be approximately 12.8 volts DC. Check all battery terminals. Be sure 12.8 volts DC is reaching solenoid input terminal.

Momentarily connect a large capacity jumper cable (No. 1/0 minimum) between hot side of starter solenoid and starter input terminal. If starter does not crank engine, proceed to step c. If starter does crank engine, proceed to step e.

Remove starter motor from engine and apply 12-V DC to test it. If it doesn’t operate, it is defective. Replace it. If starter motor does operate, proceed to step d.

If battery and starter are good and starter is unable to crank engine, internal seizure is indicated. Attempt to hand crank engine with a 3/4 inch square drive on a long flex handle on crankshaft pulley. I f engine cannot be turned one complete revolution, internal seizure is indicated. Remove engine and disassemble to locate problem.

e. Defective starter solenoid.

See fig. 1.

f. Defective auxiliary starter

solenoid. See fig. 1.

November 27/1997 Chapter 2-4

Momentarily connect a large capacity jumper cable (No. 1/0 minimum) between the auxiliary solenoid terminals (one on each side). If engine does not crank, replace starter solenoid. If engine cranks, proceed to step f below.

Momentarily jumper small lug on front of auxiliary solenoid to ground. If engine does not crank, replace auxiliary starter solenoid. If engine cranks, proceed to step g below.

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Engine Controls

Trouble, Symptom Test, Check, And/or and Condition Probable Cause Remedy

Engine will not start. Starter will NOT crank engine. (continued)

2. Engine will not start. Cranking speed low.

3. Engine WILL NOT start. Cranking speed normal. LOW OIL indicating lamp on after 5 seconds.

g.Either of two defective

relays on the generator control PC board (Fig. 3) could cause this trouble: either master relay K69 (1, Fig. 3) or bypass relay K73 (9, Fig. 3) . Or the PC board itself could have developed a malfunction.

h.Defective engine start

button, S24 (26, Fig. 3) .

a. Low battery output

b.Loose starting circuit

connections or faulty cables.

c. Improper lubricating oil

viscosity

a. No fuel or insufficient fuel in

tank. LOW FUEL indicating lamp comes ON 10 seconds after cranking is initiated.

Press lamps button. If clearance lights do not come on, replace relay K69. with a relay known to be good, and attempt to crank the engine. If engine still won’t crank, replace bypass relay K73 and try once more to crank the engine. If engine still won’t crank, proceed to step h below.

Depress button and check continuity between button contacts. If no continuity exists, replace button. If there is continuity, replace generator control PC board.

Check battery. Recharge or replace.

Check all connections and cables. Tighten or replace as required.

Check oil. See Chapter 1-2; 1, (c). Remove and replace oil

if/as necessary. Fill fuel tank if it is empty or if

amount of fuel in it is low. If necessary, fill each filter with fuel oil and prime fuel pump according to instructions in Chapter 2-1. If engine will not start after priming, mechanical pump trouble is indicated. If engine starts and stops after a short time, trouble between fuel source and suction side of pump is indicated. Check and/or remedy as follows.

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Engine Controls

Trouble, Symptom Test, Check, And/or and Condition Probable Cause Remedy

Engine WILL NOT start. Cranking speed normal. LOW OIL indicating lamp on after 5 seconds. (continued)

b.Defective or misadjusted

magnetic pickup (Chapter 2-3, Fig. 4).

c. Defective actuator

The control unit may not be receiving a signal from the magnetic pickup and the “fail-safe” feature of unit may be functioning to prevent any signal from reaching the actuator. To check the magnetic pickup for 500392-1, refer to diagram

287451. Use this diagram to disconnect pickup input leads at terminals 10 and 11 on controller.

Connect a high impedance AC voltmeter to pickup output leads. Crank engine but don’t start. Voltage reading should be a minimum of one (1) volt. If no or low voltage is indicated, check pickup adjustment [see 2-3,Para. 3, e,(2)]. If pickup is properly adjusted and voltage is still zero, replace pickup.

Apply 12-V DC to two actuator input leads (terminals 4 and 5 on terminal strip). Actuator lever should move immediately to full speed position. If lever does not move, replace actuator.

d.Faulty controller

e. Loose connections,

damaged hoses or fuel lines between tank and fuel pump

f. Plugged or defective filter

November 27/1997 Chapter 2-4

Connect a DC voltmeter to terminals 4 and 5 on the controller terminal strip. Crank engine. Voltmeter should indicate within two (2) volts of system voltage. If not, replace

controller. Tighten all fittings and

connections. Replace any damaged hoses or fuel links.

Do not overlook the possibility of restricted flow through the fuel filters. Also check gaskets for leaking or damaged condition.

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Trouble, Symptom Test, Check, And/or and Condition Probable Cause Remedy

Engine WILL NOT start. Cranking speed normal. LOW OIL indicating lamp on after 5 seconds. (continued)

4. Engine cranks, but will not start. LOW OIL indicating lamp comes on immediately.

5. Engine cranks, but will not start. LOW FUEL indicating lamp comes on immediately.

6. Engine cranks, but will not start. HIGH TEMPERATURE indicating lamp comes ON immediately.

g.Faulty fuel pump. Replace fuel pump if defective.

a. Either of two relays, the

bypass relay, K73 (9, Fig.

3), or the low oil pressure fault relay, K71 (4, Fig. 3), or the engine control PC board could be defective.

a. Either the low fuel fault

relay, K65 (10, Fig. 3), or the engine control PC board is defective.

a. Defective or incorrectly

wired high temperature switch (S49, located on engine block on right side).

Attempt to correct this malfunction by replacing, in sequence, each of these relays and the PC board. Replace the component found to be defective.

Attempt to correct this malfunction by replacing low fuel fault relay, K65. If this does not correct the malfunction, replace the engine control PC board.

Check wiring to high temperature switch according to connection diagram in Chapter 6, and see that wiring is correct. If wiring is correct, remove wires and check resistance between terminals C and N.O. A resistance of less than 10 ohms indicates a defective switch. Replace switch if defective.

7. Engine is HARD to start. Cranking speed normal, fuel supply adequate.

b.Defective over temperature

fault relay, K67 (3, Fig. 3) or engine control PC board.

a. Low compression, which

may be caused by any one of following: Sticking or burned exhaust valves, worn or broken compression rings, leaking cylinder head gasket, or improper valve clearance adjustment.

Attempt to correct this malfunction by replacing over temperature fault relay (K67). If this does not correct the malfunction, replace the engine control PC board.

Check compression in accordance with instructions in Cummins Operation Manual. Overhaul engine to make

repairs as necessary.

Chapter 2-4 November 27/1997 Page 10

Hobart 90CU24 Operation And Maintenance Manual

Specifications and Main Features

Frequently Asked Questions

User Manual