Hobart 6824-1, 6824-2, 6824-3, 6824-4, 6824A-1 Operation And Maintenance Manual
...
OM-499
Revised 053194
OPERATION AND MAINTENANCE
MANUAL
with
ILLUSTRATED PARTS LIST
for
ENGINE DRIVEN GENERATOR SETS
60-kVA, 400-Hz, 115/200-V AC, 3-Phase Units
with
PERKINS DIESEL ENGINE
Type 6.3544
SPECIFICATION MOUNTING VOLTAGE
REGULATOR
6824-1, 6824A-1 Trailer or Truck 430391C
6824-2, 6824A-2 Tractor 430391C
6824-3, 6824A-3 Stationary: With Fuel Tank & Batteries 430391C
6824-4, 6824A-4 Trailer or Truck, Dual Output 430391C
6824A-5 Trailer or Truck 489812
6824A-6 Tractor 489812
6824A-7 Stationary: With Fuel Tank & Batteries 489812
6824A-8 Trailer or Truck, Dual Output 489812
HOBART BROTHERS COMPANY
Airport Systems Group
Troy, Ohio 45373 U.S.A.
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OM-499
Safety Instructions and Warnings for Electrical Power Equipment
WARNING
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 attache equipment.
Important: 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. 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.
1. 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
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.
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.
(rather than by diesel or gasoline engines)
must be installed
(amperage)
May 31/94 Revised Safety Warnings
Page 1
OM-499
c. 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.
(1)
Before inspecting or servicing electrically-powered equipment, take the following precautions:
(2)
Shut OFF all power at the disconnecting switch or line breaker before inspecting or servicing the
equipment.
(3)
Lock switch OPEN
(4)
Disconnect power to equipment if it is out of service.
(5)
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.
2. 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.
(or remove line fuses)
so that power cannot be turned on accidentally.
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.
3. 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.
4. 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.
5. 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.
Safety Warnings May 31/94 Revised
Page 2
EMERGENCY
FIRST AID
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.
6. Equipment Precautionary Labels
Inspect all precautionary labels on the equipment monthly. Order and inspect all labels that cannot be
easily read.
OM-499
May 31/94 Revised Safety Warnings
Page 3
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Safety Warnings May 31/94 Revised
Page 4
Introduction
This manual contains operation and maintenance information for a series of 400-Hertz generator sets
manufactured by Hobart Brothers Company, Power Systems 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 seen or 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 six 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, “
information located in Chapter 2, Section 3, Paragraph B. If a Chapter and Section are not indicated in
a reference, the referenced material is located in the same section as the reference, Example,
Para. B).
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 6.
Content of the manual is arranged as follows:
Chapter 1. Description/Operation
Chapter 2. Servicing
Chapter 3. Troubleshooting
Chapter 4. Illustrated Parts List
Chapter 5. Optional Equipment
Chapter 6. Manufacturer’s Literature
(See 2-3, Para. B)”
refers to
OM-499
(See
May 31/94 Revised Introduction
Page 1
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Introduction May 31/94 Revised
Page 2
OM-499
Table of Contents
SUBJECT CHAPTER/SECTION PAGE
Chapter 1. Description / Operation 1-1 1
Section 1. Description 1-1 1
1. General 1-1 1
2. Orientation 1-1 1
3. Special Features 1-1 1
a. “Roll-Out” Feature (Tow Tractor
-Mounted Unit) . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1. . . . . . . . . . . . . . . . . 1i
b. Protective Monitor . . . . . . . . . . . . . . . . . . . . . . . . 1-1. . . . . . . . . . . . . . . . . . 2
c. Pull-out Trays . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . . 2
d. Voltage Regulator . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . . 2
e. Test Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1. . . . . . . . . . . . . . . . . . 2
f. Electric Governor . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . . 2
4. Identification 1-1 2
5. Canopy 1-1 5
6. Optional Equipment 1-1 5
a. Trailer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . . 5
b. Transformer-Rectifier . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . . 5
c. Truck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . . 5
d. Second Output and Control Box . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . . 5
e. Quick Start Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . . 5
7. Engine, Generator, and Controls
Assembly 1-1 6
a. Basic Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . . 6
b. Engine Manufacturer’s Equipment . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . . 6
c. Hobart Engine Equipment . . . . . . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . . 6
d. Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1. . . . . . . . . . . . . . . . . . 9
e. Control Box Assembly . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . . 9
f. Engine Control Panel . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . 15
g. Voltage Regulator . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . 17
h. Power Module Panel Assembly . . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . 19
8. Test Box 1-1 23
a. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1. . . . . . . . . . . . . . . . . 23
b. Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . . . . . . . . . . . . . 23
9. Dual Output Units (Specifications 6824-4,
6824A-4 and 6824A-8) 1-1 24
May 31/94 Revised Table of Contents
Page 1
OM-499
SUBJECT CHAPTER/SECTION PAGE
Section 2. Preparation For Use,
Storage, Or Shipping 1-2 1
1. Preparation for Use 1-2 1
a. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 . . . . . . . . . . . . . . . . . 1
b. Inspection/Check . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 . . . . . . . . . . . . . . . . . 1
c. Installing Output Cables . . . . . . . . . . . . . . . . . . . 1-2 . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . 4
3. Preparation for Shipment (TractorMounted Units Only) 1-2 4
Section 3. Operation 1-3 1
1. General 1-3 1
2. Operating the Generator Set 1-3 1
a. Pre-start Inspection . . . . . . . . . . . . . . . . . . . . . . . 1-3 . . . . . . . . . . . . . . . . . 1
b. Normal Engine Starting Procedures . . . . . . . . . 1-3 . . . . . . . . . . . . . . . . . 1
c. Cold Weather Engine Starting Procedures . . . . 1-3 . . . . . . . . . . . . . . . . . 4
d. Preparation for Power Delivery (Normal
Automatic Voltage Control) . . . . . . . . . . . . . . . 1-3 . . . . . . . . . . . . . . . . . 4
e. Power Delivery (Automatic Voltage Control). . . 1-3 . . . . . . . . . . . . . . . . . 5
f. Preparation for Power Delivery (Manual
Voltage Control) . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 . . . . . . . . . . . . . . . . . 6
g. Power Delivery (Manual Voltage Control) . . . . . 1-3 . . . . . . . . . . . . . . . . . 6
h. Discontinue Power Delivery . . . . . . . . . . . . . . . . 1-3 . . . . . . . . . . . . . . . . . 6
i. Stopping the Engine . . . . . . . . . . . . . . . . . . . . . . 1-3 . . . . . . . . . . . . . . . . . 6
3. Test Box Operation 1-3 6
4. Transformer-Rectifier Operation 1-3 8
a. Direct Current Power Delivery . . . . . . . . . . . . . . 1-3 . . . . . . . . . . . . . . . . . 8
b. Simultaneous 28.5-V DC and 115-V AC
Power Delivery . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 . . . . . . . . . . . . . . . . . 8
5. No. 2 Output Operation (Specifications
6824-4, 6824A-4 and 6824A-8) 1-3 9
a. Power Delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 . . . . . . . . . . . . . . . . . 9
b. Discontinue Power Delivery . . . . . . . . . . . . . . . . 1-3 . . . . . . . . . . . . . . . . . 9
6. Trailer Operation 1-3 9
a. Towing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 . . . . . . . . . . . . . . . . . 9
b. Parking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 . . . . . . . . . . . . . . . . . 10
Table of Contents May 31/94 Revised
Page 2
OM-499
SUBJECT CHAPTER/SECTION PAGE
Chapter 2. Service 2-1 1
Section 1. Maintenance 2-1 1
1. General 2-1 1
2. Operation of Roll-Out Feature (For
Tractor-Mounted Units Only) 2-1 1
a. Roll Generator-Set Out for Service . . . . . . . . . . . 2-1. . . . . . . . . . . . . . . . . . 1
b. Roll Generator-Set In to Normal Position . . . . . . 2-1. . . . . . . . . . . . . . . . . . 1
3. Inspection 2-1 1
4. Lubrication 2-1 3
a. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 3
b. Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 3
c. Generator Controls . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 3
d. Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 3
e. Starter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 4
5. Air Cleaner Service 2-1 4
a. Cartridge Removal. . . . . . . . . . . . . . . . . . . . . . . . . 2-1. . . . . . . . . . . . . . . . . . 4
b. Cartridge Installation . . . . . . . . . . . . . . . . . . . . . . 2-1. . . . . . . . . . . . . . . . . . 4
6. Engine Fuel 2-1 5
. Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 5
. Fuel Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 5
7. Engine Cooling System 2-1 6
a. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 6
b. Radiator Cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1. . . . . . . . . . . . . . . . . . 6
c. Warm Weather Operation . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 6
d. Cold Weather Operation . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 6
e. Draining the Cooling System . . . . . . . . . . . . . . . . 2-1. . . . . . . . . . . . . . . . . . 8
f. Cleaning the Cooling System . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 8
g. Cleaning the Radiator Core . . . . . . . . . . . . . . . . . 2-1. . . . . . . . . . . . . . . . . . 8
h. Filling the Cooling System . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 8
8. Generator Maintenance 2-1 9
a. Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 9
b. Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 9
9. Drive Belts 2-1 9
a. Checking Belt Tension . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 9
b. Belt Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1. . . . . . . . . . . . . . . . . . 9
10. Trailer, Truck and Battery Maintenance 2-1 9
11. Service Helps 2-1 9
a. Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . . 9
b. Control Box Trays . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . 10
c. Generator Exciter . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . 10
d. Engine Control Panel . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . . . . . . . . . . . . . 11
May 31/94 Revised Table of Contents
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OM-499
SUBJECT CHAPTER/SECTION PAGE
Section 2. Inspection / Check 2-2 1
1. General 2-2 1
2. Engine 2-2 1
a. Fuel (See Fig. 1 for time schedules). . . . . . . . . . 2-2 . . . . . . . . . . . . . . . . . 1
b. Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 . . . . . . . . . . . . . . . . . 1
c. C. Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 . . . . . . . . . . . . . . . . . 1
d. V-Belts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 . . . . . . . . . . . . . . . . . 1
e. Exhaust System . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 . . . . . . . . . . . . . . . . . 1
3. Electrical System (12-V DC) 2-2 3
a. Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 . . . . . . . . . . . . . . . . . 3
b. Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 . . . . . . . . . . . . . . . . . 3
c. Wiring and Connections . . . . . . . . . . . . . . . . . . . 2-2 . . . . . . . . . . . . . . . . . 3
4. Electrical System (115-V AC) 2-2 3
a. Monitoring Instruments . . . . . . . . . . . . . . . . . . . 2-2 . . . . . . . . . . . . . . . . . 3
b. Indicating Lights . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 . . . . . . . . . . . . . . . . . 3
c. Protective Modules . . . . . . . . . . . . . . . . . . . . . . . 2-2 . . . . . . . . . . . . . . . . . 3
d. Wiring and Connections . . . . . . . . . . . . . . . . . . . 2-2 . . . . . . . . . . . . . . . . . 4
5. Trailer and Truck 2-2 4
Section 3. Adjustment / Test 2-3 1
1. General 2-3 1
2. Test Panels 2-3 1
a. Generator Set Removed from Tractor . . . . . . . . 2-3 . . . . . . . . . . . . . . . . . 1
b. Generator Set in Tow Tractor . . . . . . . . . . . . . . . 2-3 . . . . . . . . . . . . . . . . . 1
3. Generator Set Test 2-3 2
a. Pre-operational Test Procedures . . . . . . . . . . . . 2-3 . . . . . . . . . . . . . . . . . 2
b. Operational Test Procedures . . . . . . . . . . . . . . . 2-3 . . . . . . . . . . . . . . . . . 3
4. Generator Set Adjustment 2-3 9
a. Generator Adjustment . . . . . . . . . . . . . . . . . . . . 2-3 . . . . . . . . . . . . . . . . . 9
b. Generator Control Adjustments . . . . . . . . . . . . 2-3 . . . . . . . . . . . . . . . . . 9
c. Basic Engine Adjustments . . . . . . . . . . . . . . . . . 2-3 . . . . . . . . . . . . . . . . . 12
d. Engine Accessories Adjustment . . . . . . . . . . . . 2-3 . . . . . . . . . . . . . . . . . 12
e. Electric Governor System Adjustment . . . . . . . 2-3 . . . . . . . . . . . . . . . . . 12
5. Generator and Exciter Test 2-3 17
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 . . . . . . . . . . . . . . . . . 17
6. Diode Test 2-3 17
7. Additional Test for Dual Output Unit 2-3 18
Table of Contents May 31/94 Revised
Page 4
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SUBJECT CHAPTER/SECTION PAGE
Chapter 3. Troubleshooting Procedures 1 1
Section 1. Troubleshooting 3-1 1
1. General 3-1 1
a. Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 . . . . . . . . . . . . . . . . . . 1
b. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 . . . . . . . . . . . . . . . . . . 1
c. Use of the Troubleshooting Chart . . . . . . . . . . . . 3-1. . . . . . . . . . . . . . . . . . 1
2. Equipment for Troubleshooting 3-1 2
3. Safety 3-1 2
3. Parts Replacement 3-1 2
4. Test Values 3-1 2
5. Check Connections and Leads 3-1 3
6. Electric Governor Trouble Shooting 3-1 3
7. Engine Trouble Shooting Procedures 3-1 3
a. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1. . . . . . . . . . . . . . . . . . 3
8. Illustrations 3-1 3
Chapter 4. Illustrated Parts List 4-1 1
Section 1. Introduction 4-1 1
1. General 4-1 1
2. Purpose 4-1 1
3. Arrangement 4-1 1
4. Explanation of Parts List 4-1 1
a. Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 . . . . . . . . . . . . . . . . . . 1
b. Parts List Form . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 . . . . . . . . . . . . . . . . . . 1
Section 2. Manufacturer’s Codes 4-2 1
1. Explanation of Manufacturer’s 4-2
(Vendor) Code List 4-2 1
Section 3. Parts List 4-3 1
1. Explanation of Parts List Arrangement 4-3 1
2. Symbols and Abbreviations 4-3 1
Section 4. Numerical Index 4-4 1
1. Explanation of Numerical Index 4-4 1
Chapter 5. Optional Equipment 5-0 1
Chapter 6. Manufacturer’s Literature 6-0 1
Unusual Service Conditions
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Table of Contents May 31/94 Revised
Page 6
Chapter 1. Description / Operation
Section 1. Description
1. General
The basic generator sets
Series No. 6824A. The various configurations of the set are identified by adding a dash number
suffix to the Series number.
etc.)
The generator sets in the 6824A series feature armatures with Hoover Bearings, Browning Coupler,
and different magnetic pole construction for the generator revolving field. This new armature can be
easily identified by the two copper rings on each end of the field coils and copper wedges between the
magnetic poles.
The basic generator set which includes the engine, generator and all controls is identical for all models.
Differences between models are those required by their respective mounting, such as trailer mounting,
tow tractor mounting, etc. Identification of different models within the Series will be explained later in the
Description.
Information and instructions throughout the manual apply to all models. Information which applies only
to a certain model will be qualified and identified as such.
The purpose of the generator set is to generate and deliver regulated, 400-Hz electrical power to a
parked
generators are not running. The engine, generator, and controls are designed into a compact unit which
is easily removable from a tow tractor. See Figure 2 for specifications and capabilities.
(or towed)
aircraft for operation of the aircraft’s electrical equipment when the on-board
(see Fig. 1)
covered by the manual are identified by Series No. 6824and
OM-499
(-1, -2,
2. Orientation
For purpose of orientation and to familiarize operators and maintenance personnel with the location of
components, the radiator is considered to be at the FRONT of the unit. The generator and controls are
at the REAR. RIGHT and LEFT are determined by standing at the rear end facing the machine. Thus,
the generator control box, output receptacle connector, and engine control panel are mounted on the
LEFT side at the REAR of the unit.
3. Special Features
The generator set has many special features which are later described more fully under the assemblies
in which they appear. Some of the main features are mentioned here and described briefly as follows.
a. “Roll-Out” Feature (Tow Tractor-Mounted Unit)
For a generator set mounted on a tow tractor the generator set is supplied with two-channel-like
tracks which are floor mounted in the generator compartment of the tow tractor. Tracks are
equipped with cam-follower, needle-bearing rollers which support the generator set and allow it to
roll in-and-out easily for servicing and maintenance.
Additional rollers are mounted on each side of the generator set main frame, near the rear, to add
stability and to prevent the unit from tipping downward at the front when it is rolled outward for
service.
May 31/94 Revised 1-1
(See Figure 21, Section 4-3.)
Page 1
OM-499
The set is secured in mounted position by two retaining brackets attached at the front of the unit
(See 2-1, Fig. 2).
approximately 38 inches, where a stop-bar on the main frame contacts a stop-block in the left track
to prevent further outward travel.
b. Protective Monitor
A single, solid-state device
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.
c. Pull-out Trays
The control box is equipped with pull-out, drawer-type trays
controls and equipment mounted in them. Each tray may be removed as an assembly by
disconnecting a single quick-disconnect connector and tripping two safety latches.
d. Voltage Regulator
A solid-state, adjustable voltage regulator
aircraft (or distribution panel when applicable). The regulator is also adjustable for a variety of
output cable sizes and lengths.
e. Test Circuitry
A receptacle connector
circuitry is provided for the attachment of a test box manufactured by Hobart Brothers. This test
circuitry allows electricians to perform as many as twenty-four tests and checks from one location,
conveniently and easily.
The removal of two screws from the brackets allows the set to be rolled out
(4, Fig. 8)
(19, Fig. 9)
receives signals from all of the fault sensing units in the
(Fig. 6)
(Fig. 10)
with wiring to various test points throughout the electrical
provides automatic voltage regulation at the
which provide easy access to
f. Electric Governor
The engine is equipped with an all electric type governor kit
equipment more fully described under the engine description.
(5 and 12, Fig. 3)
and other special
4. Identification
Generator sets are identified by their Specification number, which consists of a Series number plus a
dash number
set. For example, Specification number 6824A-2 identifies a machine designed for mounting on a tow
tractor.
The following identification chart identifies in greater detail the machines covered by this manual.
SPECIFICATION No. CHARACTERISTICS
6824-1, 6824A-1, and
6824A-5
6824-2, 6824A-2, and
6824A-6
6824-3, 6824A-3, and
6824A-7
6824-4, 6824A-4, and
6824A-8
(i.e. -1, -2, etc.)
suffix. The suffix number indicates the mounting design of the generator
Designed for trailer or truck mounting. 12-V DC electrical power and
fuel to be supplied from facilities on trailer or truck.
Designed for mounting on a tow tractor. 12-V DC electrical power
and fuel to be supplied by tow tractor. Furnished with roll-out tracks
for mounting on tow tractor.
Designed for stationary mounting. Equipped with two 12-V batteries
and fuel tank.
Dual output unit for trailer or truck mounting. 12-V DC electrical
power and fuel to be supplied from facilities on trailer or truck.
Generator Set Identification Chart
1-1 May 31/94 Revised
Page 2
OM-499
1. Canopy 6. Mounting frame
2. Lifting eye 7. Engine fan exhaust deflectors
3. Windows 8. Engine exhaust pipe
4. Output receptacle cover 9. Radiator cap access cover
5. Output cable horn
May 31/94 Revised 1-1
Generator Set
Figure 1
Page 3
OM-499
PHYSICAL
Length
Width 36 inches
Height
Weight
Output power rating 60 KVA
Output voltage 115/200 VAC
Rated load capacity 173 A
Frequency/cycles per second 400 Hz
Output Kilowatts 48 KW
Power factor 0.8 PF
Duty cycle 100%
Operating speed 2000 RPM
Overload capacity
Output cable size 2/0
Overvoltage relay Trips 130 V to 134 V; resets 125 V
Undervoltage relay Trips 93 V to 102 V; resets 110 V
Overfrequency relay Trips 415 Hz to 425 Hz; resets 410 Hz
Underfrequency relay Trips 375 Hz to 385 Hz; resets 385 Hz
Undervoltage time delay 4 to 12 seconds, depending upon adjustment
Overload relay Trips at 125% rated load in less than 5 minutes
(stationary units)
(overall)
(approximately)
GENERATOR CAPABILITIES
(125% of rated load)
GENERATOR PROTECTIVE SYSTEM
82 inches
(2082.8 mm)
(914.4mm)
43 inches
3300 pounds
216 A
(1092.2mm)
(1496.8 kg)
ENGINE
Manufacturer Perkins Engines, Inc.
Model T6-3544
Type In-line, 6-cylinder, 4-cycle diesel
Displacement 354 cu. in.
Compression ratio 16:1
Firing order 1 - 5 - 3- 6 - 2 - 4
Number of main bearings 7
Horsepower at 2000 RPM 107
Governed speed 2000 RPM + / - 4.5%
Idle speed 850 + / - 25 RPM
Electrical system 12 volt
Oil Capacity
Oil Capacity
Coolant capacity
Fuel Diesel oil conformint to ASTM Specification
(W/Filter)
(W/O Filter)
(approx.)
15 Quarts
14 Quarts
20 quarts
D.975-66T, No. 1-D and 2-D MIL-L-2104B
Specifications and Capabilities
Figure 2
(5.8 liters)
(14 liters)
(13.6 liters)
(19 liters)
1-1 May 31/94 Revised
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OM-499
5. Canopy
A sheet metal enclosure, identified as a canopy
and electrical controls. The canopy is designed to reduce the operational noise level in the immediate
area of the machine. Doors and panels are covered on the inside with Fiberglass acoustic material to
reduce reflected and conducted noise, and to absorb noise. Noise producing vibration in most
frequently used doors on the left side is reduced by the use of two-point slam locks. Less frequently
used doors on the right side are equipped with screw-operated latch fasteners which are tightened after
latching to reduce vibration. Insulating strips around all doors also reduce noise. Metal strips are
mounted horizontally across the front grille to deflect engine fan exhaust air and noise upward.
Two large openings in the canopy top provide an entrance for cooling air and an access to internal
components. A hood-type cover is mounted about two inches above each opening. The cover is
flanged downward and extends beyond the edges of the upwardly flanged opening to prevent entrance
of blowing rain while still allowing a good flow of air. Air enters the forward opening into the engine
compartment and is discharged through the radiator by the engine fan. Air enters the rear opening into
the generator compartment. It is then circulated over generator controls and drawn into the rear exciter
and generator housings where it passes over all windings before being discharged by the generator fan.
All generator sets in this Series except the tractor-mounted unit are equipped with a canopy having
doors on both sides. Tractor-mounted units have two large removable panels on the right side mainly
because the right side of the machine is not accessible when mounted on a tow tractor, and secondly
because the thick doors would not allow mounting in the limited space available on the tractor. Panel
mounted instruments may be observed through two Plexiglass windows in the left rear door which
covers the control box and engine control panel. The lower window is slanted outward at the bottom to
provide access to engine controls when the door is closed. A centrally-located lifting eye attached to a
lifting yoke extends through the canopy top to provide an attaching point for chains, cables, or hook
used to lift and move the generator set.
(1, Fig. 1),
provides protection for the engine, generator
6. Optional Equipment
Several items of optional equipment are available for units covered in this manual . Each piece of
optional equipment is covered by its own Instruction and Parts Manual and will not be covered in this
basic manual. When applicable, information for optional equipment will be located in Chapter 5. Options
are listed as follows:
a. Trailer
A four-wheel trailer with batteries and fuel tank is available.
b. Transformer-Rectifier
(T-R)
A transformer-rectifier
115/200-V, 400-Hz, AC power from the generator and converts it to a 28.5 V DC output.
c. Truck
Trucks with special bodies for generator set mounting are available. Compartments in the body are
provided for batteries, cable-storage, etc. Trucks available are Ford, Chevrolet, and GMC.
d. Second Output and Control Box
An auxiliary output and control box is available to provide a second independent 115-V AC output
circuit. This option is for -1, -2 and -3 generator set specification numbers if a second output is
desired for a machine purchased before dual output machines (-4 specification numbers) were
available, or if a second output is desired for a tractor-mount or stationary unit.
e. Quick Start Kit
(See Section 1-3, Para. 2C)
is available for use with the generator set. This T-R receives
May 31/94 Revised 1-1
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OM-499
7. Engine, Generator, and Controls Assembly
This assembly is the basic generator set without canopy. It includes all components required to
generate and regulate 400 Hz, 115/200 V, threephase power, and is operable when provided with fuel
and 12 V DC power. The engine-generator assembly is mounted on a welded steel frame. A
superstructure, attached to the main frame, provides mounting facilities for the canopy, control box, and
electrical equipment and controls.
a. Basic Engine
This generator set is equipped with a 6-cylinder, in-line, turbo-charged Perkins Diesel engine. See
Figure 2 for general specifications, and see Engine Operator’s Handbook in Chapter 6 for more
detailed information.
b. Engine Manufacturer’s Equipment
As received from the engine manufacturer, the engine includes the following equipment which is
described in the Perkins Shop Manual
(1)
Electronic stop control.
(2)
Fuel filter.
(3)
Reverse-flow, engine cooling fan to blow air outward through the radiator.
c. Hobart Engine Equipment
The engine is modified at Hobart Brothers by the addition of the following equipment:
(Chapter 6)
.
(1)
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
because it provides faster engine response to changes in load conditions. This fast response
results in very close frequency control. Refer to the Barber-Colman instruction book in Chapter
6 for a detailed description. A brief description is given below:
(and generator output frequency)
a. 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.
b. Control unit
The control unit
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.
(5, Fig. 3)
is a box containing a compact assembly of solid state
c. Actuator
The actuator
required to maintain a constant engine speed. The actuator is operated by a DC signal from
the control unit.
(2)
Engine electrical system
Items in the 12-volt engine electrical system that are provided by Hobart Brothers are:
(12, Fig. 3)
supplies the force needed to move and position the fuel lever as
a. A heavy-duty motor starter
b. Alternator with voltage regulator
c. Starting switch
d. Wiring harness
1-1 May 31/94 Revised
Page 6
OM-499
1. Mounting frame 7. Voltage regulator 13. Output cable terminal board
2. Generator 8. Air cleaner 14. Engine control panel
3. Power module 9. Lifting yoke 15. Cable horn and clamp
4. Control box 10. Engine 16. Radiator
5. Governor control box 11. Engine exhaust pipe 17. Oil pressure switch
6. Starting fluid container * 12. Governor actuator
* Optional
May 31/94 Revised 1-1
Generator Set Components
Figure 3
Page 7
OM-499
(3)
Engine protective devices
a. High coolant temperature switch
A high coolant temperature switch is mounted in the front of the cylinder block to monitor the
coolant temperature. If the coolant temperature reaches 210 degrees F
normally closed switch opens and actuates the fuel valve solenoid which shuts down the
engine.
(99 degrees C)
b. Oil pressure switch
A diaphragm-type switch monitors the pressure in the lubricating oil system. It is mounted in
the side of the cylinder block
(69 kPa)
engine.
(4)
Air cleaner
The diesel-engine air cleaner
eliminator and a service indicator. The indicator functions to signal the operator when the
cartridge needs changing. A red cylindrical “flag”
viewing chamber
air pressure. As the cartridge becomes loaded with dirt and air pressure within the cleaner
lessens, the “flag” gradually rises higher in the glass viewing chamber. When the “flag” reaches
the top of the chamber, it locks in that position to warn the operator that the cartridge must be
changed. The “flag” is reset
the indicator.
NOTE: The service indicator is mounted on the engine control panel and connected to the air cleaner by a
rubber hose. The indicator flag is visible only when the engine is running, or when the flag is locked
in WARNING position.
, this switch opens and actuates the fuel valve solenoid which shuts down the
(1)
when air pressure within the air cleaner housing drops below the outside
(18, Fig. 3)
(Fig. 4)
(unlocked)
. If the pressure in the lube oil system falls to 10 psi
is a dry-cartridge type. It is equipped with a moisture
(2)
is forced upward in a glass enclosed
by pushing the reset button
(3)
located on the bottom of
, this
1-1 May 31/94 Revised
Page 8
Air Cleaner and Service Indicator
Figure 4
(5)
Exhaust system
The exhaust system consists of a special noise reducing muffler
(2)
by a pipe
and noise downward.
to a conventional exhaust manifold
(1)
. Baffles in the tail pipe outlet direct exhaust
(3, Fig. 5)
OM-499
which is connected
Noise Reduction Exhaust System
Figure 5
(6)
Radiator
The radiator
disassembly for cleaning and repair.
d. Generator
The 400-Hz generator is a brushless, revolving field, three-phase, alternating current type. The
rotor assembly is mounted by two, permanently lubricated, sealed, ball bearings. The front bearing
is supported by the fan housing; the rear bearing is mounted in the exciter housing. Both of these
housings are attached to the main generator stator housing. The front end of the rotor shaft
extends forward beyond the rear bearing and into the exciter stator housing. The exciter rotor is
mounted on this shaft extension with a Woodruff key and is secured by a washer and 1/2"-13 thd,
cap screw. A rectifier with six 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 static voltage regulator. A centrifugal, radial-blade fan which is part of the hub
and 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.
e. Control Box Assembly
The control box
for generator and engine controls and monitoring equipment. The box is equipped with two, drawer
type trays which contain generator output control devices and monitoring instruments. Trays slide
in and out on nylon rollers for easy access to internally mounted components. Each tray is easily
removable by disconnecting an “Amphenol” connector, unlocking safety latches, and sliding the
complete tray assembly out of the control box. A shielded, instrument panel light is mounted on the
left side of the control box front panel, to illuminate controls and instruments in the trays.
(16, Fig. 3)
(Fig. 6)
is a sheet metal enclosure which houses and provides mounting facilities
is a tube type with bolted-on, top and bottom tanks which permit
May 31/94 Revised 1-1
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OM-499
Control Box
Figure 6
(1)
Generator control tray (See Figure 7)
The generator control tray contains instruments and controls for monitoring and controlling the
generator output.
a. Resistors
Two, 10-ohm, 100-watt, ballast resistors
DC field circuit.
A variable resistor
rheostat
voltage range through which the rheostat can control generator output voltage.
(13)
(1)
is connected in series between the manual control rectifier
. Its purpose is to adjust the DC voltage to the rheostat and thus determine the
(2)
are connected in series in the generator exciter
(14)
b. Generator output monitors (meters)
The generator output is monitored by three instruments; a frequency meter
(9)
, and an ammeter
frequency of the generator output alternating current in the range of 380 to 420 Hz
per second)
. The voltmeter indicates the generator output voltage in each phase-to-neutral
(A-N, B-N and C-N)
switch (6) and the line selector switch
voltmeter 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 switch
ammeter current transformers
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.
(7)
. The frequency meter is a resonant-reed type, and indicates the
or phase-to-phase
(A-B, B-C and C-A)
as selected by the meter selector
(5).(These switches will be described below.)
(Ref. 4, Fig. 11)
lower the output load current to a lesser
(10)
, a voltmeter
(6)
and
(cycles
The
. Three
1-1 May 31/94 Revised
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OM-499
c. Meter and line switches
These switches provide 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
(6)
or line-to-line. The meter switch
under the switch knob, is marked and lettered to indicate the three functional positions of the
meter switch.
(5)
is a twoposition, toggle switch used to select either line-to-neutral or lineto-line voltage to
the voltmeter. The nameplate is also marked to indicate the position of this switch.
(When the knob is pointing straight down, the switch is OFF.)
is a four-position, rotary type. A nameplate
d. Receptacle connector
An “Amphenol” connector
box components.
(12)
provides a means of quickly disconnecting all wires to control
e. Tray
The tray
fastener
(15)
slides in and out on nylon rollers. It is secured in place by a twist-lock, screw
(8)
.
f. Manualvoltage control
When the automatic manual switch
supplied to the rectifier
the rectifier is routed to the exciter field through a rheostat
is thereby manually controlled by adjustment of the rheostat.
(14)
rather than to the automatic voltage regulator. The DC output of
(11)
is placed in MANUAL position, AC power is
(13)
. The generator output voltage
g. Excitation-deenergization relay
The purpose of this relay
field only when engine speed is being controlled by the electric governor.
(3)
is to allow automatic excitation to be connected to the exciter
(4)
, located
The line switch
(2)
Protective relay tray (see Figure 8)
The bottom tray in the control box is identified as the protective relay tray and contains electrical
and safety devices designed to protect the aircraft electrical system against damage which
could result from overvoltage, undervoltage, overfrequency, or underfrequency. The tray also
contains devices for protection and control of the generator output electrical system.
a. Sensing modules
The voltage sensing module
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
the aircraft. Trip values are adjustable, however, adjustments should be made ONLY under
laboratory conditions.
A solid-state overload signaling device
monitor module and performs a function similar to the voltage and frequency sensing
modules.
Trip values for protective circuits are as follows:
Overvoltage trips at 130 V to 134 V
Undervoltage trips at 102 V or below
Overfrequency trips at 415 Hz to 425 Hz
Underfrequency trips at 390 Hz to 395 Hz
Undervoltage time delay
Overload circuit trips at any value over 125% rated load capacity.
See Para 6,H, (3) for more specific and detailed information regarding overload device.
(5)
and frequency sensing module
(4)
to open the load contactor and disconnect output to
(Ref. 7, Fig 11)
(adjustable)
(6)
are connected to
is also connected to the protective
May 31/94 Revised 1-1
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OM-499
1. Resistor (50 ohm, 100 watt) 9. Voltmeter
2. Resistor (25 ohm, 100 watt) 10. Frequency meter
3. Excitation-deenergization relay 11. Automatic-manual switch
4. Instruction plate 12. Receptacle connector
5. Line selector toggle switch 13. Manual voltage control rheostat
6. Meter selector rotary switch 14. Manual control rectifier
7. AC ammeter 15. Tray
8. Tray fastener
1-1 May 31/94 Revised
Page 12
Generator Control Tray
Figure 7
OM-499
b. Memory and time delay module
The memory and time delay module
is a solid-state device with a hermetically-sealed, reed-type relay. The printed circuit board or
“card” includes five memory circuits and a time delay circuit. Each circuit is connected to a
corresponding sensing circuit in the sensing modules
connected to the module relay coil, and any one of the circuits can energize the coil to open
the relay contacts. Thus, when a sensing device energizes any one of the module circuits,
the module relay is also energized to break the load contactor holding circuit and allow the
load contactor to open. All circuits, except the undervoltage circuit, function immediately to
open the load contactor. A time delay system is designed into the undervoltage circuit to
prevent nuisance opening of the contactor under conditions of momentary undervoltage in
the generator output. An undervoltage condition which continues uninterrupted for a period
of 4 to 12 seconds
Each of the five circuits is connected to a corresponding indicating light
15)
which is turned on when a fault occurs.
The module relay will remain energized
(7)
switch
normal, CLOSED position.
is pushed to break the module 12-V DC circuit, and allow the relay to return to
(adjustable)
c. Indicating lights
The function of these lights
abnormal condition of overvoltage, underfrequency, 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 reset switch
lamps in indicating lights may be tested by pressing switch
(10, 11, 13, 14 and 15)
(4)
is sometimes called the protective monitor module. It
(5 and 6)
will cause the time delay circuit to open the load contactor.
. All memory circuits are
(10, 11, 13, 14 and
(OPEN)
and the light will remain ON until the reset
is to indicate, to the operator, the
(7)
is pushed. All
(8)
.
d. Plug-interlock relay
The function of the plug interlock relay
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. Twentyeight-volt, direct current for operation of the relay is supplied
from the aircraft either through an on-board transformerrectifier, or from a twenty-eight-volt,
electrical system. Connection from the aircraft to the interlock relay is made through
terminals E and F on the output cable plug connector.
(1)
is to cause the output load contactor to open in the
e. Test-bank switch
A spst, toggle switch
supplying power to a load bank or to an aircraft not equipped with a plug interlock system.
(18)
provides a means of by-passing the interlock relay
(1)
when
f. Resistor
A 100-ohm, 25-watt resistor
the relay in the event that phase C contacts in the load contactor should fail to close when
the generator ON switch is operated.
(21)
is connected in series with the plug interlock relay to protect
g. Fuse-interlock relay
The function of the fuse-interlock relay
and remove the load in case of a “blown” fuse
(2)
is to interrupt the load contactor holding coil circuit
(17)
in the protective relay coil circuit.
h. Connector
A twenty-six contact connector
electrical components so that the complete tray assembly may be removed quickly and
easily.
(19)
provides a quick-disconnect facility for all wiring to tray
May 31/94 Revised 1-1
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OM-499
1. Plug-interlock relay 12. Tray fastener
2. Fuse-interlock relay 13. Overfrequency indicating light
3. Auxiliary underfrequency relay 14. Undervoltage indicating light
4. Memory and time delay module 15. Overvoltage indicating light
5. Over-undervoltage module 16. Load contactor circuit fuse (2-A)
6. Over-underfrequency module 17. Protective system fuse (2-A)
7. Reset switch 18. Test bank switch
8. Light test switch 19. Receptacle connector
9. Hole plug 20. Terminal board
10. Overload indicating light 21. Resistor (100 ohm, 25 watt)
11. Underfrequency indicating 22. Tray
1-1 May 31/94 Revised
Page 14
Protective Relay Tray
Figure 8
OM-499
i. Auxiliary underfrequency relay
The function of the auxiliary underfrequency relay
excitation-deenergization relay and disconnect the voltage regulator anytime generator
frequency drops to 380 Hz or below. This protects the voltage regulator
resistors
output in its attempt to maintain voltage when the generator is operating at a speed which
cannot produce normal voltage output.
NOTE: If the auxiliary underfrequency relay is tripped, it will be necessary to momentarily place engine
operating mode switch (5, Fig. 9) in BUILD-UP-VOLTAGE position to restore generator voltage.
f. Engine Control Panel (See Fig. 9)
This panel is mounted directly below the control box. In addition to engine controls and
instruments, generator output controls are mounted here. A plexiglass window in the canopy rear
door, slants outward at the bottom to form an opening for access to controls when the door is
closed.
(1)
Engine instruments
Engine operation is monitored by an ammeter
pressure gage
(2, Fig. 7)
(10)
. An hourmeter
against overload which could be caused by very high voltage regulator
(4)
(6)
records engine operating time.
a. Ammeter
The ammeter
system. Its graduated range is from -60 A through 0 A, to +60 A.
(4)
indicates the direction and value of current flow in the 12-V DC electrical
(3)
is to automatically open the
(Fig. 10)
, a coolant temperature gage
and ballast
(8)
, and an oil
b. Temperature gage
The temperature gage
mounted indicating mechanism which is connected by a capillary tube to a bulb mounted in
the engine cooling system. The gage indicates engine coolant temperature in the range of
o
F to 220oF.
100
(8)
is a mechanical type of unit construction. It consists of a panel
c. Oil pressure gage and oil pressure switch
The oil pressure gage
pressure. It is graduated from 0 PSI to 75 PSI. An oil pressure switch is mounted in a tee
fitting directly behind the gage. The switch connects 12-V DC power to the engine control
system and to the generator 12-V DC control system when the engine is running.
(10)
is a bourdon tube type and indicates engine lubricating oil
d. Hourmeter
The hourmeter
measures and records engine running time and will record up to 9999.9 hours on five
revolving drums. The hourmeter operates only when the engine is running and the oil
pressure switch is closed.
(6)
is electrically driven from the 12-V DC battery system. The hourmeter
e. Fuel gage and blocking diodes
An electric fuel gage
provided for the generator set. A sending unit mounted in the trailer or truck mounted unit
fuel tank supplies the signal to the gage. Twelve-volt DC operating power is supplied to the
fuel gage from two sources. The gage functions when the engine is running, or when the
instrument lights are ON. Since two power sources are connected to the fuel gage system, a
blocking diode
the motor-generator control circuit when panel lights are ON. Another diode prevents
operation of the panel lights by the engine-generator circuit when the engine is running. To
check fuel quantity when engine is stopped, use switch
(2, Fig. 9)
(18)
is required in each power source circuit. One diode prevents energizing
accurately indicates the quantity of fuel oil in the tank
(3)
to turn ON panel lights.
May 31/94 Revised 1-1
Page 15
OM-499
(2)
Engine and generator controls
a. Engine-generator control switch
The engine-generator control switch
idle” switch)
BUILD-UPVOLTAGE, and will automatically reposition to GENERATE position when
released. In BUILD-UP-VOLTS position it performs a dual function. First, it supplies power to
the governor control box, which allows the engine to operate at normal governed speed;
second, it momentarily supplies current for closing the excitation-deenergization relay
7)
contacts, to make three-phase, 115-V AC power available to the voltage regulator, or to
the manual voltage control circuit for excitation of the generator exciter. In GENERATE
position, power is maintained to the governor control box and to the excitation relay
. When the switch is placed in IDLE position, power is disconnected so that the engine
7)
returns to idle speed and the exciter field is deenergized.
is a three-position toggle type. It is spring-loaded in one position,
b. Contactor control switch
This is another three-position, toggle switch
control switch. When placed in the spring loaded CLOSE position, it provides 115-V AC
power directly to a rectifier which supplies DC power for closing the load contactor. When
released it returns to the normal ON position and continues to provide power to the rectifier,
but in this switch position, AC power must pass through the plug interlock and fuse interlock
relays. In OFF position the switch opens the AC circuit to the rectifier, thereby cutting off the
source of DC power to the contactor coil which allows the contactor to open.
(5) (also identified as the “build-up-voltage, generate,
(3, Fig.
(3, Fig.
(7, Fig. 9)
identical to the engine-generator
c. Instrument light and switch
A shielded, instrument panel light
controlled by a toggle switch
(1)
is mounted at the left side of the control panel. It is
(3)
, which also controls instrument lights on the control box.
d. Engine starting circuit
The pushbutton start switch
for closing an auxiliary solenoid switch. The auxiliary switch then connects power to the
starter solenoid which functions to engage the starter gear with the flywheel ring gear and
apply power to the starter motor to crank the engine. The auxiliary solenoid switch is
necessary because the start pushbutton switch is not capable of carrying the high amperage
flow to the starter solenoid which would result if the starter gear and ring gear should fail to
engage. The permissive toggle switch
in the down
(STOP)
position.
(15)
and permissive toggle switch
(18)
also stops the engine when the toggle is placed
(18)
serve to connect power
e. Indicating lights
A green indicating light
system. The light operates only when the engine is running and fuel pressure is sufficiently
high to close a fuel pressure switch. The purpose of the pressure switch is to deactivate the
protective circuit when the engine is stopped and prevent battery discharge.Another green
indicating light
power is available at the generator output terminal panel
(9, Fig. 9)
(14)
glows to indicate that power is available to the engine protective
glows when the generator output load contactor is CLOSED and
(13, Fig. 3).
f. Cold weather starting aid control
The push-pull control
starting aid consists of a group of items designed to inject a highly volatile fluid into the
engine air intake system to assist ignition of fuel when air temperature is too low for the heat
of compression to ignite a normal fuel mixture. The starting aid consists of a cylindrical, fluid
container and a valve
operated by the control
valve. Pushing the control IN forces fluid through a small tube and an atomizing nozzle into
the inlet manifold. The addition of atomized, highly volatile fuel into the inlet air assists in
igniting the diesel fuel mixture.
(11)
controls operation of a cold weather starting aid
(see 1-3, Fig. 4)
(11, Fig. 9)
which are mounted on the lifting yoke. The valve is
. Pulling the control outward allows fluid to flow into the
(Fig. 3).
The
1-1 May 31/94 Revised
Page 16
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