Generac Power Systems 53187 User Manual

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Miinual Part No. 05580

SERVICE

MANUAL

NP and IM Series

RECREATIONAL

VEHICLE &

NDUSTRIAL

MOBILE

AC GENERATORS

Liquid-Cooled Diesel Engine Models

CORPORATION

Issued- 01A>4/93

*P. O. Box 8 *Waukesha, Wisconsin 53187

Printed in U.S.A.

IMPORTANT SAFETY NOTICE

Proper service and repair is important to the safe, economicai and reliabie operation of ali recreationai vehicie and industrial mobile generators. Troubleshooting, testing and servicing procedures recommended by Generac and described in this manual are effective methods of performing such operations. Some of these operations or proce dures may require the use of specialized equipment. Such equipment should be used

when and as recommended.

It is important to note that the manual contains various DANGER, CAUTION and NOTE blocks. These should be read carefully in order to minimize the risk of personal injury or to prevent improper methods or practices from being used which could damage equipment or render it unsafe. These DANGER, CAUTION and NOTE blocks are not exhaustive. Generac could not possibly know, evaluate and advise the recreational vehicle trade of all conceivable ways in which operations described in this manual might be accomplished, or the possible hazardous consequences of each way. Consequently, Generac has not taken any such broad evaluation. Accordingly, anyone who uses any troubleshooting, testing or service procedure that is not recommended by Generac must first satisfy himself that neither his nor the equipment’s safety will be jeopardized by the procedure or method he selects.

TABLE OF CONTENTS

SERVICE

MANUAL

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

MOBILE

PART

TITLE

THE REVOLVING FIELD AC GENERATOR

ENGINE MECHANICAL

ENGINE LUBRICATION AND COOLING

SYSTEM

ENGINE FUEL SYSTEM

ENGINE ELECTRICAL SYSTEM

ELECTRICAL DATA

GENERATORS

Liquid-Cooled

Diesel Engine Models

Parti

THE REVOLVING

FIELD

GENERATOR

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

MOBILE

SECTION

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

TABLE OF CONTENTS

TITLE

Introduction

How a Generator Works

Major Components

(Units with 15 inch Stator)

Major Components

(Units with 10 Inch Stator)

Introduction to Troubleshooting

Troubleshooting

(Units with 15 Inch Stator)

Troubleshooting

(Units with 10 Inch Stator)

Insulation Resistance Tests

Operational Tests & Adjustments

AC GENERATORS

Liquid-Cooled Diesel Engine Models

PARTI

THE REVOLVING FIELD AC GENERATOR

INTRODUCTION

SECTION 1.1

INTRODUCTION

Section 1.1

Service Manual Familiarization

This SERVICE MANUAL is divided into six (6)

PARTS. Each PART consists of two or more SEC

TIONS. In turn, each SECTION is divided into SUB

SECTIONS.

At the front of the manual is a main TABLE OF

CONTENTS divider page which lists the titles of Parts

1 through 6.

Each PART of the manual is also identified by a

divider page which Identifies the SECTIONS that make

up that PART.

PMes are numbered so as to identify the PART and SECTION, as well as the specific page number. For example, "Page 2.1-3" indicates Page 3 of Part 2, Section 1. This type of numbering system permits indi vidual Sections of the manual to be kept current without affecting the entire manual.

Contents of Manual

Part 1 - The Revolving Field AC Generator

Section 1.1- Introduction Section 1.2- How a Generator Works Section 1.3- Major Components (Units with 15 inch Stator) Section 1.4- Major Components (Units with 10 inch Stator) Section 1.5- Introduction to Troubleshooting Section 1.6- Troubleshooting (Units with 15 inch

Stator) Section 1.7- Troubleshooting (Units with 10 inch

Stator)

Section 1.8- Insulation Resistance Tests

Section 1.9- Operational Tests & Adjustments

Part 2- Engine Mechanical

Section 2.1- Engine Specifications & Charts Section 2.2- General Information Section 2.3- Engine Disassembly Section 2.4- Disassembly and Inspection Section 2.5- Engine Reassembly

Part 3- Engine Lubrication & Cooling System

Section 3.1- Engine Lubrication System Section 3.2- Water Pump and Thermostat Section 3.3- Cooling and Ventilating Air Section 3.4- Periodic Maintenance

Part 4- Engine Fuel System

Section 4.1- Introduction to the Diesel Fuel System Section 4.2- Fuel Pump

Section 4.3- Governor

Section 4.4- Fuel Injection Pump Section 4.5- Fuel Nozzles and Holders

Part 5- Engine Electrical System

Section 5.1- Introduction to DC Control Systems Section 5.2- Engine Cranking System Section 5.3- Battery Charge System Section 5.4- Preheat System Section 5.5- Engine Protective Systems Section 5.6- Remote Radiator Fan (Model 9319) Section 5.7- Remote Panels Section 5.8- Troubleshooting Row Charts Section 5.9- Troubleshooting Test Procedures

Part 6- Electrical Data

Page 6.1-1- Resistances of Rotors & Stators Page 6.1-1- Index to Wiring Diagrams and Eiectrical Schematics

Identifying Units By Stator Diameter

Throughout the Manual, generators are identified as having either a "15 inch" ora "10 inch" stator. These numbers refer to the DIAMETER of the stator can laminations. See Figures 1 and 2 on next page.

In addition to the diameter and construction of the

stator assembly, the following differences exist be tween units with 10 inch stator and those having a 15 inch stator:

1. Units with 15 inch stator laminations are equipped

with a Part No. 67680 Voitage Regulator.

a. This type of Voltage Regulator mounts three advi sory lamps (LED’s) which greatly simplify trouble shooting. b. The 67680 R^ulator requires a sensing voltage of 240 volts AC. To provide the required 240 volts, a step-up transformer (120 to 240 VAC) is used.

2. Units with 10 inch stator laminations are equipped with a Part No. 81918 Voltage Regulator.

a. The 81918 Regulator mounts a single lamp (LED) which remains on as long as sensing voltage is

available. b. The 81918 Regulator requires a sensing voitage of 120 volts AC and the step-up transformer is NOT required.

Three Different Engine DC Control Sys

tems

The NP/IM series generators maybe equipped with

any one of three different kiinds of engine DC control systems. For convenience, the three different DC sys tems have been arbitrarily identified as Type 1, Type 2 and Type 3.

Refer to Part 5. "ENGINE ELECTRICAL SYS

TEM", for a description Type 1, 2 and 3 DC control systems.

PAGE 1.1-1

SECTION 1.1 INTRODUCTION

PARTI

THE REVOLVING FIELD AC GENERATOR

Figure 2. Typical 10 Inch Stator

PAGE 1.1-2

PARTI

THE REVOLVING FIELD AC GENERATOR

HOW A GENERATOR WORKS

SECTION 1.2

HOW A GENERATOR WORKS

Section i.2

It has long been known that a relationship exists

General

between magnetism and electricity. The revolving field generator (or alternator) depends on this relationship

for its operation. In order to diagnose problems and

repair a generator, the service technician must under

stand this relationship.

Why Generators Produce Electricity.

Generators produce an electrical current flow be

cause of the following laws of magnetic induction:

□ When a magnetic field is moved so that it cuts across

a conductor, a voltage and current flow are induced

into the conductor.

□ When current flows through a conductor, a magnetic

field is created around that conductor.

MAGNETIC FIELD CREATES A VOLTAGE;

See Figure 1. When a wire, or coil of wire, is moved

through a magnetic field, an electromotive force (EMF)

or voltage is induced into the wire. Conversely, move ment of the magnetic field so that its lines of flux cut across the wire will induce a voltage into the wire. If the ends of the wire are connected to form a complete circuit, current will flow in the wire. The direction in

which the current flows depends on the polarity of the

magnetic field and the direction in which the magnet is moved.

Z-

oCOIi

Figure 1. Magnetism Creates Electricity

Figure 2. Current Flow Creates a Magnetic Field

------

CURRENT FLOW CREATES A MAGNETIC FIELD:

See Rgure 2. Current flow through a wire or coil of

wire will create a magnetic field around the wire. The

strength of the magnetic field depends on the amount of current flow and the number of loops or coils in the

wire. The direction (polarity) of the magnetic field de

pends on the direction of current flow through the wire.

A Simple AC Generator

See Figure 3. In the simple generator shown, the

revolving magnetic field (Rotor) is a permanent mag net. As the magnet rotates, its magnetic lines of flux cut across a stationary coil of wire called a STATOR. If the stator circuit is completed (by adding a load such as the light bulb), current will flow through the circuit.

A More Sophisticated Generator

In Figure 4, direct current (DC) is delivered to the ROTOR coil through CARBON BRUSHES and SLIP RINGS, to create a magnetic field around the ROTOR. The greater the current flow through the ROTOR wind ings, the stronger the magnetic field around the ROTOR. The ROTOR’S magnetic field cuts across the stationary STATOR windings, to induce a voltage into those windings, with the induced voltage proportional to the strength of the ROTOR’S magnetic field.

STATOR

Û. T 1«V.

üэ”r^

¿»V.

< o

UJ-

u 3

Figure 4. A More Sophisticated Generator

BRUSHES

RINGS

PAGE 1.2-1

SECTION 1.2 HOW A GENERATOR WORKS

Operational Analysis- Units with 10 inch Stator Laminations

NOTE: See "IDENTIFYING UNITS BY STATOR DIAMETER" on Page 1.1-1.

PARTI

THE REVOLVING FIELD AC GENERATOR

Generator Operation may be briefly described as

follows:

CZl The ROTOR is attached to the engine PTO shaft

and rotates at the same speed as the engine.

□ As the Rotor turns, its magnetic lines of flux cut

across the stationary coils of (a) a stator excitation winding and (b) dual stator AC power windings. A voltage is induced into these stationary windings.

□ Current flow from the Stator excitation winding is

delivered to the Voltage Regulator as unregulated alternating current.

□ Current flow from the Stator AC power windings is

delivered to connected electrical loads.

□ Sensing leads deliver a signal of ACTUAL power

winding output voltage to the Voltage Regulator,

from the Stator AC power windings.

□ The Voltage Regulator electronically compares the

ACTUAL power winding voltage to a REFERENCE voltage which was pre-set.

□ If the ACTUAL power winding voltage is less than the

Regulator’s REFERENCE voltage. Regulator action will (a) change the excitation winding output to direct current (DC), and (b) increase the excitation current flow to the Rotor.

□ If the ACTUAL power winding voltage is more than

the Regulator’s REFERENCE voltage, regulator ac tion will (a) change the excitation current to direct current, and (b) decrease excitation current to the

Rotor.

□ The regulated direct current flow to the Rotor is

delivered via brushes and slip rings.

□ A regulated voltage is induced into the Stator AC

power windings as the Voltage Regulator acts to

maintain an ACTUAL voltage as close as possible to

an adjusted REFERENCE voltage.

A = EXCITATION WINDING B = STATOR AC POWER WINDING C = STATOR AC POWER WINDING CB1 = MAIN CIRCUIT BREAKERS

CB4 = EXCITATION CIRCUIT BREAKER TP = THERMAL PROTECTOR

PAGE 1.2-2

Figure 5. Operating Diagram- Units with 10 Inch Stator Laminations

PART 1 THE REVOLVING FIELD AC GENERATOR

Operational Analysis- Units with 15 Inch Stator Laminations

Some differences exist between generator models

having a 10 inch diameter stator and those with a 15 inch diameter Stator. You may wish to review "IDENTI FYING UNITS BY STATOR DIAMETER" on Page 1:1-

Figure 6 is an Operating Diagram for NF eries

generators with a 15* inch diameter stator. T units are equipped with a Part No. 67680 voltagi n rewhich requires 240 volts AC sensing. Tf ram,

SENSING TRANSFORMER serves to itor’s stator’s line-to-neutral sensing voltage to 24 ts.

SECTION 1.2

HOW A GENERATOR WORKS

Figure 7. Voltage Regulator Part No. 67680

A = EXCITATION WINDING B = STATOR AC POWER WINDING C = STATOR AC POWER WINDING CB1 = MAIN CIRCUIT BREAKERS CB4 = EXCITATION CIRCUIT BREAKER TP = THERMAL PROTECTOR

Operating Diagram- Units with 15 Inch Diameter Stator Laminations

PAGE 1.2-3

SECTION 1.2

HOW A GENERATOR WORKS

PARTI

THE REVOLVING FIELD AC GENERATOR

PAGE 1.2-4

PARTI

THE REVOLVING FIELD AC GENERATOR

MAJOR COMPONENTS

(UNITS WITH 15 INCH DIAMETER STATOR)

SECTION 1.3- MAJOR COMPONENTS

(UNITS WITH 15 INCH STATOR)

Section 1.3

ITEM

QTY DESCRIPTION

2 4 3 4 1 Rear Bearing Carrier 5 6 1 7 1

8 10 9 6

10 4 Hex Head Flanged Bolt

11 4 Screw

12 13 1 Flexible Coupling 14

15 1 Flywheel 16

17 1 Air Ring Baffle 18 4 Vibration Mount

19 6

20 2 Socket Head Capscrew

4 Taptite Screw

4 Stud

4 Hex Head Capscrew

Taptite Screw

Rotor Bearing

Rotor Assembly

Stator Assembly

Hex Head Capscrew

Lockwasner

Lockwasher

Fan Ring

Flatwasher

2®

ITEM

21 22 23 24 25 26 27 8 Lockwasher

28 29

30 31

32 4 33

34 4 35

36 37 1 38

QTY

■ 1

DESCRIPTION

4' 2 2

4 2

Battery Cable Boot

Starter Motor

Engine Adapter

Hex Head Capscrew

Vibration Isolator

Flatwasher

Hex Head Screw

Hex Nut

Brush

Brush Holder

Screw

Brush Cover

stud

Flanged Nut

Red Starter Cable

Lockwasher

Hex Nut

Lockwasher

Hex Head Capscrew

Figure 1. Exploded View of AC Generator with 15 Inch Stator

PAGE 1.3-1

SECTION 1.3- MAJOR COMPONENTS (UNITS WITH 15 INCH STATOR)

AC Generator Disassembly

BRUSH ACCESS AND REMOVAL Figures 1 & 2);

See Rgure 1. Remove the TAPTITE SCREWS

(Item 2) that retain the two BRUSH COVERS (Item 33) to the REAR BEARING CARRIER (Item 4). Remove the BRUSH COVERS (Item 33) to gain access to the

BRUSH HOLDERS (Item 31).

See Figure 2, below. Remove Wires No. 1 and 4

from the BRUSHES in both BRUSH HOLDERS. Re

move the TAPTITE SCREWS that retain the BRUSH

HOLDERS to the REAR BEARING CARRIER. Re move both BRUSH HOLDERS, along with the

BRUSHES

PARTI

THE REVOLVING FIELD AC GENERATOR

To remove the FLEXIBLE COUPLING (Item 13)

from the ROTOR (Item 6), remove four HEX HEAD FLANGED BOLTS (Item 10).

FLYWHEEL REMOVAL (Figure 1):

Remove four SCREWS (Item 11) and

LOCKWASHERS (Item 12). Then, remove FLY WHEEL (Item 15). If desired, the FAN RING (Item 14) can be removed by removing HEX HEAD CAPSCREWS (Item 8) and LOCKWASHERS (Item 9).

ENGINE ADAPTER REMOVAL (Figure 1);

To remove AIR RING BAFFLE (Item 17), remove

CAPSCREWS (Item 8) that retain It to the ENGINE

ADAPTER (Item 23).

Support the engine and remove all fasteners that

retain the ENGINE ADAPTER to the BASE ASSEM BLY. Remove HEX HEAD CAPSCREWS (Item 40) and LOCKWASHERS (Item 27). Finally, remove the EN GINE ADAPTER.

Components Inspection and Testing

REAR BEARING CARRIER REMOVAL (Figure 1):

Remove HEX NUTS (Item 29), LOCKWASHERS (Item 27) and STUDS (Item 3) that retain the REAR BEARING CARRIER (Item 4). To free the REAR BEARING CARRIER (Item 4) from the ROTOR BEAR ING (Item 5), use a soft mallet to tap around the outer

periphery of the BEARING CARRIER. Continue tap ping until the BEARING CARRIER is free of the bear

ing.

STATOR REMOVAL (Figure 1):

The STATOR (Item 7) is "sandwiched" between the ENGINE ADAPTER (Item 23) and the REAR BEARING

CARRIER (Item 4). Carefully remove the STATOR

(Item 7). DO NOT PERMIT THE STATOR TO DROP

OR BUMP THE ROTOR DURING REMOVAL.

ROTOR REMOVAL (Figure 1):

Remove the four FLANGED NUTS (Item 35) from STUDS (Item 34). The ROTOR (Item 6), with FLEXI BLE COUPLING (Item 13) attached, can now be pulled

free of the FLYWHEEL (Item 15).

GENERAL;

Following disassembly, generator components

should be cleaned, dryed and inspected or tested.

Never reassemble a generator having defective parts.' Keep major parts separated and keep the mounting hardware along with the parts they are used with. Store

parts in a clean, dry area where condensation, dirt, or

moisture will not damage them.

REAR BEARING CARRIER:

The Rear Bearing Carrier (Figure 1, Item 4) is an aluminum casting. Clean the casting and blow dry with air. Inspect carefully for cracks, obvious damage. An

insert has been pressed into the Carrier center bore, to accommodate the Rotor Bearing. Replace the Rear Bearing Carrier if the center bore diameter is not within

the following dimensions:

BEARING CARRIER CENTER BORE

2.9527-2.9533 Inches (74.999-75.014mm)

ROTOR BEARING:

The rotor bearing is a prelubricated and sealed ball

bearino that requires no additional lubrication for the life of the bearing. Spin the Rotor bearing by hand and check it for binding, seizing, roughness, etc. If the bearing is defective, it must be replaced.

The bearing may be removed from the Rotor shaft

using a bearing puller. A new bearing can then be pressed onto the shaft. Exert pressing force on the bearing inner race only- NEVER on the bearing outer/'"~^^ race.

PAGE 1.3-2

PART 1

THE REVOLVING FIELD AC GENERATOR

SECTION 1.3- MAJOR COMPONENTS

(UNITS WITH 15 INCH STATOR)

Components Inspection and Testing

(Continued)

ROTOR ASSEMBLY;

Clean the Rotor with dry, low pressure air (25 psi

or less). If the slip rings are dirty or tarnished, clean them with fine sandpaper. Inspect the Rotor for dam age.

Check the resistance of Rotor windings with a

volt-ohm-milliammeter (VOM). Refer to Section 1.6,

"TROUBLESHOOTING (UNITS WITH 15 INCH STA

TOR)".

Use an Insulation resistance tester, megohmmeter,

or Hi-Pot tester to test the resistance of Rotor insula tion. See Section 1.8,

TESTSr.

If the Insulation resistance is low, dry the Rotor with

warm, dry air. DO NOT EXCEED 185* F. (85’ C.). If

resistance is still low after drying, replace the Rotor

Assembly.

STATOR ASSEMBLY:

Clean the Stator Assembly in the same manner as

the Rotor was cleaned. Inspect ther Stator for damage.

Use a VOM to check Stator windings resistance

(see Section 1.6).

Check the insulation resistance of Stator windings,

as outlined in Section 1.8.

FLEXIBLE COUPLING:

Carefully inspect the Flexible Coupling (Figure 1, Item 13) for damage, cracking. Check mounting holes on couplino for elongation and damage. Replace the Coupling, if it is damaged.

FAN RING AND AIR RING BAFFLE:

Inspect the Fan Ring (Figure 1, Item 14) and the

Air Ring Baffle (Item 17) for damage, cracking. Re place, if damaged.

•INSULATION RESISTANCE

Reassemble the generator In the reverse order of

Generator Reassembly

disassembly. The reassembly process requires a great deal of care. Components must be properly aligned and

retained. Tighten all fasteners to the recommended

torque values (see Part 6, "SPECIFICATIONS AND

CHARTS"). Following reassembly, perform an opera tional test of the unit (Section 1.9).

Components In Generator Control Panel

INTRODUCTION:

Rgure 3 (next page) Is an exploded view of the generator control panel. The Panel houses or mounts several Important AC generator components, as well as components that are part of the engine DC electrical systems.

ENGINE ELECTRICAL SYSTEM COMPONENTS;

The Control Panel houses the following compo

nents that are part of the engine electrical system. For Information on these components, refer to Part 5 of this Manual, "ENGINE ELECTRICAL SYSTEM".

□ The 14 and 30 amp Fuses (Items 4 and 5). □ The 10 amp DC Circuit Breaker (Item 6). □ The two 12 volts DC Relays (Items 7 and 8). □ The DC Voltage Regulator (Item 13). □ Engine Control Circuit Board (Item 39).

□ Hourmeter (Item 23).

□ Start-Stop Switch (Item 24).

□ Preheat Switch (Item 25).

AC GENERATOR COMPONENTS:

The following components, housed in the control

panel, are major generator components and will be discussed in this Section and Sub-Section.

□ Excitation Circuit Breaker (Item 11). □ AC Voltage Regulator (Item 14). □ The Sensing Transformer (Item 15). □ AC Circuit Breaker (Item 16).

FLYWHEEL;

Clean the flywheel. Inspect for damage, cracks,

wear, etc. Replace, if necessary.

ENGINE ADAPTER;

Clean the Engine Adapter (Figure 1, Item 23).

Inspect the Adapter carefully for damage, wear, crack

ing, etc. Replace, if necessary.

BRUSH HOLDERS AND BRUSHES:

Inspect Brush Holders and Brushes for damage, cracking, chipping, excessive wear, etc. Replace any defective or damaged part. Brushes must always be

replaced in complete sets.

In addition to the above components, a THERMAL

PROTECTOR is physically imbedded in the wire wind ings of the Stator Assembly. A discussion of this com ponent will also be included in this Section.

EXCITATION CIRCUIT BREAKER;

The excitation circuit breaker is housed in the con

trol panel and connected in series with .the Stator Excitation winding output to the Voltage Regulator.

If this Breaker should open, loss of unregulated

excitation current to the Regulator will occur. The Reg ulator will then shut down and loss of regulated excita tion current to the Rotor will occur. Generator AC output will then be proportional to Rotor residual magnetism only (about 2-7% of rated voltage).

PAGE 1.3-3

SECTION 1.3- MAJOR COMPONENTS (UNITS WITH 15 INCH STATOR)

PARTI

THE REVOLVING FIELD AC GENERATOR

ITEM

QTY

1 2* 3* 1 4* 5*

r 1

8* 9 10 1

11** 1

12 13*

14“ 15“

16 17

18 19 20 1 21 1 22 2

* See Part 5,

1 1

EXCITATION CIRCUIT BREAKER 1 1 1 1 1

4 4 1

'* Part of AC generator circuit, Included in this Section.

"ENGINE ELECTRICAL SYSTEM".

DESCRIPTION

Snap Bushing FUSE HOLDER- 30 amp FUSE HOLDER-14 amp

30 AMP FUSE 14 AMP FUSE

10 amp DC Circuit Breaker

12 volts DC RELAY 12 volts DC RELAY

Solderless Lug

90 Conduit Clamp

Control Panel Box DC VOLTAGE REGULATOR AC VOLTAGE REGULATOR

SENSING TRANSFORMER

AC CIRCUIT BREAKER

Pan Head Screw

Lockwasher Lockwasher

Control Panel

Panel Decal

Pan Head Screw

ITEM

23* 1 24* 1 25*

26 2

28 29 30 31 32 1 33 34 35 36 37 4

39*

40 41 42 2 44 1 45 46 47 48

QTY

1 2

8 8

•

8 Pan Head Screw

8 8 4

1 6

1 4 4 4

DESCRIPTION

HOURMETER

START-STOP SWITCH

PREHEAT SWITCH

Hex Head Capscrew

External Lockwasher

Lockwasher Flatwasher

Hex Head Capscrew

Customer Leeds (Not Shown).

Pan Head Screw

Lockwasher

Hex Nut

Self Tapping Screw

ENGINE CONTROL CIRCUIT

Spacer Tlut

BOARD

Lockwasher

Hex Nut

Hex Head Capscrew

Panel Wiring Harness

Engine Wire Harness

Vibration Dampener

Hex Nut

Flatwasher

Figure 3. Exploded View of Control Panel

/ 13

PAGE 1.3-4

PARTI

THE REVOLVING FIELD AC GENERATOR

Components In Generator Control Panel (Continued)

AC VOLTAGE REGULATOR:

The Voltage Regulator is powered by stator excitation

winding AC output. Approximately 4 to 8 volts is required from that power source to turn the regulator on.

The Regulator is equipped with three (3) lamps

(LED’s or "light emitting diodes). See Figure 5. These lamps are normally on during operation with no faults in the system. The green EXCITATION lamp and the red REGULATOR lamp are both turned on by stator excita tion winding output. If, for any reason, stator excitation winding output were to be reduced, the two lamps would begin to dim. Finally, at some mid-point voltage and current, the two lamps will no longer glow visibly.

SECTION 1.3- MAJOR COMPONENTS

(UNITS WITH 15 INCH STATOR)

NOTE: Sensing input to the Regulator Is actually taken

from Hne-to-neutra! stator leads and Is about 120 volts

AC. However, this voltage Is boosted to about 240 volts AC by the action of a sensing transformer.

The following facts apply to Voltage Regulator opera

tion:

1. The Regulator will shut down on occurence of one or

more of the following conditions:

a. Loss of sensing voltage. b. Loss of stator excitation voltage Input to the

Regulator.

c. Loss of circuit reference.

NOTE: The term "circuit reference" refers to voltage

regulator settings. The Regulator "regulates" excitation

winding current flow to the Rotor windings in order to

maintain a sensing (actual) voltage that Is commen surate with a preset "reference" voltage. The reference

voltage is adjustable within a 20 percent range at the Regulator. Voltage regulation Is accomplished by electronically maintaining an ACTUAL voltage that Is

very close to the Regulator's preset REFERENCE volt age.

The yellow SENSING lamp Is powered by sensing

input to the Regulator from the stator AC power wind ings. The brightness of this lamp (LED) will depend on available sensing voltage.

2. During generator operation, all three Regulator lamps should be ON.

a. REGULATOR lamp ON Indicates the Regulator is functioning normally. b. SENSING lamp ON indicates that normal sensing voltage Is available to the Regulator. c. EXCITATION lamp ON Indicates that unregulated excitation winding output Is available to the Regulator.

3. If the red REGULATOR lamp is OUT, a Voltage Regulator fault exists or the Regulator has shut down due to occurence of one or more Regulator shutdown conditions. See Step 1 above for conditions that will result in Regulator shutdown.

a. Expect to see a generator AC output voltage that is commensurate with the Rotor’s residual mag netism. b. Rotor residual magnetism will supply approximate ly 2 to 7 percent of the unit’s rated voltage.

NOTE: "Residual" magnetism Is that magnetism that Is normally always present In the Rotor. The Rotor may be considered a "permanent magnet".

PAGE 1.3-5

SECTION 1.3- MAJOR COMPONENTS

(UNITS WITH 15 INCH STATOR)

Components In Generator Control Panel (Continued)

AC VOLTAGE REGULATOR (CONT’D):

4. If the green EXCITATION lamp goes out, loss of stator excitation winding output to the Regulator has occured.

a. Loss of excitation winding output will result in

Regulator shutdown. The red REGULATOR lamp will

then go out, as well. b. Under this condition, look for a generator AC output voltage that is commensurate with residual Rotor magnetism (about 2-7% of rated volts). c. When the REGULATOR and EXCITATION lamps are both out, the excitation circuit from the stator excitation windings to the voltage regulator Is suspect (inclusive).

5. Should the yellow SENSING lamp go out, loss of

sensing voltage to the Regulator has occured.

a. Loss of sensing may cause the Regulator to shut

down. Both the SENSING lamp and the

REGULATOR lamp will then go out. b. Generator AC output voltage will then be commen

surate with Rotor residual magnetism (2-7% of rated volts). c. Look for a fault in the sensing circuit.

6. If all three lamps go out, look for a fault that might cause both sensing and excitation to fail.

a. Look for dirty or corroded slip rings, bad brushes, defective Rotor. b. Look for open circuit in Wires No. 1 and/or 4.

7. If the red REGULATOR lamp flashes, the Regulator’s STABILITY potentiometer requires ad justment.

PART 1

THE REVOLVING FIELD AC GENERATOR

AC CIRCUIT BREAKER:

The AC circuit breaker protects the unit against cur

rent overload by opening the AC output circuit in the event the generator’s current (amperage) capacity is,/'”^

exceeded. The amperage at which the breaker will trip

(open) is the breaker’s trip rating.

SENSING TRANSFORMER:

The Part No. 67680 Voltage Regulator requires a "line-to-line" sensing voltage (240 volts) for proper operation. However, the sensing Is taken from "line-toneutral" Wires No. 11 and 22 (120 volts). For that reason, the primary coil of a sensing transformer is

connected in series with the sensing leads. The sensing transformer is a "step-up" type. That is, 120 volts AC in its primary coil will induce 240 volts into its secondary coil. It is the secondary coil voltage that is delivered to the regulator as sensing voltage.

The sensing transformer is housed in the generator control panel and is used on generator’s with the Part No. 67680 Voltage Regulator and with 15 inch diameter stator laminations.

The sensing transformer Is shown pictorially and schematically in Figure 6.

PAGE 1.3-6

The AC circuit breaker used on any specific generator

model will depend on the rated current (amperage) capacity of that model.

PART 1

THE REVOLVING FIELD AC GENERATOR

Thermal Protector !

A Thermal Protector is physically imbedded in the wire windings of the Stator and electrically connected In series with the excitation winding output leads to the Regulator. The device is a normally-closed (N.C.),

temperature sensitive switch. The switch contacts will open when stator temperatures exceed a safe level. The switch is self resetting. That Is, it will re-dose when stator temperatures decrease to a safe level.

If the switch contacts should op>en, excitation winding AC output to the Voltage Regulator will be terminated and the Regulator’s green EXCITATION lamp will go out. Since the Regulator cannot op>erate without excita tion winding output, the red REGULATOR lamp will also go out. Generator AC output voltage will then drop to a value commensurate with the Rotor’s residual mag netism.

If the Thermal Protector contacts open during opera

tion due to a stator overtemperature condition, the cause of the overtemperature condition must be found and corrected. High Internal stator temperatures can be caused by any one of the following:

SECTION 1.3- MAJOR COMPONENTS

(UNITS WITH 15 INCH STATOR

rings. The direct current (approximately 9-10 volts DC) flows through the Rotor windings, the negative (-) slip ring and brush, and to ground.

Field boost current creates a magnetic field strength

that is additive to the Rotor’s residual magnetism. The

Increased magnetic field strength during engine crank ing provides an early "pickup* voltage In the stator. The Regulator is turned on more quickly and AC output

occurs sooner. In effect, field boost current "flashes the field" on every startup.

Failure of the field boost system nr^y or may not result In a reduction of AC output to that produced by residual Rotor magnetism. If residual magnetism Is adequate to turn the Regulator on and provide the required pickup voltage, the generator will operate normally with or without field boost. However, if residual magnetism Is not adequate, generator AC output will not build and will be comrr^nsurate with Rotor residual magnetism.

D Insufficient cooling air flow into the generator

interior. Look for blockage of cooling air inlet/outlet openings, air openings that are too small, ambient temperatures that are too high, etc.

□ Exceeding the wattage/amperage capacity of the

generator. If the unit is overloaded for a period of time, internal stator temperatures can rise quickly and cause the Thermal Protector contacts to open.

D A shorted condition in the generator stator wind

ings or in an electrical load connected to the generator’s AC output.

The Thennal Protector is not accessible and cannot be removed and replaced. If the device has failed open, it can be bypassed by connecting excitation lead No. 2

to a bypass lead (Wire No. 5). Once the device has been

bypassed, stator overtemperature protection Is no longer available.

Field Boost

When the generator engine Is cranked, direct current (DC) Is delivered to the Rotor windings. The cunent flow is provided by the action of an Engine Control circuit board housed In the control panel and Is delivered to the Rotor via Wire No. 9, a Field Boost Resistor (R2), a Field Boost Diode (D2), Wire No. 4, and the brushes and slip

PART OF CONTROL PANEL WIRING HARNESS

rrSM

• 2 3 4

Figure 9. The Field Boost Circuit

DIODE-600V., 6 AMP

RESISTOR-5 WATT. 10 OHMS

DESCRIPTION

HEAT SHRINK

BARREL LUG

PAGE 1.3-7

SECTION 1.3- MAJOR COMPONENTS

(UNITS WITH 15 INCH STATOR)

PARTI

THE REVOLVING FIELD AC GENERATOR

PAGE 1.3-8

PARTI THE REVOLVING FIELD AC GENERATOR

MAJOR COMPONENTS

(UNITS WITH 10 INCH STATOR)

SECTION 1.4- MAJOR COMPONENTS

(UNITS WITH 10 INCH STATOR)

Section 1.4

l~47.ir>r« description

■ n Rotor Assembly

2 3 2

4 1 5 6 7 8 9 10 11 12 2 13 14 15 1

16 1 17 18 6 19 20 1 21 22

4 16 12

4 Vibration Dampener

1 Stator Assembly 1 Rear Bearing Carrier

4 Capscrew 2

Drive Key

Dowel Pin

Blower Housing

Air Outlet Screen

Hex Head Capscrew

Lock Wasner

Flat Washer

Brush Holder

Hex Head Capscrew

Bearing Carrier Gasket

Rame Arrestor 37

Bearing Carrier Cover

Bolt

Lock Washer

Starter Assembly

Socket Head Capscrew

Lock Washer

•i'" -W'

TUFT

23 24 25 26 10

27 12 28 29 30 1 31 32 33 1 34 35 36

38 6 39 2 40 2 42 43 2 44 1 45 1

QTY

1 1

6 Socket Head Capscrew 1 1 Cooling Fan 1

2 Hex Nut

DESCRIPTION

Ratwasher

Engine Plate

Hex Head Capscrew Hex Head Capscrew

Hex Head Capscrew

Flywheel

Hex Head Capscrew

Spacer

Hex Head Capscrew

Lock Washer

Flexible Coupling

Drive Hub

Starter Solenoid

Hex Head Capscrew

Rat Wasner

Hex Nut

Hex Head Capscrew

DC Voltage Regulator

Starter to Starter Solenoid Ci

Figure 1. Exploded View of Generator with 10 Inch Diameter Stator

PAGE 1.4-1

SECTION 1.4- MAJOR COMPONENTS

^UNnrewmjno^mc^T^OR^^^

AC Generator Disassembly

BEARING CARRIER COVER:

Remove four (4) CAPSCREWS (Item 19), FLAT WASHERS (Hem 8), and LOCK WASHERS (Item 7). Then, remove the BEARING CARRIER COVER (Item

16) and the BEARING CARRIER GASKET (Item 14).

PARTI

THE REVOLVING FIELD AC GENERATOR

Remove all four long stator bolts along with washers.

Turn the large boH at center of Bearing Carrier puller until end of bolts is flush wHh the puller. Retain the puller to the Bearing Carrier with original Carrier Cover screws. Turn the large center bolt of puller until the bearing carrier Is free of the Rotor Bearing. Completely remove the Bearing Carrier.

Figure 2. Bearing Carrier Cover Removal

BRUSH HOLDERS AND BRUSHES:

Remove wires from BRUSHES (Item 12). Remove

SCREWS (Item 13) and remove BRUSH HOLDERS (Item 12) with brushes.

REAR BEARING CARRIER:

A bearing carrier puller (Figure 4) can be used to

remove the Rear Bearing Carrier. Retain the puller to the Bearing Caller using the same saews that original ly held the Bearing Carrier Cover.

Remove fasteners that retain the Bearing Carrier to

the mounting rail.

Figure 5. Removal of Mounting Rail Fasteners and

Stator Bolts

STATOR REMOVAL:

CAUTION. Use care when removing the Stator. Do NOT allow It to drop or bump the Rotor during removal.

Free the Stator from the Blower Housing and remove.

See Figure 6.

PAGE 1.4-2

PARTI THE REVOLVING FIELD AC GENERATOR

Figure 6. Stator Removal

BLOWER HOUSING REMOVAL:

Remove the capscrews that retain the Blower Hous

ing to the Engine Plate, along with flat washers, lock washers and hex nuts. Note positions of longer and shorter screws, for reassembly.

SECTION 1.4- MAJOR COMPONENTS

(UNITS WITH 10 INCH STATOR)

ENGINE PLATE REMOVAL:

Remove starter retaining bolts and remove starter.

Remove bolts that retain the engine plate. Remove the engine plate.

ROTOR REMOVAL;

Remove capscrews and washers that retain the Cou

pling Plate to the Ring Gear. Remove Rotor, Cooling Fan, Drive Hub and Coupling Plate as a unit.

If desired, the Cooling Fan, Drive Hub and Coupling

Plate may be removed from the Rotor.

Components Inspection and Testing

GENERAL;

Follovving disassembly, generator components should be cleaned, dryed and inspected or tested. Never reassemble a generator with defective or damaged parts. Store parts In a dean, dry area.

PAGE 1.4-3

SECTION 1.4- MAJOR COMPONENTS (UNITS WITH 10 INCH STATOR)

Components Inspection

REAR BEARING COVER AND GASKET:

Clean the Beeuing Cover in a suitable non-flammable commercial cleaner. Blow dry with compressed air. Inspect the Cover for obvious damage, clogged air slots, etc. Replace, if necessary. Inspect gasket, replace if damaged or defective.

REAR BEARING CARRIER;

The Rear Bearing Carrier is an aluminum casting.

Clean the casting and blow dry with air. Inspect carefully

for cracks, damage. An insert is pressed into the Bear ing Carrier center bore, to accommodate the Rotor bearing. Use an inside micrometer to check the inside diameter of the insert. Replace the Bearing Carrier if the insert inside diameter is not within the following:

PARTI

THE REVOLVING FIELD AC GENERATOR

and Testing (Continued)

the Rotor with dry, heated airfor several hours. DO NOT

EXCEED 185* F. (85* C.). if Insulation resistance is still

low after drying, replace the Rotor Assembly.

FAN AND RING GEAR ASSEMBLY:

The FAN, DRIVE HUB, COUPLING PLATE and RING GEAR are assembled and balanced as a unit. Clean and inspect parts, replace the entire assembly if necessary.

BRUSH HOLDER AND BRUSHES:

Inspect both brush holders and both sets of brushes. Look for cracks, excessive wear, cracks, chipping, etc. Replace any damaged brush holder. Brushes should be replaced as a complete set

2.834-2.836 inches (71.996-72.012mm)

STATOR ASSEMBLY:

Clean the stator can exterior surfaces with a soft brush or cloth. Use clean, dry low pressure air (25 psi maximum) to clean the stator. Use an ohmmeter to test the resistance of Stator AC power and excitation wind ings. Use an insulation resistance tester (megohmmeter or Hi-Pot tester) to check condition of Stator insulation (see Section 1.8). If Stator insulation fails the test, the

Stator may be dried by blowing warm, dry air across it for several hours. DO NOT EXCEED 185* F. (85* C.). If

insulation resistance is still low after drying, replace the

Stator.

BLOWER HOUSING:

Clean with a commercial solvent that is suitable for

use with aluminum. Inspect the Housing carefully for cracks, damage, etc. Replace, if necessary.

ROTOR ASSEMBLY:

Clean with dry, low pressure air (25 psi maximum).

Test Rotor winding resistance with an ohmmeter. Check

Rotor bearing for binding, seizing, roughness. If the

bearing is defective, replace the Rotor assembly. In spect the keyway in the tapered shaft for wear, damage.

If slip rings are dull or tarnished, clean with fine

sandpaper. Use an insulation resistance tester

(megohmmeter or Hi-Pot tester) to test for insulation

breakdown (see Section 1.8). If resistance is low, dry

Inspect brush leads No. 1 and 4. Replace any

damaged or defective brush lead.

Generator Reassembly

Reassemble the generator in the reverse order of disassembly. The reassembly process requires a great deal of care. All components must be properly aligned and retained. Tighten all fasteners to the recommended torque values. Following reassembly, perform an opera tional test of the unit.

Components In Generator Control Panel

INTRODUCTION:

The following AC generator components are

mounted on or housed in the generator control panel:

□ Voltage Regulator Assembly. □ An AC Circuit Breaker (CB1 and CB2). □ Exdtation Circuit Breaker (CB4). □ A field boost circuit.

In addition to the above AC generator components

housed in the control panel, aTHERMAL PROTECTOR is physicaliy imbedded in the wire windings of the Stator Assembly.

Other components are housed in the control panel,

as well. However, these components are part of the engine's DC control system and will be discussed in PART 5, "ENGINE ELECTRICAL SYSTEM".

PAGE 1.4-4

PARTI

THE REVOLVING FIELD AC GENERATOR

Components in Generator Control Panel (Continued)

SECTION 1.4- MAJOR COMPONENTS

THE AC VOLTAGE REGULATOR:

The VoKage Regulator used on units with 10 inch stator is shown In Figure 10. The Regulator has a single red lamp (LED) which will remain on during operation as long as stator AC power winding "sensing* voitage is avaiiabie. Three sets of leads connect to the Regulator

terminals as follows:

D Unregulated AC output from the stator excitation

winding connect to the two terminals indicated by "DPE*.

□ Sensing (actual) voltage signals from the stator

AC power windings are delivered to the Regulator terminals indicated by "SEN".

□ Rectified and regulated (DC) current Is delivered

to the Rotor winding from Regulator terminals Indicated by a"+" and

The Regulator provides over-voltage protection. On loss of "sensing", the Regulator will shut down and regulated excitation current to the Rotor will terminate.

A single adjustment potentiometer permits the gener

ator's AC output voltage to be adjusted. Perform this adjustment with the engine running at no-load and with

AC frequency at 62 Hertz (1860 rpm). At 62 Hertz, set the line-to-neutral AC output voltage to 124 volts AC; or the line-to-line AC output voltage to 248 volts AC.

AC CIRCUIT BREAKERS:

Two AC output circuit breakers (CB1 and CB2) are provided, one for each line of the 240 volts AC output circuit. The trip rating of these breakers depends on the rated maximum amperage capacity of the generator. Units rated at 8000 watts (8.0 kW) are equipped with AC breakers rated at 35 amperes.

Schematic

Pictorial

SEE FIGURES 4 & 5 ON PAGE 1.5-2 FOR WIRING CONNECTIONS

Figure 11. AC Output Circuit Breakers

EXCITATION CIRCUIT BREAKER (CB4):

An AC circuit breaker, rated 5 amperes, is electrically connected in series with Wires No. 2 and 2A betwen the stator excitation winding and the Voltage Regulator. If the breaker should trip (open) due to an overload, loss of excitation current to the Rotor will occur. Generator AC output voltage will then decrease to a value that is commensurate with Rotor residual magnetism (about 2 to 7% of the unit's rated voltage). The breaker is self resetting and cannot be reset manually.

Figure 12. Excitation Circuit Breaker

PAGE 1.4-5

SECTION 1.4- MAJOR COMPONENTS (UNITS WITH 10 INCH STATOR)

Components In Generator Control Panel (Continued)

FIELD BOOST CIRCUIT

During engine cranking, an engine controi circuit board deiivers battery voltage to the Rotor windings. This "Field Boost" current is delivered to the Rotor via Wire 4A, a field boost resistor, and Wire 4. The Field Boost feature provides the following benefits:

□ In effect, field boost current "flashes the field" on

every engine startup. Thus, if Rotor residual magne tism was lost for any reason, it would be restored by the act of "flashing the field" during cranking.

□ Approximately 4-8 volts AC output from the stator

excitation winding is needed to turn the voltage reg ulator on. Reid boost current builds Rotor magnetism early which, in turn, develops voltage early during startup. The result of field boost is an early "pickup"

voltage in the stator windings.

THERMAL PROTECTOR:

Refer to " THERMAL PROTECTOR' on Page 1.3-7.

PARTI

THE REVOLVING FIELD AC GENERATOR

PAGE 1.4-6

PARTI

THE REVOLVING FIELD AC GENERATOR

Section 1.5

INTRODUCTION TO TROUBLESHOOTING

DANGER: GENERATORS PRODUCE EXTREMELY HIGH AND DANGEROUS VOLTAGES. CONTACT WITH LIVE WIRES OR TERMINALS WILL RESULT

IN HAZARDOUS AND POSSIBLY FATAL ELECTRI-

<CAL SHOCK. ONLY PERSONNEL WHO HAVE

BEEN TRAINED IN THE SERVICING AND REPAIR OF RV GENERATORS SHOULD ATTEMPT TO TROUBLESHOOT, TEST OR REPAIR THESE GEN ERATORS.

Tools and Test Equipment

An RV generator service technician shouid have a

weii stocked tool box that is fiiied with a good seiection

of common hand tools. The tool box should contain combination wrenches and socket wrenches in both standard and metric sizes. Also, a good nut driver set is recommended.

SECTION 1.5

INTRODUCTION TO TROUBLESHOOTING

Figure 1. Typical Volt-Ohm-Mllllamm eter (VOM)

The following test equipment is recommended:

□ An accurate volt-ohm-milliammeter (VOM),

preferably a precise digital type.

□ A good AC frequency meter.

D An insulation resistance tester (megohmmeter or

Hi-Pot tester).

O A load bank or some means of applying a known

electrical load to the generator.

Volt-Ohm>Milllammeter (VOM)

If desired, three separate meters may be used, i.e., a voltmeter, ohmmeter and ammeter. Recommended is an accurate digital type VOM having a ’Diode Check' mode.

The service technician must be familiar with his VOM

and must know how to use it. He must also be familiar

with generator electrical circuits and must be able to

read electrical vriring diagrams and schematics.

Frequency Meter

The generator’s AC output frequency must be known

if engine governed speed Is to be property adjusted. See "ROTOR ROTATIONAL SPEED’ in this section.

Figure 2. One Kind of AC Frequency Meter

Testing Insulation Resistance

Insulation resistance Is a measurement of the In

tegrity of the Insulating materials that separate the electrical windings from the generator’s steel core. This resistance can degrade over time due to contaminants such as dust, dirt, grease and especially moisture.

Information on Insulation resistance test can be found

in Section 1.8, "INSULATION RESISTANCE TESTS'.

PAGE 1.5-1

SECTION 1.5

INTRODUCTION TO TROUBLESHOOTING

Rotor Rotational Speed

"NP" series generators are equipped with a 4-pole Rotor. That is, the Rotor has two south magnetic poles

and two north magnetic poles. A 4-pole Rotor must be operated at 1800 rpm to obtain a 60 Hertz AC output frequency. The following formulas apply when calculat ing frequency, rpm and number of Rotor poles:

Hertz = RPM X No. of Rotor Poles

2x 60

RPM = 2 X 60 X Hertz

No. of Rotor Poles

PART 1

THE REVOLVING FIELD AC GENERATOR

A second alternative Is to connect the wiring to supply

120 volts AC only (Figure 5). When this connectior method Is used, a jumper wire must be connected between the two main circuit breakers (CB1 and CB2), as shown.

No. of = Poles

2 X 60 X Hertz

RPM

Voltage and Frequency

The generator's solid state Voltage Regulator will maintain an AC output voltage that is at a fixed ratio to frequency. For example, at a frequency of 60 Hertz, AC output voltage will be maintained at about 120/240 volts (plus or minus 2%). Should frequency drop to 30 Hertz, voltage will decrease proportionally to about 60/120

volts.

For generators rated 120/240 volts, the engine gover

nor should be set to maintain a NO-LOAD frequency of about 60.5-63.5 Hertz. The Voltage Regulator should then be set to maintain a voltage of about 121-127 volts

(line-to-neutral); or 242-254 volts (line-to-line).

Stator AC Connection Systems

1-PHASE, DUAL WINDING TYPE:

Some NP/IM series generators have dual AC

power windings (Figure 3). Each winding supplies a

120 volts AC output. When the two windings are con

nected in series (Figure 4), a 240 volts AC output results.

When installed, the unit may have ben connected to supply a dual voltage output (120 and/or 240 volts). This is shown In Figure 4. A 3-wire connection system Is used. Stator leads No. 11 and 44 form the two "hot" leads; the Junction of stator leads 22 and 33 form the "Neutral" lead. Notice the "Neutral" line is grounded.

Figure 3. The Dual Stator AC Power Windings

nnrowi fWtrCPi

,, 22 33 44

)CB. ‘f CBzS

-120 V.----------------^

T1 (RED)

Figure 4. Connected for Dual Voltage AC Output

(WHnE)

■ 24-3V.

22 33 1

------------------------------------

L 1

K—

-------------

T3 (BLACK)

I«

-----------------

120V.

---------------------------------

T1 (RED)

-----------------

Figure 5. Connected for 120 Volts AC Output

■ 120V.-

120 V.

---------

(BLACK)

------

-------

(WHITE)

PAGE 1.5-2

PART1 I SECTION 1.5

THE REVOLVING FIELD AC GENERATOR ■ INTRODUCTION TO TROUBLESHOOTING

Stator AC Connection Systems (Continued)

3-PHASE DELTA STATOR WINDING:

Some units may be equipped with a 3-phase delta type stator winding, shown in Figure 6. Phase rotation is L1-L2-L3. The ^Neutral* line is designated as "LO’. Generator Model No. 9422 uses this type of stator to deliver 120 volts AC (line-to-neutral); or 240 volts AC

(line-to-line).

3-PHASE. WYE-CONNECTED SYSTEM:

Figure 7 shows a 3-phase Wye-Type stator which

has 12 AC output leads that are reconnectable to

supply several voltages. Generator Model 9318 uses

this type of statorto supply 220/380 volts AC at 50 Hertz (i.e., 220 volts AC line-to-neutral; 380 volts AC line-toline).

Figure 6. A 3-Phase Delta Stator

PAGE 1.5-3

SECTION 1.5 INTRODUCTION TO TROUBLESHOOTING

PARTI

ITHE REVOLVING FIELD AC GENERATOR

PAGE 1.5-4

PARTI

THE REVOLVING FIELD AC GENERATOR

SECTION 1.6- TROUBLESHOOTING

(UNITS WITH 15 INCH STATOR)

Section 1.6

TROUBLESHOOTING

(UNITS WITH 15 INCH STATOR)

Introduction

The 'Troubleshooting Flow Charts' that follow have been carefully formulated to help the technician find the cause of problems quickly and easily. Use the Charts as a guide In troubleshooting RV generator problems, to help avoid the unnecessary labor and expense of replacing parts needlessly. Test numbers in the Charts correspond to the numbered tests In the 'DETAILED INSTRUCTIONS' that follow the Flow Charts.

Problem 1- Generator Produces Zero or Residual Voltage at No-Load

REPLACE STATOR

BYPASS

THERMAL PROTECTOR

RECONNECT,

REPAIR OR REPLACE

PAGE 1.6-1

/•.'3c

SECTION 1.6- TROUBLESHOOTING (UNITS WITH 15 INCH STATOR)

Problem 1 - Generator Produces Zero or Residual Voltage at No-Load (Continued)

PART 1

THE REVOLVING FIELD AC GENERATOR

TEST 8- CHECK

SENSING LEADS

BAD

AT/M3

RECONNECT, REPAIR OR REPLACE BAD LEADS AS NECESSARY

TEST 11-TEST ROTOR WINDINGS

BAD

REPLACE ROTOR

---------

O.K._^ BRUSHES AND

r\ 1/ w

TEST 9-TEST

TRANSFORMER

REPLACE BAD

TRANSFORMER

TEST 12- CHECK

REPLACE BRUSHES

OR CLEAN SLIP RINGS,

AS NECESSARY

CCKICIAI/^

BAD

SLIP RINGS

rsr\r\r\^

«O.K.^

TEST 10- TEST

CTATnn An

POWER

WtNniNnft

BAD

REPLACE

STATOR

ASSEMBLY

TEST 13- CHECK

WIRES NO.

1 AND 4

BAD

RECONNECT,

REPAIR OR REPLACE

BADWIRE(S)

TEST 14- TEST

FIELD

BOOST

BAD

REPAIR BAD WIRE(S) OR

REPLACE BAD

PART(S)

Problem 2- Generator Produces Low Voltage and Frequency at No-Load

(Greater than Residual Voltage)

TESTIS- CHECK

VOLTAGE AND FREQUENCY

FREQUENCY GOOD,

VOLTAGE IS LOW

NOTE: A shorted stator winding can cause rpm, frequency and voltage to droop excessively In the same manner as when the unit’s wattage/amperage capacity Is exceeded.

BOTH

__ AREbh^

LOW

TEST 17-CHECK

AND ADJUST

VOLTAGE

REGULATOR

TEST 16-ADJUST

ENGINE

GOVERNOR

LOW VOLTAGE

, AND/OR LOW FREQUENCY!

CONDITION

IS NOT CORRECTED

FREQUENCY AND I VOLTAGE GOOD-

AFTER ADJUSTMENT

^1 STOP TESTS

GOTO

PROBLEM 1

PAGE 1.6-2

PARTI

THE REVOLVING FIELD AC GENERATOR

Problem 3- Generator Produces High Voltage at No-Load

SECTION 1.6- TROUBLESHOOTING

(UNITS WITH 15 INCH STATOR)

TESTIS- CHECK BOTH

VULi AuiC MHil/

FREQUENCY

FREQUENCY GOOD, VOLTAGE IS HIGH

TEST 17- CHECK

Problem 4- Voltage and Frequency Drop Low When Electrical Loads are Applied

TESTIS- CHECK

FOR OVERLOAD

CONDITION

1 la

HIGH

AND ADJUST

VOLTAGE

REGULATOR

TEST 16-ADJUST

GOVERNOR

UNIT IS NOT

HIGH VOLTAGE

CONDITION w

CORRECTED

O.K.

ADJUSTMENT

VOLTAGE REGULATOR,

TEST 16-ADJUST

ENGINE

GOVERNOR

TESTS- REPLACE

TEST AND ADJUST

.. NOWHii|

I O.K. NOW-

UNIT IS OVERLOADED

REDUCE LOAD TO UNIT’S

RATED WATTAGeAMPERAGE

CAPACITY

VOLTAGE/FREQUENCY

STILL DROP LOW

WHEN LOADS ARE

APPLIED

TEST 19- CHECK

CMr^lMC D/MAICn

AND CONDITION

I^STOPTIST^

REPAIR

NEEDED

PAGE 1.6-3

SECTION 1.6- TROUBLESHOOTING (UNITS WITH 15 INCH STATOR)

Detailed Instructions

INTRODUCTION:

The following diagnostic test instructions are num

bered to correspond with the numbered tests in the

troubleshooting 'Row Charts’ on Pages 1.6-1 through

1.6-3. Read the instructions carefully.

PARTI

THE REVOLVING FIELD AC GENERATOR

Results: Analyze the results of the AC output voltage

test as follows:

1. If the reading is zero volts or residual volts, perform

tests as indicated under Problem 1 of the Flow Charts.

TEST 1- CHECK AC OUTPUT VOLTAGE:

Discussion; In order to identify the specific probiem,

it is necessary to measure the generator’s AC output

voltage. Some Installations may Include an optional AC

meter package. Even when this is the case, it is a good idea to verify the AC voltage with an external meter. In some cases, the AC meter(s) on the optional package may be reading incorrectly.

Remember, some installed units may be connected for dual voltage AC output (120 and/or 240 volts). Some units may be connected for 120 volts AC output only. Also see "STATOR AC CONNECTION SYSTEM" on Page 1.5-2.

Procedure; An AC voltmeter or a volt-ohm-milliammeter (VOM) may be used to measure voltage. If the unit is installed in a vehicle, the meter may be connected to a convenient receptacle. For uninstalled units, con nect the VOM across Wires No. T1 (red) and T3 (black)

to obtain a line-to-line voltage reading (240 volts). For a

line-to-neutral reading (120 volts), connect the VOM

across line T1 (red) and T2 (white); or across line T3

(black) and T2 (white). With the unit runing at no-load,

read the AC voltage. Voltage should be 121-127 volts

(line-to-neutral): or 242-254 volts (line-to-line).

NOTE: "Residual" voltage Is that voltage produced as a result of Rotor residual magnetism only. It Is equal to approximately 2 to 7percent of the unit’s rated voltage. For units rated 120/240 volts, residual

voltage will be approximately 2.4-0.4 volts (llne-to-

neutral); or 4.8-16.8 volts (llne-to-llne).

2. If the voltage is low, but greater than residual, go to Problem 2 of the Flow Charts.

3. If AC output voltage is high, go to Problem 3 of the Flow Charts.

4. If AC output voltage Is normal at no-load, but drops excessively when electrical loads are applied, go to Problem 4 of the Flow Charts.

Test 2- Check Voltage Regulator Lamps

Discussion: Refer to 'AC VOLTAGE REGULATOR'

on Pages 1.3-5 and 1.3-6.

Procedure: Gain access to the AC Voltage Regulator in the control panel. With the generator running at no-load, observe the condition of the Regulator lamps (LED’s).

nrSMiTi nnrotRPi

1 22 33 44

CB1 CB2 )

)

Qy )—1

T2 (WHITE)

-120V

___________

SHOWN CONNECTED FOR DUAL (BLACK)

VOLTAGE AC OUTPUT. FOR 120 VOLTS OUTPUT, SEE FIGURE 5 ON PAGE 1.5-2.

Figure 1. Stator AC Output Leads

NOTE: Line T1 (red) and T3 (black) are the two "hot'' lines. Line T2 (white) Is the "Neutral" line.

^ 4

• 240V. •

---------

120V.

■ K

PAGE 1.6-4

The Voltage Regulator lamps are normally ON

during engine-generator operation. It is suggested that

■ AC VOLTAGE REGULATOR' on Pages 1.3-5 and

1.3-6 be read carefully. The REGULATOR lamp will go out if (a) a Regulator fault exists, or (b) if the Regulator has shut down due to occurence of one or more Reg ulator shutdown conditions. The EXCITATION lamp will go out on loss of stator excitation winding output to the Regulator. The SENSING lamp will go out on loss of sensing input to the Regulator.

Resülts:

1. if ail lamps are out, go to Test 11.

2. If the 'Sensing' lamp is out, go to Test 8.

3. If the ’Excitation* lamp is out, go to Test 4.

4. If the 'Regulator* lamp Is out, go to Test 3.

PARTI

THE REVOLVING FIELD AC GENERATOR

Detailed Instructions

TEST 3- REPLACE REGULATOR, TEST/ADJUST;

Discussion: The Voltage Regulator lamps (LED’s) are normally ON. If the 'Regulator* lamp is OUT, the Voltage Regulator has shut down or has failed. A

'Regulator lamp ON condition indicates the Regulator’s SCR’s (silicone controlled rectifiers) are firing.

---

" ^ .

----------------------------------

Figure 2. The Part No. 67680 Voltage Regulator

Procedure: Unplug the voltage regulator connec

tor plug. Remove the screws, flatwashers and lockwasners that retain the regulator to the control panel. Remove the regulator. Install the new regulator, test and adjust as outlined in Section 1.9, ‘OPERA

TIONAL TESTS AND ADJUSTMENTS'.

NOTE: Before attempting to adjust the voltage reg ulator, the engine governor must be properly ad

justed to maintain a no-load frequency of 60.5-63.5

Hertz (1815-1905 rpm). Correct no-load AC output

voltage setting Is 121-127 volts AC (llne-to-neutral), or 242-257 volts AC (llne-to-llne).

Results: If problem is corrected, discontinue tests.

If problem still exists, continue troubleshooting as indi cated in the 'Flow Charts".

TEST 4- TEST EXCITATION CIRCUIT BREAKER:

Discussion: See Figure 3. The excitation circuit

breaker is electrically connected in series with the stator excitation winding AC output to the voltage reg ulator. It is physically mounted in the control panel interior. Should the breaker fail open, loss of excitation winding output to the regulator will occur. Without exci tation current, the regulator will shut down and gener ator AC output will drop to a voltage commensurate with

Rotor residual magnetism. The breaker cannot be reset manuaily (it is normally self-resetting). If it has failed

open, it must be replaced.

VOCTAQE ADJUST

UNOERFREOUENCY

— .. - 1 ^

OAIN

STABIUmr

ADJUST

REGULATOR

SENSING

EXCITATION

In^

Ine®

r«®

SECTION 1.6- TROUBLESHOOTING

(UNITS WITH 15 INCH STATOR)

from excitation grinding

to voltage regulator

Figure 3. Excitation Circuit Breaker

Procedure: To prevent interaction, disconnect

Wires No. 2 and 162 from the circuit breaker terminals.

Set a VOM to its "Rxl' scale and zero the meter. Connect thè VOM test probes across the two circuit breaker terminals. The meter should read "continuity*.

Resuits: •

1. If the meter displays any reading o(;her than "conti nuity", replace the excitation circuit breaker.

2. If the VOM reads "continuity", go on to Test 5.

NOTE: When reading resistance across the circuit

breaker contacts, a very small resistance reading

Is acceptable. An oxide film can build up on circuit breaker contact surfaces, causing the small resis tance.

TEST 5- TEST STATOR EXCITATION WINDING:

Discussion: An open circuit in the stator excitation

(OPE) winding will result in loss of excitation current to the Voltage Regulator. An excitation winding AC output of approximately 4-8 volts AC is required to turn the Voltage Regulator on. Thus, on loss of excitation wind

ing output, the Regulator will shut down and regulated

excitation current to the Rotor will terminate. Generator

AC ou^ut voltage will then drop to a value commensu

rate with Rotor residual magnetism plus field boost

current (about one-half normal no-load AC output volt

age). An open winding will be Indicated by a VOM

reading of 'infinity* or a very high resistance reading. A shorted excitation winding will be Indicated by a veiy low resistance reading. In the following 'Procedure*^, the excitation winding will also be testedfor a grounded condition.

Procedure: See Figure 4, next page. In the control panel, locate unattached Wire No. 5. This is the thermal protector bypass lead. Remove the wire nut from end of Wire No. 5. Also locate Wire No. 6, connected to Pin 6 of the voltage regulator plug. On some units, a barrel lug may be used to connect Wire No. 6 between the voltage regulator and the stator excitation winding. Test the stator excitation winding for an open, shorted or grounded condition as follows:

PAGE 1.6-5

SECTION 1.6- TROUBLESHOOTING (UNITS WITH 15 INCH STATOR)

Detailed Instructions (Continued)

PART 1

THE REVOLVING FIELD AC GENERATOR

1. Set a VOM to Its ’Rxl ’ scale eind zero the meter.

2. Connect the VOM test probes across Wire No. 5 and Pin 6 of the Voltage Regulator. The meter should read the resistance of the stator excitation winding (about

0. 53.ohm).

3. Now, set the VOM to a very high resistance scale such as ’Rx10,000" or "Rx1 K". Again, zero the meter.

a. Connect one VOM test lead to bypass Wire No. 5, the other to a clean frame ground on the stator. The meter should Indicate "infinity". b. Any reading other than "infinity" indicates a shorted condition and the stator should be replaced.

4. With the VOM still set to a high resistance scale, connect one VOM test probe to stator Wire No. 5, the other to stator ac output Wire No. 11 or 22. "Infinity" should be Indicated.

5. Connect the VOM test probes across Wire No. 5 and stator AC output Wire No. 33. "Infinity" should be indi cated.

Results:

1. If the stator excitation winding fails any part of the test, replace the stator assembly.

2. If the stator excitation winding checks good, go on to Test 6.

Results:

1. If normal excitation winding resistance was indi

cated in Test 5, but "infinity" was Indicated in Test 6, the thërmal protector is open and must be bypassed.

2. If normal excitation winding resistance was indi

cated in both Tests 5 and 6, the thermal protector is good. Go on to Test 7.

TEST 7- TEST EXCITATION LEADS:

Discussion: An open or shorted condition in the

stator excitation winding's output leads to the Regulator

will cause complete or partial loss of the unregulated excitation current to the Regulator.

Procedure: Inspect Wires No. 2,6 and 162, between

the stator and the Voltage Regulator. Make sure they

are properly connected and undamaged. Use a VOM to

test the wires tor "continuity".

Results:

1. Reconnect, repair or replace any damaged, discon

nected or shorted wire(s). /

2. If all excitation leads are good, go to Test 11.

Figure 4. Excitation Winding Test Points

TEST 6- TEST THERMAL PROTECTOR:

Discussion: You may wish to review the information

on the thermal protector. See Page 1.3-7.

Procedure: Set a VOM to its "Rxl" scale and zero the meter. Connect the VOM test probes across stator wires No. 2 and 6. See Table 1, Page 6.1-1 for nominal

resistances.

TEST 8- CHECK REGULATOR SENSING LEADS:

Discussion: An open or shorted condition in the

sensing leads to the Voltage Regulator will result in loss of sensing (actual voltage) signals to the Voltage Reg ulator. The Regulator’s "Sensing" lamp will then go out.

Procedure: Carefully inspect Wires SI 5 and SI6,

between the Regulator and the sensing transformer. Also inspect Wires No. 11 and 22, between the sensing transformer and the stator. Use a VOM to test all wires for an open or shorted condition.

Results:

1. Reconnect, repair or replace any disconnected,

damaged or defective wire(s).

2. If the sensing leads are good, go on to Test 9.

TEST 9- TEST SENSING TRANSFORMER:

Discussion: The Part No. 67680 Voltage Regulator requires a 240 volts AC sensing signal to operate properly. You may wish to review the information on the sensing transfonmer on Page 1.3-6.

PAGE 1.6-6

PARTI

THE REVOLVING FIELD AC GENERATOR

Detailed Instructions (Continued)

SECTION 1.6- TROUBLESHOOTING

(UNITS WITH 15 INCH STATOR)

Procedure: Gain access to the sensing trans

former, inside the control panel. Use a volt-ohm-milli-

ammeter (VOM) to test the sensing transformer as

follows:

1. Disconnect Wires No. 11 and 22 from the

transformer’s PRIMARY terminals, to prevent interac tion.

2. Connect the VOM test leads across the two PRI

MARY (120 volts) terminals. Resistance of this winding

should be approximately 120 ohms (plus or minus 2%).

3. Disconnect Wires No. SI5 and SI 6 from the trans former SECONDARY (240 volts) terminals, to prevent

interaction.

4. Connect the VOM test leads across the two SEC ONDARY (240 volts) terminals. Resistance should be approximately 950 ohms (plus or minus 2%).

Results:

1. If the transformer fails the test, it should be replaced.

2. If the transformer checks good, go on to Test 10.

PRIMARY 120 VAC

[qooopI

oaoWflÒSbì

2. Set a VOM to its ■ Rxl’’ scale and zero the meter.

3. Test the windings as follows:

a. Connect the meter test leads across Wires No. 11 and 22. Resistance reading should be approximately as listed in chart in Part 6. b. Connect the meter test leads across Wires No. 33 and 44. Resistance reading should be approximately as listed in chart in Part 6.

c. Set the VOM to a very high resistance scale, such as 'Rxl 0,000" or "RxlK". Then, zero the meter. d. Make sure none of the stator leads are touching the generator or each other at any point. Connect one VOM test probe to Wire No. 11, the other test probe to Wire No. 33. The VOM should read "Infinity“. Any reading other than "infinity" indicates a short between the stator windings. e. Connect one VOM test probe to Wire No. 11, the other to a clean frame ground on the stator. VOM should read "infinity". f. Connect one VOM test probe to Wire No. 33, the other to a clean frame ground. Reading should be

"infinity".

nmnrin

rWiRRTi

■ 6

SECONDARY 20 VAC

Figure 5. The Sensing Transformer

TEST 10- TEST STATOR AC POWER WINDINGS:

Discussion: An open condition in eitherof the dual stator AC power windings will result In loss of AC output from the affected winding. A shorted condition in those windings will cause a reduction in AC voltage that is commensurate with the number of shorted turns. A shorted condition can also impose such a heavy load on the engine that engine speed and AC frequency will

also drop sharply. This test will check the stator AC power windings for (a) an open condition, (b) a shorted condition, and (c) a grounded condition.

Procedure: To test 1-phase, dual winding stators, proceed as follows:

1. Disconnect Wires No. 11, 22, 33 and 44 from the main circuit breaker (CB1) and from the unit grounding

lug.

11 22 33 44

SEE SECTION 1.5, PAGE 1.5-3 FOR SOME OTHER STATOR CONFIGURATIONS.

ALSO SEE PART 6, PAGE 6.1-1 FOR SOME

RESISTANCE VALUES.

Figure 6. Stator Windings Schematic

TEST 11- TEST ROTOR WINDINGS;

Discussion: An open circuit condition in the Rotor windings means that excitation current cannot flow in the circuit. Field boost current will be unable to flow in an open circuit either.

Procedure: Use a VOM to check the resistance of Rotor windings. Connect the positive (+) VOM test probe to the positive (+) Rotor slip ring (nearest the

Rotor bearing). Connect the common (-) VOM test

probe to the negative (-) slip ring. The VOM should

indicate approximately as listed in the chart in Part 6 (Page 6.1-1).

Remove both brush holders to prevent interaction.

Set VOM to a high resistance scale and zero the meter. Connect the positive (+) test probe to the positive (+1 slip ring (nearest the Rotor bearino); the common (•) test probe to a clean frame ground. "Infinity" must be indicated.

PAGE 1.6-7

SECTION 1.6- TROUBLESHOOTING (UNITS WITH 15 INCH STATOR)

Detailed Instructions (Continued)

Results:

1. Replace the Rotor if it fails test.

2. If Rotor checks good, go to Test 12.

PARTI

THE REVOLVING FIELD AC GENERATOR

ulated excitation current (DC) is delivered from the Regulator to the Rotor via these wires.

Figure 7. Rotor Assembly Test Points

TEST 12- CHECK BRUSHES AND SLIP RINGS:

Discussion: The brushes and slip rings are de

signed for long life and dependability. Problems with therse components are very infrequent. It is possible that, after a prolonged non-operating period, the slip rings can develop a corrossive film around their outer periphery. This film can separate the brushes from the slip rings and open the excitation circuit.

Procedure: Remove wires from the brushes. Re

move the brush holders from the rear bearing carrier. Carefully inspect brushes, brush holders, wires and slip

rings. Replace brushes that are chipped, cracked, or

worn excessively. Replace brushes as complete sets.

Replace any damaged brush holders. If the slip rings have a dull or tarnished appearance, they may be

cleaned with fine sandpaper. DO NOT USE ANY ME TALLIC GRIT TO CLEAN SLIP RINGS. Polish the slip

rings until shiny.

Results:

1. Replace any damaged brushes or brush holders. Clean and polish slip rings, if necessary.

2. If brushes and slip rings are good, go to Test 13.

TEST 13- CHECK WIRES NO. 1 AND 4:

Discussion: Wire No. 1 is routed from the nega

tive (-) brush to the unit grounding lug; and from the grounding lug to Pin 1 of the Voltage Regulator. Wire No. 4 is routed from the positive (+) brush (nearest the

Rotor bearing) to Pin 4 of the Voltage Regulator. Reg

' Procedure: Inspect Wires No. 1 and 4 along their entire length. Use a VOM to check the wires for an open or shorted condition. Make sure wires are properly connected.

Results:

1. Reconnect, repair or replace any damaged or defec

tive wire(s).

2. If Wires are good, go to Test 14.

TEST 14- TEST FIELD BOOST:

Discussion; During engine cranking, the action of

an engine control circuit board delivers battery voltage

(12 volts DC) to the Rotor windings via Wire No. 9, a

field boost resistor (R^, a field boost diode (D2) and Wire No. 4. Resistor (R2) reduces this voltage to ap

proximately 7-10 volts DC. As soon as engine cranking stops, circuit board action terminates field boost cur rent. Field boost current flow to the Rotor windings while cranking turns the Voltage Regulator on earlier and ensures mat a ’pickup* voltage is available to start the generation of electricity. Loss of field boost current may or may not affect generator AC output voltage. If

Rotor residual magnetism is sufficient to provide the required ’pickup" voltage in the stator, loss of field

boost will have no affect. However, if Rotor residual

magnetism is not adequate to produce the required ’pickup’ voltage, generator AC output voltage will build only to a value commensurate with Rotor residual mag netism (about 2-7% of rated voltage).

The field boost, in effect, flashes the field eveiy

time the engine is cranked and started. This test will check the field boost circuit to determine if it is function ing properly while the engine is cranking.

PAGE 1.6-8

PARTI

THE REVOLVING FIELD AC GENERATOR

Detailed Instructions (Continued)

SECTION 1.6- TROUBLESHOOTING

(UNITS WITH 15 INCH STATOR)

The field boost resistor, field boost diode, Wire No. 9 and Wire No. 4 are part of the control panel wiring harness. See Figure 9. The resistor and diode are connected in series with Wires No. 9 and 4, and are encased in heat shrink tubing.

Procedure: In the control panel, locate the voltage

regulator and the engine control circuit board. Test field

boost system operation as follows:

1. Unplug the 6-pln connector from the voltage regula tor. Tnis will prevent you from reading regulated exci tation voitage during the test.

2. Set a VOM to read DC volts.

3. Field boost Wire No. 9 attaches to Terminal 8 of the engine control circuit board.

a. Connect the positive (+) VOM test lead to Terminal

8 of the engine control circuit board. b. Connect the VOM common (-) test lead to frame ground.

4. Crank the engine and note the DC voltage reading.

Meter should indicate approximately 12 volts DC while

the engine is cranking.

5. Now, connect the VOM positive (+) test lead to Pin 4 of the regulator connector plug; connect the common test lead to a clean frame ground. Crank the engine and

the meter should indicate 7-10 volts DC.

Results:

1. If no voltage is indicated in Step 4, a problem exists in the engine control circuit board, or in the engine DC control circuits. See Part 5, "ENGINE ELECTRICAL

SYSTEM".

2. If no voltage is indicated in Step 5, an open circuit exists in Wire No. 9, the field boost diode, field boost

resistor, or Wire No. 4 to the Regulator.

TEST 15- TEST VOLTAGE AND FREQUENCY:

Discussion: The generator's AC output frequency is directiy proportional to engine speed. Generator’s having a 4-pole Rotor will produce a 60 Hertz frequency at 1800 rpm. Voltage is also proportional to AC fre quency. The unit will supply 120 volts (line-to-neutral) or 240 volts (line-to-line) at 60 hertz; if frequency should drop to 30 Hertz, voltage output will decrease propor tionally to 60/120 volts. It is apparent that a low gov

erned speed will result In a reduced AC frequency and

voltage. Conversely, a high governed speed will pro

duce an increased frequency and voltage.

Procedure; See Test 1. Check AC output voltage as outlined (at no-load). Use an accurate AC frequency meter to check frequency (at no-load). The no-load frequency should be 62 Hertz. No-load AC output volt age should be 121-127 (line-to-neutral); or 242-254 volts (line-to-line).

Results:

1. If both frequency and voltage are low, go to Test 16.

2. If frequency is good, but voltage is low, go to Test

17.

3. If no-load voltage and frequency are both high, go to Test 16.

4. If frequency is good, but voltage is high, go to Test

17.

TEST 16- ADJUST ENGINE GOVERNOR:

Discussion: Refer to "DISCUSSION' under Test

15.

Procedure: See Section 1.9, "OPERATIONAL

TESTS AND ADJUSTMENTS'.

NOTE: By removing the heat shrink tubing around the

diode and resistor, these two components can be

tested individually. The defective part can then be removed and replaced. The resistor (Part No. 51980) is rated 5 watts, W ohms. The diode (Part No. 49903) is ra ted 600 volts, 6 amps. ' -,, -

©■

PART OF CONTROL PANEL WIRING HARNESS

ITEM

1 2 3 4

Figure 9. Field Boost Part of Wiring Harness

DESCRIPTION

heaT shrInk

BARREL LUG

DIODE- 60DV., 6 AMP

RESISTOR-5 WATT. 10 OHMS

TEST 17- ADJUST VOLTAGE REGULATOR:

Discussion: Procedures for this test and adjust

ment are outlined in Section 1.9.

TEST 18- CHECK FOR OVERLOAD CONDITION:

Discussion: The rated maximum wattage/amper-

age capacity of the generator should not be exceeded for continuous operation. Overloading the unit will re sult in rpm, frequency and voltage droop. Excessive overloading will cause the AC circuit breaker(s) to trip.

Procedure: If an optional remote gauge panel is

installed, load current can be checked by observing the

AC ammeter on that panel. If such a panel is not

available, a clamp-on ammeter can be used to check amperage.

Results:

1. If unit is not overloaded, go to Test 16.

2. If the unit is overloaded, reduce the total electrical load to the rated wattage/amperage capacity.

PAGE 1.6-9

SECTION 1.6- TROUBLESHOOTING (UNITS WITH 15 INCH STATOR)

Detailed Instructions (Continued)

TEST 19- CHECK ENGINE POWER & CONDITION:

Discussion: Quite often excessive rpm, frequency

and voltage droop that occurs when loads are applied

is not the fault of the generator. An under-powered engine may be the cause of the problem.

Procedure: Refer to Sections of this manual per

taining to the diesel engine. The following tune-up

checks are recommended:

1. Inspect engine air cleaner. A clogged air cleaner element can rob engine power.

2. Perform a compression test on engine cylinders.

3. Check for proper operation of the diesei fuel system.

Results: Repair engine as required to restore it to

fuii power.

PARTI

THE REVOLVING FIELD AC GENERATOR

PAGE 1.6-10

PARTI

THE REVOLVING FIELD AC GENERATOR

TROUBLESHOOTING

(UNITS WITH 10 INCH STATOR)

SECTION 1.7- TROUBLESHOOTING

(UNITS WITH 10 INCH STATOR)

Section 1.7

The following "Troubleshooting Flow Charts" have been carefully formulated as an aid to the quick and accurate

analysis of AC generator problems. Test numbers in the Flow Charts correspond to numbered tests in the "Detailed

Instructions" that follow.

Problem 1- Generator Produces Zero or Residual Voltage at No-Load

Introduction

TEST 1-CHECK

AC OUTPUT

VOLTAGE

IcZERO

OR RESIDUAL

PAGE 1.7-1

SECTION 1.7- TROUBLESHOOTING (UNITS WITH 10 INCH STATOR)

Problem 2- Generator Produces Low Voltage at No-Load

(Voltage Is Greater Than Residual)

PARTI

THE REVOLVING FIELD AC GENERATOR

1 CO 1 1H*

AC VOLTAGE AND FREQUENCY

FREQUENCY IS O.K.

BUT VOLTAGE IS LOW

TEST 12-CHECK WIRES NO. 1 AND 4

BAD

RECONNECT, REPAIR OR REPLACE BAD

WIRE(S)

DATU

« ARE-^

LOW

—O.K..^ BRUSHES AND

TCOTiC. AnillOT

1 CO 1 1 9* 1

ENGINE

GOVERNOR

FREQUENCY IS NOW O.K.

BUT VOLTAGE IS STILL

LOW

_________

TEST 11-CHECK

SLIP RINGS

BAD

REPLACE BAD BRUSHES

CLEAN SLIP RINGS

ARE BOTH O.K. NOW

TCQT a. nn A

FIXED

EXCITATION

r*'

AC OUTPUT IS LESS THAN

40”/. OF RATED VOLTAGE

i^O.K.»^ ROTOR

TEST

TEST 10-TEST

ASSEMBLY

BAD

REPLACE BAD ROTOR

RTHP

TESTS

AC OUTPUT

IS ABOUT 40-60”/.

OF RATED

VOLTAGE

TEST 13- TEST

».O.K.-^ STATOR AC

POWER

WINDINGS

BAD

REPLACE

STATOR

ASSEMBLY

TEST 7- TEST STATOR EXCrrATION WINDING

BAD

REPLACE STATOR ASSEMBLY

PAGE 1.7-2

ITEST 16-CHECK 1 1 AND 6 1

bId

RECONNECT, REPAIR OR

REPLACE WIRE(S)

AS REQUIRED

TEST 9- CHECK

VOLTAGE

REGULATOR

VOLTAGE IS STILL LOW

REPLACE VOLTAGE REGULATOR

TEST AND ADJUST

PARTI THE REVOLVING FIELD AC GENERATOR

Problem 3- Generator Produces High Voltage at No-Load

SECTION 1.7- TROUBLESHOOTING

(UNITS WITH 10 INCH STATOR)

TEST 14- CHECK AC VOLTAGE AND FREQUENCY

FREQUENCY O.K. VOLTAGE IS HIGH

TEST 9- CHECK

VOLTAGE

REGULATOR

TEST 17- CHECK

CnD n\/Ptai rtAH CONDITION

BOTH

■ ARE-

HIGH

I VOLTAGE IS STILL HIGHi

Problem 4- Frequency and Voltage Drop Sharply When Load is Applied

NOT

LOADED

TESTIS

FREQUENCY & VOLTAGE,

ARE BOTH GOOD NOW

GO TO PROBLEM 2

- ADJUST

ENGINE

GOVERNOR

TEST 15-ADJUST

ENGINE

GOVERNOR

.O.K.—

STOP

TESTS

STOP

TESTS

UNIT IS OVERLOADED

REDUCE LOAD TO

WATTAGE/AMPERAGE

CAPACITY OF UNIT

PROBLEM STILL EXISTS

I TEST 18- CHECK

ENGINE POWER

1 AND CONDITION

REPAIR ENGINE

^ AS

NEEDED

PAGE 1.7-3

SECTION 1.7- TROUBLESHOOTING (UNITS WITH 10 INCH STATOR)

PARTI

THE REVOLVING FIELD AC GENERATOR

Diagnostic Tests

INTRODUCTION:

The following ‘Diagnotic Tests" correspond to the numbered tests In the troubleshooting “Flow Charts" on Pages 1.7-1 through 1.7-3. When performing tests, it is recommended that the wiring diagram and/or electrical schematic for the appropriate generator model be re ferred to as often as necessary.

TEST 1- CHECK AC OUTPUT VOLTAGE:

Discussion: This test must be performed to help you determine if a problem exists and the exact nature of the problem. Some installed units will include an* optional meter package, which includes an AC voltme ter. Even if such an optional package is installed, it is a good idea to check the voltage with an external meter such as a VOM. Using an external meter will help you determine if the AC voltmeter on the optional meter

panel is accurate.

Procedure: If the generator is installed in a motor

home, the VOM test probes can be inserted into a convenient AC outlet that is supplied by the generator. If uninstalled, connect the VOM test leads across AC outlet leads T1 (red), T2 (white) and T3 (black). See Figure 1.

NOTE: Remember, the unit may be connected for either singie voltage (120 voits) or duai voitage (120/240 voits). See "STATOR AC CONNECTiON SYSTEM" on Page 1.5-2.

Start the generator engine, let it stabilize and warm

up. Read the line-to-line or line-to-neutral voltage from

the VOM. Reading should be as follows:

Line T1 (red) to T2 (white) = 121-127 volts

Line T3 (black) to T2 (white) = 121-127 volts

Line T1 (red) to T3 (black) = 242-254 volts

Results;

1. If zero or residual voltage at no-load is indicated, go to Problem 1 of the "Flow Charts".

2. If the no-load voltage Is low, but is greater than residual voltage, go to Problem 2 of the "Flow Charts'.

3. If no-load voltage is high, go to Problem 3 of the "Flow Charts".

TEST 2- CHECK MAIN CIRCUIT BREAKERS:

Discussion: The generator is equipped with two main circuit breakers, designated CB1 and CB2, as standard equipment. If these circuit breakers are set to their "Off" or "Open" position, or if they have failed open, generator AC ou^ut voltage to the load(s) will not be available.

Procedure: Check the main circuit breakers, make sure they are set to "On" or "Closed". If the breakers are set to "On* or "Closed", but AC output voltage is not available, use a VOM to test the breakers as follows:

1. Shut the engine down.

2. Inspect the AC wiring connections carefully. Make sure wiring is properly connected for the correct volt age. See "STATOR AC CONNECTION SYSTEM" on Page 1.5-2.

3. Set the VOM to its "Rxl" scale and zero the meter. Then, test the breakers as follows:

a. Connect the VOM test probes across circuit breaker CB1 terminals. When breaker is set to its'"^ , "On" or "Closed" position, the VOM should read "continuity". When set to "Off" or "Open" position, “infinity" should be read.

b. Repeat the above test for circuit breaker CB2.

Results should be the same.

Results:

1. If circuit breakers are good, go to Test 3.

2. Replace any defective circuit breaker(s).

fWiRm rtrwtRPi

CB1

)

T2 (WHFTE)

-120V.

------------

►

T1 (RED)

SHOWN CONNECTED FOR DUAL (BLACK) VOLTAGE AC OUTPUT. FOR 120 VOLTS OUTPUT, SEE FIGURE S ON PAGE 1.5-2.

Figure 1. Stator AC Output Voltage

PAGE 1.7-4

■ 240V. ■

<«

--------

120V.

CB2 )

Figure 2. Main Circuit Breaker Test Points

PARTI

THE REVOLVING FIELD AC GENERATOR

Diagnostic Tests (Continued)

SECTION 1.7- TROUBLESHOOTING

(UNITS WITH 10 INCH STATOR)

TEST 3- DO A FIXED EXCITATION TEST:

Discussion: This test will help you narrow the

possible causes of zero, residual or low AC output voltage down to Just a few possible causes.

The test consists of disdonnectlng regulated exci

tation current flow to the Rotor, but leaving the field boost circuit to the Rotor Intact. With regulated excita tion current disconnected, the generator’s AC output voltage will be commensurate with Rotor residual mag

netism plus field boost.

Procedure: Disconnect Wires No. 1 and 4 from the

Voltage Regulator terminals, so that regulated excita tion current Is not available to the Rotor. Connect an AC Voltmeter across the generator AC output leads

(T1, T2, T3). Start the engine, let It stabilize and warm up. The AC voltage reading should be commensurate

with Rotor residual magnetism plus field boost, as

follows:

1. Une-to-neutral voltage should be approximately 2540 volts AC.

2. Line-to-Une voltage should be approximately 50-80 volts AC.

Results:

1. If line-to-neutral voltage is lower than 25-40 VAC, go to Test 10. if line-to-line voltage is less than 50-80 VAC, go to Test 10.

2. If 25-40 VAC line-to-neutral voltage is indicated (or 50-80 VAC line-to-line), go to Test 4.

If sensing (actual voltage) signals to the Regulator

should be lost, the Regulator would interpret such a

loss as ‘’zero* actual volts. Regulator action would then increase excitation current flow to the Rotor until a ‘full

field' condition existed. The result would be a high voltage condition. However, the Part No. 81918 Regu

lator will shut down automatically on loss of sensing voltage. With the Regulator shut down, excitation cur rent to the Rotor will terminate and AC output voltage will drop to a value commensurate with the Rotor's residual magnetism plus field boost.

Procedure: Inspect Wires No. 11 and 22, between the Voltage Regulator and the engine control circuit board. These are the sensing (actual voltage) leads.

Use a VOM to test the wires for "continuity*.

Results:

1. Reconnect, repair or replace bad wire(s) as required.

2. If the sensing circuit is good, go on to test 5.

TEST 5- TEST THERMAL PROTECTOR:

Discussion: You may wish to review “ THERMAL

PROTECTOPT on Page 1.3-7.

Procedure: To test the thermal protector, proceed

as follows:

1. in the control panel, locate (a) Wire No. 5, (b) Wire No. 2, and (c) Wire No. 6. Wire No. 5 is unconnected and has a wire nut at its end. Wire No. 2 connects to the excitation circuit breaker. Wire No. 6 attaches to the Voltage Regulator plug.

2. Set a VOM to its "Rxl ‘ scale and zero the meter.

3. Disconnect Wire No. 2 from the excitation circuit breaker. Unplug the Voltage Regulator plug. Remove the wire nut from Wire No. 5.

4. Connect one VOM test probe to Wire No. 5 and the

other end to Pin 2 of the Regulator plug, to which Wire No. 6 attaches. The meter should read the resistance of the excitation winding (about 1.00 ohm).

5. Now, connect the VOM test probes across Wire No.

2 and Wire No. 6. Again, excitation winding resistance should be read.

Results:

1. If excitation winding resistance is indicated in Step

4, but not in Step 5, the thermal protector is open and must be bypassed.

2. If excitation winding resistance is indicated in both

Steps 4 and 5, go on to Test 6.

TEST 4- CHECK REGULATOR SENSING CIRCUIT:

Discussion: The sensing circuit is the Regulator's

ACTUAL voltage signal. The Regulator electronically compares the actual voltage with a pre-set REFER

ENCE voltage. If ACTUAL voltage is less than REFER

ENCE voltage, the Regulator will increase excitation current flow to the Rotor. If ACTUAL voltage is greater than REFERENCE voltage, it will decrease excitation current flow to the Rotor. In this manner, Rotor mag

netic field strength and AC voltage are regulated.

TEST 6- TEST EXCITATION CIRCUIT BREAKER:

Discussion: This test will determine if the excita

tion circuit breaker has failed open. If the breaker is open, loss of excitation current to the Rotor windings will result and AC output will drop to residual voltage. The breaker is mounted in the control panel.

Procedure: Disconnect Wires 2 and 2A from the

circuit breaker. Connect VOM test ieads across the two

breaker terminals. The VOM should read "continuity". If not, the breaker is open and should be replaced.

PAGE 1.7-5

SECTION 1.7- TROUBLESHOOTING (UNITS WITH 10 INCH STATOR)

Diagnostic Tests (Continued)

PART 1

THE REVOLVING FIELD AC GENERATOR

Results:

1. Replace excitation circuit breaker if it fails the test.

2. If the circuit breaker tests good, go on to Test 7.

TEST 7- TEST STATOR EXCITATION WINDING:

Discussion: An open or shorted stator excitation winding can seriously affect the generator’s AC output. For example, an open condition will result in loss of loss of excitation AC output to the Regulator. Excitation current flow to the Rotor will then drop to zero and generator AC output voltage will drop to a value com

mensurate with residual magnetism plus field boost.

Procedure: Refer to Test 5. A VOM, connected across Wires No. 5 and 6, should read the resistance of the stator excitation winding (about 1.00 ohm). A reading of "infinity" indicates an open winding. A very low reading indicates a possible shorted condition. To test for a GROUNDED condition, proceed as follows:

It is normal for some residual magnetism to be

present in the Rotor at all times. This residual magne tism can be lost under certain conditions. If Rotor residual magnetism has been lost, it will normally be restored by field boost current during engine cranking. However, if Rotor residual magnetism has been lost AND field boost does not "flash the field" during crank ing, sufficient voltage to turn the Regulator on may not be developed. Loss of residual magnetism accompa

nied by loss of field boost current will likely result in a reduction of generator AC output to zero volts.

Reid boost current Is always available to the Rotor

when the engine is running, by the action of an endne

control circuit board housed in the control panel. Bat tery voltage is delivered to the Rotor via Terminal 8 of that circuit board. Wire 4A, field boost resistor, and Wire

1. Set a VOM to a very high resistance scale, such

as “Rx10,000" or “Rxl K". Zero the meter.

2. Connect one VOM test probe to stator lead No. 5; connect the other test probe to a clean frame ground on the stator. The meter should read "infinity". Any reading other than "infinity" indicates a grounded con dition.

Results:

1. If excitation winding is open, shorted or

grounded, replace the stator assembly.

2. If excitation winding checks good, go to Test 8.

TEST 8- CHECK FIELD BOOST:

Discussion: Approximately 4 to 8 volts output from the stator excitation winding is required to turn the Voltage Regulator on. The field boost feature delivers additional current to the Rotor during engine cranking. The additional field boost current creates a Rotor mag netic field strength that is additive to the Rotor’s resid ual magnetism. The end result of field boost is an early

"pickup" voltage to build induced voltage into the stator

windings early during startup.

PAGE 1.7-6

Procedure: To test the field boost function, pro

ceed as follows:

1. Disconnect Wires No. 4 from the Voltage Regulator.

This is a "piggy-back" terminal with one Wire No. 4

routed to the brushes and one Wire No. 4 coming from the engine control circuit board. The latter wire, with in-line resistor, is the field boost circuit.

2. Connect a DC voltmeter across the terminal end of Wire No. 4 at the Voltage Regulator and Terminal 2 of the engine control circuit board (to which Wires No. 0 [ground] connect).

3. Crank the engine. During cranking, the meter should read approximately 9-10 volts DC, indicating that field

boost voltage is available.

a. If field boost voltage is indicated, end the test and go to Test 9.

b. If voltage is NOT indicated, go to Step 4.

4. Connect the DC voltmeter across Terminal 8 (Wire No. 4A) of the engine control circuit board and Terminal 2 (Wire No. 0) of the circuit board. Crank engine and meter should read battery voltage (about 12-13 volts DC).

PARTI

THE REVOLVING FIELD AC GENERATOR

Diagnostic Tests (Continued)

SECTION 1.7- TROUBLESHOOTING

(UNITS WITH 10 INCH STATOR)

Results:

1. If field boost voltage Is NOT indicated in Step 4, a

problem exists In the field boost wiring.

2. If field boost voltage Is NOT indicated in Step 3, but IS indicated in Step 4, replace Wires 4,4A and the field

boost resistor.

3. If field boost voltage is indicated in Step 3, go to Test

TEST 9- CHECK VOLTAGE REGULATOR:

Discussion: If you followed the troubleshooting

"Flow Chart* carefully, the only remaining possible

cause of zero, residual, low or high voltage is the voltage regulator.

Procedure: Try adjusting the voltage regulator as

outlined in Section 1.9, "OPERATIONAL TESTS AND ADJUSTMENTS".

Results: If Regulator adjustment does not correct

the problem, remove and replace the Regulator. Then, test the unit and adjust the Regulator.

4. Connect the positive (+) meter test probe to the positive (+) slip ring. This slip ring is the one nearest

the Rotor beanng.

5. Connect the common (•) VOM test probe to the negative (•) slip ring. The meter should indicate the resistance of the Rotor windings.

Rotor Winding Nominal Resistance

Approximately 8.5 Ohms

NOTE: A reading of 'Infinity' Indicates an open circuit.

A very high resistance Indicates a partial open. A low

reading Indicates shorted turns.

6. Now, set the VOM to a very high resistance scale, such as "Rxl0,000* or "RxlK* and zero the meter. Then, check the Rotor for a grounded condition as follows:

a. Connect the positive (+) VOM test probe to the

ositive (+) slip ring, nearest the Rotor bearing.

. Connect the common (-) VOM test probe to frame

ground, such as the Rotor shaft, c. The meter should read *infinity*. Any reading other than "infinity* indicates a grounded condition.

Results:

1. If the Rotor is good, go on to Test 11.

2. If Rotor is open, shorted or grounded, it must be

replaced.

TEST 10- TEST ROTOR ASSEMBLY:

Discussion: If fixed excitation voltage is applied to the Rotor and the generator’s AC output voltage does not read about half rated voltage, the Rotor side of the voltage regulator circuit is suspect. This test will outline the procedure for testing the Rotor winding.

Procedure: To test the Rotor windings for an open,

shorted or grounded condition, proceed as follows:

1. To gain access to the -Rotor slip rings, remove the

rear bearing carrier cover and gasket.

2. Disconnect Wires No. 1 and 4 from the brushes, then remove the brush holders with brushes to prevent interaction during the test.

3. Set a VOM to its ’Rx1’ scale and zero the meter.

TEST 11- CHECK BRUSHES AND SLIP RINGS:

Discussion: Refer to Test 12 in Section 1.6.

Procedure: See Test 12 in Section 1.6.

Results: Clean slip rings or replace brushes as necessary. Brushes should be replaced in completes sets. If brushes and slip rings are good but the problem persists, go to Test 12 on the next page.

PAGE 1.7-7

SECTION 1.7- TROUBLESHOOTING (UNITS WITH 10 INCH STATOR)

Diagnostic Tests (Continued)

PART 1

THE REVOLVING FIELD AC GENERATOR

TEST 12- CHECK WIRES 1 AND 4;

Discussion: An open or shorted condition in Wires

1 and 4 will have the same result as an open or shorted Rotor winding.

Procedure: Carefully inspect Wires No. 1 and 4,

between the Voltage Regulator and the Brushes. Look

for improper connections, damaged insulation, condi tion of wire terminal ends, etc. Use a VOM to check the wires for an open or shorted condition.

Results:

1. Reconnect, repair or replace defective wire(s) as necessary.

2. If wires are good, go to Test 13.

TEST 13- TEST STATOR AC POWER WINDINGS:

Discussion: During the fixed excitation test, the

generator’s AC output voltage should have been ap proximately one-half rated voltage. It voltage was less than one-half rated voltage, one possible cause might be an open, shorted or grounded stator AC power winding. You may wish to review 'STATOR AC CON

NECTION SYSTEM' on Page 1.5-2.

Procedure: To test the stator’s AC power winding,

proceed as follows:

1. Disconnect and isolate stator leads 11, 22, 33 and

44. See appropriate wiring diagram.

2. Set an accurate VOM to its "Rxl" scale and zero the

meter.

3. Check for an open circuit condition or for "turn-to-

turn" shorts as follows:

a. Connect the VOM test probes across stator leads

11 and 22. The resistance of the stator winding

should be indicated, about 0.21 ohm. b. Connect the VOM test probes across stator leads 33 and 44. Reading should be approximately 0.21 ohm. c. A reading of "infinity" indicates an open circuit. A very high reading, indicates a nearly open circuit. A very low reading indicates "turn-to-turn" shorts.

4. Check for a short between parallel windings as follows:

a. Set the VOM to a high resistance scale, such as "Rxl 0,000" or "RxlK". Zero the meter. b. Connect one VOM test probe to stator lead 11, the other to stator lead 33. The meter should read "infinity".

5. Check for a grounded condition as follows:

a. Set the VOM to a high resistance scale, such as "Rxl0,000" or "RxlK". zero the meter.

b. Connect one VOM test probe to stator lead 11, the other to a clean frame ground on the stator. The VOM should read "infinity". c. Now, connect one VOM test probe to stator lead

33, the other to a clean frame ground on the stator.

The meter should read "infinity".

Results: Replace the stator if it is open, shorted or

grounded.

TEST 14- CHECK AC VOLTAGE & FREQUENCY:

Discussion:You may wish to review 'ROTOR RO

TATIONAL SPEECr, as well as 'VOLTAGEAND FREQUENCV on Page 1.5-2.

Procedure: Refer to Test 1, "CHECK AC OUTPUT VOLTAGE". Use an accurate AC frequency meter to check AC output frequency, as well. No-load voltage and frequency readings should be as follows:

LIne-to-Neutral Voltage = 121-127 volts AC

LIne-to-llne Voltage = 242-254 volts AC

AC Output Frequency = 60.5-63.5 Hertz

Results:

1. If voltage and frequency are both correspondingly low or high, go to Test 15.

2. If frequency is good, but voltage is LOW, go to Test

3. If frequency is good, but voltage Is HIGH, go to Test

9. TEST 15- ADJUST ENGINE GOVERNOR:

Discussion: See "Discussion" under Test 14,

above.

Procedure: Check and adjust the engine governor

as outlined in Section 1.9, “OPERATIONAL TESTS

AND ADJUSTMENTS'.

Results:

1. If voltage and frequency are now acceptable, stop

tests.

2. If frequency is now acceptable, but voltage is low, go to Test 3.

TEST 16- CHECK WIRES 2, 2A, AND 6:

Discussion: Unregulated AC output voltage from

the stator excitation windings is deiivered to the voltage

regulator via Wires 2, 2A and 6. An open condition in any part of this circuit will prevent excitation current from reaching the reguiator and the Rotor.

Procedure: Refer to appropriate wiring diagram.

Carefully inspect the wires for damage, incorrect con nections, burned insulation, etc. Use a VOM to test each wire for an open or shorted condition.

Results: Reconnect, repair or replace any dam

aged or defective wire(s).

TEST 17- CHECK FOR OVERLOAD CONDITION:

Discussion: The generator should never be over

loaded. That is, the total of all electrical loads con nected at one time should not be greater than the unit’s

rated wattage/amperage capacity. If the generator is overloaded, rpm, frequency and voltage can drop sharply. In addition, the stator windings can heat up and cause the thermal protector to trip (open). If frequency

and voltage drop excessively when electrical loads are

applied, make sure the unit is not overloaded.

PAGE 1.7-8

PART 1

THE REVOLVING FIELD AC GENERATOR

Diagnostic Tests (Continued)

Procedure: Add up the watts or amperes required to run all lights, appliances, motors, tools, etc., that will be powered by the generator at one time. This totatl should not be greater than the generator’s rated watt age and/or amperage capacity. Rated wattage and amperage of the generator can be found on the unit’s

DATA PLATE.

Results:

1. If frequency and voltage drop excessively when load is applied, but unit is NOT overloaded, go to Test 15.

2. If unit is overloaded, reduce the total load to a wattage or amperage value that is within the unit's rated capacity.

NOTE: A badly shorted condition in the load circuit can

also cause frequency and voltage to drop drastically

when the load is applied.

TEST 18- CHECK ENGINE POWER & CONDITION:

Discussion: If the engine has lost power, AC out

put voltage and frequency will droop when the load is applied. The limit to AC output current (amps) is often established by available engine power. Loss of engine power can resuit from such things as a dirty air cleaner, burned valves, mechanical damage, out-of-time, etc.

Procedure: Inspect and test the engine. Look for

anything that might cause the engine to lose power.

SECTION 1.7- TROUBLESHOOTING

(UNITS WITH 10 INCH STATOR)

PAGE 1.7-9

SECTION 1.7-TROUBLESHOOTING (UNITS WITH 10 INCH STATOR)

PART 1

THE REVOLVING FIELD AC GENERATOR

PAGE 1.7-10

PARTI

THE REVOLVING FIELD AC GENERATOR

INSULATION RESISTANCE TESTS

SECTION 1.8

INSULATION RESISTANCE TESTS

Section 1.8

Effects of Dirt and Moisture on Genera

tors

If moisture is permitted to remain in contact with the generator windings, some of it will be retained in voids and cracks of the winding insulation. This will cause a reduced insulation resistance and, eventually, genera tor AC output will be affected. Winding Insulation used in 'NP' and "IM" series generators is moisture resistant. However, prolonged exposure to water, high humidity, salt air, etc., will gradually degrade the resistance of winding insulation.

Dirt can make the problem even worse, since dirt tends to hold moisture into contact with the windings. Salt (as from sea air) will also worsen the problem, since salt tends to absorb moisture from the air. When salt and moisture combine, they make a good electrical conductor.

Because of the detrimental effects of moisture, dirt

and salt, the generator should be kept as dry and clean as possible. Stator and rotor winding insulation resis tance should be tested periodically. If insulation resis tance is low, drying may be necessary. If resistance is still low after drying, replacement of defective windings may be required.

Insulation Resistance

Insulation resistance is a measurement of the in tegrity of the insulating materials that separate the electrical windings from the generator's steel core. Most winding failures are caused by a breakdown in the insulation system. In many cases, low insulation resis-. tance is caused by moisture that has collected when the generator is shut down. The problem can often be corrected by drying out the windings.

Normally, the resistance of the insulation system is on the order of millions of ohms. It can be measured with a device called a "megger" or "megohm meter" (meg is for million) and a power supply. The power supply voltage varies, but the most common is 500 volts. A megger voltage greater than 500 is not recom mended.

Another device used to check for insulation break down is called a "Hi-Pot Tester". See Figure 1. A typical Hi-Pot Tester has a "Pilot" lamp which turns on to indicate that power is availabie; and a "Breakdown" lamp which turns on if the insulation is breaking down under an appiied voltage. The Hi-Pot Tester shown also has a "Voltage Selector" switch which allows the user to select the voltage that will be applied to the winding being tested.

To measure insulation resistance, connect one test lead to the leads of the winding to be tested. Connect the other test iead to the generator frame. Make sure the ieads of the part being tested are not touching metal parts of the generator. If the "Neutral" line of a stator is grounded, it must be disconnected.

CAUTION: Before attempting to test Insulation resistance, first disconnect all electronic com ponents, regulators, diodes, surge protectors, protective relays, etc. The high tester voltages

will destroy such components.

Figure 1. One Kind of Hl-Pot Tester

_______________

Using a Hi-Pot Tester

The Hi-Pot Tester shown in Figure 1 is one of many

brands that are commerciaily available. Insulation

breakdown tests outlined In this section use the tester

shown in the illustration. The tester shown has a

"Breakdown" lamp which turns on to indicate an insu lation breakdown. If you are using another tester or megger, follow the manufacturer’s instructions care

fully. Do not exceed the voltages reconvnended in this

manual.

All stator leads must be isolated from ground and

connected together. On systems with a grounded neu

tral, the neutral can be isolated from ground and used

as a test point.

DANGER: MEGGERS AND HI-POT TESTERS DELIVER A HIGH VOLTAGE TO WINDINGS

BEING TESTED. DO NOT TOUCH THE GENER ATOR, THE WINDING BEING TESTED, OR THE TEST LEADS WHEN PERFORMING TESTS. CARELESS USE OF SUCH TESTERS CAN RE SULT IN DANGEROUS ELECTRICAL SHOCK.

CAUTION: Do not apply tester voltages to the stator or rotor windings longer than 1 second.

Turn the tester switch ^0 N"; check that the Pilot

lamp is "ON"; wait 1 second while observing the "Breakdown" lamp; turn the tester switch "OFF".

PAGE 1.8-1

SECTION 1.8 INSULATION RESISTANCE TESTS

PARTI

THE REVOLVING FIELD AC GENERATOR

Testing Stator Insulation Resistance

To test tne resistance of stator insulation, proceed

as follows:

1. To test all stator leads to ground:

a. Connect the ends of stator leads 11,22,33,44,2, 5 and 6 together. Make sure none of the wi re terminal ends are touching any part of the generator. b. Connect the red test lead of the Hi-Pot Tester to the bunched terminal ends of Wires 11, 22, 33, 44, 2, 5 and 6. c. Connect the black test lead of the Hi-Pot Tester to a clean frame ground on the stator. d. Turn the Hi-Pot Tester Switch OFF.

e. Plug the Hi-Pot Tester into a 120 volts AC wall P0Q 0 pt3cl6 •

f. Set the Tester’s Voltage Switch to "SOO' volts. g. Turn the Hi-Pot Tester switch ON. Check that the Tester’s Pilot lamp is ON. h. Set the Tester Voltage Switch to ''2000" volts and watch the "Breakdown' lamp. After 1 second, turn the Tester switch OFF and reset Voltage switch to "500" volts. DO NOT APPLY VOLTAGE LONGER THAN 1 SECOND.

2. To test between isolated windings:

a. Connect the red Tester lead to terminal end of stator lead No. 2. Connect the black tester lead to terminal end of stator lead No. 11.

b. Turn the Tester switch to ON (Pilot lamp should

come ON). c. Set the Voltage Selector switch to "1500" volts. APPLY VOLTAGE FOR ONE SECOND ONLY WHILE OBSERVING THE "BREAKDOWN" LAMP.

CAUTION: Rotor must be completely Isolated

from the Voltage Reoulator. Brush Wires No. 1

and 4 must not touch any part of frame during

the test, or damage to the Regulator will result.

1. Connect the red test lead to the positive (+) slip ring.

This is the slip ring nearest the Rotor bearing.

2. Connect the tester black lead to a clean frame ground on the Rotor.

3. Turn the Tester switch OFF.

4. Plug the tester into a 120 volts AC wall receptacle.

5. Set the Tester Voltage switch to "500" volts.

6. Turn the tester ON and check that the Pilot lamp is ON.

7. Set the tester Voltage switch to "1250" volts. Wait one (1) second, then turn the tester switch OFF. DO NOT APPLY VOLTAGE LONGER THAN ONE SEC OND.

If the tester "Breakdown" lamp comes on during the

one second test, cleaning and drying may be neces sary. After cleaning and drying, repeat the insulation breakdown test. If "Breakdown" lamp comes on during the second test (after cleaning and drying), replace the

Rotor.

d. Turn the Tester switch to OFF and reset the Voltage switch to "500" volts.

3. To test between parallel windings:

a. Connect the red tester lead to terminal end of

stator lead No. 11; the black tester lead to terminal end of stator lead No. 33. b. Turn the tester switch to ON (pilot lamp should come ON).

c. Set the Voltage Selector switch to "500" volts.

APPLY VOLTAGE FOR ONE SECOND WHILE OB SERVING THE "BREAKDOWN" LAMP. After one second, turn the tester switch to "Off".

If the tester "Breakdown" lamp came on during any one second test, clean and dry the stator. Then, repeat the insulation breakdown test. If the "Breakdown" lamp

illuminates during the second test, replace the stator

assembly.

Testing Rotor Insulation

Before testing the Rotor, make sure brushes and

brush holders are removed and Rotor is completely isolated from ground and from other components.

Disconnect excitation leads No. 1 and 4 from the

brushes. Remove the brush holders with brushes. Make sure Rotor is completely isolated from frame

ground.

PAGE 1.8-2

PARTI

THE REVOLVING FIELD AC GENERATOR

SECTION 1.8

INSULATION RESISTANCE TESTS

Grease or caked-on dirt can be removed with a saoft brush or a clean, damp cloth. A vacuum system may be used to remove loosened dirt. Loose dust and dirt may aiso be blown away with clean, dry, low pres

sure air (25 psi maximum).

CAUTION: Do NOT use a forceful spray of water to clean the generator. Some of the water will

be retained on generator windings.

To dry the generator, proceed as follows;

1. Open the generator's main circuit breakers or the

main line switch. NO ELECTRICAL LOADS MUST BE APPLIED WHILE THE GENERATOR IS DRYING.

2. Disconnect the voltage regulator.

3. Provide an external source of warm, diy air. This air must be drawn through the generator's air inlet, blown over the rotor and stator, and must then exit throuah the cooling air outlet opening(s). DO NOT EXCEED

185' F. (85* C.).

4. Start the generator, let it run for about 2 to 3 hours.

5. Afterthe recommended drying time of 2-3 hours, shut the engine down.

6. Retest the stator and rotor insulation for breakdown.

Cleaning the Generator

___________

Drying the Generator

PAGE 1.8-3

SECTION 1.8 INSULATION RESISTANCE TESTS

PARTI

THE REVOLVING FIELD AC GENERATOR

PAGE 1.8-4

PARTI

THE REVOLVING FIELD AC GENERATOR

OPERATIONAL TESTS AND ADJUSTMENTS

SECTION 1.9

OPERATIONAL TESTS & ADJUSTMENTS

Section 1.9

Introduction

Following major maintenance, an operational test

of the generator should be conducted. Any required adjustments should be completed at this time. Opera tional testing may be accomplished on either an in stalled or uninstalled generator.

Preparation Before Operation

Before you attempt to crank or start the generator,

be sure to check the following:

□ Check engine oil level. □ Check engine coolant level.

□ Check fuel supply. □ Check cooling air flow.

CHECK ENGINE OIL LEVEL:

Remove the engine dipstick and wipe end with a clean, lint-free cloth. Insert dipstick again and check oil level. Add the recommended oil, if necessary, to the dipstick "FULL" mark only. DO NOT OVERFILL ABOVE THE "FULL" MARK. NEVER OPERATE THE ENGINE WITH OIL LEVEL BELOW THE "ADD" MARK.

Engine oil capacity without oil filter change is 3.7

U.S. quarts; with oil filter change, capacity is 4.0 U.S.

quarts.

Use a high quality detergent oil classified "For

Service CC or CD". Detergent oils keep the engine

cleaner and reduce carbon deposits. Use oil having the

following SAE (Society of Automotive Engineers) vis

cosity rating, based on the ambient temperature range

anticipated before the next oil change:

AMBIENT TEMPERATURE

Above 100’ F.

40MOO' F.

Below 40‘ F.

CHECK COOLANT LEVEL:

Some generator models will be equipped with a remote mounted radiator, some models with a unitmounted radiator. Before starting, be sure to check the coolant level in the radiator as well as the coolant

recovery bottle.

Recommended coolant is a 50-50 mixture of ethyl

ene glycol base anti-freeze and soft water. Use only a

low silicate type anti-freeze. When adding coolant, always add the recommended 50-50 mixture.

CHECK FUEL SUPPLY:

Recommended fuel is a high quality, automotive

type DIESEL fuel conforming to JIS No. 2D diesel fuel. The fuel supply must be kept CLEAN.

RECOMMENDED SAE VISCOSITY

Use SAE 4tTo1l

SAE10W-30orSAE30 0ll

SAE SW-20 or SW-30 Oil

CHECK COOLING AIR FLOW;

If the generator is installed, make sure all cooling

air inlet and outlet openings are open and unot^

staicted. Without adequate cooling air flow, the unit will quickly overheat and cause problems.

Starting the Engine

Before startup, turn OFF all electrical loads. Initial

tests and adjustments are accomplished with the unit

at no-load. To crank and start engine, hold the engine's startfstop switch at START. Release the switch when the engine starts. Let the engine stabilize and warm up.

Operational Tests

PRELIMINARY CHECKS:

When the engine has stabilized and warmed up,

check all gauge and instrument readings available (oil pressure, coolant temperature, DC voltmeter, AC volt age, AC frequency).

NOTE: Some Installations may Include a gauge and meter panel. See Part S, Section 5.8, "REMOTE PANELS AND CABLES".

Listen to the engine-generator while it is running. Unusual noises should be investigated and corrected. If the exhaust system is defective, shut down and complete the necessary repairs.

DANGER: ENGINE EXHAUST GASES CONTAIN DEADLY CARBON MONOXIDE GAS. CARBON MONOXIDE IS AN ODORLESS AND COLOR LESS GAS THAT IS FORMED DURING THE COMBUSTION OF HYDROCARBON FUELS. DO NOT OPERATE THE GENERATOR IF ITS EX

HAUST SYSTEM IS DAMAGED OR LEAKING. EXHAUST FUMES, IF BREATHED IN SUFFI

CIENT CONCENTRATIONS, CAN CAUSE UN CONSCIOUSNESS OR EVEN DEATH. PROVIDE

ADEQUATE VENTILATION TO PREVENT THIS DANGEROUS GAS FROM ACCUMULATING.

Inspect the engine carefully for signs of oil, fuel or

coolant leaks. No leakage should be permitted.

CHECK AC OUTPUT VOLTAGE & FREQUENCY:

With the engine running at no-load, use an accu

rate AC voltmeter and frequency meter to check volt

age and frequency output. Record all readings for future reference. Frequency should bo 60.5-63.5 Hertz.

Line-to-neutral voltage should be 121-127 volts AC; line-to-line voltage should be 242-254 volts AC at noload. Setting the no-load frequency slightly high helps

revent excessive rpm and frequency droop under

eavy electrical loading.

PAGE 1.9-1

SECTION 1.9 OPERATIONAL TESTS & ADJUSTMENTS

PARTI

THE REVOLVING FIELD AC GENERATOR

Operational Tests (Continued)

If AC output voltage and frequency are not within

the stated limits, some adjustments will have to be made as follows:

□ If voltage and frequency are both correspondingly

high or low, check and adjust the engine governor.

□ If AC frequency is good, but voltage is high or low,

try adjusting the Voltage Regulator.

NOTE: Do NOT attempt an adjustment If the engine Is running rough. If engine runs rough or Is hard to start, air may be present In the diesel fuel system. If necessary, bleed the fuel system as outlined In PART 4, "ENGINE FUEL SYSTEM".

NOTE: If problems are encountered, refer to the appropriate troubleshooting section In this manual.

See Section 1.6 If troubleshooting units with 15 Inch stator. See Section 1.7 for troubleshooting units with 10 Inch stator.

CHECK OPERATION UNDER LOAD:

Turn on electrical loads equal to the generator’s rated wattage and/or amperage capacity. Engine speed (frequency) may drop off momentarily when load is applied, but should recover within a short time. With the unit loaded to its rated capacity, frequency should not droop below about 58 Hertz.

5. If no-load AC frequency is high or low, adjust the / engine governor as follows Rgure 1):

a. Turn the GOVERNOR ADJUSTING SCREWS as

required to obtain a no-load frequency as close as

possible to 62 Hertz. b. With no-load frequency close to 62 Hertz, apply an electrical load as close as possible to the unit's

rated load. If frequency drops below 58 Hertz, repeat Step 5(a), but set the no-load frequency slightly higher than 62 Hertz. DO NOT EXCEED 63.5

HERTZ. c. Again load to the unit to its rated load capacity.

Frequency under load should not drop below 58

Hertz. d. Continue to check frequency at no-load and under

rated load until frequency at rated load is 58 Hertz or

more. DO NOT EXCEED A NO-LOAD SPEED OF

63.5 HERTZ.

You may wish to read Section 1.5, ‘INTRODUC

Engine Governor Adjustment

TION TO TROUBLESHOOTINCr.

Initial adjustment of governed speed should be accomplished at no-load condition. Prior to engine startup, turn OFF all electrical loads by whatever means available (such as the generator main circuit breakers).

To adjust the engine governor, proceed as follows:

1. Connect an accurate AC frequency meter and volt

meter to the proper generator leads.

2. Start the engine, let it stabilize and warm up at no-load.

3. Read the no-load AC frequency and voltage from the previously connected meters.

a. AC frequency at no-load should be 60.5-63.0 Hertz. b. Line-to-line voltage should be 242-254 volts. c. Line-to-neutral voltage should be 121-127 volts.

4. Analyze the voltage and amperage readings as follows:

a. If frequency and voltage are both good, no adjust ment is needed. b. If frequency is high or low, go on to Step 5 of this test. c. If frequency is good, but voltage is high or low, adjust the voltage regulator.

Figure 1. Engine Governor Adjustment

Voltage Regulator Adjustment

UNITS WITH 10 INCH STATOR:

To obtain correct AC voltage when frequency is

correct, proceed as follows (Rgure 2):

1. Make sure the unit’s no-load frequency is correct. Readjust the engine governor, if necessary.

2. When frequency is correct, and with unit running at

no-load, slowly tumthe VOLTAGE ADJUST potentiom eter on the voltage regulator until voltage is within the specified limits.

a. Line-to-neutral voltage should be 121-127 volts. b. Line-to-line voltage should be 242-254 volts.

CAUTION: Do NOT force the Regulator’s adjust ment potentiometer past its stops or damage to

the Regulator can result.

___________________

PAGE 1.9-2

PARTI

THE REVOLVING FIELD AC GENERATOR

SECTION 1.9

OPERATIONAL TESTS & ADJUSTMENTS

Voltage Regulator Adjustment (Contin

ued):

VOLTAGE REGULATOR

“ +

2 6 1 4 11 22

000000

Figure 2. Voltage Regulator (Units with 10" Stator)

UNITS WITH 15 INCH STATOR:

The voltage regulator used on NP series units with

15 inch stator is shown in Figure 4. To adjust the regulator, proceed as follows:

1. Gain access to the voltage regulator in the generator control panel.

2. If a new replacement regulator is being installed, locate Switch ‘SWr on the regulator circuit board. Set the switch to Position “2". Position "1“ is used only for brushless generators.

5. If so equipped, set the control panel’s voltage adjust pot to its centered or mid-position.

6. Turn OFF ail electrical loads. Startup and initial adjustments will be accomplished under a "no-load" condition.

7. Start the engine, let it stabilize and warm up at no-load.

8. Check the reading on the frequency meter. a. Frequency shouid be 60.5-63.5 Hertz.

b. If necessary, adjust the engine governor to obtain

a no-load frequency reading as ciose to 62 Hertz as

possible. See adjustment procedure for governor. c. Do NOT' proceed until governor is properly ad

justed and frequency reading is correct.

9. Check the lamps (LED’s) on the voltage regulator.

All lamps should be ON. If any lamp is OUT, see appropriate troubleshooting section.

10. Turn the reguiator's "Voltage Adjust" pot to obtain

a line-to-line voltage of 242-254 volts; a line-to-neutral voltage of 121 -127 volts. Try to get the voltage as close as possible to 124 volts (line-to-neutral): or 248 volts

(line-to-line).

11. If the red "Regulator" lamp is flashing, turn the

"Stability" pot either direction until the flashing stops.

12. Apply an electrical load and check engine speed recovery.

a. Adjust the "Underfrequency Adjust" counterclock wise to unload the unit and reduce load voltage while the engine recovers. b. For flat regulation (no voltage decrease as fre quency drops), turn the ’’Underfrequency Adjust" fully clockwise. Set point for this adjustment is 62

Hertz (counterclockwise) to 52 Hertz (clockwise).

c. To obtain a constant voltage reduction as fre quency drops, set "Underfrequency Adjust" fully counterclockwise.

13. With electrical load still applied, check the "Regu

lator" lamp for flashing. If lamp is flashing, adjust the "Stability" pot until flashing stops.

14. If better response is needed, adjust the "Gain" pot

clockwise as needed. Then, if needed, correct for insta

bility by adjusting the "Stability" pot.

3. Connect an accurate AC voltmeter and frequency meter to the generator’s AC output leads.

4. With unit shut down, set the voltage regulator poten tiometers as follows:

a. Turn the “Voltage Adjust’' pot fully counterclock wise.

b. Set "Gain" to its centered or mid-position. c. Set "Stability" to its centered or mid-position. d. Do NOT adjust the ’’Underfrequency Adjust" pot.

SECTION 1.9 OPERATIONAL TESTS AND ADJUSTMENTS

Voltage Regulator Adjustment (Contln>

ued)

UNITS WITH 15 INCH STATOR (CONT’D);

14. Turn OFF all electrical loads and check the voltage

regulator lamps at no-load.

15. When all adjustments have been completed, let the

engine run at no-load for a few minutes to stabiiize internal engine-generator temperatures.

16. Shut the engine down.

PARTI

THE REVOLVING FIELD AC GENERATOR

GENERAL;

matic shutdown system which will stop the engine in

the event of an overspeed. Shutdown will occur auto matically when AC frequency (engine speed) exceeds approximately 69-71 Hertz (2070-2130 rpm). Adjust

ment of the overspeed shutdown setting is required

when the unit’s engine control circuit board is replaced.

Overspeed Shutdown Adjustment

NP series generators are equipped with an auto

Figure 5. Engine Control Circuit Board

ADJUSTMENT PROCEDURE:

To adjust the overspeed shutdown setting, proceed

as follows;

1. On the engine controi circuit board, turn the OVER SPEED SHUTDOWN POTENTIOMETER counter

clockwise until it just contacts its stop. DO NOT

FORCE.

2. Connect an accurate AC frequency meter across the

generator’s AC output leads.

3. Start the engine, let it stabilize and warm up.

4. Use the injection pump throttle lever to SLOWLY increase engine speed untii the frequency meter reads

69-71 Hertz.

5. Hold the thrtottle at 69-71 Hertz and SLOWLY turn the OVERSPEED SHUTDOWN POT clockwise. When

the engine shuts down, overspeed setting is correct.

PAGE 1.9-4

SECTION

2.1

TABLE OF CONTENTS

TITLE

Engine SpecUlcatlons & Charts

PART 2

ENGINE

MECHANICAL

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

MOBILE

AC GENERATORS

Liquid-Cooled

Diesel Engine Models

2.2

2.3

2.4

2.5

General Information

Engine Disassembly Disassembly and Inspection

Engine Reassembly

PART 2 ENGINE MECHANICAL!

ENGINE SPECIFICATIONS & CHARTS

SECTION 2.1

ENGINE SPECIFICATIONS & CHARTS

Section 2.1

Engine Cross Section- Side View

■9

¿1

:13'

1. Head cover

2. Piston pin

3. Push rod

4. Tappet

5. Ring gear

6. Fly wheel

7. Crank shaft

8. Fly wheel cover

9. Exhaust valve

10. Intake valve

- 14'

-16

-20

11. Thermostat

12. Water pump

13. Camshaft gear

14. V belt

15. Idle gear

16. Oil pump

17. Crankshaft gear

18. Crankshaft pulley

19. Oil pan

20. Suction filter

PAGE 2.1-1

SECTION 2.1 ENGINE SPECIFICATIONS & CHARTS

Engine Cross Section - Frontal View

PART 2

ENGINE MECHANICAL

PAGE 2.1-2

1. Level gauge

2. Nozzle and holder

3. Glow plug

4. Injection pump

5. Camshaft

6. Oil filter

7. Rocker arm

8. Cylinder head

9. Piston

10. Cylinder block

11. Connecting rod

12. Relief valve

PART 2 ENGINE MECHANICAL

General Engine Specifications

Type of Engine......................4-cyde diesel

Cooling Method Cylinder Arrangement Combutlon Chambers Number of Cylinders Bore X Stroke Total Displacement Compression Ratio

Fuel Injection Pump Injection Nozzles

Recommended Fuel ..............J IS No. 2D Diesel

.....................

...........

............

.......................

...............

................

..............

..................

Water-Cooled Vertyical In-Line ¿pedal Swirl Type 3

2.95 x 2.83 Inches 954 cc

23 to 1 Bosch Type Throttle Type

Torque Values for Metric Bolts

ENGINE SPECIFICATIONS & CHARTS

Pump

.............................

Oil Fitter Crankcase Oil Capacity

Oil Pressure

.............................

With Filter Change Without Filter Change ... 3.7 U.S. Quarts

.........................

............

TrtocholdType Full-Flow Spbi-On

4.0 U.S. Quarts

28-71 psi(195-490 kPa)

SECTION 2.1

SIZE OF SCREW

CLASS.

M10

Ml 2

M14 77

M16

M18

COARSE THREAD

PITCH

(mm)

4T 7T

1.00

8T 4T

1.25

4T 7T

1.50

8T 4T

77 1.75

2.00

8T 4T

2.00

8T 4T

2.50

FINE THREAD

TIGHTENING

TORQUE

3.6-5.0 Ft.-Lbs. (0.50-0.70 m-kg)

5.8-9.4 Ft.-Lbs. (0.80-1.30 m-kg.)

PITCH

(mm)

••••• —

TIGHTENING

TORQUE

—

7.2-10.0 Ft.-Lbs. (1.00-1.40 m-kg) 10-13 Ft.-Lbs. (1.00-1.40 m-kg)

17.3-21.7 Ft.-Lbs. (2.4-3.0 m-kg)

1.00

11.5-16.5 Ft.-Lbs. (1.6-2.3 m-kg)

18.8-26.7 Ft.-Lbs. (2.6-3.7 m-kg)

19.5-24.6 Ft.-Lbs. (2.7-3.4 m-kg)

34.0-39.0 Ft.-Lbs. (4.7-5.S m-kg)

39.0-45.0 Ft.-Lbs. (5.3-6.3 m-kg)

29.0-33.0 Ft.-Lbs. (3.9-4.7 m-kg)

52.0-58.0 Ft.-Lbs. (7.1-8.1 m-kg)

57.0-65.0 Ft.-Lbs. (7.9-9.1 m-kg)

49.0-56.0 Ft.-Lbs. (6.8-7.8 m-kg)

81.0-92.0 Ft.-Lbs. (11.2-12.8 m-kg)

97.0-109.0 Ft.-Lbs. (13.3-15.1 m-kg)

67.0-77.0 Ft.-Lbs. (9.5-11.5 m-kg)

1.25

1.50 90.0-105.0 Ft.-Lbs. (12.4-14.6 m-kg)

20.0-28.0 Ft.-Lbs. (2.8-4.0 m-kg)

36.0-46.0 Ft.-Lbs. (4.9-6.5 m-kg)

40.0-52.0 Ft.-Lbs. (5.S-7.2 m-kg) 31-41 Ft.-Lbs. (4.3-5.7 m-kg)

56.0-68.0 Ft.-Lbs. (7.7-9.4 m-kg)

62.0-75.0 Ft.-Lbs. (8.6-10.04 m-kg)

52.0-63.0 Ft.-Lbs. (7.2-8.8 m-kg)

107.0-124.0 Ft.-Lbs. (14.8-17.2 m-kg)

69.0-83.0 Ft.-Lbs. (9.5-11.5 m-kg)

116.0-130.0 Ft.-Lbs. (16.0-18.0 m-kg) 1.50 120.0-137.0 Ft.-Lbs. (16.5-19.0 m-kg)

130.0-145.0 Ft.-Lbs. (17.9-20.1 m-kg)

140.0-158.0 Ft.-Lbs. (19.4-21.9 m-kg)

88.0-99.0 Ft.-Lbs. (12.2-13.8 m-kg) 100.0-116.0 Ft.-Lbs. (13.8-16.1 m-kg)

150.0-167.0 Ft.-Lbs. (20.8-23.3 m-kg) 1.5 178-198.0 Ft.-Lbs. (24.5-27.5 m-kg)

175.0-193.0 Ft.-Lbs. (24.2-26.8 m-kg) 202-231.0 Ft.-Lbs. (28.0-32.0 m-kg)

M20

4T 7T 8T

47...... SS41 or S20C material

109.0-130.0 Ft.-Lbs. (15.0-18.0 m-kg) 133.0-149.0 Ft.-Lbs. (18.3-20.7 m-kg)

2.50

186.0-205 Ft.-Lbs. (25.7-28.3 m-kg) 1.5 214-249.0 Ft.-Lbs. (29.5-34.5 m-kg)

(Standard bolt)

7T S45C

8T SCr2 - 3or

SCM2 - 3 material

(Special bolt)

206.0-240.0 Ft.-Lbs. (28.5-33.5 m-kg)

246.0-289.0 Ft.-Lbs. (34.0-40.0 m-kg)

heQC^)

PAGE 2.1-3

SECTION 2.1 ENGINE SPECIFICATIONS & CHARTS!

Engine Tolerances and Fits

CYLINDER HEAD: Compression Pressure:

Standard Value

Repair Required If ...............Less than 284.4 psI

Check Pressure at

...................

................

More than 426.6 psi

200 rpm

Clearance to Cylinder:

Standard Value

Allowable Limit

Measure at

.....................

....................

...........................

PART 2

ENGINE MECHANICAL

0.003-0.004 Inch

0.010 inch 20" C.

Maximum Cylinder Head Face Distortion:

Standard Value

Repair if..............................More than 0.005 inch

Valve Seat (Intake and Exhaust):

Standard Recess Repair if Greater than Valve Seat Standard Width . 0.047-0.059 inch Repair Width if More Than .. 0.079 inch Valve Seat Angle

Cylinder Head Tightening Torque:

Torque Value

CYLINDER BLOCK:

Type

...................................

Cylinder Block Bore:

Standard Dimension Standard Value Repair if More Than Allowable Limits

Oversize.............................. 0.020, 0.040 inch

Maximum Distortion of Cylinder Block Upper Face:

Standard Value

Repair if More Than.............. 0.005 inch

...................

..........

..................

.......................

.............

....................

.............

..................

...................

Less than 0.0020 inch

0.033 inch

0.070 inch

45’

32.5-36.0 Ft-Lbs

Wet, Single Piece

2.95 inches

2.9527-2.9535 Inches

2.9606 inches

3.000 inches

0.0020 inch

Inside Diameter of Piston Pin:

Standard Dimension

Standard Value

Piston Pin Hole to Pin Clearance:

Standard Value Allowable Limit

Piston Pin Outer Diameter:

Standard Dimension Standard Value

Allowable Limit

Small End Bushing to Pin Oil Clearance:

Standard Value Allowable Limit

Piston Ring Gap:

No. 1 Ring Standard Value .. 0.008-0.014 inch No. 2 Ring Standard Value .. 0.006-0.012 inch

Oil Ring Standard Value .... 0.008-0.014 inch

Allowable Limit (All Rings) .. 0.039 inch

Piston Ring Groove to Ring Clearance:

No. 1 Ring Standard Value .. 0.002-0.004 Inch No. 2 Ring Standard Value .. 0.002-0.012 inch

Oil Ring Standard Clearance

Allowable Limit (No. 1,2) ... 0.001 inch

Allowable Limit (Oil Ring) ... 0.006 inch

Piston Ring Width:

No. 1 Ring Std. Dimension No. 1 Ring Std. Value No. 2 Ring Std. Dimension

No. 2 Ring Std. Value ....

Oil Ring Std. Dimension .. Oil Ring Std. Value Oversize Rings Available .

............................

..............

.....................

....................

..............

.....................

....................

.....................

....................

_____

............

0.827 inch

0.8267-0.8269 inch

-0.00008 to +0.0003

0.0008 inch

0.8268 inch

0.8266-0.8268 inch

0.8260 Inch

0.0006-0.0012 inch

0.003 inch

0.002-0.004 inch

0.079 inch

0.0776-0.0783 inch

0.059 inch

0.0579-0.0587 inch

0.1575 inch

0.1563-0.1571 inch

0.020, 0.040 Inch

MAIN REVOLVING SYSTEM: Piston Skin Maximum Diameter:

Standard Dimension Standard Value

Allowable Limit

Oversize.............................. 0.020, 0.040 inch

.............

...................

....................

2.9527 inches

2.9134 inches

2.9409 inches

PAGE 2.1-4

Connecting Rod:

Allowable Twist Between Small and large End

Holes (Per 3.94 inches) Not to Exceed Front to Rear Play Between Conecting Rod and Crankpin Allowable Limit

................................

..................................

0.008 inch

0.028 inch

PART 2

ENGINE MECHANICAL

SECTION 2.1

ENGINE SPECIFICATIONS & CHARTS

Engine Tolerances

MAIN REVOLVING SYSTEM (CONT’D); Connecting Rod (Continued):

Connecting Rod to Crankpin Oil Clearance

Allowable Limit

Connecting Rod Bolt Torque

Crankshaft:

Standard Diameter of Main Journal Standard Tolerance of Main Journal Allowable Limit of Main Journal Main Journal Undersize Cramkpln Standard

Diameter ............................ 1.5354 Inch

Crankpin Standard

Tolerance............................ 1.5340-1.5344 inch

Allowable Crankping Limit .. 1.5118 Inch

Crankpin Undersize.............. 0.010, 0.020 inch

Standard Crankshaft Deflection

Maximum Allowable

Crankshaft Deflection .......... 0.002 inch

Standard Axial Crankshaft Play Maximum Allowable Axial Crankshaft Play Standard Thickness of Thrust Washer Standard Tolerance of Thrust Washer Maximum Allowable Thickness of Thrust Washer Tolerance of Oil Clearance

Between Crankshaft Journal

and Center Bearing

Maximum Allowable Oil Clearance Between Crankshaft

Journal and Center Bearing . 0.0078 Inch

VALVE SYSTEM: Camshaft:

Standard Height of Cam

Tolerance for Intake &

Exhaust............................... 1.0413-1.0433 inch

Minimum Allowable Cam Height

for Intake & Exhaust

Standard Cam Height

for Injection Pump

Minimum Allowable Injection Pump Cam Height

Standard Cam Height for

Feed Pump Minimum Alowable Cam Hieght

for Feed Pump Standard Cam Gear

Backlash ............................. 0.003 Inch

Maximum Cam Gear

Backlash .............................0.012 inch

....................

........................

......................

_____

...........................

...................

.....................

.................

..............

............

...............

................

.........................

.....................

0.008 Inch 22-25 Ft.-Lbs.

1.8110 inch

1.8096-1.8100 Inch

1.7874 Inch

0.010, 0.020 Inch

Less than 0.001 inch

0.002 inch

0.020 inch

0.079 inch

0.077-0.079 inch

0.071 inch

0.0015-0.0036 Inch

1.0276 Inch

0.9425-0.9472 inch

0.9370 inch

1.0590-1.0630 inch

1.0236 Inch

and Fits (Continued)

^ “ (thickness)

Valves:

Standard Diameter of

Intake Valve Stem Maximum Allowable Diameter

of Intake Valve Stem

Standard Diameter of Exhaust Valve Stem

Maximum Allowable Diameter

of Exhaust Valve Stem...........0,

Standard Clearance Between

Intake Valve Stem and Valve

Guide..................■

Maximum Clearance Between Intake Valve Stem and Valve

Guide

..................................

Standard Clearance Between

Exhaust Valve Stem and

Guide...................................0

Maximum Clearance Between Exhaust Valve Stem and

Guide...................................0

Valve Standard Thickness .. 0 Valve Thickness Standard

Tolerance.............................0

Maximum Allowable Valve

Thickness

Valve Clearance- Intake &

Exhaust (When Cold).............0

Valve Springs:

Force Required to Compress Springs to a Length of 1.197

inch.....................................17.86 pounds

Valve Spring Standard

Free Length Valve Spring Minimum Free Length Standard Valve Spring

Squareness ..........................Less than 0.047 inch

Replace Spritig if Out-of-

Square More Than................. 0.079 Inch

.............................

................

.............

..............

...............

.........................

2744-0.2738 Inch

2713 inch

2740-0.2736 Inch

0. 2693 inch

001-0.002 inch

,0079 inch

.0016-0.0026 inch

.010 Inch .039 inch

.036-0.042 inch

,020 Inch

.008-0.020 inch

1.3779 Inch

1.3189 Inch

SECTION 2.1

=NniMF SPFCinCATIONS & CHARTS

Engine Tolerances and Fits (Continued) VALVE SYSTEM (CONT'D): Valve Timing:

Intake Valve

Open ..............................

closed

Exhaust Valve

Push Rods:

Standard Overall Length .., Overall Length Standard

Tolerance

Push Rod Outer Diameter .,

Rorkpr Arm:

Rocker Arm Standard Diameter Rocker Arm Standard

Tolerance..........................

Maximum Allowable Wear .

FUEL SYSTEM: Injection Pump:

Diameter of Pump Plunger. Pump Plunger Stroke

Fuel Injection Timing

.............................

Open

............................

Closed

............................

..........................

............................

.........

, 13’ BTDC , 43' BTDC

. 43’ BTDC

, 13* BTDC

,5.181 inch , 5.173-5.189 inch

. 0.248 inch

. 0.459 inch . 0.4586-0.4594 inch

. 0.4555 Inch

. 0.1969 inch . 0.2362 inch . 20’-2V BTDC

LUBRICATION SYSTEM:

Oil Pump:

Discharge Volume

In Quarts

Liters.............................

Relief Pressure...................

Pump Rotor to Vane Tip Clearance (Standard Tolerance) Pump Rotor to Vane Maximum Allowable Tip Clearance

Pump Rotor to Cover Side Clearance (Standard Tolerance) Pump Rotor to Cover Maximum Side Clearance .

........................

..........................

........................

PART 2

FMfilNE MECHANICAL

. Over 10.57/Minute . Over 10.00/Minute . 43-71 psi

. 0.0004-0.0059 inch

. 0.010 inch

. 0.004-0.006 inch

. 0.008 inch

Injection Nozzle:

Injection Pressure

Angle of Injection

Connecting Rod Bearing Cap

Foot-Pounds

m-kg

.................................

Main Bearing Holders

Foot-Pounds m-kg

.................................

Flywheel Cover

Foot-Pounds m-kg

.................................

Flywheel

Foot-Pounds m-kg

.................................

Suction Filter

Foot-Pounds m-kg

.................................

Camshaft Plate

Foot-Pounds m-kg

.................................

............

..............

......................

. 1706.4-1848.6 psi . 12’

Engine Special Torque Values

. 22-25 . 3.0-3.5

. 18-22 . 2.5-3.0

. 34-40 . 4.7-5.S

. 43-51 . 6.0-7.0

. 7.0-9.0 . 0.9-1.3

. 7-9 . 0.9-1.3

Oil Pipe Eyebolts

Foot-Pounds....................... . 7-9

m-kg..................................

Cylinder Head

Foot-Pounds.......................

m-kg..................................

Rocker Arm Assembly

Foot-Pounds.......................

m-kg..................................

Cylinder Head Cover

Foot-Pounds....................... . 6-8

m-kg..................................

Fuel Injection Pipes

Foot-Pounds....................... . 18-22

m-kg.................................. . 2.5-3.0

Injection Nozzle Holders

Foot-Pounds.......................

m-kg..................................

. 1.0-1.3

. 33-36 . 4.5-5.0

. 15-18 . 2.0-2.5

. 0.8-1.2

. 58-61 . 8.0-8.5

Crankshaft Pulley

Foot-Pounds...

PAGE 2.1-6

72-80

PART 2 ENGINE MECHANICAL

SECTION 2.2

GENERAL INFORMATION

Section 2.2

GENERAL INFORMATION

Introduction

Read this section carefuily before you attempt to

repair the diesei engine. The section contains vaiuabie tips pertaining to the repair and/or repiacement of en

gine parts.

When is Major Maintenance Required?

Major engine repairs are usualiy required as a result

of excessively worn cylinders, pistons, rings and valves.

Data that is gathered from periodic maintenance and

inspections will Indicate the need for major main tenance. Occurence of any one or more of the following will indicate a need for major repairs:

□ Loss of compression pressure below the stated

limit.

□ An increase in oil consumption.

D Increase in fuel consumption.

□ Engine won’t start or starts with difficulty.

D Loss of engine power. D Rough or noisy operation.

□ Excessive blowby of combustion gases through

the engine breather.

Some of the major causes of the symptoms listed above are (a) Weak battery or defective starter motor, (b) worn cylinders, pistons or rings, (c) incorrect valve clearance, (d) malfunctioning fuel injection pump, (e) incorrect injection timing, (f) defective injection nozzles.

General Rules of Repair

When performing maintenance on the engine, the

following general rules should be compiled with:

Keep the work area neat and uncluttered. Ar

□

range work table(s), engine stands, parts bins, etc., in a logical sequence of disassembly. Prior to disassembly, locate any alignment or

□

reassembly marks on parts to be disassembled.

If alignment marks cannot be found, place your

own alignment marks on the parts. Pay close attention to the condition of parts

□

during disassembly. Many defects will be evident prior to the actual disassembly of parts. Use the proper tools for each job.

□

Use new gaskets, seals and o-rings during reas

□

sembly. Use a torque wrench to ensure that all fasteners

□

are properly tightened.

NOTE: Some components require a special torque

value which Is given In the reassembly sequence In this manual. Parts not requiring a special torque value should be tightened to the value recom

mended In "TORQUE VALUES FOR METRIC

BOLTS" on Page 2.1-3.

PAGE 2.2-1

SECTION 2.2 GENERAL INFORMATION

PART 2

ENGINE MECHANICAL

PAGE 2.2-2

PART 2 ENGINE MECHANICAL

SECTION 2.3

ENGINE DISASSEMBLY

Section 2.3

ENGINE DISASSEMBLY

General

The following engine disassembly procedure covers complete disassembly of the engine. You may wish to disassemble only to the extent needed for repairs. Most disassembly Is a matter of common sense and simple logic.

AC Generator Disassembly

Disassemble the AC generator and remove gener

ator parts from the engine. Refer to either Section 1.3

or 1.4 of this manual as appropriate.

Drain Engine Fluids

Before starting the disassembly process, drain ail

fluids from the engine block.

□ Drain oil completely from the engine aankcase.

If complete disassembly will be required, remove

the engine oil filter.

□ Drain the engine cooiing system and the engine

water Jacket.

□ If complete disassembly Is planned, remove en

gine cooling system and fuel system hoses.

Remove the Head Cover

Remove the cylinder head cover and gasket.

Head cover

Figure 1. Head Cover and Gasket

Rocker Arm, Push Rod and Cap

Remove the rocker arm assembly and push rods.

Remove caps from the intake and exhaust valves. Store

all parts together In a safe place.

NOTE: Some Installations may be equipped with an attached radiator, others with a remote-mounted

radiator.

Miscellaneous Parts

□ Remove the engine fuel filter. □ Remove the oil dipstick tube and the dipstick. □ Remove engine v-belts. □ Remove fuel injection hoses, pipes and return

pipes.

D Remove fuel Injection nozzles and nozzle

holders.

□ Remove the engine water pump assembly and

gasket.

Figure 2. Rocker Arm, Push Rods and Caps

PAGE 2.3-1

SECTION 2.3 ENGINE DISASSEMBLY

Cylinder Head Assembly

Remove the oil pipe bolts (head side). To remove the

bolts, loosen them In about two or three increments. Finally, remove the glow plugs.

PART 2

ENGINE MECHANICAL

NOTE: Injection timing Is determined by SHIMS at

the pum p mounting face. Be sure to check and record the thicknes and number of shims to ensure

proper Installation of the pump.

Figure 3. Cylinder Head Assembly

Remove the tappets by pulling them up from the

cylinder block.

Remove Feed Pump Assembly

Remove the feed pump assembly.

Figure 5. Fuel Injection Pump Removal

Oil Pipe Removal

Loosen the EYE BOLT and remove the OIL PIPE.

See Figure 6.

Fuel Injection Pump Removal

Remove bolts and nuts that retain the fuel injection pump. Move the pump straight up and puli out the snap pin. Remove the link from the pump control rack. Finally, remove the Injection pump.

PAGE 2.3-2

Crankshaft Pulley

Remove the crankshaft pulley retaining nut and

washer. Remove the crankshaft pulley and its key. See

Figure 7.

PART 2

ENGINE MECHANICAL

Crankshaft Pulley (Continued)

Key-

Crankshaft pulley

SECTION 2.3

ENGINE DISASSEMBLY

Crankshaft

Figure 7. Crankshaft Pulley Removal

Timing Gear Assembly

Remove timing gear case and gasket (Figure 8).

Figure 9. Idler Gear, Shim, Clip, Thrust Washer

Figure 10. Camshaft Assembly and Plate

Idler Gear and Oil Pump Assembly

Remove the CLIP. Then, remove oil pump and IDLE

GEAR. See Figure 9.

Camshaft Assembly and Plate

Remove two bolts that retain the PLATE. Remove the

CAMSHAFT and PLATE. See Figure 10. Remove the

FRONT PUkTE and GASKET (Figure 11.

PAGE 2.3-3

SECTION 2.3 ENGINE DISASSEMBLY

Oil Pan Removal

Remove the oil pan screws, then remove oil pan.

Remove the SUCTION FILTER and the SUCTION

PIPE.

Suction pipe

Suction filter

Figure 12. Suction Filter and Pipe

PART 2

ENGINE MECHANICAL

Flywheel Cover and Oil Seal

Remove the flywheel cover. Then, remove the OIL

SEAL (Figure 14).

Crankshaft and Bearing Holder

Connecting Rods and Pistons

Remove the BOLTS that retain the bearing holder

(Figure 15). Remove the crankshaft and the bearing

PAGE 2.3-4

PART 2

ENGINE MECHANICAL

DISASSEMBLY AND INSPECTION

General

Before starting the disassembly and Inspection pro

cedure, check the folowing:

Section 2.4

DISASSEMBLY AND INSPECTION

Wear of rocker arm shaft! o )

Standard dimension

SECTION 2.4

Allowable limit

GCarefully Inspect the cylinder block and cylinder

head for damage and evidence of water leakage.

DUse pressure air to blow out all oil holes, make sure

none of the holes are plugged.

□wash al parts to remove dirt, dust, dirty oil and

carbon deposits.

□clean all carbon deposits from the piston, cylinder

head and valves. Make sure these parts are not damaged. Pay special attention to aluminum alloy parts.

□Place match marks on mating parts for correct

reassembly.

Rocker Arm Assembly

Remove bolt at end of rocker arm shaft. Remove ROCKER ARM, ROCKER ARM BRACKET and springs. Pull out the spring pin from from the No. 1 cylinder ROCKER ARM BRACKET. Remove ROCKER

ARMS, SPRINGS and BRACKETS.

Rocker arm

11.65 to 11.67 mm

■ i

______^^__________1______

1/ _ ^ “

I 1 I

Figure 2. Wear Limits of Rocker Arm Shaft

Measure the inside diameter of the rocker arm. Cal

culate the clearance between the rocker arm and the rocker arm shaft. If allowable limits are exceeded, replace the part(s).

11.57 mm

1 ]_

t 1 t

\y'

Rocker arm bracket

Figure 1. Rocker Arms and Rocker Arm Brackets

Use a micrometer to check the outside diameter of

the rocker arm shaft If allowable limits are exceeded, replace the rocker arm shaft.

Figure 3. Rocker Arm to Shaft Clearance

Check the valve stem face for step wear or scoring.

Slight wear or scoring may be corrected using an oil stone or grinder (Figure 4).

Figure 4. Removing Slight Wear or Scoring

PAGE 2.4-1

SECTION 2.4 DISASSEMBLY AND INSPECTION

PART 2

ENGINE MECHANICAL

VALVE PARTS:

Cylinder Head Assembly

Use a valve spring compressor to compress the

SPRINGS. Then, remove the VALVE COTTER. RE TAINER, SPRING and VALVE. Also remove the VALVE GUIDE SEAL.

CHECK CYLINDER HEAD WARP:

Use a straight edge and a thickness gauge to check

warpage on the cylinder head lower face. Check with the straight edge at six (6) points, as shown in Figure

6. If warped excessively, correct with a surface grinder.

MAXIMUM CYUNDER HEAD WARP

STANDARD VALUE - LESS THAN 0.0020 INCH

REPAIR IF MORE THAN 0.005 INCH

VALVE STEM:

Inspect valve stem for damage and excessive

wear. Replace if damaged or worn excessively. Use a

micrometer to check valve stem diameters at locations 1,11 and III (Figure 7). If the stem is worn beyond limits, replace the valve. Also check valve head thickness

(Figure 7), replace valve if worn excessively.

Standard Diameter 0.2740-0.2744 inch Allowable Limit 0.24 inch (6.09mm)

Standard Diameter 0.2736-0.2740 Inch

Allowable Limit 0.2693 inch (6.84mm)

Intake Valve:

(6.955-6.97mm)

Exhaust Valve

(6.95-6.96mm)

Stem end

i/^

Standard Thickness 0.036-0.042 inch Allowable Limit 0.0197 inch (0.5mm)

Figure 7. Valve Stem and Valve Head Inspection

VALVE TO VALVE GUIDE CLEARANCE:

Check clearance between valve and valve guide

(Figure 8). If beyond limits, replace worn parts.

Thickness of Valve Head

(0.925-1.075mm)

Intake valve

Figure 6. Check Points for Cylinder Head Warp

PAGE 2.4-2

/—

Clearance

Figure 8. Valve to Valve Guide Clearance

VALVE SEAT:

Always check for valve guide wear before correct

ing valve seat. Use 15‘, 45' and 75" cutters to correct the valve seat (Figure 9).

Standard clearance

0.03 to 0.06 mm

Exhaust valve Standard clearance

0.04 to 0.065 mm

Allowable limit

0.2 mm

Allowable limit

0.25 mm

PART 2 ENGINE MECHANICAL

SECTION 2.4

DISASSEMBLY AND INSPECTION

VALVE SEAT (CONTO):

Cylinder Head Assembly (Continued)

Valve seat contact width

Standard width

1.2 to 1.5 mm

Figure 9. Correcting the Valve Seat

VALVE RECESS:

If the valve recess (Figure 10) exceeds allowable

limits, replace the valve seat.

Recess of Valve Seat

Standard Recess 0.033-0.045 inch Allowable Limit 0.071 inch (1.8mm)

Recess

Allowable limit

2.0 mm

(0.85-1.15mm)

Figure 11. Grinding the Valve Seat

Squareness (mm) Free length (mm)

Spring force 130.4mm at compressioned) (kg)

Standard value

1.2 35

8.1

Allowable limit

2.0

33.5 7

Squareness

Free len

Figure 10. Checking Recess of Valve Seat

GRINDING VALVE SEAT;

See Figure 11. Use a valve seat grinder and valve

grinding compound to grind valve seats. Check the valve contact face for correct contact and positioning.

NOTE: When Installing a new cylinder head, use the

valve seat cutter to obtain correct seat contact with

recess of seat. Then, use lapping compound to lap

the valve In.

VALVE SPRINGS:

Inspect valve springs for damage. Check spring

squareness. Use a spring force tester to test for cor-

rectspring force and free length.

Figure 12. Valve Springs Inspection

CAP AND INSERT:

Remove CAP and INSERT from the cylinder. In

spect and clean the combustion chamber.

PAGE 2.4-3

SECTION 2.4 DISASSEMBLY AND INSPECTION

PART 2

ENGINE MECHANICAL

Cylinder Head Assembly (Continued)

HEAD REASSEMBLY;

Reassemble all parts In the reverse order of disas

sembly. When assembling the VALVE SPRING, RE TAINER and COTTER, use care to avoid damage to the VALVE GUIDE SEAL.

Cylinder Block

TOP FACE;

Inspect the cylinder block top face for damage, cracks, warpage. Use the same method that was used for checking the cylinder head warp (Figure 6, Page

2.4-2). Allowable warp limit is the same as for the cylinder head.

CYLINDER BORE;

Visually inspect the cylinder bore. There should be no scoring, rust or corrosion. Measure thye cylinder bore at its upper, middle and lower areas, at positions A and B (Figure 14). If the bore diameter exceeds limits, rebore to the correct oversize dimension.

HONING THE CYLINDERS;

After boring is completed, hone the cylinder in two

stages to obtain a diamond or "cross-hatch" finish. See

Rgure 15. The following specifications apply to honing:

□ Use a rough finishing stone that corresponds to (a)

Tokyo DIA, (b) SD120/140, (c) N100M (bronze se ries).

□ Use finishing stone GC600JB. □ Use a grinding stone 100mm long by 4mm wide (3.94

X 0.157 inch). □ Drill speed should be 162 rpm. □ Feed should be 13m per minute (42.6 ft. per minute). □ Rough finishit^ gauge pressure should be 213 psi

(15 kg percm^.

□ Rnjshing pressure should be 71.12 psi (5 kg per

cm^). □ Perform the finishing strokes nine (9) times. □ Honing depths should be 0. 0015 inch (0.04mm). □ Cross hatch angles should be 40*. □ Surface roughness should be 2 to 4p.

Standard bore

75 - 75.019

Allowable limit

b 75.2

Front

Slide range

of piston ring

Figure 14. Checking Cylinder Bore

NOTE; In Figure 14, see "Slide Range of Piston Ring". The upper area corresponds to the top ring when the piston Is at top dead center (TDC), or about 0.39 Inch below the cylinder block top sur face. The lower area corresponds to position of oil ring when the piston Is at bottom dead center (B DC) or about 3.94 Inches from cylinder block top sur face.

Use a cylinder (inside diameter) gauge to measure

the cylinder bore.

First boring

0.5 mm

Standard bore

b 75.5 ~ 75.519

Second

boring

0.5 mm

Standard bore

b 76 - 76.019 b 76.2

Figure IS. Cylinder Boring Specifications

Allowable limit

b 75.7

Allowable limit

Replace the block

Piston and Piston Rings

Use a ring compressor to remove piston rings.

Remove one snap ring, then remove the piston pin (Figure 16). With connecting rod and piston pin re moved proceed with inspections as follows.

PAGE 2.4-4

PART 2 ENGINE MECHANICAL

SECTION 2.4

DISASSEMBLY AND INSPECTION

Pistons and Piston Rings (Continued)

Figure 16. Piston Pin Removal

PISTON INSPECTION:

Inspect the piston, replace if damaged, cracked, scored, burned, etc. Check the diameter of the piston skirt, about 0.394 incvh (10mm) from bottom. Also check the inside diameter of the cylinder. Then, calcu late the piston to cylinder clearance. If the clearance exceeds the allowable limit or if the piston diameter is

less than the allowable limit, replace the piston. When a cylinder is oversized, use a correspondingly oversize

piston. The following apply:

□ Standard piston to cylinder clearance Is 0.003-

0.005 Inch (0.070-0.119mm). Allowable limit is

0.010 Inch (0.25mm).

□ Standard largest diameter of the piston skirt Is

2.9488-2.9500 inch (74.900-74.930mm). Allow able limit is 2.9409 inch (74.7mm).

Check the diameter of the piston pin hole and the

outside diameter of the piston pin. Calculate the clear ance between the piston pin and piston pin hole. If clearance is greater than the allowable limit, replace the piston.

□ standard piston pin hole to pin clearance is

minus 0.00008-plus 0.0003 Inch (-0.002-

••■0.008mm).

□ Allowable hole to pin clearance limit is 0.0008

Inch (0.02mm).

PISTON RINGS:

Inspect rings, replace if worn or damaged. Install the rings into the cylinder skirt and check ring gaps with a feeler gauge. Replace rings if allowable limits are exceeded.

□ standard gap of No. 1 Ring = 0.008-0.014 inch

(0.2-0.35mm)

□ standard Gap of No. 2 Rlng=0.006-0.012 inch

(0.15-0.3mm)

□ Standard Gap of Oil Ring=0.008-0.01 Inch (0.2-

0.35mm)

□ Allowable Limit (All Rings) = 0.039 inch (1.0mm)

PISTON PART NO. Standard

0.5mm O.S

1.0mm O.S

' Largest diameter of piston skirt is given.

214- 7093& 215- 70939 216- 70939

Figure 17. Checking Piston Fit

PISTON SKIRT DIAMETER*

2.9488-2.9500 inches

2.9685-2.9697 inches

2.9682-2.9894 inches

PISTON RING GROOVE TO RING CLEARANCE:

Measure the clearance between the piston ring

groove and the ring. If allowable limits are exceeded^ replace the ring.

□ No. 1 Ring Standard Clearance s 0.002-0.004 inch

(0.06-0.1 mm)

□ No. 2 Ring Standard Clearance = 0.002-0.0035

Inch (0.05-0.09mm)

□ No. 1 and 2 Ring Allowable Limit = 0.010 inch

(0.25mm)OII Ring Standard Clearance = 0.0008-

0.006 inch (0.02-0.06mm)

□ Oil Ring Allowable Limit = 0.006 inch (0.15mm)

PAGE 2.4-5

SECTION 2.4

DISASSEMBLY AND INSPECTION

Pistons and Piston Rings (Continued)

If the cylinder Is oversized, use an oversized piston

ring set.

□ Standard Piston Ring Set Is Part No. 211-70939 □ 0.5mm O.S. Rings, Part No. 212-70939 □ 1.0mm O.S. Rings, Part No. 213-70939

When installing the Piston Rings, instail them as

shown in Figure 19.

PART 2

ENGINE MECHANICAL

ROD BUSHING TO PISTON PIN CLEARANCE;

Measure the inside diameter of the connecting rod

small end bushing. Also, measure the piston pin. Cal culate the pin to bushing clearance. It clearance ex ceeds allowable limits, repiace the connecting rod.

□ standard Clearance = 0.0006-0.001 inch (0.015-

0.03mm)

□ Allowable Limit = 0.003 inch (0.08mm)

ROD TO CRANKPIN CLEARANCE:

Assemble the connecting rod to the crankshaft and

measure the play in the shaft direction. If play is greater than ailowable limit, replace the connecting rod.

□ Standard Play = 0.004-0.012 inch (0.1-0.3mm) □ Allowable Limit = 0.028 inch (0.7mm)

CONNECTING ROD BEARING;

Inspect the connecting rod bearing for peeiing,

cracks, etc. Replace, if defective. Use ‘i^astigauge' to check bearing oil clearance as follows;

1. Remove oil and dirt from rod bearing and from

crankpin.

2. Cut a iength of plastigauge to the same length as the width of the bearing. Place It on the crankpin, parallel with the crankshaft. DO NOT PLACE OVER AN OIL

HOLE. See Rgure21.

3. Assemble the connecting rod bearing and cap to the crankpin. Tighten to 22-25 foot-pounds (3.0-3.5 m-kg).

CHECK BENDING, PARALLELISM, DAMAGE;

Connecting Rods

Use a connecting rod alignment tool to check the

connecting rod for bending and parallelism. If allowable limits are exceeded, replace the connecting rod.

CAUTION: DO NOT rotate the connecting rod or crankshaft while plastigauge Is Installed.

4. Remove the connecting rod and bearing. Use the plastigauge scale to measure the oil clearance. Be sure to measure the widest area of the plastigauge.

______

PAGE 2.4-6

PART 2 ENGINE MECHANICAL

SECTION 2.4

DISASSEMBLY AND INSPECTION

Install the rings Into piston with scribed marks at

Connecting Rods (Continued)

end of rings facing upward.

CRANKSHAFT JOURNAL DIA. BEARING SIZE

1.B09S-1.8100tnch

(45.964-45.975mm)

1.7998-1.8002 inch (45.714-45.725mm) L7899-1.7903 fcich (45.464-45.475mm)

Carefully inspect the THRUST WASHER for wear,

poor contact, burning, other defects. Replace washer if

It is damaged or defective.

□ Standard Thickness of Thrust Washer

Standard

iTSSmrfniS:

0.50mm U.S.

0.077-

0.079 Inch (1.95-2.0mm)

□ Allowable Limit = 0.071 Inch (1.8mm)

Bearing holder (Upper)

Metal ,

(Upper) Oil groove

CAUTION: The difference In weight between cylinders of the assembled piston, piston pin, connecting rod and rings should not exceed

0.35 ounce (10 grams).

Main Bearing Holders

Remove the bearing holder and inspect for peeling, cracking, wear, etc. Replace holder, if defective. Use plastigauge to measure the oil clearance between the crankshaft center journal and the bearing. If oil clear ance exceeds allowable limits, either replace the bear ing or grind the crankshaft center journal and use an undersize bearing.

□ Standard Oil Clearance = 0.0015-0.0036 Inch

(0.039-0.092mm)

□ Allowable Limit = 0.0078 Inch (0.2mm)

‘ Bite -^-Chamfered part

Thrust Chamfered part

washer

Figure 23. Main Bearing Holders

Reassemble the bearing holder, center bearing

and thrust washer as follows:

1. Face the chamfered part of the bearing holder toward the front. Install the bearing holder which has reference bite at its center. Then, install the bearing holder which is to be mounted at the flywheel side.

2. Install the thrust washer. Face oil groove of thrust washer toward the thrust face of crankshaft.

3. Place the bearing with oil groove at the upper side.

Place the bearing without oil groove at the lower side.

NOTE: Tightening torque of bearing holder Is 18-22

foot-pounds (2.S-3.0 m-kg).

Crankshaft Bearing

INSPECTION

1. Check crankshaft bearir^s for peeling, weld cracks,

burning, poor contact, etc. Replace beanng(s), if defec

tive.

2. Use a cylinder gauge and micrometer to measure oil clearance between the bearing and the crankshaft jour

nal.

PAGE 2.4-7

SECTION 2.4

DISASSEMBLY AND INSPECTION

3. If oil clearance exceeds the allowable limit, replace the bearino or grind the crankshaft journal and use an

undersize bearing.

□ standard Oil Clearance = 0.0015*0.0024 Inch

(0.039-0.106mm)

□ Allowable Limit = 0.0079 inch (0.2mm)

CRANK JOURNAL O.D.

1.8096-1.8100 Inch (45.964-45.975mm)

1.7998-1.6002 inch

45.714-45.725mm)

1.7899-1.7903 Inch (45.464-45.475mm)

Crankshaft Bearing (Continued)

BEARING SIZE

Standard

0.25mm U.S.

0.50mm U.S.

PART 2

ENGINE MECHANICAL

a. Position the dial indicator on the crankshaft center/"~\^

ournal. Then, turn the crankshaft slowly one full turn.

). If the gauge reading exceeds the allowable limit.

replace the crankshaft. c. Inspect the oil seal contact face for damage or wear. d. Check for clogged oil holes.

□ standard Deflection = 0.0012 Inch (0.03mm) or

less

□ Allowable Limit = 0.0024 inch (0.06mm)

2. See Figure 26. Inspect crankshaft journal and pin sections for damage, uneven abrasion, out-of-roundness, and axle diameter.

a. Take measurements as shown in the illustration, at points 1 and 2 and in the directions A-A and B-B.

b. Avoid the oil holes when measuring.

Figure 24. Crankshaft Bearing Oil Clearance

See Figure 25. Measure inside diameters at posi

tions 1 and 2. At each of the positions, measure in directions A and B as shown.

NOTE; When changing the bushing, press fit using a press. If the crankshaft Journal has been ground, check oil clearance before Installing crankshaft.

Crankshaft

1. Support the crankshaft on a V-Block. Then, check

with a dial indicator as follows:

SHAFT Dl

BEARING

SIZE

bianaara

0.25mm U.S. 1.7998-1.8002 Inch

0.50mm U.S.

* If crankshaft journal or crankshaft pin d

this value, replace the crankshaft

SHAFT Dl

BEARING

SIZE

"sranusra

0.25mm U.S.

0.50mm U.S. 1.5143-1.5148 Inch

AMETER OF CRANKS

STANDARD

DIAMETER

T.8Uyb’"-r8iuu men

(45.964-45.975mm)

(45.714-45.725mm)

1.7899-1.7903 inch

(45.464-45.475mm)

AMETER OF CRANKS

STANDARD

DIAMETER

1.5340-1.5344 IhCn

(38.964-38.975mm)

1.5242-1.5246 Inch

(38.714-38.725mm)

(38.464-38.475mm)

HAFT JOURNAL

ALLOWABLE

LIMIT

i.BU/u men

(45.9mm)

1.7972 inch

(45.65mm)

1.7874 In* (45.4mm)*

lameter Is less than

HAFT PIN

ALLOWABLE

LIMIT

1men

(38.9mm)

1.5216 Inch

(38.65mm)

1.5118 inch*

(38.40mm)*

PAGE 2.4-8

PART 2 ENGINE MECHANICAL

SECTION 2.4

DISASSEMBLY AND INSPECTION

3. When grinding the crankshaft, the foiiowing specifi

Crankshaft (Continued)

cations appiy (Figure 27);

A Radius at PInAJoumal ■ 0.11B * 0.004 In. (3tnm-M).1mm)

В Finish precision 1.62 (VW) C Radius around oil hole & 0.079 In. (2mm) шах., 0.020 In.

(0.5mm) mln.

NOTE: Use No. 400 sandpaper for final polishing.

Figure 28. Camshaft Assembly

Inspect the journals and cams for wear and dam

Camshaft Assembly

age. If allowable limits are exceeded, replace the cam shaft.

See Figure 28. Cam height tolerances are as fol

lows;

A INTAKE/EXHAUST VALVE CAM HEIGHT;

Standard Value: 1.0413-1.0433 inch (26.45-

26.50mm) Allowable Limit: 1.0275 inch (26.1mm)

B INJECTION PUMP CAM HEIGHT;

Standard Value: 0.9425-0.9472 Inch (23.94-

24.06mm) Allowable Limit: 0.9370 inch (23.8mm)

C FUEL FEED PUMP CAM HEIGHT;

Standard Value: 1.0590-1.0630 inch (26.9-27.0mm) Allowable Limit: 1.0236 Inch (26.0mm)

Timing Gear

Inspect timing gears for wear or damage at their engag ing areas. Replace if damaged or worn excessively. Use a thickness gauge or a dial indicator to measure gear backlash. If allowable limits are exceeded, replace the timing gears as a set.

BACKLASH OF TIMING GEARS: Standard Backlash: 0.003 inch (0.08mm)

Allowable Limit: 0.010 Inch (0.25mm)

REMOVAL AND DISASSEMBLY;

1. See Figure 30. Remove the SNAP RING.

2. Remove COLLAR, SPRING and SHIM.

3. Remove IDLE GEAR, VANE and OIL PUMP COVER as a unit.

4. Rermove ROTOR and THRUST WASHER.

5. Remove OIL PUMP COVER from the IDLE GEAR.

6. Remove SPRING from the IDLE GEAR. Remove the KNOCK PIN.

7. Remove the VANE from the IDLE GEAR.

Thrust washer

Rotor r

Shim' ’ vine Idle gear

Collar • Oil pump cover

Snap ring

Figure 30. Oil Pump Assembly

Oil Pump

Spring

-Spring

Knock

■ I pin

PAGE 2.4-9

SECTION 2.4 DISASSEMBLY AND INSPECTION

PART 2

ENGINE MECHANICAL

INSPECTION AND REASSEMBLY:

Oil Pump (Continued)

1. Inspect the OIL PUMP COVER, ROTOR and VANE for wear. Replace if worn or damaged.

2. Check the clearance be tween the ROTOR and

VANE. If clearance Is exces sive, replace parts.

3. Reassemble the oil pump in the reverse order of

disassembly.

a. When reassembling, align the set marks on the crankshaft gear and the idle gear. b. Adjust the side clearance between the rotor and vane to 0.0039-0.0059 inch (0.1-0.15mm).

Oil Filter

CONSTRUCTION AND FUNCTION:

The oil filter is a cartridge type. A SAFETY VALVE will open to bypass oil around the filter if the filter should become clogged. See Figure 32. Pressure oil from the oil pump enters at “A". The oil is filtered and then exits the filter at “B".

Refer to Part 3, •ENGINE LUBRICATION AND

Water Pump & Thermostat

COOLING SYSTEM".

Fuel Filter & Feed Pump

See Part 4 of this manual, ’ENGINE FUEL SYS

TEM’.

Governor & Injection Pump

See Part 4, ’ENGINE FUEL SYSTEhT.

Nozzles and Holders

See Part 4, ’ENGINE FUEL SYSTEM".

REPLACEMENT;

Replace the oil filter every 200 hours of operation.

Prior to installing a new filter, coat its mounting face with

clean oil. Tighten the filter with the hand only. Do not

reuse the removed filter.

Figure 32. Oil Filter

PAGE 2.4-10

PART 2 ENGINE MECHANICAL

SECTION 2.5

ENGINE REASSEMBLY

Section 2.5

ENGINE REASSEMBLY

This section provides instructions for the reassem

General

bly of the engine. Be sure to wash all parts prior to reassembly. In addition, be sure to coat all sliding and rotating surfaces with fresh, clean, new engine oil. Such surfaces as cylinder bores, pistons, bearings, bearing surfaces, etc., should be liberally coated with oil. Use new gaskets, seals and o-rings. Always tighten bolts to the recommended tightness. Never overtighten any fasteners that thread into aluminum.

Relief Valve

See Figure 16 on Page 2.3-4. Install a new o-ring

onto the relief valve assembly. Install the relief valve and tighten to the recommended torque.

RELIEF VALVE TORQUE

43-61 Ft-Lbs. m-kg)'

Crankshaft and Bearing Holder

1. Instali bearing holder onto crankshaft and into bush ing at front of cylinder block.

2. Align bolt holes at lower part of cylinder block with threaded holes on bearing holder, install and tighten bolts. Use two hex head bolts at flywheel side.

BEARING HOLDER TORQUE

18-22 Ft.-Lbs. (2.S-3.0 m-kg)

Figure 2. Cheeking Crankshaft End Play

CRANKSHAFT END PLAY

Standard = 0.0020-0.0118 inch (0.05-0.30mm)

Allowable Limit = 0.020 Inch (O.Smm)

4. Install oil seal at flywheel end of crankshaft (Figure

3).

3. Measure the crankshaft end play, in the direction of the crankshaft.

5. Install flywheel cover. Spread liquid packing over the M10 screw hole of the cylinder block flywheel cover face (Rgure 4), then fit the flywheel over it.

FLYWHEEL TIGHTENING TORQUE

—34-40Tt:-Lb8. (4.T-S.S m-kgj—

6. Install the flyvyheel. Pay close attention to location of the alignment pin. Retain flywheel with bolts and lock ring. See Figure 5.

FLYWHEEL TIGHTENING TORQUE

43-Si Ft.-Lbs. (6-y m-ltg)

PAGE 2.5-1

SECTION 2.5 ENGINE REASSEMBLY

Crankshaft & Bearing Holder (Continued)

Liquid packing

Figure 4. Liquid Packing

PART 2

ENGINE MECHANICAL

1. Coat parts with clean engine oil. Move the piston

Piston and Connectinq Rod

rings around to provide plenty of oil in the ring grooves.

2. Set the ring gaps 90' apart from each other. How ever, do NOT place the ring gaps toward the piston pin or at right angles to the piston pin.

3. Use a ring compressor to compress the rings around

the piston.

4. Face the alignment mark on the connecting rod toward the injection pump. Install the parts, starting at the front and moving toward the rear.

5. Tighten the connecting rod caps to their specified

torque.

CONNECTING ROD CAP TIGHTNESS

22-25 Ft.-Lbs. (3.0-3.5 m-kg)

6. After installation, check that the crankshaft can move

slightly the specified axial distance.

Install an o-ring onto the suction pipe. Install the

Suction Pipe and Filter

pipe into the cylinder block. Install the suction filter.

SUCTION FILTER TIGHTNESS

7-9 Ft.-Lbs. (0.9-1,3 m-kg)

Oil Pan

Tighten oil pan boltsevenly and in diagonal incre

ments. Install the front plate.

Camshaft Assembly

Install the camshaft assembly ana plate. Tighten

the plate to the specified torque. See Figure 8.

PAGE 2.6-2

CRANKSHAFT AXIAL PLAY

0.004-0.012 Inch (0.1-0.3mm)

PLATE TIGHTENING TORQUE

7-9 h.-Lbs. (0.9-1.3 m-kg)

PART 2 ENGINE MECHANICAL

SECTION 2.5

ENGINE REASSEMBLY

Camshaft Assembly (Continued)

Idler Gear and Oil Pump

1. Install thrust washer onto the idler gear shaft. Assem

ble vane, knock pin and spring to the idler gear.

CAUTION: Coat BOTH faces of the rotor and vane with grease prior to assembly. DO NOT

ROTATE THE CRANKSHAFT UNTIL THE TIM

ING GEAR CASE IS MOUNTED.

5. Rotate the oil pump cover to place the spring pin insert hole to the center position. Then, assemble the gear case.

Timing Gear Case

Install the start spring. Insert the link into the cylin

der block hole. Install the gasket. Install the timing gear case.

2. Align the timino marks of the idler gear, crankshaft gear and camshaft gear (Rgure 10).

Figure 10. Idler, Crankshaft and Camshaft Gears

3. Install the oil pump rotor.

4. Install the oil pump cover, shim, spring and collar. Retain with snap ring. Adjust with shim so that side

clearance between pump, rotor and vane is 0.004-

0.006 inch (0.1-0.15mm).

Figure 11. Timing Gear Case and Gasket

Crankshaft Pulley

Align pulley with key and install. Tighten to the

recommended torque.

CRANKSHAFT PULLEY TORQUE

72-80 Ft.-Lbs. (10-11 m-kg)

Crankshaft

Crankshaft pulley

Figure 12. Crankshaft Pulley

PAGE 2.5-3

SECTION 2.5

ENGINE REASSEMBLY

PART 2

ENGINE MECHANICAL

Install the injection pump, using the same shims

Injection Pump Asembly

that were removed during disassembly. Connect con trol rack of pump with LINK and retain with SNAP PIN.

Retain pump with bolts and nuts.

NOTE: The pump shims establish the Injection pump timing. When reinstalling the same Injection pump that was removed, use the same shims that were removed. Fuel Injection timing must be ad

justed whenever (a) a new Injection pump Is In

stalled, (b) a new camshaft Is Installed, or (c) a ne w cylinder block Is used. See Part 4, "ENGINE FUEL SYSTEM" for timing adjustment procedure.

1. Set each piston at top dead center (TDC), one at a

Cylinder Head Assembly

time. When the pistons are at top dead center (TDC),

measure their protrusion above the cylinder block with a depth gauge or a dial indicator. Measure the protrustion of all three pistons. Use the largest protrusion to select a cylinder head gasket having the correct thick ness.

PR^R%I?(Jn TH?ClfNKS

0.018-0.021 inch (0.45-0.55mm)

0.022-0.026 inch

(0.55-0.65mm)

0.026-0.029 inch

(0.65-0.75mm)

NOTE: The thickness of the head gasket, when tightened. Is stamped at top of gasket (as. 1, .2, .3).

158-70939

159-70939

0.043 inch (1.1 mm)

0.047 inch (1.2 mm)

0.051 inch (1.3 mm)

Oil Filter, Oil Pipe, Feed Pump and Tap

pets

1. Coat oil filter mounting face with light film of oil and install. Tighten by hand.

2. Install the feed pump assembly, using two bolts.

3. Coat tappets with oil and install.

OIL PIPE EYEBOLT TORQUE

7-9 Ft.-Lbs. (1.0-1.3m-kg)

Figure 15. Piston Protrusion above Cylinder Block

2. Install the glow plugs.

3. Tighten the cylinder head bolts in three (3) phases and in the sequence shown in Figure 16. Alignment pins are provided for proper positioning. Coat all bolt threads with molybdenum disulphide grease.

CYL. HEAD FINAL TIGHTENING TORQUE

33-36 Ft.-Lbs. (4.5-5.0 m-kg)

Figure 16. Cylinder Head Tightening Sequence

PAGE 2.5-4

PART 2 ENGINE MECHANICAL

SECTION 2.5

ENGINE REASSEMBLY

Cylinder Head Assembly (Continued)

4. Install CAPS on end of valve stems. Install the PUi

RODS and the ROCKER ARM ASSEMBLY.

ROCKER ARM TIGHTENING TORQUE

15-18 Ft.-Lbs. (2.0-2.5 m-kg)

Figure 17. Caps, Push Rods, Rocker Arm

Valve Clearance Adjustment

See Figure 18. Loosen the NUT, then adjust intake

and exhaust valve clearance to 0.008 inch (0.2mm) by turning the ADJUST SCREW. Use the following proce dure:

1. Adjust valve clearance with engine cold.

2. Set No. 1 pistonattopdeadcenter(TDC). then adjust the intake and exhaust valves of No. 1 cylinder and the exhaust valve of No. 2 cylinder.

3. Turn the crankshaft 240* counterclockwise (as viewed from the front).

4. Adjust No. 3 cylinder intake and exhaust valves and the intake valve of No. 2 cylinder.

CYLINDER HEAD COVER TORQUE

6-8 Pt.-Lbs. (0.8-1.2 m-kg.)

Water Pump Assembly

Install the water pump assembly, gasxet and hose.

Figure 19. Water Pump, Gasket & Hose

Nozzles and Nozzle Holders

Install caps and gaskets. Install nozzle holders and

tighten to specified torque. Install the return pipe and the injection pipes, tighten to specified torque.

NOZZLE HOLDER TIGHTENING TORQUE

58-61 Ft.-Lbs. (8.0-8.5 m-kg)

INJECTION PIPE TIGHTENING TORQUE

18-22 Ft.-Lbs. (2.5-3.0 m-kg)

Complete the Assembly

Install any remaining engine components.

Nut

Figure 18. Adjusting Valve Clearance

Adjust screw

Valve clearance

Cylinder Head Cover

Install cover gasket and cover. Tighten the cover evenly

to recommended torque.

PAGE 2.5-5

SECTION 2.5

ENGINE REASSEMBLY

PART 2

ENGINE MECHANICAL

PAGE 2.5-6

Part 3

ENGINE

LUBRICATION

& COOLING

SYSTEM

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

SECTION

3.1

3.2

3.3

3.4

TABLE OF CONTENTS

TITLE

Engine Lubrication System

Water Pump and Thermostat

Cooling and Ventilating Air

Periodic Maintenance

MOBILE

AC GENERATORS

Liquid-Cooled Diesel Engine Models

PART 3- ENGINE LUBRICATION & COOLING SYSTEM

ENGINE LUBRICATION SYSTEM

SECTION 3.1

ENGINE LUBRICATION SYSTEM

Section 3.1

on Pump Removal

See “OilPump’ on Page 2.4-9 (Part 2, Section 2.4).

Oil Pump Inspection & Reassembly

See "0)7 Pump" on Page 2.4-10 (Part 2, Section

2.4).

Idler Gear & oil Pump Installation

Refer to "Idler Gear and Oil Pump' on Page 2.5-3

(Part 2, Section 2.5).

Oil Filter

The cartridge type oil filter is equipped with a SAFETY VALVE. Should the filter become clogged, the safety valve will open and allow unfiltered oil to flow to all parts of the engine.

See Figure 1. Oil enters the filter at "A", flows

through the filtering element, then exits the filter at "B”.

The diesel engine is equipped with a normally-

Low Oil Pressure Shutdown

closed low oil pressure switch (Figure 2). The switch is held open by engine oil pressure during engine crank ing, startup and running operations. Should oil pressure drop below approximately 15 psi, the switch contacts

will close to effect an automatic engine shutdown.

To test the low oil pressure shutdown feature, start the engine and let it run at NO-LOAD (electrical loads turned off). Remove the wire from the switch terminal.

Hold the wire terminal end against a clean frame ground and the engine should shut down.

Figure 2. Low Oil Pressure Shutdown Switch

Figure 1. Oil Filter

PAGE 3.1-1

SECTION 3.1 ENGINE LUBRICATION SYSTEM

PART 3- ENGINE

LUBRICATION & COOLING SYSTEM

PAGE 3.1-2

PART 3- ENGINE LUBRICATION & COOLING SYSTEM

WATER PUMP & THERMOSTAT

SECTION 3.2

WATER PUMP & THERMOSTAT

Section 3.2

3. Use a press to remove the bearing from the water pump (Figure 2).

4. See Figure 1. Remove the IMPELLER and MECHANiCAL SEAL from the casing.

5. See Figure 3. Use a press to separate the bearing from the fan pulley.

1. Inspect all parts of water pump for cracks, wear,

damage. Replace any defective part(s).

2. Replace bearing if it rotates rough or if its conbtact with the casing is defective.

3. Replace the bearing if shaft play at end of shaft exceeds 0.008 inch (0.2mm).

WATER PUMP REASSEMBLY:

1. Apply liquid packing (Threebond 2) to the casing side of the mechanical seal. Press fit the seal into the casing.

2. Press fit the bearing into the casing.

3. Align the pump case end face with the bearing end face, as shown in Figure 4.

Figure 4. Pump Alignment

PAGE 3.2-1

SECTION 3.2

WATER PUMP & THERMOSTAT

PART 3- LUBRICATION

AND COOLING SYSTEM

REASSEMBLY (CONT’D):

Water Pump (Continued)

4. Install a mechanical seal into the impeller by hand. Apply 4 or 5 drops of silicon oil to the contact surface of the mechanical seal.

5. Press the impeller into the casing until the impeller

end is O.70 inch (17.8mm) from the end of the bearing. See Figure 5.

Figure 5. Press Impeller Into Casing

7. Assemble the thermostat and spring to the water pump casing. Install gaskets, plate and cover. Retain with bolts.

Figure 7. Thermostat Assembly

8. Rotate the fan pulley to ensure there is no interfer ence.

9. Adjust fan belt tension to obtain a 0.20 inch (5mm)

belt deflection when a 2.2 pound (1 kg) force is applied to center of belt.

10. Test run the engine until hot toconfirm there are no

water leaks.

6. Use a SETSCREW to retain the bearing (Figure 6). Then, press the fan pulley into place until the bearing shaft end is aligned with the end face of the fan holder.

Figure 6. Fan Pulley & Setscrew Installation

To test thermostat operation, immerse it in water. Raise the water temperature gradually. Check the valve opening temperatures and the valve lift.

NOTE: About 3 to 5 minutes will be required before

the valve starts to operate.

Starts to Open:

Fully Open at:

Valve Lift at

Fully Open:

Figure 8. Testing the Thermostat

Thermostat

158’ F. (70‘ C.)

185* C. (85’ C.)

0.31 inch (8.0mm)

PAGE 3.2-2

PART 3- ENGINE LUBRICATION & COOLING SYSTEM

COOLING & VENTILATING AIR

SECTION 3.3- COOLING

& VENTILATING AIR

Section 3.3

Service technicians who work on the Series NP

General

(recreational vehicle) and IM (industrial mobile) gener ators should be familiar with the air flow requirements forthese units. Adequate air flow for cooling, ventilation and engine combustion MUST be provided or serious problems will result.

Types of Cooling Fans

Engine-generator sets may be equipped with either

(a) a PUSHER type fan, or (b) a SUCTION type fan.

The suction type (squirrel cage) fan may be Installed

on units with either a 10 or 15 inch stator. Pusher type fans are used primarily on units having a 10 inch stator.

Air Flow- Pusher Fan Units

See Figure 1 below. A blower fan attached to the generator rotor draws air into the generator interior to cool generator internal parts. The heated generator cooling air is expelled through a blower air outlet duct on the side of the unit. The engine’s pusher fan draws air around the generator, forces it through the radiator, and outward, away from the unit.

Figure 2. Air Flow Suction Fan Units

Air Inlet- Suction Fan Units

When the engine-generator is installed in a com partment (as in a recreational vehicle), the following rules apply to air inlet openings in the compartment;

□ Ideally, the air inlet opening should be close to the

generator's rear bearing carrier. This will allow air to circulate the full length of the compartment and around the entire generator.

□ Unrestricted air inlet opening area must be at least

150 square inche (15 Inch stator units): or 300 square

inches (10 inch stator units).

□ If louvers, screening or expanded metal are used to

cover an air inlet opening, the restriction to air flow offered by such materials must be compensated for. This is done by making the actual air inlet opening

size proportionally larger.

A centrifugal blower fan rotates with the generator

Air Flow- Suction Fan Units

rotor to cool generator internal parts. The heated gen

erator cooling air is expelled outward through a blower

air outlet duct on the side of the generator.

The suction type fan is a high capacity 'squirrel

cage" type which draws air in, across the radiator, then

directs the air downward and away from the unit

through an air duct. See Figure 2.

Installation Manual

Additional information on cooling and ventiiating requirements can be found in the 'INSTALLATION MANUAL" for water-cooled recreational vehicle gener ators. Installation Manuals can be ordered from Generac Corporation.

Other Rules for Suction Fan Units

Some installations provide a compartment, to house the generator set. In some installations, a floor less compartment or no compartment at all may be

rovided. The following rules apply:

I If a compartment is used, the unit radiator must not

contact the compartment wall. A minimum of at least 3-1/2 inches (90mm) of clearance is recommended between the front and sides of the radiator and the compartment walls. Such clearance is required so the suction fan can draw air around the radiator edges.

□ If a floorless compartment (or no compartment) is

used, the generator must be protected against road

splash and debris by such means as anti-splash baffles.

PAGE 3.3-1

SECTION 3.3- COOLING & VENTILATING AIR

Compensating for Restrictions

Air openings may be covered with louvers, ex

panded metal or screening. These materials offer a

restriction to the flow or air. Such restrictions must be

compensated for by the installer.

To determine the actual air opening size required when an air opening is covered by some material, the material's "PERCENT OF FREE AIR INLET AREA“ must be known. This value can usually be obtained from the manufacturer of the material. Some materials may provide only a 60 percent free air inlet area. Even the most efficient materials may offer only an 80-90 percent free air inlet area.

To calculate the actual air opening size required, divide the unrestricted air opening size required by the percent of free air inlet area of the material to be used.

PART 3- ENGINE

LUBRICATION & COOLING SYSTEM

EXAMPLE 1;

The recommended unrestricted air opening for

units with 15 inch stator Is 150 square inches. Air

openings are to be covered with a material having a 70

percent free air inlet area. Divide “150“ by “0.70" to

obtain “214.28 square inches“. In this case the actual

air opening size should be about 215 square inches.

EXAMPLE 2:

The recommended unrestricted air opening for units with 10 inch stator is 300 square inches. Air openings are to be covered by expanded metal having an 80 percent free air inlet area. Divide *300 by 0.80’

to obtain “375 square inches“. The actual air opening size should be about 375 square inches.

PAGE 3.3-2

Figure 3. Typical Installation- Units with Suction Fan

PART 3- ENGINE LUBRICATION & COOLING SYSTEM

PERIODIC MAINTENANCE

SECTION 3.4

PERIODIC MAINTENANCE

Section 3.4

OIL RECOMMENDATIONS:

Use a high quality detergent oil classified 'For

Service CC or CD". Detergent oils keep the engine cleaner and reduce carbon deposits. Use oil having the following SAE (Society of Automotive Engineers) vis cosity rating, based on the ambient temperature range anticipated before the next oil change. Engine crank case oil capacity is 3,7 U.S. quarts (3.5 liters) without

oil filter change, or 4.0 U.S. quarts (3.7 liters) with oil

filter change.

AMBIENT TEMPERATURE

Above 100' F. (37.8’ C.) 40*-100’ F. (4.4‘-37.8* C.)

Below 40" F. (4.4* C.) SAE 5W-20

CAUTION: After refilling the crankcase with oil, check oil level on dipstick. NEVER OPERATE THE ENGINE WITH OIL LEVEL BELOW THE

"ADD" MARK.

NOTE: On new engines, check oH level frequently

during the break-ln period (first 25 hours of opera

tion). Add oil as required. It Is normal for the engine

to consume more oil than normal until the piston

rings have seated properly.

Engine Oil System

SAE VISCOSITY

SAE 40 Oil

SAE 10W-30

or SAE 30 Oil

or SAE 5W-30 Oil

add only the recommended 50-50 mixture.

When adding coolant to the coolant recovery bottle,

COOLING SYSTEM MAINTENANCE;

□ Inspect the entire cooling system at least once every

month or every 100 hours of operation, whichever occurs first. Check carefully for leaks, condition of hoses, tightness of clamps, etc.

□ Every two (2) years, the cooling system should be

drained, flushed and refilled with the recommended coolant.

OIL & FILTER CHANGE FREQUENCY:

Change engine oil and oil filter after the first 25 hours of operation. Thereafter, change oil and filter every six (6) months or every 250 operating hours, whichever occurs first.

Engine Cooling System

RECOMMENDED COOLANT:

Use a 50-50 mixture of low silicate, ethylene glycol

base anti-freeze and soft water. Use only S(jFT

WATER and LOW SILICATE anti-freeze, if desired, a

high quality rust inhibitor may be added to the recom mended mixture.

CAUTION: DO NOT use any chromate base rust inhibitor with ethylene glycol base antl-freeze or the formation of chromium hydroxide (green slime) will result. Green slime in the cooling system will cause overheating. Engines that have been run with a chromate base inhibitor must be chemically cleaned before adding ethylene glycol type antl-freeze.

________________

PAGE 3.4-1

SECTION 3.4 PERIODIC MAINTENANCE

PART 3- ENGINE

LUBRICATION & COOLING SYSTEM

PAGE 3.4-2

Part 4

ENGINE

FUEL

SYSTEM

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

SECTION

4.1

4.2

4.3

4.4

4.5

TABLE OF CONTENTS

TITLE

Introduction to the Diesel

______

Fuel Nozzles and Holders

Fuel System

Fuel Pump

Governor

Fuel Injection Pump

______

MOBILE

AC GENERATORS

Liquid-Cooled Diesel Engine Models

PART 4 ENGINE FUEL SYSTEM

INTRODUCTION TO THE DIESEL FUEL SYSTEM

SECTION 4.1- INTRODUCTION TO

THE DIESEL FUEL SYSTEM

Section 4.1

General

The diesel engine does not require an electrical ignition system. The diesel fuel is ignited by heat which is created by extremely high pressures In the combus

tion chambers during the compression stroke. The compression ratio of the engine is 23 to 1, to provide à

cylinder compression pressure of nearly 340 psi.

Fuel Recommendations

Diesel fuels are less volatile than gasoline and gaseous fuels. For that reason, diesel fuel is consid ered safer than the more volatile fuels. Because diesel

fuels are safer, careless practices often result which

can lead to serious problems with engine performance and reliability.

RECOMMENDED FUEL:

Use clean, fresh. No. 2D diesel fuel having a Ce tane number of at least “40". Where the vehicle is equipped with a diesel engine, the vehicle fuel tank may also supply fuel to the NP series generator.

KEEP DIESEL FUEL CLEAN:

Dirt or water in the fuel system is a major cause of engine, injection pump or injection nozzle failure. Fuel must be kept clean and free of moisture.

DO NOT ALTER THE INSTALLATION:

When installed, the fuel system was in full compli ance with applicable codes, standards and regulations. Do NOT make any changes that might render the system unsafe or in non-compliance with such codes, standards and regulations.

CHECK FOR LEAKS PERIODICALLY:

Fuel lines and fittings must be kept tight and must be maintained free of leaks. An improperly tightened fuel line might show no evidence of leakage, but may permit air to enter the fuel system. Air In the system will cause hard starting and rought operation.

NOTE: The diesel engine Is self-bleeding and should never require hand priming or bleeding of air from the system.

Fuel System Components

See Figure 1, below. During operation, fuel is

pumped from the fuel tank, to a 12 volts DC electric fuel pump, through a fuel filter, a fuel injector pump, fuel injectors, and into the engine combustion chambers.

The following facts apply to the various fuel system

components:

INJECTORS

Figure 1. Engine Fuel System (Typical)

PAGE 4.1-1

SECTION 4.1- INTRODUCTION TO

THE DIESEL FUEL SYSTEM

Fuel System Components (Continued)

□ The FUEL INJECTOR PUMP must be properly

timed, to deliver the required amount of fuel to each cylinder at the precise moment the fuel is needed. Firing order of engine cylinders is 1-2-3. Fuel injec tion occurs at 20’-21' BTDC.

□ Injectors pressure is approximately 1707 psi (11,769

kPa).

□ Rated lift of the electric fuel pump is approximately 9

to 10 feet (200 mm of Hg).

□ Excess fuel is returned to the fuel tank, via one or

more return lines.

PART 4

ENGINE FUEL SYSTEM

PAGE 4.1-2

PART 4 ENGINE FUEL SYSTEM

SECTION 4.2

FUEL PUMP

Section 4.2

FUEL PUMP

The electric fuel pump is turned on by the action of

General

an engine control circuit board, housed in the unit control panel. Power for pump operation is supplied via

Wire No. 14 which is electrically hot only during engine

running condition. Wire No. 14 also energizes a FUEL SOLENOID (FS) which then opens to supply fuel to the system.

NOTE: For additional Inforniatlon on the engine control circuit board, refer to Part 5 of this manual,

"ENGINE ELECTRICAL SYSTEM".

An ohmmeter or a volt-ohm-milliammeter (VOM)

Testing the Fuel Pump

may be used to test fuel pump windings for continuity.

To perform an operational test, disconnect the pump outlet line from the pump and connect the pump inlet line to a suitable fuel supply. Connect a 12 volts

DC power supply to the white pump wire (+); a negative (-) DC power supply to the black wire (-). The pump

should operate and pump fuel out of the outlet side, if

not, replace the pump.

PAGE 4.2-1

SECTION 4.2 FUEL PUMP

PART 4

ENGINE FUEL SYSTEM

PAGE 4.2-2

PART 4 ENGINE FUEL SYSTEM

Section 4.3

GOVERNOR

General

A mechanical all-speed governor is used, it is

housed in the gear case.

A flyw/eight assembly Is mounted on the camshaft.

Flyweight movement is transmitted to the injection pump control rack by way of the slider, control lever and link. A spring is attached to the arm complete and the tension lever. The spring regulates flyweight move ment.

Link

SECTION 4.3

GOVERNOR

Tension lever

Arm

complete

Idling

Figure 1. Governor to Pump Connections

By changing the set angle of the oovernor lever, tension on the tension lever spring is cnanged. In this manner, engine speed can be regulated by the gover nor lever.

Governor Adjustment

Governor adjustment procedure may be found on Page 1.9-2 of this manual (Part 1, Section 9). Governed speed adjustment is accomplished by limiting the movement of the arm complete.

Figure 2. The Engine Governor

Generac Power Systems 53187 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

SERVICE

MANUAL

IMPORTANT SAFETY NOTICE

INTRODUCTION

HOW A GENERATOR WORKS

^UNnrewmjno^mc^T^OR^^^

INTRODUCTION TO TROUBLESHOOTING

nmnrin

INSULATION RESISTANCE TESTS

OPERATIONAL TESTS AND ADJUSTMENTS

GENERAL INFORMATION

ENGINE DISASSEMBLY

DISASSEMBLY AND INSPECTION

ENGINE REASSEMBLY

ENGINE LUBRICATION SYSTEM

WATER PUMP & THERMOSTAT

COOLING & VENTILATING AIR

PERIODIC MAINTENANCE

INTRODUCTION TO THE DIESEL FUEL SYSTEM

FUEL PUMP

GOVERNOR