Generac Power Systems 53187 User Manual

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

+ 122 hidden pages

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