Guardian Technologies 4270 User Manual

DIAGNOSTIC REPAIR MANUAL

QUIETPACT®75D

RECREATIONAL VEHICLE GENERATOR

MODEL 4270

SAFETY

Throughout this publication, "DANGER!" and "CAUTION!" blocks are used to alert the mechanic for special instructions concerning a particular service or operation that might be hazardous if performed incorrectly or carelessly. PAY CLOSE ATTENTION TO THEM.

DANGER! UNDER THIS HEADING WILL BE FOUND SPECIAL INSTRUCTIONS WHICH, IF NOT COMPLIED WITH, COULD RESULT IN PERSONAL INJURY OR DEATH.

CAUTION! Under this heading will be found special instructions which, if not complied with, could result in damage to equipment and/or property.

These "Safety Alerts" alone cannot eliminate the hazards that they signal. Strict compliance with these special Instructions plus "common sense" are major accident prevention measures.

NOTICE TO USERS OF THIS MANUAL

This SERVICE MANUAL has been written and published by Generac to aid our dealers, mechanics, and company service personnel when servicing the products described herein.

It is assumed that these personnel are familiar with the servicing procedures for these products, or similar products manufactured and marketed by Generac; that they have been trained in the recommended servicing procedures for these products, including the use of common hand tools, special Generac tools, or tools from other suppliers.

Generac could not possibly know of and advise the service trade of all conceivable procedures by which a service might be performed and of the possible hazards and/or results of each method. Generac has not undertaken any such wide evaluation. Therefore, anyone who uses a procedure or tool not recommended by Generac, must ensure that neither personal safety nor the products safety will be endangered by the service procedure selected.

All information, illustrations and specifications in this manual are based on the latest product information available at the time of publication.

When working on these products, remember that the electrical system and engine ignition system are capable of violent and damaging short circuits or severe electrical shocks. If work must be done where electrical terminals could be grounded or touched, the battery cables should be disconnected at the battery.

Any time the intake or exhaust openings of the engine are exposed during service, they should be covered to prevent accidental entry of foreign material. Entry of such materials will result in extensive damage when the engine is started.

During any maintenance procedure, replacement fasteners must have the same measurements and strength as the fasteners that were removed. Metric bolts and nuts have numbers that indicate their strength. Customary bolts use radial lines to indicate strength, while most customary nuts do not have strength markings. Mismatched or incorrect fasteners can cause damage, malfunction and possible injury.

REPLACEMENT PARTS

Components on Generac recreational vehicle generators are designed and manufactured to comply with Recreational Vehicle Industry Association (RVIA) Rules and Regulations to minimize the risk of fire or explosion. The use of replacement parts that are not in compliance with such Rules and Regulations could result in a fire or explosion hazard. When servicing this equipment, It is extremely important that all components be properly installed and tightened. If parts are improperly installed or tightened, sparks could ignite fuel vapors from fuel system leaks.

Table of Contents

Page 1

SAFETY ............................ INSIDE FRONT COVER

SECTION 1:

GENERATOR FUNDAMENTALS ...................... 3-7

MAGNETISM ................................................................ 3

ELECTROMAGNETIC FIELDS .................................... 3

ELECTROMAGNETIC INDUCTION .............................. 3

A SIMPLE AC GENERATOR ........................................ 4

A MORE SOPHISTICATED AC GENERATOR ............ 4

FIELD BOOST .............................................................. 6

GENERATOR AC CONNECTION SYSTEM ................ 6

SECTION 2:

MAJOR GENERATOR COMPONENTS............ 8-11

ROTOR ASSEMBLY ...................................................... 8

STATOR ASSEMBLY .................................................... 8

BRUSH HOLDER .......................................................... 9

BATTERY CHARGE COMPONENTS .......................... 9

EXCITATION CIRCUIT COMPONENTS ...................... 9

VOLTAGE REGULATOR ............................................ 10

CONTROL PANEL

COMPONENT IDENTIFICATION ................................ 11

SECTION 3:

INSULATION RESISTANCE TESTS ............ 12-14

EFFECTS OF DIRT AND MOISTURE ........................ 12

INSULATION RESISTANCE TESTERS ...................... 12

DRYING THE GENERATOR ...................................... 12

CLEANING THE GENERATOR .................................. 12

STATOR INSULATION RESISTANCE ........................ 13

TESTING ROTOR INSULATION ................................ 14

THE MEGOHMMETER .............................................. 14

SECTION 4:

MEASURING ELECTRICITY ........................ 15-17

METERS ...................................................................... 15

THE VOM .................................................................... 15

MEASURING AC VOLTAGE ...................................... 15

MEASURING DC VOLTAGE ...................................... 15

MEASURING AC FREQUENCY ................................ 16

MEASURING CURRENT ............................................ 16

MEASURING RESISTANCE ...................................... 16

ELECTRICAL UNITS .................................................. 17

OHM’S LAW ................................................................ 17

SECTION 5:

ENGINE DC CONTROL SYSTEM ................ 18-28

INTRODUCTION ........................................................ 18

OPERATIONAL ANALYSIS .................................. 18-23

ENGINE CONTROLLER CIRCUIT BOARD ................ 24

BATTERY .................................................................... 24

14 AMP FUSE ............................................................ 26

PRE-HEAT SWITCH .................................................. 26

START-STOP SWITCH .............................................. 26

STARTER CONTACTOR & MOTOR ........................ 26

ENGINE GOVERNOR .................................................. 27

FUEL INJECTION PUMP ............................................ 27

FUEL NOZZLES/INJECTORS ...................................... 27

GLOW PLUGS .............................................................. 27

ENGINE PROTECTIVE DEVICES .............................. 28

LOW OIL PRESSURE SWITCH .................................. 28

HIGH COOLANT TEMPERATURE SWITCH .............. 28

OVERSPEED PROTECTION ...................................... 28

SECTION 6:

TROUBLESHOOTING FLOWCHARTS .................. 29-36

IF PROBLEM INVOLVES AC OUTPUT ...................... 29

PROBLEM 1 VOLTAGE & FREQUENCY ARE BOTH

HIGH OR LOW ............................................................ 29

PROBLEM 2 GENERATOR PRODUCES ZERO VOLTAGE OR

RESIDUAL VOLTAGE (5-12 VAC) ........................ 30-31

PROBLEM 3 -

NO BATTERY CHARGE OUTPUT .............................. 31

PROBLEM 4 EXCESSIVE VOLTAGE/FREQUENCY DROOP

WHEN LOAD IS APPLIED .......................................... 32

PROBLEM 5 -

PRIMING FUNCTION DOES NOT WORK .................. 32

PROBLEM 6 -

ENGINE WILL NOT CRANK ...................................... 33

PROBLEM 7 ENGINE CRANKS BUT WILL NOT START /

RUNS HARD .............................................................. 34

PROBLEM 8 -

ENGINE STARTS THEN SHUTS DOWN .................. 35

PROBLEM 9 -

14 AMP (F1) FUSE BLOWING .................................... 36

SECTION 7:

DIAGNOSTIC TESTS...................................... 37-57

INTRODUCTION ........................................................ 37

TEST 1 -

Check No-Load Voltage And Frequency...................... 37

TEST 2 -

Check Engine Governor.......................................... 37-38

TEST 3 -

Test Excitation Circuit Breaker .................................... 38

TEST 4 -

Fixed Excitation Test/Rotor Amp Draw .................. 38-39

TEST 5 -

Wire Continuity ............................................................ 39

TEST 6 -

Check Field Boost .................................................. 39-40

TEST 7 -

Test Stator DPE Winding ........................................ 40-41

TEST 8 -

Check Sensing Leads/Power Windings ...................... 41

TEST 9 -

Check Brush Leads ................................................ 41-42

TEST 10 -

Check Brushes & Slip Rings ........................................ 42

TEST 11 -

Check Rotor Assembly............................................ 42-43

TEST 12 -

Check Main Circuit Breaker.......................................... 43

TEST 13 -

Check Load Voltage & Frequency................................ 43

TEST 14 -

Check Load Watts & Amperage .................................. 43

TEST 15 -

Check Battery Charge Output ................................ 43-44

TEST 16 -

Check Battery Charge Rectifier.................................... 44

TEST 17 Check Battery Charge Windings/

Battery Charge Resistor.......................................... 44-45

TEST 18 -

Try Cranking the Engine .............................................. 45

TEST 19 -

Test Pre-Heat Switch.................................................... 45

TEST 20 -

Check Fuel Pump.................................................... 45-46

TEST 21 -

Check 14 Amp Fuse .................................................... 46

TEST 22 -

Check Battery & Cables................................................ 46

TEST 23 -

Check Power Supply to Circuit Board .................... 46-47

TEST 24 -

Check Start-Stop Switch.......................................... 47-48

TEST 25 -

Check Power Supply to Wire 56 .................................. 48

TEST 26 -

Check Starter Contactor .............................................. 48

TEST 27 -

Check Starter Motor .............................................. 48-50

TEST 28 -

Check Fuel Supply........................................................ 51

TEST 29 -

Check Wire 14 Power Supply ...................................... 51

TEST 30 -

Check Wire 18.............................................................. 51

TEST 31 -

Check Fuel Solenoid .............................................. 51-52

TEST 32 -

Test Pre-Heat Contactor .............................................. 52

TEST 33 -

Test Glow Plugs............................................................ 52

TEST 34 -

Test D1 Diode .............................................................. 52

TEST 35 -

Check Valve Adjustment .............................................. 53

TEST 36 -

Fuel Injector Pump ................................................ 53-54

TEST 37 Check Engine / Cylinder Leak Down Test /

Compression Test .................................................. 54-55

TEST 38 -

Check Oil Pressure Switch .......................................... 55

TEST 39 -

Check Circuit Board for Ground .................................. 55

TEST 40 -

Test Water Temperature Switch ............................ 55-56

TEST 41 Check Wire 14 and Connecting

Components for Ground .............................................. 56

TEST 42 Check Wire 56 and Starter Contactor

for Short to Ground ...................................................... 56

TEST 43 -

Check Wire 15 for Short to Ground .............................. 56

SECTION 8:

ASSEMBLY .................................................... 57-59

MAJOR DISASSEMBLY .............................................. 57

Enclosure/Panel Removal ...................................... 57

Stator Removal ........................................................ 57

Rotor Removal ........................................................ 57

Belt Tensioning ........................................................ 57

Engine Removal ...................................................... 57

Starter Removal ...................................................... 58

Fuel Injector Pump Removal .................................... 58

Radiator Removal .................................................... 58

Re-assembly ............................................................ 58

Belt Tensioning .................................................. 58-59

SECTION 9:

EXPLODED VIEWS / PART NUMBERS ...... 60- 87

SECTION 10:

SPECIFICATIONS & CHARTS ...................... 88-90

MAJOR FEATURES AND DIMENSIONS .................... 88

ENGINE SPECIFICATIONS ........................................ 89

GENERATOR SPECIFICATIONS .............................. 89

ROTOR/STATOR RESISTANCE VALUES ................ 90

TORQUE SPECIFICATIONS ...................................... 90

SECTION 11:

ELECTRICAL DATA ............................................ 92

Page 2

Table of Contents

Section 1

GENERATOR FUNDAMENTALS

MAGNETISM

Magnetism can be used to produce electricity and electricity can be used to produce magnetism.

Much about magnetism cannot be explained by our present knowledge. However, there are certain patterns of behavior that are known. Application of these behavior patterns has led to the development of generators, motors and numerous other devices that utilize magnetism to produce and use electrical energy.

See Figure 1-1. The space surrounding a magnet is permeated by magnetic lines of force called “flux”. These lines of force are concentrated at the magnet's north and south poles. They are directed away from the magnet at its north pole, travel in a loop and reenter the magnet at its south pole. The lines of force form definite patterns which vary in intensity depending on the strength of the magnet. The lines of force never cross one another. The area surrounding a magnet in which its lines of force are effective is called a “magnetic field”.

Like poles of a magnet repel each other, while unlike poles attract each other.

Figure 1-1. – Magnetic Lines of Force

ELECTROMAGNETIC FIELDS

All conductors through which an electric current is flowing have a magnetic field surrounding them. This field is always at right angles to the conductor. If a compass is placed near the conductor, the compass needle will move to a right angle with the conductor. The following rules apply:

• The greater the current flow through the conductor, the stronger the magnetic field around the conductor.

• The increase in the number of lines of force is directly proportional to the increase in current flow and the field is distributed along the full length of the conductor.

• The direction of the lines of force around a conductor can be determined by what is called the “right hand rule”. To apply this rule, place your right hand around the conductor with the thumb pointing in the direction of current flow. The fingers will then be pointing in the direction of the lines of force.

NOTE: The “right hand rule” is based on the “current flow” theory which assumes that current flows from positive to negative. This is opposite the “electron” theory, which states that current flows from negative to positive.

Figure 1-2. – The Right Hand Rule

ELECTROMAGNETIC INDUCTION

An electromotive force (EMF) or voltage can be produced in a conductor by moving the conductor so that it cuts across the lines of force of a magnetic field.

Similarly, if the magnetic lines of force are moved so that they cut across a conductor, an EMF (voltage) will be produced in the conductor. This is the basic principal of the revolving field generator.

Figure 1-3, below, illustrates a simple revolving field generator. The permanent magnet (Rotor) is rotated so that its lines of magnetic force cut across a coil of wires called a Stator. A voltage is then induced into the Stator windings. If the Stator circuit is completed by connecting a load (such as a light bulb), current will flow in the circuit and the bulb will illuminate.

Figure 1-3. – A Simple Revolving Field Generator

Page 3

Section 1 GENERATOR FUNDAMENTALS

A SIMPLE AC GENERATOR

Figure 1-4 shows a very simple AC Generator. The generator consists of a rotating magnetic field called a ROTOR and a stationary coil of wire called a STATOR. The ROTOR is a permanent magnet which consists of a SOUTH magnetic pole and a NORTH magnetic pole.

As the MOTOR turns, its magnetic field cuts across the stationary STATOR. A voltage is induced into the STATOR windings. When the magnet's NORTH pole passes the STATOR, current flows in one direction. Current flows in the opposite direction when the magnet's SOUTH pole passes the STATOR. This constant reversal of current flow results in an alternating current (AC) waveform that can be diagrammed as shown in Figure 1-5.

The ROTOR may be a 2-pole type having a single NORTH and a single SOUTH magnetic pole. Some ROTORS are 4-pole type with two SOUTH and two NORTH magnetic poles. The following apply:

1. The 2-pole ROTOR must be turned at 3600 rpm to produce an AC frequency of 60-Hertz, or at 3000 rpm to deliver an AC frequency of 50-Hertz.

2. The 4-pole ROTOR must operate at 1800 rpm to deliver a 60Hertz AC frequency or at 1500 rpm to deliver a 50-Hertz AC frequency.

Figure 1-4. – A Simple AC Generator

Figure 1-5. – Alternating Current Sine Wave

A MORE SOPHISTICATED AC GENERATOR

Figure 1-6 represents a more sophisticated generator. A regulated direct current is delivered into the ROTOR windings via carbon BRUSHES AND SLIP RINGS. This results in the creation of a regulated magnetic field around the ROTOR. As a result, a regulated voltage is induced into the STATOR. Regulated current delivered to the ROTOR is called “EXCITATION” current.

Figure 1-6. – A More Sophisticated Generator

See Figure 1-7 (next page). The revolving magnetic field (ROTOR) is driven by the engine at a constant speed. This constant speed is maintained by a mechanical engine governor. Units with a 2-pole rotor require an operating speed of 3600 rpm to deliver a 60-Hertz AC output. Engine governors are set to maintain approximately 3720 rpm when no electrical loads are connected to the generator.

SLIP

Page 4

(+)

(-)

CURRENT

180

ONE CYCLE

VOLTAGE

360

TAT

ROT

MAGNETIC FIEL

T TP

RRENT

240

120

BRUSHE

RIN

TAT

Section 1

GENERATOR FUNDAMENTALS

NOTE: AC output frequency at 3720 rpm will be about 62-Hertz. The “No-Load” is set slightly high to prevent excessive rpm, frequency and voltage droop under heavy electrical loading.

Generator operation may be described briefly as follows:

1. Some “residual” magnetism is normally present in the rotor and is sufficient to induce approximately 7 to 12 VAC Into the stator's AC power windings.

2. During startup, an engine controller circuit board delivers battery voltage to the rotor, via the brushes and slip rings.

a. The battery voltage is called “Field Boost”. b. Flow of direct current through the ROTOR

increases the strength of the magnetic field above that of “residual” magnetism alone.

3. “Residual” plus “Field Boost” magnetism induces a voltage into the Stator excitation (DPE), battery charge and AC Power windings.

4. Excitation winding unregulated AC output is delivered to an electronic voltage regulator, via an excitation circuit breaker.

a. A “Reference” voltage has been pre-set into

the Voltage Regulator.

b. An “Actual” (“sensing”) voltage is delivered

to the Voltage Regulator via sensing leads from the Stator AC power windings.

c. The Regulator “compares” the actual (sens-

ing) voltage to its pre-set reference voltage.

(1) If the actual (sensing) voltage is greater than the pre-set reference voltage, the Regulator will decrease the regulated current flow to the Rotor.

(2) If the actual (sensing) voltage is less than the pre-set reference voltage, the Regulator will increase the regulated current flow to the Rotor.

(3) In the manner described, the Regulator maintains an actual (sensing) voltage that is equal to the pre-set reference voltage.

NOTE: The Voltage Regulator also changes the Stator excitation windings alternating current (AC) output to direct current (DC).

5. When an electrical load is connected across the Stator power windings, the circuit is completed and an electrical current will flow.

6. The Rotor's magnetic field also induces a voltage Into the Stator battery charge windings.

a. Battery charge winding AC output is deliv-

ered to a battery charge rectifier (BCR) which changes the AC to direct current (DC).

b. The rectified DC is then delivered to the unit

battery, to maintain the battery in a charged state.

c. A one ohm, 25 watt Resistor is installed in

series with the grounded side of the battery charge circuit.

Page 5

Figure 1-7. – Generator Operating Diagram

Section 1 GENERATOR FUNDAMENTALS

FIELD BOOST

When the engine is cranked during startup, the engine control circuit board Terminals 9, 10, and 11 (Wire 14) are energized with 12 VDC. Connected to a Wire 14 is a resistor (R2) and a diode (D2). Battery current flows through the 20 ohm 12-watt resistor and the field boost diode D2, the voltage is reduced to 3-5 VDC. After passing through R2 and D2 it becomes Wire 4 and current travels to the Rotor via brushes and slip rings. This is called “Field Boost” current.

The effect is to “flash the field” every time the engine is cranked. Field boost current helps ensure that sufficient “pickup” voltage is available on every startup to turn the Voltage Regulator on and build AC output voltage.

NOTE: Loss of the Field Boost function may or may not result in loss of AC power winding output. If Rotor residual magnetism alone is sufficient to turn the Regulator on, loss of Field Boost may go unnoticed. However, if residual magnetism alone is not enough to turn the Regulator on, loss of the Field Boost function will result in loss of AC power winding output to the load. The AC output voltage will then drop to a value commensurate with the Rotor's residual magnetism (about 7-12 VAC).

GENERATOR AC CONNECTION SYSTEM

The generator set is equipped with dual stator AC power windings. These two stator windings supply electrical power to customer electrical loads by means of a dual two-wire connection system.

Generators may be installed to provide the following outputs:

1. 120/240 VAC loads — one load with a maximum total wattage requirement equal to the generator’s rated power output, and 240 VAC across the generator output terminals; or two separate loads, each with a maximum total wattage requirement equal to half of the generator’s rated power output (in watts), and 120VAC across the generator output terminals. Figure 1.9 shows the generator lead wire connections for 120/240 VAC loads.

2. 120 VAC loads only — one load with a maximum total wattage requirement equal to the generator’s rated power output (in watts), and 120V across the generator output terminals. Figure

1.8 shows the generator lead wire connections for 120VAC ONLY.

The generator set can be used to supply electrical power for operating one of the following electrical loads:

• QUIETPACT 75D: 120 and/or 240 VAC, single phase, 60-Hertz electrical loads. These loads can require up to 7500 watts (7.5 kW) of total power, but cannot exceed 62.5 AC amperes of current at 120 VAC or exceed 31.2 AC amperes at 240 VAC.

CAUTION! Do not overload the generator. Some installations may require that electrical loads be alternated to avoid overloading. Applying excessively high electrical loads may damage the generator and may shorten its life. Add up the rated watts of all electrical lighting, appliance, tool and motor loads the generator will power at one time. This total should not be greater than the wattage capacity of the generator. If an electrical device nameplate gives only volts and amps, multiply volts times amps to obtain watts (volts x amps = watts). Some electric motors require more watts of power (or amps of current) for starting than for continuous operation.

LINE BREAKERS (120 VAC ONLY): Protects generator’s AC output circuit against

overload (i.e., prevents unit from exceeding wattage/amperage capacity). The circuit breaker ratings are as follows:

GENERATOR CONVERSION TO

120 VAC ONLY — DUAL CIRCUITS

NOTE: Conversion of a QUIETPACT™ generator from "120/240 VAC dual voltage" to "120 VAC only - dual circuits" (or vice-versa) requires rerouting wires within the unit enclosure. It is recommended that this conversion be performed by a Generac Authorized Service Dealer.

Figure 1-9 shows the stator power winding connections for 120 VAC only - dual circuits. Two stator power windings are used, with each winding capable of supplying half of the unit's rated wattage/amperage capacity. The circuit from each winding is protected against overload by a line breaker (CB1 and CB1A). Line breakers CB1 and CB1A have a trip rating of 35 amps.

To convert from "120/240 VAC dual voltage" to "120 VAC only - dual circuits", disconnect battery power from the generator and reverse stator lead Wires 33 and 44 as follows:

NOTE: It is necessary to feed stator lead Wires 33 and 44 through grommets on the electrical enclosure and engine control box in order to perform the rerouting outlined below. The front and top unit enclosure panels, as well as the user control panel, must be removed to perform this. After rerouting, wires should be properly tied down to prevent chafing or contact with moving internal components

1. Remove stator lead Wire 33, as shown in Figure 1-8, from the ground stud adjacent to the four-position terminal block.

Page 6

Model Circuit Breaker 1 Circuit Breaker 2

QuietPact 75D 35A 35A

Section 1

GENERATOR FUNDAMENTALS

Reroute stator lead 44 from the line side terminal of CB1 (renamed as CB1A in Figure 1-9) to the ground stud location previously occupied by stator lead Wire 33.

2. Move smaller gauge (#18 AWG) Wire labeled #44 (not shown), from the top of CB1A to the top of CB1. Renumber this Wire 11.

3. Reroute stator lead Wire 33, removed in step 1, to the line side terminal on CB1A.

4. Renumber ground Wire 33, located between the four-position terminal block and ground in Figure 1-8, as ground Wire 44, as shown in Figure 1-9.

5. Renumber Wire 44A from Figure 1-8 as Wire 33A in Figure 1-9.

6. Connect a 12 AWG jumper wire between line breakers CB1 and CB1A, as shown in Figure 1-9.

7. Remove the "tie bar" between the two-line breaker switch handles.

When connecting vehicle load leads, the following rules apply:

• Connect 120 VAC, single-phase, 60-Hertz, AC electrical loads, requiring up to the trip rating of circuit breaker CB1, across AC output leads T1 (red) and T2 (white).

• Connect 120 VAC, single-phase, 60-Hertz, AC electrical loads, requiring up to the trip rating of circuit breaker CB1A, across AC output leads T3 (black) and T2 (white).

• Try to keep the load balanced between the two circuit breakers and the stator windings.

• The neutral line (T2, white) on all units is a grounded neutral.

Do NOT connect electrical loads in excess of any circuit breaker rating, or problems will develop with circuit breaker tripping, which causes a loss of AC output. Also, do NOT exceed the generator's rated wattage capacity. Add the watts or amps of all lighting, appliance, tool, and motor loads the generator will operate at one time. This total should be less than the unit's rated wattage/amperage capacity.

Figure 1-8. – Connection for 120/240 VAC Dual

Voltage

Figure 1-9 - Connection for 120 VAC Only —

Dual Circuits

Page 7

Section 2 MAJOR GENERATOR COMPONENTS

ROTOR ASSEMBLY

The Rotor is sometimes called the “revolving field”, since it provides the magnetic field that induces a voltage into the stationary Stator windings. Slip rings on the Rotor shaft allow excitation current from the voltage regulator to be delivered to the Rotor windings. The Rotor is driven by the engine at a constant speed through a pulley and belt arrangement.

The QUIETPACT 75D utilizes a 2-pole Rotor. This type of Rotor must be driven at 3600 rpm for a 60Hertz AC output, or at 3000 rpm for a 50-Hertz output.

Slip rings should be cleaned. If dull or tarnished, clean them with fine sandpaper (a 400 grit wet sandpaper is recommended). DO NOT USE ANY METALLIC GRIT OR ABRASIVE TO CLEAN SLIP RINGS.

STATOR ASSEMBLY

The Stator is assembled between the front and rear bearing carriers and retained in that position by four Stator studs. Windings included in the Stator assembly are (a) dual AC power windings, (b) an excitation or DPE winding, and (c) a battery charge winding. A total of eleven (11) leads are brought out of the Stator as follows:

1. Four (4) Stator power winding output leads (Wires No. 11, 22, 33 and 44). These leads deliver power to connected electrical loads.

2. Stator Power winding “sensing” leads (11 and 22). These leads deliver an “actual voltage signal to the electronic Voltage Regulator.

Page 8

Figure 2-1. Exploded View of Generator

BEARING CARRIER

BRUSH HOLDER

STATOR

BEARING

ENGINE

ROTOR

BEARING

PULLEY

FLYWHEEL/PULLEY

TENSIONER

BELT

Section 2

MAJOR GENERATOR COMPONENTS

3. Two excitation winding output leads (No. 2 and 6). These leads deliver unregulated excitation current to the voltage regulator.

4. Three (3) battery charge output leads (No. 55, 66 and 77).

Figure 2-2. – Stator Output Leads

BRUSH HOLDER

The brush holder is retained in the rear bearing carrier by two M5 screws. It retains two brushes, which contact the Rotor slip rings and allow current flow from stationary parts to the revolving Rotor. The positive (+) brush is located nearest the Rotor bearing.

Figure 2-3. – Brush Holder

BATTERY CHARGE COMPONENTS

The Stator incorporates dual battery charge windings. A battery charge rectifier (BCR) changes the AC output of these windings to direct current (DC). Battery charge winding output is delivered to the unit battery via the rectifier, a 14 amp fuse and Wire No. 15. A one ohm, 25 watt resistor is connected in series with the grounded side of the circuit.

Figure 2-4. – Battery Charge Circuit

EXCITATION CIRCUIT COMPONENTS

GENERAL: During operation, the Rotor's magnetic field induces a

voltage and current flow into the Stator excitation winding. The resultant AC output is delivered to a voltage regulator via an excitation circuit breaker (CB2).

Figure 2-5. – Schematic: Excitation Circuit

EXCITATION CIRCUIT BREAKER: The excitation circuit breaker (CB2) is self-resetting

and cannot be reset manually. Should the breaker open for any reason, excitation current flow to the Rotor is lost. The unit’s AC output voltage will then drop to a value equal to the Rotor's residual magnetism (about 7-12 VAC).

CB2

CIRCU

Page 9

ENGIN

NTROLLE

IT BOAR

Leads 2 & 6 =Stator Excitation Winding Leads 11 & 22 = Voltage Sensing Leads Leads 11 & 22, 33 & 44 = AC Power Windings Leads 55, 66, 77 = Battery Charge Windings

TO BATTERY

BATTERY CHARGE WINDIN

BCR = Battery Charge Rectifie R1 = One Ohm, 25 Watt Resistor

POWER WINDIN

BRUSHES

ELECTRONI

VOLTA

REGULAT

DPE WINDIN

Section 2 MAJOR GENERATOR COMPONENTS

Figure 2-6. – Excitation Circuit Breaker

VOLTAGE REGULATOR: Six (6) leads are connected to the voltage regulator

as follows:

• Two (2) SENSING leads deliver ACTUAL AC output voltage signals to the regulator. These are Wires No. 11 and 22.

• Two (2) leads (4 and 1) deliver the regulated direct current to the Rotor, via brushes and slip rings.

• Two (2) leads (No. 6 and 162) deliver Stator excitation winding AC output to the regulator.

The regulator mounts a “VOLTAGE ADJUST” potentiometer, used for adjustment of the pre-set REFERENCE voltage. An LED will turn on to indicate that SENSING voltage is available to the regulator and the regulator is turned on.

Figure 2-7. – Voltage Regulator

ADJUSTMENT PROCEDURE: With the frequency set at 62.5-Hertz and no load on

the generator, slowly turn the voltage adjust pot on the voltage regulator until 124 VAC is measured. If voltage is not adjustable, proceed to Section 6 Troubleshooting.

NOTE: If, for any reason, sensing voltage to the regulator is lost, the regulator will shut down and excitation output to the Rotor will be lost. The AC output voltage will then drop to a value that is equal to Rotor residual magnetism (about 7-12 VAC). Without this automatic shutdown feature, loss of sensing (actual) voltage to the regulator would result in a “full field” or “full excitation” condition and an extremely high AC output voltage.

NOTE: Adjustment of the regulator's “VOLTAGE ADJUST” potentiometer must be done only when the unit is running at its correct governed no-load speed. Speed is correct when the unit's no-load AC output frequency is about 62.5-Hertz. At the stated frequency, AC output voltage should be about 125 volts.

Page 10

VOLTAGE ADJUST POT

LED

162

Section 2

MAJOR GENERATOR COMPONENTS

Page 11

CONTROL PANEL COMPONENT IDENTIFICATION

Figure 2-9. – Control Panel Components

Section 3 INSULATION RESISTANCE TESTS

EFFECTS OF DIRT AND MOISTURE

Moisture and dirt are harmful to the continued good operation of any generator set.

If moisture is allowed to remain in contact with the Stator and Rotor windings, some of the moisture will be retained in voids and cracks of the winding insulation. This will result in a reduced insulation resistance and, eventually, the unit's AC output will be affected.

Insulation used in the generator is moisture resistant. However, prolonged exposure to moisture will gradually reduce the resistance of the winding insulation.

Dirt can enhance the problem, since it tends to hold moisture into contact with the windings. Salt, as from sea air, contributes to the problem since salt can absorb moisture from the air. When salt and moisture combine, they make a good electrical conductor.

Due to the detrimental affects of dirt and moisture, the generator should be kept as clean and as dry as possible. Rotor and Stator windings should be tested periodically with an insulation resistance tester (such as a megohmmeter or hi-pot tester).

If the insulation resistance is excessively low, drying may be required to remove accumulated moisture. After drying, perform a second insulation resistance test. If resistance is still low after drying, replacement of the defective Rotor or Stator may be required.

INSULATION RESISTANCE TESTERS

Figure 3-1 shows one kind of hi-pot tester. The tester shown has a “Breakdown” lamp that will glow during the test procedure to indicate an insulation breakdown in the winding being tested.

Figure 3-1. – One Type of Hi-Pot Tester

DANGER! INSULATION RESISTANCE TESTERS SUCH AS HI-POT TESTERS AND MEGOHMMETERS ARE A SOURCE OF HIGH AND DANGEROUS ELECTRICAL VOLTAGE.

FOLLOW THE TESTER MANUFACTURER'S INSTRUCTIONS CAREFULLY. USE COMMON SENSE TO AVOID DANGEROUS ELECTRICAL SHOCK

DRYING THE GENERATOR

GENERAL: If tests indicate the insulation resistance of a winding

is below a safe value, the winding should be dried before operating the generator. Some recommended drying procedures include (a) heating units and (b) forced air.

HEATING UNITS: If drying is needed, the generator can be enclosed in

a covering. Heating units can then be installed to raise the temperature about 15°-18° F. (8°-10° C.) above ambient temperature.

FORCED AIR: Portable forced air heaters can be used to dry the

generator. Direct the heated air into the generator’s air intake openings. Remove the voltage regulator and run the unit at no-load. Air temperature at the point of entry into the generator should not exceed 150° F. (66° C.).

CLEANING THE GENERATOR

GENERAL: The generator can be cleaned properly only while it is

disassembled. The cleaning method used should be determined by the type of dirt to be removed. Be sure to dry the unit after it has been cleaned.

NOTE: A shop that repairs electric motors may be able to assist you with the proper cleaning of generator windings. Such shops are often experienced in special problems such as a sea coast environment, marine or wetland applications, mining, etc.

USING SOLVENTS FOR CLEANING: If dirt contains oil or grease a solvent is generally

required. Only petroleum distillates should be used to clean electrical components. Recommended are safety type petroleum solvents having a flash point greater than 100° F. (38° C.).

CAUTION!: Some generators may use epoxy or polyester base winding varnishes. Use solvents that will not attack such materials.

Use a soft brush or cloth to apply the solvent. Be careful to avoid damage to wire or winding insulation. After cleaning, dry all components thoroughly using moisture-free, low-pressure compressed air.

Page 12

Section 3

INSULATION RESISTANCE TESTS

DANGER!: DO NOT ATTEMPT TO WORK WITH SOLVENTS IN ANY ENCLOSED AREA. PROVIDE ADEQUATE VENTILATION WHEN WORKING WITH SOLVENTS. WITHOUT ADEQUATE VENTILATION, FIRE, EXPLOSION OR HEALTH HAZARDS MAY EXIST . WEAR EYE PROTECTION. WEAR RUBBER GLOVES TO PROTECT THE HANDS.

CLOTH OR COMPRESSED AIR: For small parts or when dry dirt is to be removed, a

dry cloth may be satisfactory. Wipe the parts clean, then use low pressure air at 30 psi (206 Kpa) to blow dust away.

BRUSHING AND VACUUM CLEANING: Brushing with a soft bristle brush followed by vacuum

cleaning is a good method of removing dust and dirt. Use the soft brush to loosen the dirt, then remove it with the vacuum.

STATOR INSULATION RESISTANCE

GENERAL: Insulation resistance is a measure of the integrity of

the insulating materials that separate electrical windings from the generator's steel core. This resistance can degrade over time due to the presence of contaminants, dust, dirt, grease and especially moisture.

The normal insulation resistance for generator windings is on the order of “millions of ohms” or “megohms”.

When checking the insulation resistance, follow the tester manufacturer's instructions carefully. Do NOT exceed the applied voltages recommended in this manual. Do NOT apply the voltage longer than one (1) second.

CAUTION!: DO NOT connect the Hi-Pot Tester or Megohmmeter test leads to any leads that are routed into the generator control panel. Connect the tester leads to the Stator or Rotor leads only.

STATOR SHORT-TO-GROUND TESTS: See Figure 3-2. To test the Stator for a short-to-

ground condition, proceed as follows:

1. Disconnect and isolate all Stator leads as follows: a. Disconnect sensing leads 11 and 22 from

the voltage regulator.

b. Disconnect excitation winding lead No. 6

from the voltage regulator.

c. Disconnect excitation lead No. 2 from the

excitation circuit breaker (CB2).

d. Disconnect battery charge winding leads

No. 66 and 77 from the battery charge rectifier (BCR).

e. Disconnect battery charge winding lead No.

55 from the battery charge resistor (R1).

f. At the main circuit breakers, disconnect sta-

tor power leads No. 11P and 33.

g. At the ground stud (GND5), disconnect

Stator power leads No. 22 and 33.

2. When all leads have been disconnected as outlined in Step 1 above, test for a short-to-ground condition as follows:

a. Connect the terminal ends of all Stator leads

together (11, 22, 33, 44, 2,6, 55, 66, 77).

b. Follow the tester manufacturer's instructions

carefully. Connect the tester leads across all Stator leads and to frame ground on the Stator can. Apply a voltage of 1500 volts. Do NOT apply voltage longer than one (1) second.

If the test indicates a breakdown in insulation, the Stator should be cleaned, dried and re-tested. If the winding fails the second test (after cleaning and drying), replace the Stator assembly.

TEST BETWEEN ISOLATED WINDINGS:

1. Follow the tester manufacturer's instructions carefully. Connect the tester test leads across Stator leads No. 11 (POWER) and No. 2. Apply a voltage of 1500 volts- DO NOT EXCEED ONE SECOND.

Figure 3-2. – Stator Leads

2. Repeat Step 1 with the tester leads connected across the following Stator leads:

Page 13

Leads 2 & 6 =Stator Excitation Winding Leads 11 & 22 = Voltage Sensing Leads Leads 11 & 22, 33 & 44 = AC Power Windings Leads 55, 66, 77 = Battery Charge Windings

Section 3 INSULATION RESISTANCE TESTS

a. Across Wires No. 33 and 2. b. Across Wires No. 11 (POWER) and 66. c. Across Wires No. 33 and 66. d. Across Wires No. 2 and 66.

If a breakdown in the insulation between isolated windings is indicated, clean and dry the Stator. Then, repeat the test. If the Stator fails the second test, replace the Stator assembly.

TEST BETWEEN PARALLEL WINDINGS: Connect the tester leads across Stator leads No. 11

(POWER) and 33. Apply a voltage of 1500 volts. If an insulation breakdown is indicated, clean and dry the Stator. Then, repeat the test between parallel windings. If the Stator fails the second test, replace it.

TESTING ROTOR INSULATION

To test the Rotor for insulation breakdown, proceed as follows:

1. Remove the brush holders with brushes.

2. Connect the tester positive (+) test lead to the positive (+) slip ring (nearest the Rotor bearing). Connect the tester negative (-) test lead to a clean frame ground (like the Rotor shaft).

Figure 3-3. – Rotor Test Points

3. Apply 1000 volts. DO NOT APPLY VOLTAGE LONGER THAN 1 SECOND.

If an insulation breakdown is indicated, clean and dry the Rotor then repeat the test. Replace the Rotor if it fails the second test (after cleaning and drying).

THE MEGOHMMETER

GENERAL: A megohmmeter, often called a “megger”, consists of

a meter calibrated in megohms and a power supply. Use a power supply of 1500 volts when testing Stators; or 1000 volts when testing the Rotor. DO NOT APPLY VOLTAGE LONGER THAN ONE (1) SECOND.

TESTING STATOR INSULATION: All parts that might be damaged by the high megger

voltages must be disconnected before testing. Isolate all Stator leads (Figure 3-2) and connect all of the Stator leads together. FOLLOW THE MEGGER MANUFACTURER'S INSTRUCTIONS CAREFULLY.

Use a megger power setting of 1500 volts. Connect one megger test lead to the junction of all Stator leads, the other test lead to frame ground on the Stator can. Read the number of megohms on the meter.

MINIMUM INSULATION

GENERATOR RATED VOLTS

RESISTANCE =

__________________________

(in “Megohms”)

1000

The MINIMUM acceptable megger reading for Stators may be calculated using the following formula:

EXAMPLE: Generator is rated at 120 VAC. Divide “120” by “1000” to obtain “0.12”. Then add “1” to obtain “1.12” megohms. Minimum insulation resistance for a 120 VAC Stator is 1.12 megohms.

If the Stator insulation resistance is less than the calculated minimum resistance, clean and dry the Stator. Then, repeat the test. If resistance is still low, replace the Stator.

Use the Megger to test for shorts between isolated windings as outlined “Stator Insulation Resistance”.

Also test between parallel windings. See “Test Between Parallel Windings”on this page.

TESTING ROTOR INSULATION: Apply a voltage of 1000 volts across the Rotor posi-

tive (+) slip ring (nearest the rotor bearing), and a clean frame ground (i.e. the Rotor Shaft). DO NOT EXCEED 1000 VOLTS AND DO NOT APPLY VOLTAGE LONGER THAN ONE SECOND. FOLLOW THE MEGGER MANUFACTURER'S INSTRUCTIONS CAREFULLY.

ROTOR MINIMUM INSULATION RESISTANCE:

1.5 megohms

Page 14

POSITIVE (+) TEST LEAD

Section 4

MEASURING ELECTRICITY

METERS

Devices used to measure electrical properties are called meters. Meters are available that allow one to measure (a) AC voltage, (b) DC voltage, (c) AC frequency, and (d) resistance in ohms. The following apply:

• To measure AC voltage, use an AC voltmeter.

• To measure DC voltage, use a DC voltmeter.

• Use a frequency meter to measure AC frequency in “Hertz” or “cycles per second”..

• Use an ohmmeter to read circuit resistance, in “ohms”.

THE VOM

A meter that allows both voltage and resistance to be read is the “volt-ohm-milliammeter” or “VOM”.

Some VOM's are of the “analog” type (not shown). These meters display the value being measured by physically deflecting a needle across a graduated scale. The scale used must be interpreted by the user.

“Digital” VOM's (Figure 4-1) are also available and are generally very accurate. Digital meters display the measured values directly by converting the values to numbers.

NOTE: Standard AC voltmeters react to the AVERAGE value of alternating current. When working with AC, the effective value is used. For that reason a different scale is used on an AC voltmeter. The scale is marked with the effective or “rms” value even though the meter actually reacts to the average value. This is why the AC voltmeter will give an incorrect reading if used to measure direct current (DC).

Figure 4-1. – Digital VOM

MEASURING AC VOLTAGE

An accurate AC voltmeter or a VOM can be used to read the generator's AC output voltage. The following apply:

1.Always read the generator's AC output voltage only at the unit's rated operating speed and AC frequency.

2. The generator's voltage regulator can be adjusted for correct output voltage only while the unit is operating at its correct rated speed and frequency.

3. Only an AC voltmeter may be used to measure AC voltage. DO NOT USE A DC VOLTMETER FOR THIS PURPOSE.

DANGER!: RV GENERATORS PRODUCE HIGH AND DANGEROUS VOLTAGES. CONTACT WITH HIGH VOLTAGE TERMINALS WILL RESULT IN DANGEROUS AND POSSIBLY LETHAL ELECTRICAL SHOCK.

MEASURING DC VOLTAGE

A DC voltmeter or a VOM can be used to measure DC voltages. Always observe the following rules:

1. Always observe correct DC polarity.

a. Some VOM's may be equipped with a polar-

ity switch.

b. On meters that do not have a polarity

switch, DC polarity must be reversed by reversing the test leads.

2. Before reading a DC voltage, always set the meter to a higher voltage scale than the anticipated reading. If in doubt, start at the highest scale and adjust the scale downward until correct readings are obtained.

3. The design of some meters is based on the “current flow” theory while others are based on the “electron flow” theory.

a. The “current flow” theory assumes that

direct current flows from the positive (+) to the negative (-).

b. The “electron flow” theory assumes that

current flows from negative (-) to positive (+).

NOTE: When testing generators, the “current flow” theory is applied. That is, current is assumed to flow from positive (+) to negative (-).

Page 15

Section 4 MEASURING ELECTRICITY

MEASURING AC FREQUENCY

The generator's AC output frequency is proportional to Rotor speed. Generators equipped with a 2-pole Rotor must operate at 3600 rpm to supply a frequency of 60-Hertz.

Correct engine and Rotor speed is maintained by an engine speed governor. For models rated 60-Hertz, the governor is generally set to maintain a no-load frequency of about 62-Hertz with a corresponding output voltage of about 125 VAC line-to-neutral. Engine speed and frequency at no-load are set slightly high to prevent excessive rpm and frequency droop under heavy electrical loading.

MEASURING CURRENT

To read the current flow, in AMPERES, a clamp-on ammeter can be used. This type of meter indicates current flow through a conductor by measuring the strength of the magnetic field around that conductor. The meter consists essentially of a current transformer with a split core and a rectifier type instrument connected to the secondary. The primary of the current transformer is the conductor through which the current to be measured flows. The split core allows the instrument to be clamped around the conductor without disconnecting it.

Current flowing through a conductor may be measured safely and easily. A line-splitter can be used to measure current in a cord without separating the conductors.

Figure 4-2. – Clamp-On Ammeter

Figure 4-3. – A Line-Splitter

NOTE: If the physical size of the conductor or ammeter capacity does not allow all lines to be measured simultaneously, measure current flow in each individual line. Then, add the individual readings.

MEASURING RESISTANCE

The volt-ohm-milliammeter may be used to measure the resistance in a circuit. Resistance values can be very valuable when testing coils or windings, such as the Stator and Rotor windings.

When testing Stator windings, keep in mind that the resistance of these windings is very low. Some meters are not capable of reading such a low resistance and will simply read “continuity”.

If proper procedures are used, the following conditions can be detected using a VOM:

• A “short-to-ground” condition in any Stator or Rotor winding.

• Shorting together of any two parallel Stator windings.

• Shorting together of any two isolated Stator windings.

• An open condition in any Stator or Rotor winding.

Component testing may require a specific resistance value or a test for “infinity” or “continuity.” Infinity is an OPEN condition between two electrical points, which would read as no resistance on a VOM. Continuity is a closed condition between two electrical points, which would be indicated as very low resistance or “ZERO” on a VOM.

Page 16

Section 4

MEASURING ELECTRICITY

ELECTRICAL UNITS

AMPERE: The rate of electron flow in a circuit is represented by

the AMPERE. The ampere is the number of electrons flowing past a given point at a given time. One AMPERE is equal to just slightly more than six thousand million billion electrons per second.

With alternating current (AC), the electrons flow first in one direction, then reverse and move in the opposite direction. They will repeat this cycle at regular intervals. A wave diagram, called a “sine wave” shows that current goes from zero to maximum positive value, then reverses and goes from zero to maximum negative value. Two reversals of current flow is called a cycle. The number of cycles per second is called frequency and is usually stated in “Hertz”.

VOLT: The VOLT is the unit used to measure electrical

PRESSURE, or the difference in electrical potential that causes electrons to flow. Very few electrons will flow when voltage is weak. More electrons will flow as voltage becomes stronger. VOLTAGE is considered to be a state of unbalance and current flow as an attempt to regain balance. One volt is the amount of EMF that will cause a current of one ampere to flow through one ohm of resistance.

Figure 4-4. – Electrical Units

OHM: The OHM is the unit of RESISTANCE. In every circuit

there is a natural resistance or opposition to the flow of electrons. When an EMF is applied to a complete circuit, the electrons are forced to flow in a single direction rather than their free or orbiting pattern. The resistance of a conductor depends on (a) its physical makeup, (b) its cross-sectional area, (c) its length, and (d) its temperature. As the conductor's temperature increases, its resistance increases in direct proportion. One (1) ohm of resistance allows one (1) ampere of current to flow when one (1) volt of electromotive force (EMF) is applied.

OHM'S LAW

A definite and exact relationship exists between VOLTS, OHMS and AMPERES. The value of one can be calculated when the value of the other two are known. Ohm's Law states that in any circuit the current will increase when voltage increases but resistance remains the same, and current will decrease when resistance increases and voltage remains the same.

Figure 4-5.

If AMPERES is unknown while VOLTS and OHMS are known, use the following formula:

AMPERES =

VOLTS

OHMS

If VOLTS is unknown while AMPERES and OHMS are known, use the following formula:

VOLTS = AMPERES x OHMS

If OHMS is unknown but VOLTS and AMPERES are known, use the following:

OHMS

VOLTS

AMPERES

Page 17

VOLTS

(E)

Conductor of a Circuit

OHM - Unit measuring resistance

or opposition to flow

AMPERE - Unit measuring rate of

current flow (number of electrons past a given point)

VOLT - Unit measuring force or

difference in potential causing current flow

AMPS

(I)

OHMS

(R)

Section 5 ENGINE DC CONTROL SYSTEM

INTRODUCTION

The engine DC control system includes all components necessary for the operation of the engine. Operation includes off, preheat, cranking/starting, running, shutdown, and fault shutdown. The system is shown schematically.

OPERATIONAL ANALYSIS

CIRCUIT CONDITION- OFF: Battery voltage is available to the engine controller

circuit board from the unit BATTERY and via (a) the RED battery cable, Wire 13, a 14 amp FUSE (F1), Wire 15 and engine controller Terminal 1. However, circuit board action is holding the circuit open and no action can occur.

Battery voltage is available to the contacts of a STARTER CONTACTOR (SC), but the contacts are open.

Battery voltage is available to the contacts of a PREHEAT CONTACTOR (PHC), but the contacts are open.

Battery voltage is available to the PREHEAT SWITCH (SW).

The switch is open and the circuit is incomplete. Battery voltage is also available to the remote connection for a remote preheat switch.

Battery voltage is available to the BATTERY CHARGE RECTIFIER (BCR). This is used as a return path for Battery Charge Winding current.

Page 18

Section 5

ENGINE DC CONTROL SYSTEM

Page 19

CIRCUIT CONDITION- PRE-HEAT: When the PRE-HEAT SWITCH (SW) or the

REMOTE PANEL PRE-HEAT SWITCH is closed by the operator, battery voltage is delivered across the closed switch contacts to the PRE-HEAT CONTACTOR (PHC) via Wire 150. The PRE-HEAT CONTACTOR (PHC) is now energized. The normally open (PHC) contacts close, battery voltage is now available to Wire 157.

The GLOW PLUGS (GP) are energized via Wire 157. Wire 157 is also connected to a DIODE (D1), current

is allowed to pass through (D1) and Wire 14 will now have battery voltage applied to it " Engine Controller Terminals 9, 10 , and 11 are connected".

The FUEL PUMP (FP), FUEL SOLENOID (FS), and HOURMETER (HM) will be energized via Wire 14.

Wire 14 is also connected to RESISTOR (R2) and DIODE (D2). After passing through R2 and D2 reduced voltage is applied to Wire 4.

Section 5 ENGINE DC CONTROL SYSTEM

Page 20

CIRCUIT CONDITION- CRANKING: When the START-STOP-SWITCH (SW1) or REMOTE

PANEL START-STOP-SWITCH is held at "START" position, Wire 17 from the Engine Control circuit board is connected to Ground. Engine control circuit board action will then deliver battery voltage to a STARTER CONTACTOR (SC) via Terminal 7 Wire 56.

The STARTER CONTACTOR (SC) energizes and its contacts close, battery output is delivered to the STARTER MOTOR (SM) via Wire 16.The STARTER MOTOR energizes and the engine cranks.

Also, while cranking, engine control circuit board action energizes Terminals 9, 10, and 11 which delivers battery voltage to the Wire 14 circuit. This energizes the FUEL PUMP (FP), FUEL SOLENOID (FS), HOURMETER (HM), and optional light or hourmeter in remote panel.

Wire 14 is also connected to RESISTOR (R2) and DIODE (D2). After passing through R2 and D2 reduced voltage is applied to Wire 4. The reduced voltage, approximately 3-5VDC, is sent to the ROTOR via The BRUSHES and SLIP RINGS. This voltage is used for Field Boost.

Also while cranking, engine control circuit board action energizes Terminal 12 which delivers battery voltage to Wire 85. "Refer to Circuit Condition-Fault Shutdown for operation".

Section 5

ENGINE DC CONTROL SYSTEM

Page 21

CIRCUIT CONDITION-RUNNING: With the FUEL PUMP (FP) and FUEL SOLENOID

(FS) operating the engine should start. The STARTSTOP SWITCH (SW1) is then released. Engine control circuit board action terminates DC output to the STARTER CONTACTOR (SC), which then de-energizes the (SC) to end cranking.

While running, engine control circuit board action keeps Terminals 9, 10, and 11 energized which delivers battery voltage to the Wire 14 circuit. This energizes the FUEL PUMP (FP), FUEL SOLENOID (FS), HOURMETER (HM), and optional light or hourmeter in remote panel. This will maintain engine operation.

While running, engine control circuit board action keeps Terminal 12 (Wire 85) energized with battery voltage. Connected in parallel to Wire 85 are the LOW OIL PRESSURE SWITCH (LOS) and HIGH WATER TEMP SWITCH (HWT). The (LOS) has normally closed contacts. After start-up, engine oil pressure will open the contacts. The HWT has normally open contacts. High coolant temperature will close the contacts. "Refer to Circuit Condition-Fault Shutdown for operation".

A voltage is induced into the Stator's POWER WINDING. This voltage is delivered to the Engine control circuit board Terminals 5 & 6 (via Wires 22 & 44). The engine control circuit board uses this frequency signal to determine engine speed for overspeed sensing and starter disengage.

Section 5 ENGINE DC CONTROL SYSTEM

Page 22

CIRCUIT CONDITION- SHUTDOWN: Setting the START-STOP SWITCH (SW1) or the

REMOTE PANEL START-STOP SWITCH to its "STOP" position, connects the Wire 18 circuit to ground. ENGINE CONTROL circuit board action deenergizes DC output to Terminal 9,10, & 11 (Wire

14). The FUEL PUMP (FP), FUEL SOLENOID (FS) and HOURMETER (HM) are de-energized by the loss of DC to Wire 14. Fuel flow terminates and the engine shuts down.

Section 5

ENGINE DC CONTROL SYSTEM

Page 23

CIRCUIT CONDITION- FAULT SHUTDOWNS: The engine has mounted to it a HIGH WATER TEM-

PERATURE SWITCH (HWT) and a LOW OIL PRESSURE SWITCH (LOS). While running, ENGINE CONTROL circuit board action keeps Terminal 12 Wire 85 energized with battery voltage. Connected in parallel to (Wire 85) are the LOW OIL PRESSURE SWITCH (LOS) and HIGH WATER TEMP SWITCH (HWT). The (LOS) has normally closed contacts. After start-up, engine oil pressure will open the contacts. The HWT has normally open contacts. High coolant temperature will close the contacts.

Should engine water temperature exceed a preset value, the switch contacts will close. Wire 85 from the circuit board will connect to ground. Circuit board action will then initiate a shutdown.

Should engine oil pressure drop below a safe pre-set value, the switch contacts will close.

On contact closure, Wire 85 will be connected to ground and circuit board action will initiate an engine shutdown.

The circuit board has a time delay built into it for the Wire 85 fault shutdowns. At STARTUP ONLY the circuit board will wait approximately six (6) seconds before looking at the Wire 85 fault shutdowns. Once running after the six (6) second time delay, grounding Wire 85 through either switch will cause an immediate shutdown.

The ENGINE CONTROL circuit board also has overspeed protection. The circuit board senses the AC output from the stators POWER winding at Terminals 5 & 6 via Wires 22 & 44. This AC voltage and frequency signal is used indirectly to monitor engine RPM. If the frequency should increase above a preset "adjustable" limit, the ENGINE CONTROL circuit board will cause an immediate shutdown.

Section 5 ENGINE DC CONTROL SYSTEM

ENGINE CONTROL CIRCUIT BOARD

GENERAL: The ENGINE CONTROL circuit board is responsible

for cranking, startup, running, and shutdown operations. The board interconnects with other components of the DC control system to turn them on and off at the proper times. It is powered by fused 12 VDC power from the unit battery.

CIRCUIT BOARD CONNECTIONS: The circuit board mounts two, six-wire terminal strips. They are labeled 1-6 and 7-12. The following chart shows the associated wires and

the function(s) of each terminal and wire.

TERMINAL WIRE FUNCTION

1 15 Power supply (12VDC) for the circuit board

and DC control system. 2 0 Common Ground 3 17 To Start Stop Switch and remote connector.

When grounded by setting Start-Stop

Switch to "START", engine will crank. 4 18 To Start-Stop Switch and remote connector.

When grounded by setting Start-Stop-

Switch to "STOP", engine shuts down. 5 44 Frequency signal for overspeed

shutdown/starter disengage. 6 22 Frequency signal for overspeed

shutdown/starter disengage. 7 56 Delivers 12 VDC to Starter Contactor (SC)

while cranking only. 8 __ Not Used 9 14 Engine run circuit. Delivers 12 VDC during

cranking and running.

Connected to Fuel Pump, Fuel Solenoid,

Hourmeter, and field boost circuit.

10 14 Engine run circuit. Delivers 12 VDC during

cranking and running.

Connected to Fuel Pump, Fuel Solenoid,

Hourmeter, and field boost circuit.

11 14 Engine run circuit. Delivers 12 VDC during

cranking and running.

Connected to Fuel Pump, Fuel Solenoid,

Hourmeter, and field boost circuit.

12 85 Fault shutdown circuit. When grounded by

High Water Temperature or Low Oil

Pressure switch, engine will shut down.

LED FUNCTIONS: Green LED will be illuminated when Wire 14 is ener-

gized during cranking and running. Red LED will be illuminated when Wire 56 is ener-

gized during cranking only.

OVERSPEED SHUTDOWN POTENTIOMETER: The overspeed shutdown potentiometer is used to set

the frequency at which the board will initiate a engine shutdown. Proper setting of the potentiometer is critical to the correct operation of the generator.

ADJUSTMENT PROCEDURE: The overspeed shutdown potentiometer MUST be

adjusted on replacement circuit boards. If not replacing a board, start at STEP 6.

1. Remove 14 amp fuse (F1) from control panel.

2. Disconnect all wires from circuit board terminals.

3. Remove old circuit board and install new circuit board.

4. Connect all wires to proper circuit board terminals. Follow electrical schematic if needed.

5. Reinstall 14 amp (F1) fuse into control panel.

6. Turn the overspeed shutdown potentiometer slowly counterclockwise until it stops. DO NOT FORCE.

Note: If immediate shutdown occurs when the engine starts and the START/STOP switch is released, reverse overspeed shutdown pot setting, turn pot clockwise and proceed. In Step 10 and Step 11, turn the overspeed shutdown pot counterclockwise.

7. Connect an accurate AC frequency meter across the generator's AC output leads.

8. Start the generator, let it stabilize and warm up.

9. Use the injection throttle lever to SLOWLY increase engine speed until the frequency meter reads 64 hertz.

10.Hold the throttle at 64 hertz and SLOWLY turn the overspeed shutdown potentiometer clockwise until engine shutdown occurs.

11. Turn the overspeed shutdown potentiometer clockwise an additional 1/8 turn. The overspeed setting is now correct.

BATTERY

RECOMMENDED BATTERY: When anticipated ambient temperatures will be con-

sistently above 32° F. (0° C.), use a 12 VDC automotive type storage battery rated 70 amp-hours and capable of delivering at least 360 cold cranking amperes.

The QUIETPACT 75D generator is rated at about 160 DC Amps of cranking current to operate the starter and glow plugs.

BATTERY CABLES: Use of battery cables that are too long or too small in

diameter will result in excessive voltage drop. For best cold weather starting, voltage drop between the

Page 24

Section 5

ENGINE DC CONTROL SYSTEM

battery and starter should not exceed 0.12 VDC per 100 amperes of cranking current.

Select the battery cables based on total cable length and prevailing ambient temperature. Generally, the longer the cable and the colder the weather, the larger the required cable diameter.

The following chart applies:

CABLE LENGTH (IN FEET) RECOMMENDED CABLE SIZE

0-10 No. 2 11-15 No. 0 16-20 No. 000

EFFECTS OF TEMPERATURE: Battery efficiency is greatly reduced by a decreased

electrolyte temperature. Such low temperatures have a decided numbing effect on the electrochemical action. Under high discharge rates (such as cranking), battery voltage will drop to much lower values in cold temperatures than in warmer temperatures. The freezing point of battery electrolyte fluid is affected by the state of charge of the electrolyte as indicated below:

SPECIFIC GRAVITY FREEZING POINT

1.220 -35° F. (-37° C.)

1.200 --20° F. (-29° C.)

1.160 0° F. (-18° C.)

ADDING WATER: Water is lost from a battery as a result of charging

and discharging and must be replaced. If the water is not replaced and the plates become exposed, they may become permanently sulfated. In addition, the plates cannot take full part in the battery action unless they are completely immersed in electrolyte. Add only

DISTILLED WATER to the battery. DO NOT USE TAP WATER.

NOTE: Water cannot be added to some “maintenance-free” batteries.

CHECKING BATTERY STATE OF CHARGE: Use an automotive type battery hydrometer to test the

battery state of charge. Follow the hydrometer manufacturer's instructions carefully. Generally, a battery may be considered fully charged when the specific gravity of its electrolyte is 1.260. If the hydrometer used does not have a “Percentage of Charge” scale, compare the readings obtained with the following:

SPECIFIC GRAVITY PERCENTAGE OF CHARGE

1.260 100%

1.230 75%

1.200 50%

1.170 25%

CHARGING A BATTERY: Use an automotive type battery charger to recharge a

battery. Battery fluid is an extremely corrosive, sulfuric acid solution that can cause severe burns. For that reason, the following precautions must be observed:

• The area in which the battery is being charged must be well ventilated. When charging a battery, an explosive gas mixture forms in each cell.

• Do not smoke or break a live circuit near the top of the battery. Sparking could cause an explosion.

• Avoid spillage of battery fluid. If spillage occurs, flush the affected area with clear water immediately.

• Wear eye protection when handling a battery.

Page 25

Figure 5-4 – Engine Control Circuit Board

TERMINALS:

7 8 9 10 11 12

GREEN LED

RED LED

TERMINALS:

1 2 3 4 5 6

OVERSPEED SHUTDOWN POTENTIOMETER

Section 5 ENGINE DC CONTROL SYSTEM

14 AMP FUSE

This panel-mounted Fuse protects the DC control circuit against overload and possible damage. If the Fuse has melted open due to an overload, neither the priming function nor the cranking function will be available.

Figure5-4

PREHEAT SWITCH

The diesel engine is equipped with glow plugs, one for each cylinder. When the preheat switch is pressed, voltage will go through the switch to the preheat contactor. The preheat contactor (normally open) now closes, allowing battery voltage to go to the glow plugs via Wire 157. Power from Wire 157 goes through a diode and changes to Wire 14. This Wire 14 goes to the circuit board powering the fuel pump, fuel solenoid, hourmeter, and field boost through another diode and resistor. The glow plugs now heat the engine combustion chamber, and the injector pump is primed with fuel for starting.

Figure 5-5. – Pre-heat Switch

START/STOP SWITCH

The start/stop switch allows the operator to control cranking, startup, and shutdown. The following wires connect to the start/stop switch:

WIRE 17 (FROM THE ENGINE CONTROL BOARD): This is the crank and start circuit. When the switch is

set to start, Wire 17 is connected to ground via Wire

0. With Wire 17 grounded, a crank relay on the circuit board energizes and battery voltage is delivered to the starter contactor via Wire 56. The starter contactor energizes and its normally open contacts close allowing battery voltage through Wire 16 to the starter motor and the engine will now crank. With Wire 17 grounded, a run relay on the circuit board energizes and battery voltage is delivered to the Wire 14 circuit. Now the fuel pump, fuel solenoid, hourmeter, and field boost has battery voltage for operation.

WIRE 18 (FROM THE ENGINE CONTROL BOARD): This is the engine stop circuit. When the start/stop

switch is set to stop, Wire 18 is connected to ground via Wire 0. Circuit board action then opens the circuit to Wire 14, stopping fuel flow, causing the unit to stop.

WIRE 0: Connects the switch to ground.

Figure 5-6. – Start/Stop Switch

STARTER CONTACTOR & MOTOR

Figure 5-7. – Starter Contactor and Connections

)

Page 26

START

STOP

A. Schematic

B. Pictorial

BH1-1

150

B. Schematic

A. Pictorial

TO FUSE

OUTER POSTS

SMALL

LUGS

TO GROUND

TO BOARD

TO STARTER

TO BATTERY

Section 5

ENGINE DC CONTROL SYSTEM

The positive (+) battery cable (13) attaches to one of the outer posts of the contactor along with Wire 13 for the DC supply to the fuse (F1). The starter cable (16) attaches to the remaining outer post. Attached to the small 2 lugs are Wires 56 and 0. When the start/stop switch is set to start, the circuit board delivers battery voltage to the contactor coil via Wire 56. The contactor energizes and its contacts close. Battery voltage is then delivered from the positive battery cable, across contacts and to the starter motor via Wire 16.

ENGINE GOVERNOR

A mechanical, all-speed governor is used on the diesel engine. It is housed in the gear case. A 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 and the tension lever. The spring regulates flyweight movement. By changing the set angle of the governor lever, tension on the tension lever spring is changed. In this manner, engine speed can be regulated by the governor lever.

The generators A/C output frequency is directly proportional to engine speed. Low governor speed will result in a reduced A/C frequency and voltage, and high governor speed will produce an increased frequency and voltage.

FUEL INJECTION PUMP

Figure 5-8. – Fuel Injection Pump

The fuel injection pump is mounted on the side of the engine and rides on a three-lobe camshaft. The lobes on the camshaft press the bottom of the pump, which mechanically opens the fuel path to deliver fuel to the fuel injectors. Timing for the fuel injector pump is determined by the distance between the camshaft lobes and the pump. This distance is regulated by metal shims. If the shim space is incorrect, the fuel pressure will be incorrect and combustion will not occur. When the fuel injector pump is removed for maintenance, be sure to reassemble with the same number of shims. The engine governor controls the fuel injector pump by linkage connecting the two.

FUEL NOZZLES/INJECTORS

Fuel supplied by the injector pump is delivered to the nozzle holder and to the nozzle body. When fuel pressure is sufficient to compress the spring, fuel is supplied from the nozzle and into the combustion chamber. Due to the high pressure of fuel being ejected from the nozzle, there is no safe test. If faulty fuel is suspected and a clogged injector pump was diagnosed, the replacement of the injector nozzles would be needed.

Figure 5-9. – Fuel Injectors

Figure 5-10. – Fuel Injector Nozzles

GLOW PLUGS

The glow plug consists of a thin coiled heat-wire that is encased in sintered magnesium oxide powder and enclosed by a stainless steel sheath. One end of the wire is welded to the sheath and the other end is welded to the center electrode. When voltage is applied to the center electrode, it heats the heat-wire, which in turn, heats the combustion chamber.

Glow plugs are connected in parallel. For that reason, if one plug fails open, the other plugs will continue to operate. However, loss of one plug will increase the possibility of the heat-wire melting open in the remaining plugs.

PINSERT

Page 27

INJECT

ASKE

CONTROL RACK

SHIM

INJECTOR PUMP

VALVE

CLOSED

VAL VE

OPEN

FULLY OPEN

Section 5 ENGINE DC CONTROL SYSTEM

Figure 5-11. –

Glow Plug

ENGINE PROTECTIVE DEVICES

The engine will shut down automatically in the event of anyone or more of the following occurrences:

• Low oil

• High engine coolant temperature

• Engine overspeed

LOW OIL PRESSURE SWITCH

The oil pressure switch has normally-closed contacts. When the engine is cranking or running, oil will pass through the switch, which opens the contacts. If oil pressure should drop below 10 PSI, the contacts will close to ground sending a signal to the printed circuit board to shut unit down on wire 85.

Figure 5-12. –

Low Oil Pressure Switch

HIGH COOLANT TEMPERATURE SWITCH

The high coolant temperature switch has normally open contacts. This switch is immersed in engine coolant. If the coolant temperature should exceed 245-266 degrees F, the switches contacts will close to ground, sending a signal to the printed circuit board to shut down the unit via wire 85.

Figure 5-13. – High Coolant Temperature Switch

OVERSPEED PROTECTION

Generator A/C frequency signals are delivered to Terminals 5 and 6 of the engine control circuit board via wires 22 and 44. Should engine/generator speed exceed 69 to 71 Hertz for longer than 4 seconds, the circuit board will cause an engine shutdown.

Page 28

HEAT-WIRE

MAGNESIUM

SHEATH

OXIDE

POWDER

ASBESTOS

BODY

INSULATING

BUSHING

NUT

CENTER

ELECTRODE

LOW OIL

PRESSURE

SWITCH

ADAPTER

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