Generac Power Systems 65, 55 Engine Controller Circuit Board, Battery, Circuit Board Connections

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Section 5

ENGINE DC CONTROL SYSTEM

ENGINE CONTROLLER CIRCUIT BOARD

a.To operate the electric Fuel Pump (FP).

b.To energize the Fuel Solenoid.

GENERAL:

The engine controller board is responsible for crank- ing, 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 a 15-pin receptacle (J1) and two single pin terminals (J2 and J3, see Figure 5.3). Figure 5-2 shows the 15-pin receptacle (J1), the asso- ciated wires and the function(s) of each pin and wire.

PIN

WIRE

FUNCTION

1

56

Delivers 12 VDC to Starter Contactor (SC)

 

 

while cranking only.

2

90

Delivers 12 VDC to Choke Solenoid coil

 

 

while cranking only. (Two seconds ON, Two

 

 

seconds OFF)

3

—

Not used.

4

18A

Grounds Magneto for Shutdown.

5

—

Not used.

6

17

To Start-Stop switch. When wire is grounded

 

 

by setting Start-Stop switch to “START”,

 

 

engine will crank.

7

17

To Start-Stop switch on optional Remote

 

 

Panel.

8

—

Not used.

9

4

Field Boost DC to Voltage Regulator and to

 

 

Rotor windings.

10

66

Starter Lockout. Prevents cranking while

 

 

engine is running.

11

85

Fault shutdown circuit. When grounded by clo-

 

 

sure of High Oil Temperature or Low Oil

 

 

Pressure Switch engine will shut down.

12

0

Common Ground.

13

16

12 VDC Input to Field Boost circuit while

 

 

cranking only.

14

18

To Start-Stop switch. When grounded by set-

 

 

ting Switch to “STOP” engine shuts down.

15

18

To Start-Stop Switch on optional Remote Panel.

 

 

 

c.To operate the Choke Heater.

d.To the Remote Wire Harness to operate an hourmeter or a light.

2.Wire 15 connects to Terminal J3. This is the power supply (12 VDC) for the circuit board and the DC control system.

Figure 5-3. – Engine Controller Circuit Board

BATTERY

RECOMMENDED BATTERY:

When anticipated ambient temperatures will be con- sistently above 32° F. (0° C.), use a 12 volts automo- tive type storage battery rated 70 amp-hours and capable of delivering at least 400 cold cranking amperes.

If ambient temperatures will be below 32° (0° C.), use a 12 volt battery rated 95 amp-hours and having a cold cranking capacity of 400 amperes.

Figure 5-2. – Receptacle J1

In addition to the 15-pin receptacle (J1), the circuit board is equipped with two single pin terminals (J2 and J3). These terminals may be identified as follows:

1.Wire 14 connects to Terminal J2. During cranking and running, the circuit board delivers battery voltage to the Wire 14 circuit for the following functions:

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 battery and starter should not exceed 0.12 volt 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 larg- er the required cable diameter.

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Contents Diagnostic Repair Manual Safety Replacement PartsTable of Contents Section Specifications & Charts Section Exploded Views / Part NumbersElectromagnetic Induction MagnetismElectromagnetic Fields Simple AC Generator More Sophisticated AC GeneratorGenerator Operating Diagram Line Breakers 120 Volts only Field BoostGenerator AC Connection System Connection for 120 Volts Only Reconnection for Dual Voltage OutputRotor Assembly Stator AssemblyExcitation Circuit Components Battery Charge ComponentsBrush Holder GeneralVoltage Regulator Adjustment ProcedureCrankcase Breather DescriptionControl Panel Component Identification Install BreatherInstall oil vapor collector and retainer Check BreatherInsulation Resistance Testers Cleaning the GeneratorEffects of Dirt and Moisture Drying the GeneratorCloth or Compressed AIR Brushing and Vacuum CleaningStator Insulation Resistance Stator SHORT-TO-GROUND TestsTesting Rotor Insulation Testing Rotor InsulationTesting Stator Insulation MegohmmeterMeasuring AC Voltage MetersVOM Measuring DC VoltageMeasuring Resistance Measuring AC FrequencyMeasuring Current Ampere Electrical UnitsOhms LAW VoltCircuit CONDITION- Rest IntroductionOperational Analysis Circuit CONDITION- Priming Circuit CONDITION- Cranking Circuit CONDITION-RUNNING Choke Heater CHCircuit CONDITION- Shutdown Circuit CONDITION- Fault Shutdown Sure Switch LOPBattery Cables BatteryRecommended Battery Engine Controller Circuit BoardAMP Fuse Fuel Primer SwitchSTART-STOP Switch Starter Contactor Relay Starter Motor Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Test 2- Check Engine Governor ProcedureTest 1- Check NO-LOAD Voltage Frequency DiscussionTest 4- Fixed Excitation TEST/ROTOR AMP Draw Governor AdjustmentTest 3- Test Excitation Circuit Breaker If continuity was indicated, go to TestSet the VOM to measure AC voltage Test 5- Wire ContinuityRe-connect Wire 11 and Wire 22 to the Voltage Regulator Set a VOM to its Rx1 scaleIf field boost checks good, replace the Voltage Regulator Test 6- Check Field BoostTest 7 Test Stator DPE Winding 11S 22S Test 8- Check Sensing Leads / Power WindingsAcross Wires Ohms Model OhmsTest 9- Check Brush Leads Test 10 Check Brushes & Slip RingsTest 12 Check Main Circuit Breaker Test 11- Check Rotor AssemblyTance Tests Procedure Replace the Rotor if it fails the testBattery Charge Rectifier BCR is a full wave rectifier Test 15 Check Battery Charge OutputTest 16 Check Battery Charge Rectifier Test 13- Check Load Voltage Frequency10. Battery Charge Rectifier Short to GroundAlso see Fuel Primer Switch, Test 19- Test Primer SwitchSet a VOM to read battery voltage 12 VDC Test 18 TRY Cranking the EngineTest 20- Check Fuel Pump 13. The LPG Fuel Solenoid FSTest 21- Check 7.5 AMP Fuse Test 22- Check Battery & CablesTest 23- Check Power Supply to Circuit Board Test 24 Check START-STOP Switch 17. Start-Stop SwitchTest 26- Check Starter Contactor Relay Set a VOM to measure DC voltage 12 VDCConditions Affecting Starter Motor Performance Test 26A Check Starter ContactorTest 27 Check Starter Motor Measuring Current Checking the PinionTools for Starter Performance Test TachometerTest Bracket Testing Starter MotorTest 28- Check Fuel Supply Remove Starter Motor28 LP Gas Carburetion Diagram Discussion LPG ModelsBattery voltage is not measured, proceed to Step Test 29 Check Wire 14 Power SupplyTest 30 Check Wire Crank the engine. The meter should indicate battery voltageTest 31 Check Fuel Solenoid Gasoline Models Test 32 Check Ignition SparkCylinder Balance Test Conclusion No cylinder is weakest of the two cylindersTest 34 Check and Adjust Ignition Magnetos Test 33 Check Spark Plugs37. Setting Ignition Magneto Armature Air Gap Checking Flywheel Magnet Test 35 Check Valve AdjustmentAdjusting Valve Clearance Flywheel KEYTest 37 Check Choke Solenoid Install Rocker ARM CoverTest 36 Check Carburetion 43. Connector Repeat Steps 1 through 8 on remaining cylinder Adjust the regulated pressure on the gauge to 80 psiDown Test / Compression Test Check CompressionIf all steps check GOOD, go to Test Test 39 Check OIL Pressure SwitchTest 40 Test OIL Temperature Switch Short to Ground Test 41 Test Choke HeaterTest 42 Check LPG Fuel Solenoid 49. Fuel Solenoid Stator Removal Major DisassemblyENCLOSURE/PANEL Removal Rotor RemovalStarter Removal Belt TensioningEngine Removal FLYWHEEL/MAGNETO Removal Page Section Exploded Views / Part Numbers Part NO. QTY Description Enclosure Drawing No E1011-B QTY Description Sheet Metal Drawing No E1012-E QTY Description Flywheel Assy GT-990Control Panel Drawing No E1013-A Switch 6A Spdt Not Shown Wire ASM GRD STD ConnSwitch Spdt ON-MOM-ON PANEL, TOP ControlTwin Engine Drawing No E1014-B ASSEMBLY, Head #1 ASSEMBLY, Crankcase RVASSEMBLY, Breather ASSEMBLY, OIL Fill CAPLP Regulator Drawing No E1530 SOLENOID, Twin Regulator CASTING, Twin Regulator HousingWasher Flat M4 SPRING-SOLENOID PlungerSpecifications & Charts Generator Specifications Nominal Resistances of Generator Windings AT 68FEngine Speeds and Voltage Specifications Page Electrical Data Electrical Data PO BOX 297 WHITEWATER, WI

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