Generac Power Systems 75, 55, 65 manual Test 29 Check Wire 14 Power Supply, Test 30 Check Wire

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Section 7

DIAGNOSTIC TESTS

water column as measured with a manometer. The LP system must be able to maintain 11-14 inches water column under all load requirements.

1.Turn LP supply to generator off.

2.Remove the Gas Pressure Tap from the fuel regulator and install manometer to this port.

3.Turn LP supply to generator on, the gauge should read 11-14 inches water column.

4.For Problem 8 only (Section 6), start the engine and the gauge should read 11-14 inches water column.

RESULTS:

1.If the LP gas pressure is less than 11-14 inches water column the fuel supply system must be corrected in order to maintain 11-14 inches water column.

2.If the LP gas pressure is between 11-14 inches water Column, proceed to Test 29 for Problem 7 (Section 6). Proceed to Test 32 for Problem 8 (Section 6).

Figure 7-29. – Fuel Regulator

TEST 29 - CHECK WIRE 14 POWER SUPPLY

DISCUSSION:

When the engine is cranked, Engine Controller Circuit Board action must deliver battery voltage to the Wire 14 circuit, or the engine will not start. This is because the Wire 14 circuit will operate the Fuel Pump and Fuel Solenoid on Gasoline models. On LP models it operates the LPG Shut-off valve.

PROCEDURE:

Inside the generator panel, locate the 4-tab terminal connector (Figure 7-30). Then, proceed as follows:

1.Set a VOM to read battery voltage (12 VDC).

2.Connect the meter positive (+) test lead to the 4-tab terminal connector, the common (-) test lead to frame ground.

3.Crank the engine and the meter should read battery voltage. If

battery voltage is not measured, proceed to Step 4.

4.Connect the positive (+) meter test lead to Terminal J2 on the Engine Controller Circuit Board. Connect the negative (-) test lead to a clean frame ground (see Figure 5-3, Page 24).

5.Crank the engine. The meter should indicate battery voltage.

Figure 7-30. – The 4-tab Connector

RESULTS:

1.If the meter indicated battery voltage, go to Test 19.

2.If battery voltage was NOT indicated in Step 3 but is indicated in Step 5, check Wire 14 between the 4-tab connector and the Engine Controller circuit board.

a.Repair, reconnect or replace Wire 14 as neces- sary.

3.If battery voltage was not indicated in Step 5, replace the Engine Controller Circuit Board.

TEST 30 - CHECK WIRE 18

DISCUSSION:

Wire 18 controls sending the STOP signal to the Engine Controller Circuit Board. If Wire 18 contacts ground it will initiate a shutdown. Coach manufactur- ers sometimes install a 15 to 30 foot remote harness. A ground on Wire 18 in a remote harness can also cause a shutdown.

PROCEDURE:

1.Remove the remote harness connector from the generator and re-test. If generator continues to run, a short is present in the remote harness. Repair or replace the remote harness.

2.Remove the J1 connector from the Engine Controller Circuit Board. Set the VOM to measure resistance. Connect one test lead to Pin Location J1-14. Connect the other test lead to a clean frame ground. “Infinity” should be measured.

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Contents Diagnostic Repair Manual Safety Replacement PartsTable of Contents Section Specifications & Charts Section Exploded Views / Part NumbersElectromagnetic Fields MagnetismElectromagnetic Induction Simple AC Generator More Sophisticated AC GeneratorGenerator Operating Diagram Generator AC Connection System Field BoostLine Breakers 120 Volts only 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 Current Measuring AC FrequencyMeasuring Resistance Ampere Electrical UnitsOhms LAW VoltOperational Analysis IntroductionCircuit CONDITION- Rest 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 BoardSTART-STOP Switch Fuel Primer SwitchAMP Fuse 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 scaleTest 7 Test Stator DPE Winding Test 6- Check Field BoostIf field boost checks good, replace the Voltage Regulator 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 23- Check Power Supply to Circuit Board Test 22- Check Battery & CablesTest 21- Check 7.5 AMP Fuse Test 24 Check START-STOP Switch 17. Start-Stop SwitchTest 26- Check Starter Contactor Relay Set a VOM to measure DC voltage 12 VDCTest 27 Check Starter Motor Test 26A Check Starter ContactorConditions Affecting Starter Motor Performance 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 36 Check Carburetion Install Rocker ARM CoverTest 37 Check Choke Solenoid 43. Connector Repeat Steps 1 through 8 on remaining cylinder Adjust the regulated pressure on the gauge to 80 psiDown Test / Compression Test Check CompressionTest 40 Test OIL Temperature Switch Test 39 Check OIL Pressure SwitchIf all steps check GOOD, go to Test Test 42 Check LPG Fuel Solenoid Test 41 Test Choke HeaterShort to Ground 49. Fuel Solenoid Stator Removal Major DisassemblyENCLOSURE/PANEL Removal Rotor RemovalEngine Removal Belt TensioningStarter 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

65, 75, 55 specifications

Generac Power Systems has established itself as a leader in power generation, offering a range of high-performance generators suited for residential and commercial applications. Among its lineup, the Generac 55, 65, and 75 kW generators stand out for their reliability, efficiency, and advanced features.

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