Generac Power Systems 65, 55, 75 manual Test 26- Check Starter Contactor Relay

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Section 7

DIAGNOSTIC TESTS

2.If engine cranks in Step 3 when Wire 17 is grounded, but will not crank when the Switch is set to “START”, replace the Start- Stop Switch.

3.If the Start-Stop Switch (SW1) failed any part of Steps 5 or 6, replace the switch.

4.If engine will not crank when Wire 17 is grounded, proceed as follows:

a.Use a jumper wire to connect the circuit board's Wire 17 (pin location J1-6) to ground. If engine does NOT crank, proceed to Test 25.

b.If engine cranks now, but would not crank in Step 3 of the procedure, check Wire 17 for con- tinuity between the circuit board and Start-Stop Switch. If “Continuity” is not measured, repair or replace Wire 17 between the engine control board and the Start-Stop Switch.

5.For Problem 9 (Section 6), if switch tests GOOD, go to Test 30.

TEST 25 - CHECK POWER SUPPLY TO WIRE 56

DISCUSSION:

If battery voltage is available to the Engine Controller board in Test 23, then DC voltage should be delivered to Wire 56 when the Start-Stop Switch is set to “START” (Test 24). This test will check to see if the circuit board is delivering battery voltage to the Wire 56 terminal.

PROCEDURE:

1.Set a VOM to measure DC voltage (12 VDC).

2.Disconnect Wire 56 from its Starter Contactor Relay terminal.

3.Connect the meter positive (+) test lead to Wire 56, just discon- nected. Connect the other test lead to frame ground. No volt- age should be indicated.

4.Actuate the Start-Stop Switch to its “START” position. The meter should indicate battery voltage. If battery voltage is pre- sent, stop the procedure.

5.Connect the VOM positive (+) test lead to Wire 56 (Pin Location J1-1) at the Engine Controller Circuit Board. Connect the other test lead to frame ground.

6.Actuate the Start-Stop Switch to the “START” position. The meter should indicate battery voltage.

RESULTS:

1.If battery voltage was measured in Step 6, but not in Step 4, repair or replace Wire 56 between the Engine Controller Circuit Board and Starter Contactor Relay.

2.If battery voltage was not available in Step 6, replace the Engine Controller Circuit Board.

3.If battery voltage is available in Step 4 but engine does not crank, go to Test 26.

TEST 26- CHECK STARTER CONTACTOR

RELAY

DISCUSSION:

If battery voltage is available to Wire 56 but the engine won't crank, the possible cause could be a failed Starter Contactor Relay.

PROCEDURE:

1.Set the VOM to measure resistance (“R x 1” scale). Remove Wire 0 from the Starter Contactor Relay (SCR). Connect one meter test lead to Wire 0, and connect the other meter test lead to frame ground. “Continuity” should be measured. Reconnect Wire 0.

2.Set the VOM to measure resistance (“R x 1” scale). Disconnect Wire 16 and Wire 13 (Wire 13 is 12VDC isolate from ground) from the Starter Contactor Relay (SCR). Connect one meter test lead to an SCR terminal, and connect the other meter test lead to the remaining SCR terminal. “Infinity” should be mea- sured. Set the Start-Stop Switch to “START”. The meter should now read “Continuity”.

Short to Ground:

3.Set the VOM to measure resistance (“R x 1” scale). Disconnect Wire 56 from the Starter Contactor Relay (SCR). Connect one meter test lead to the SCR terminal from which Wire 56 was just removed. Connect the other meter test lead to a clean frame ground. Starter Contactor Relay coil resistance of 155 ohms should be measured. If “Continuity” is measured a short to ground exists.

Note: Current draw of the Starter Contactor Relay coil at nominal voltage is approximately 80ma.

Figure 7-19. – Starter Contactor Relay

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Contents Diagnostic Repair Manual Replacement Parts SafetyTable of Contents Section Exploded Views / Part Numbers Section Specifications & ChartsElectromagnetic Induction MagnetismElectromagnetic Fields More Sophisticated AC Generator Simple AC GeneratorGenerator Operating Diagram Line Breakers 120 Volts only Field BoostGenerator AC Connection System Reconnection for Dual Voltage Output Connection for 120 Volts OnlyStator Assembly Rotor AssemblyBrush Holder Battery Charge ComponentsExcitation Circuit Components GeneralCrankcase Breather Adjustment ProcedureVoltage Regulator DescriptionInstall oil vapor collector and retainer Install BreatherControl Panel Component Identification Check BreatherEffects of Dirt and Moisture Cleaning the GeneratorInsulation Resistance Testers Drying the GeneratorStator Insulation Resistance Brushing and Vacuum CleaningCloth or Compressed AIR Stator SHORT-TO-GROUND TestsTesting Stator Insulation Testing Rotor InsulationTesting Rotor Insulation MegohmmeterVOM MetersMeasuring AC Voltage Measuring DC VoltageMeasuring Resistance Measuring AC FrequencyMeasuring Current Ohms LAW Electrical UnitsAmpere VoltCircuit CONDITION- Rest IntroductionOperational Analysis Circuit CONDITION- Priming Circuit CONDITION- Cranking Choke Heater CH Circuit CONDITION-RUNNINGCircuit CONDITION- Shutdown Sure Switch LOP Circuit CONDITION- Fault ShutdownRecommended Battery BatteryBattery Cables 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 1- Check NO-LOAD Voltage Frequency ProcedureTest 2- Check Engine Governor DiscussionTest 3- Test Excitation Circuit Breaker Governor AdjustmentTest 4- Fixed Excitation TEST/ROTOR AMP Draw If continuity was indicated, go to TestRe-connect Wire 11 and Wire 22 to the Voltage Regulator Test 5- Wire ContinuitySet the VOM to measure AC voltage 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 Across Wires Ohms Test 8- Check Sensing Leads / Power Windings11S 22S Model OhmsTest 10 Check Brushes & Slip Rings Test 9- Check Brush LeadsTance Tests Procedure Test 11- Check Rotor AssemblyTest 12 Check Main Circuit Breaker Replace the Rotor if it fails the testTest 16 Check Battery Charge Rectifier Test 15 Check Battery Charge OutputBattery Charge Rectifier BCR is a full wave rectifier Test 13- Check Load Voltage FrequencyShort to Ground 10. Battery Charge RectifierSet a VOM to read battery voltage 12 VDC Test 19- Test Primer SwitchAlso see Fuel Primer Switch, Test 18 TRY Cranking the Engine13. The LPG Fuel Solenoid FS Test 20- Check Fuel PumpTest 21- Check 7.5 AMP Fuse Test 22- Check Battery & CablesTest 23- Check Power Supply to Circuit Board 17. Start-Stop Switch Test 24 Check START-STOP SwitchSet a VOM to measure DC voltage 12 VDC Test 26- Check Starter Contactor RelayConditions Affecting Starter Motor Performance Test 26A Check Starter ContactorTest 27 Check Starter Motor Tools for Starter Performance Test Checking the PinionMeasuring Current TachometerTest 28- Check Fuel Supply Testing Starter MotorTest Bracket Remove Starter MotorDiscussion LPG Models 28 LP Gas Carburetion DiagramTest 30 Check Wire Test 29 Check Wire 14 Power SupplyBattery voltage is not measured, proceed to Step Crank the engine. The meter should indicate battery voltageTest 32 Check Ignition Spark Test 31 Check Fuel Solenoid Gasoline ModelsConclusion No cylinder is weakest of the two cylinders Cylinder Balance TestTest 33 Check Spark Plugs Test 34 Check and Adjust Ignition Magnetos37. Setting Ignition Magneto Armature Air Gap Adjusting Valve Clearance Test 35 Check Valve AdjustmentChecking Flywheel Magnet Flywheel KEYTest 37 Check Choke Solenoid Install Rocker ARM CoverTest 36 Check Carburetion 43. Connector Down Test / Compression Test Adjust the regulated pressure on the gauge to 80 psiRepeat Steps 1 through 8 on remaining cylinder 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 ENCLOSURE/PANEL Removal Major DisassemblyStator 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 Flywheel Assy GT-990 QTY DescriptionControl Panel Drawing No E1013-A Switch Spdt ON-MOM-ON Wire ASM GRD STD ConnSwitch 6A Spdt Not Shown PANEL, TOP ControlTwin Engine Drawing No E1014-B ASSEMBLY, Breather ASSEMBLY, Crankcase RVASSEMBLY, Head #1 ASSEMBLY, OIL Fill CAPLP Regulator Drawing No E1530 Washer Flat M4 CASTING, Twin Regulator HousingSOLENOID, Twin Regulator SPRING-SOLENOID PlungerSpecifications & Charts Nominal Resistances of Generator Windings AT 68F Generator SpecificationsEngine Speeds and Voltage Specifications Page Electrical Data Electrical Data PO BOX 297 WHITEWATER, WI

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