Generac Power Systems 55, 75, 65 Test 26A Check Starter Contactor, Test 27 Check Starter Motor

Page 54

Section 7

DIAGNOSTIC TESTS

RESULTS:

1.If “Continuity” is not measured in Step 1, repair or replace Wire 0 between the Starter Contactor Relay and the ground terminal.

2.If “Continuity” was not measured in Step 2 when the Start-Stop switch was activated to “START”, replace the Starter Contactor Relay.

3.If “Continuity” is measured in Step 2, go to Test 26A.

TEST 26A - CHECK STARTER CONTACTOR

DISCUSSION:

The Starter Contactor (SC) must energize and it's heavy duty contacts must close or the engine will not crank. This test will determine if the Starter Contactor is in working order. The Starter Contactor is connect- ed to the Starter Motor (see Figure 7-20).

Figure 7-20. – The Starter Contactor (SC)

PROCEDURE:

1.Carefully inspect the starter motor cable that runs from the Battery to the Starter Motor. Cable connections should be clean and tight. If connections are dirty or corroded, remove cable and clean cable terminals and studs. Replace any cable that is defective or badly corroded. Set the VOM to measure DC voltage. Connect the positive (+) meter test lead to the Starter Contactor stud that the battery cable is connected to. Connect the negative (-) meter test lead to a clean frame ground. Battery voltage should be measured (see Figure 7-20,

STEP 1 TEST POINT).

2.Set the VOM to measure DC voltage. Disconnect Wire 16 from the Starter Contactor. Connect the positive (+) meter test lead to Wire 16. Connect the negative (-) meter test lead to a clean frame ground. Set the Start-Stop Switch to “START”. Battery voltage should be indicated. Reconnect Wire 16 to the Starter Contactor.

3.Set the VOM to measure DC voltage. Connect the positive (+) meter test lead to the Starter Contactor stud that has the small jumper wire connected to the Starter. Connect the negative (-) meter test lead to a clean frame ground. Set the Start-Stop Switch to “START”. Battery voltage should be measured (see Figure 7-20, STEP 2 TEST POINT).

RESULTS:

1.If battery voltage was not measured in Step 1, repeat Test 22.

2.If battery voltage was not measured in Step 2, repair or replace Wire 16 between the Starter Contactor Relay (SCR) and the Starter Contactor (SC).

3If battery voltage was measured in Step 1, but not in Step 3, replace the Starter Contactor.

4.If battery voltage was measured in Step 3 but the engine still does not crank, go to test 27.

TEST 27 - CHECK STARTER MOTOR

CONDITIONS AFFECTING STARTER MOTOR PERFORMANCE:

1.A binding or seizing condition in the Starter Motor bearings.

2.A shorted, open or grounded armature.

a.Shorted, armature (wire insulation worn and wires touching one another). Will be indicated by low or no RPM.

b.Open armature (wire broken) will be indicated by low or no RPM and excessive current draw.

c.Grounded armature (wire insulation worn and wire touching armature lamination or shaft). Will be indicated by excessive current draw or no RPM.

3.A defective Starter Motor switch.

4.Broken, damaged or weak magnets.

5.Starter drive dirty or binding.

DISCUSSION:

Test 25 verified that circuit board action is delivering DC voltage to the Starter Contactor Relay (SCR). Test 26 verified the operation of the SCR. Test 26A verified the operation of the Starter Contactor (SC). Another possible cause of an "engine won't crank" problem is a failure of the Starter Motor.

Page 52

Page 53 Page 55
Image 54
Page 53 Page 55
Contents Diagnostic Repair Manual Safety Replacement PartsTable of Contents Section Specifications & Charts Section Exploded Views / Part NumbersMagnetism Electromagnetic FieldsElectromagnetic Induction Simple AC Generator More Sophisticated AC GeneratorGenerator Operating Diagram Field Boost Generator AC Connection SystemLine 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 AC Frequency Measuring CurrentMeasuring Resistance Ampere Electrical UnitsOhms LAW VoltIntroduction Operational AnalysisCircuit 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 BoardFuel Primer Switch START-STOP 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 6- Check Field Boost Test 7 Test Stator DPE WindingIf 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 22- Check Battery & Cables Test 23- Check Power Supply to Circuit BoardTest 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 26A Check Starter Contactor Test 27 Check Starter MotorConditions 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 KEYInstall Rocker ARM Cover Test 36 Check CarburetionTest 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 39 Check OIL Pressure Switch Test 40 Test OIL Temperature SwitchIf all steps check GOOD, go to Test Test 41 Test Choke Heater Test 42 Check LPG Fuel SolenoidShort to Ground 49. Fuel Solenoid Stator Removal Major DisassemblyENCLOSURE/PANEL Removal Rotor RemovalBelt Tensioning Engine RemovalStarter 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.

The Generac 55 kW generator is designed to provide a powerful backup solution for medium to large homes or small businesses. It features a robust engine that delivers dependable performance while maintaining fuel efficiency. One of its key characteristics is the True Power Technology, which produces clean and stable power, ensuring that sensitive electronic devices run smoothly without risk of damage. This generator is equipped with a fully automatic transfer switch, allowing for seamless power transition during outages, with minimal disruption.

Moving to the 65 kW model, it offers increased capacity while retaining the fundamental qualities of the 55 kW version. This unit is particularly suited for larger homes or commercial applications that require greater power demands. The 65 kW generator utilizes Generac’s G-Force engine, known for its durability and reduced maintenance needs. Advanced features such as remote monitoring capabilities allow users to check the generator's status from anywhere, providing peace of mind and convenience.

The 75 kW generator takes performance to the next level, making it ideal for even more significant power needs. It is engineered for both quiet operation and enhanced performance, accommodating a wide range of requirements from residential to larger commercial operations. The 75 kW model includes a full-load voltage regulation system that maintains stable power output under varying loads, safeguarding appliances and equipment.

All three models incorporate advanced air-cooled technology, which enhances their efficiency and operational lifespan. Additionally, their corrosion-resistant enclosures ensure durability even in harsh weather conditions, making them suitable for diverse environments. The intuitive LCD display on each unit provides critical information, including runtime hours and maintenance reminders, empowering users with easy access to the generator's performance data.

Overall, Generac Power Systems' 55, 65, and 75 kW generators represent a commitment to quality, reliability, and innovation in backup power solutions. They are designed to meet the demands of modern power consumption while ensuring peace of mind through robust engineering and advanced technology. Whether for home use or commercial applications, these generators provide an effective means to stay prepared for unexpected power outages.
Top Page Image Contents