Manuals / Generac Power Systems / Lawn and Garden / Portable Generator

Generac Power Systems 65, 55 Section ENGINE DC CONTROL SYSTEM, Introduction, Operational Analysis

Models: 65 75 55

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Section 5

ENGINE DC CONTROL SYSTEM

INTRODUCTION

The engine DC control system includes all com- ponents necessary for the operation of the engine. Operation includes rest, priming, crank- ing, starting, running and shutdown. The system is shown schematically.

OPERATIONAL ANALYSIS

CIRCUIT CONDITION- REST:

Battery voltage is available to the engine controller cir- cuit board (PCB) from the unit BATTERY and via (a) the RED battery cable, Wire 13, a 7.5 amp FUSE (F1), Wire 15 and circuit board Terminal J3. However, circuit board action is holding the circuit open and no action can occur.

Battery output is available to the contacts of a

STARTER CONTACTOR (SC) and STARTER CON-

TACTOR RELAY (SCR), but the contacts are open.

Battery voltage is also delivered to the FUEL PRIMER SWITCH (SW2). The switch is open and the circuit is incomplete.

Battery voltage is also available to the REMOTE FUEL PRIMER SWITCH. The switch is open and the circuit is incomplete.

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Generac Power Systems 65, 55, 75 manual Section ENGINE DC CONTROL SYSTEM, Introduction, Operational Analysis

Contents

Diagnostic Repair Manual QUIETPACT 55/65/75RECREATIONAL VEHICLE GENERATOR Model 4702, 4703, 4707, 4705, 4706,NOTICE TO USERS OF THIS MANUAL SAFETYREPLACEMENT PARTS Table of Contents Table of Contents SECTIONSection GENERATOR FUNDAMENTALS MAGNETISMELECTROMAGNETIC FIELDS ELECTROMAGNETIC INDUCTIONA SIMPLE AC GENERATOR A MORE SOPHISTICATED AC GENERATORFigure 1-5.– Alternating Current Sine Wave Figure 1-6.– A More Sophisticated GeneratorFigure 1-7.- Generator Operating Diagram Section GENERATOR FUNDAMENTALSSection GENERATOR FUNDAMENTALS FIELD BOOSTGENERATOR AC CONNECTION SYSTEM Figure 1-8.– Connection for 120 Volts Only Section GENERATOR FUNDAMENTALSROTOR ASSEMBLY STATOR ASSEMBLYSection MAJOR GENERATOR COMPONENTS Figure 2-1.Exploded View of GeneratorBATTERY CHARGE COMPONENTS Figure 2-4.– Battery Charge CircuitFigure 2-5.– Schematic: Excitation Circuit BRUSH HOLDERSection MAJOR GENERATOR COMPONENTS CRANKCASE BREATHERFigure 2-6.– Excitation Circuit Breaker Section MAJOR GENERATOR COMPONENTS CONTROL PANEL COMPONENT IDENTIFICATIONFigure 2-9.– Control Panel Components CLEANING THE GENERATOR Section INSULATION RESISTANCE TESTSEFFECTS OF DIRT AND MOISTURE INSULATION RESISTANCE TESTERSSTATOR INSULATION RESISTANCE Section INSULATION RESISTANCE TESTSTESTING ROTOR INSULATION THE MEGOHMMETERFigure 3-2.– Stator Leads Figure 3-3.– Rotor Test PointsSection MEASURING ELECTRICITY METERSTHE VOM MEASURING AC VOLTAGEMEASURING AC FREQUENCY MEASURING CURRENTMEASURING RESISTANCE Figure 4-3.– A Line-SplitterELECTRICAL UNITS OHMS LAWFigure AMPERES = VOLTSOHMSOPERATIONAL ANALYSIS Section ENGINE DC CONTROL SYSTEMINTRODUCTION Page Section ENGINE DC CONTROL SYSTEMCIRCUIT CONDITION- PRIMING Section ENGINE DC CONTROL SYSTEM CIRCUIT CONDITION- CRANKINGSection ENGINE DC CONTROL SYSTEM CIRCUIT CONDITION-RUNNINGSection ENGINE DC CONTROL SYSTEM CIRCUIT CONDITION- SHUTDOWNCIRCUIT CONDITION- FAULT SHUTDOWN Section ENGINE DC CONTROL SYSTEMBATTERY ENGINE CONTROLLER CIRCUIT BOARDFigure 5-3.– Engine Controller Circuit Board Figure 5-2.- Receptacle J1FUEL PRIMER SWITCH START-STOPSWITCHFigure 5-5.– Primer Switch 7.5 AMP FUSEFigure 5-6.– Start-StopSwitch Section ENGINE DC CONTROL SYSTEMSTARTER CONTACTOR RELAY & STARTER MOTORSection TROUBLESHOOTING FLOWCHARTS INTRODUCTIONSection TROUBLESHOOTING FLOWCHARTS PageSection TROUBLESHOOTING FLOWCHARTS PageSection TROUBLESHOOTING FLOWCHARTS PageSection TROUBLESHOOTING FLOWCHARTS PageSection TROUBLESHOOTING FLOWCHARTS PageSection TROUBLESHOOTING FLOWCHARTS PageSection TROUBLESHOOTING FLOWCHARTS PageSection TROUBLESHOOTING FLOWCHARTS PageSection TROUBLESHOOTING FLOWCHARTS PageSection TROUBLESHOOTING FLOWCHARTS PageSection DIAGNOSTIC TESTS Figure 7-1.– Governor Adjustment PointsTEST 1- CHECK NO-LOADVOLTAGE AND FREQUENCY TEST 2- CHECK ENGINE GOVERNORTEST 3- TEST EXCITATION CIRCUIT BREAKER TEST 4- FIXED EXCITATION TEST/ROTOR AMP DRAWFigure 7-2.– Excitation “DPE” Circuit Breaker Figure 7-3.- Fixed Excitation TestTEST 5- WIRE CONTINUITY Section DIAGNOSTIC TESTSTEST 6- CHECK FIELD BOOST TEST 7 - TEST STATOR DPE WINDINGFigure 7-4.- The Field Boost Circuit Figure 7-5.– Stator Excitation WindingTEST 8- CHECK SENSING LEADS / POWER WINDINGS Section DIAGNOSTIC TESTSFigure 7-6.– Stator Power Winding Leads TEST 9- CHECK BRUSH LEADSTEST 10 - CHECK BRUSHES & SLIP RINGS Figure 7-7.– Brush LeadsTEST 11- CHECK ROTOR ASSEMBLY Figure 7-8.– Rotor AssemblyTEST 12 - CHECK MAIN CIRCUIT BREAKER Figure 7-9.– Main Breaker TypicalTEST 15 - CHECK BATTERY CHARGE OUTPUT TEST 16 - CHECK BATTERY CHARGE RECTIFIERTEST 13- CHECK LOAD VOLTAGE & FREQUENCY TEST 14- CHECK LOAD WATTS & AMPERAGETEST 17 - CHECK BATTERY CHARGE WINDINGS / BATTERY CHARGE RESISTORFigure 7-10.- Battery Charge Rectifier Section DIAGNOSTIC TESTSTEST 19- TEST PRIMER SWITCH Figure 7-11.– Primer SwitchFigure 7-12.– Harness End of Connector TEST 18 - TRY CRANKING THE ENGINETEST 20- CHECK FUEL PUMP Figure 7-13.- The LPG Fuel Solenoid FSFigure 7-14.– Electric Fuel Pump Section DIAGNOSTIC TESTSTEST 22- CHECK BATTERY & CABLES TEST 23- CHECK POWER SUPPLY TO CIRCUIT BOARDTEST 21- CHECK 7.5 AMP FUSE Figure 7-15.– Harness to Fuel PumpTEST 24 - CHECK START-STOPSWITCH Figure 7-17.- Start-StopSwitchFigure 7-18.– Test 24, Step Section DIAGNOSTIC TESTSTEST 25 - CHECK POWER SUPPLY TO WIRE TEST 26- CHECK STARTER CONTACTOR RELAYFigure 7-19.– Starter Contactor Relay Section DIAGNOSTIC TESTSTEST 26A - CHECK STARTER CONTACTOR TEST 27 - CHECK STARTER MOTORFigure 7-20.– The Starter Contactor SC STEP 1 TEST POINTSection DIAGNOSTIC TESTS Figure 7-21.- Starter Motor SMFigure 7-22.- Check Pinion Gear Operation Figure 7-26.– Testing Starter Motor Performance TEST 28- CHECK FUEL SUPPLYFigure 7-24.– Tachometer Section DIAGNOSTIC TESTSSection DIAGNOSTIC TESTS Figure 7-28– LP Gas Carburetion DiagramFigure 7-27- Typical Propane Gas Fuel System TEST 29 - CHECK WIRE 14 POWER SUPPLY TEST 30 - CHECK WIREFigure 7-30.– The 4-tabConnector Figure 7-29.– Fuel RegulatorFigure 7-31.– Remote Harness Connector TEST 31 - CHECK FUEL SOLENOID GASOLINE MODELSTEST 32 - CHECK IGNITION SPARK Section DIAGNOSTIC TESTSFigure 7-32.– Testing Ignition System Figure 7-33.– Checking Engine MissFigure 7-34.– Cylinder Balance Test Section DIAGNOSTIC TESTSTEST 34 - CHECK AND ADJUST IGNITION MAGNETOS Figure 7-35– Setting Spark Plug GapFigure 7-36.– Ignition Magneto Assembly TEST 33 - CHECK SPARK PLUGSFigure 7-37.– Setting Ignition Magneto Armature Air GapFigure 7-38.– Engine Ground Harness Figure 7-39.– Diode Failure DiagnosisTEST 35 - CHECK VALVE ADJUSTMENT Figure 7-41– Adjusting Valve ClearanceFigure 7-40.- Engine Ground Harness Test Points Section DIAGNOSTIC TESTSTEST 36 - CHECK CARBURETION TEST 37 - CHECK CHOKE SOLENOIDFigure 7-42- Tightening the Jam Nut Section DIAGNOSTIC TESTSFigure 7-43.- Connector Figure 7-44.– Exploded View of Choke AssemblyFigure 7-45.– Automatic Choke Assembly Section DIAGNOSTIC TESTSSection DIAGNOSTIC TESTS DOWN TEST / COMPRESSION TESTTEST 38 - CHECK ENGINE / CYLINDER LEAK TEST 39 - CHECK OIL PRESSURE SWITCH TEST 40 - TEST OIL TEMPERATURE SWITCHFigure 7-46.– Oil Pressure Switch Figure 7-47.– Oil Temperature SwitchFigure 7-48.– Testing Oil Temperature Switch TEST 41 - TEST CHOKE HEATERTEST 42 - CHECK LPG FUEL SOLENOID Section DIAGNOSTIC TESTSFigure 7-49.– Fuel Solenoid Section DIAGNOSTIC TESTSSection ASSEMBLY MAJOR DISASSEMBLYFigure 8-1.– Drive Belt Tension Section ASSEMBLYSection ASSEMBLY 10.Remove blower housingNOTES PageSection Exploded Views / Part Numbers Base & Pulley – Drawing No. 0E1323-ASection Exploded Views / Part Numbers ITEMPART NO. QTY DESCRIPTIONSection Exploded Views / Part Numbers Enclosure – Drawing No. 0E1011-BSection Exploded Views / Part NumbersITEM PART NOSection Exploded Views / Part Numbers Sheet Metal – Drawing No. 0E1012-ESection Exploded Views / Part Numbers ITEMSection Exploded Views / Part Numbers Control Panel - Drawing No. 0E1013-ASection Exploded Views / Part Numbers 0C2375Section Exploded Views / Part Numbers 760 V-TwinEngine – Drawing No. 0E1014-BSection Exploded Views / Part Numbers 0C5730ASection Exploded Views / Part Numbers LP Regulator - Drawing No. 0E15300D5694 SectionExploded Views / Part Numbers Section SPECIFICATIONS & CHARTS SPECIFICATIONS & CHARTS GENERATOR SPECIFICATIONSNOMINAL RESISTANCES OF GENERATOR WINDINGS AT 68F SectionENGINE SPEEDS AND VOLTAGE SPECIFICATIONS LONG BLOCK TORQUE REQUIREMENTSTRIM TORQUE REQUIREMENTS RV TORQUE REQUIREMENTSNOTES PageSection ELECTRICAL DATA Section ELECTRICAL DATA PagePRINTED IN THE USA/9.03 PO BOX 297 WHITEWATER, WIP/N OE7225 REV O