Generac Power Systems 55, 75, 65 manual Discussion LPG Models, LP Gas Carburetion Diagram

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Section 7

DIAGNOSTIC TESTS

DISCUSSION (LPG MODELS):

LP gas is stored in pressure tanks as a liquid. The gas systems used with these generators were designed only for vapor withdrawal type systems. Vapor withdrawal systems use the gas vapors that form above the liquid fuel in the tank. Do NOT attempt to use the generator with any liquid withdrawal type system.

Gas pressure delivered to the solenoid valve must be properly regulated by means of a primary gas regula- tor. Mount the primary regulator at the gas tank outlet or in the supply line from the gas tank. The following rules apply:

•For best results, the primary regulator supplies gaseous fuel to the secondary regulator at 11 inch- es water column. Do NOT exceed 14 inches water column.

•The installer must be sure the primary regulator is rated at sufficient gas flow to operate the generator plus all other gas appliances in the circuit.

CAUTION!: Use only approved components in the fuel supply system. All components must be properly installed in accordance with applicable codes. Improper installation or use of unautho- rized components may result in fire or an explo- sion. Follow approved methods to test the sys- tem for leaks. No leakage is permitted. Do not allow fuel vapors to enter the vehicle interior.

LP gas vapors should be supplied to the secondary regulator inlet at about 11 inches water column (posi- tive pressure). The engine pistons draw air in during the intake stroke (Figure 7-28). This air passes through a carburetor venturi, which creates a low pressure that is proportional to the quantity of air being pumped. The low pressure from the carburetor venturi acts on the regulator diaphragm to pull the diaphragm toward the source of low pressure. A lever attached to the diaphragm opens a valve to permit gas glow through the carburetor.

Figure 7-27 – Typical Propane Gas Fuel System

NOTE: Recommended MINIMUM gas flow rate for all air-cooled QUIETPACT series generators is 67 cubic feet per hour.

If an existing primary gas regulator does not have a sufficient flow capacity for the generator and other gas appliances in the circuit, (a) install a pri- mary regulator with adequate flow rate, or (b) install a separate regulator only and rated at least 67 cubic feet per hour. The inlet side of any prima- ry regulator that supplies the generator must con- nect directly to a gas pressure tank. Do NOT tee the generator line into a gas circuit feeding other areas.

Figure 7-28 – LP Gas Carburetion Diagram

The greater the airflow through the carburetor venturi, the lower the pressure at the venturi throat. The lower the pressure at the venturi throat, the greater the diaphragm movement, and the greater the move- ment of the regulator valve. The more the regulator valve opens, the greater the gas flow that is propor- tional to airflow through the generator.

The following facts about the secondary regulator must be emphasized:

•The regulator must be sensitive to venturi throat pressure changes throughout the operating range.

•The regulator must be properly adjusted so it will stop the flow of gas when the engine is not running (no air flow through the carburetor).

•The slightest airflow (and vacuum in the venturi throat) should move the regulator valve off its seat and permit gas to flow.

PROCEDURE:

A water manometer or a gauge that is calibrated in “ounces per square inch” may be used to measure the fuel pressure. Fuel pressure at the inlet side of the LPG Shut Off Valve should be between 11-14 inches

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Contents Diagnostic Repair Manual Replacement Parts SafetyTable of Contents Section Exploded Views / Part Numbers Section Specifications & ChartsMagnetism Electromagnetic FieldsElectromagnetic Induction More Sophisticated AC Generator Simple AC GeneratorGenerator Operating Diagram Field Boost Generator AC Connection SystemLine Breakers 120 Volts only 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 AC Frequency Measuring CurrentMeasuring Resistance Ohms LAW Electrical UnitsAmpere VoltIntroduction Operational AnalysisCircuit CONDITION- Rest 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 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 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 scaleTest 6- Check Field Boost Test 7 Test Stator DPE WindingIf field boost checks good, replace the Voltage Regulator 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 22- Check Battery & Cables Test 23- Check Power Supply to Circuit BoardTest 21- Check 7.5 AMP Fuse 17. Start-Stop Switch Test 24 Check START-STOP SwitchSet a VOM to measure DC voltage 12 VDC Test 26- Check Starter Contactor RelayTest 26A Check Starter Contactor Test 27 Check Starter MotorConditions Affecting Starter Motor Performance 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 KEYInstall Rocker ARM Cover Test 36 Check CarburetionTest 37 Check Choke Solenoid 43. Connector Down Test / Compression Test Adjust the regulated pressure on the gauge to 80 psiRepeat Steps 1 through 8 on remaining cylinder 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 ENCLOSURE/PANEL Removal Major DisassemblyStator 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 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

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.
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