Generac Power Systems 65, 55, 75 manual Meters, Vom, Measuring AC Voltage, Measuring DC Voltage

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Section 4

MEASURING ELECTRICITY

METERS

Devices used to measure electrical properties are called meters. Meters are available that allow one to measure (a) AC voltage, (b) DC voltage, (c) AC fre- quency, and (d) resistance In ohms. The following apply:

To measure AC voltage, use an AC voltmeter.

To measure DC voltage, use a DC voltmeter.

Use a frequency meter to measure AC frequency In “Hertz” or “cycles per second”..

Use an ohmmeter to read circuit resistance, in “ohms”.

THE VOM

A meter that will permit both voltage and resistance to be read is the “volt-ohm-milliammeter” or “VOM”.

Some VOM's are of the “analog” type (not shown). These meters display the value being measured by physically deflecting a needle across a graduated scale. The scale used must be Interpreted by the user.

“Digital” VOM's (Figure 4-1) are also available and are generally very accurate. Digital meters display the measured values directly by converting the values to numbers.

NOTE: Standard AC voltmeters react to the AVER- AGE value of alternating current. When working with AC, the effective value is used. For that rea- son a different scale is used on an AC voltmeter. The scale is marked with the effective or “rms” value even though the meter actually reacts to the average value. That is why the AC voltmeter will give an Incorrect reading if used to measure direct current (DC).

Figure 4-1. – Digital VOM

MEASURING AC VOLTAGE

An accurate AC voltmeter or a VOM may be used to read the generator's AC output voltage. The following apply:

1.Always read the generator's AC output voltage only at the unit's rated operating speed and AC frequency.

2.The generator's voltage regulator can be adjusted for correct output voltage only while the unit is operating at its correct rated speed and frequency.

3.Only an AC voltmeter may be used to measure AC voltage. DO NOT USE A DC VOLTMETER FOR THIS PURPOSE.

DANGER!: RV GENERATORS PRODUCE HIGH AND DANGEROUS VOLTAGES. CONTACT WITH HIGH VOLTAGE TERMINALS WILL RESULT IN DANGEROUS AND POSSIBLY LETHAL ELECTRICAL SHOCK.

MEASURING DC VOLTAGE

A DC voltmeter or a VOM may be used to measure DC voltages. Always observe the following rules:

1.Always observe correct DC polarity.

a.Some VOM's may be equipped with a polar- ity switch.

b.On meters that do not have a polarity switch, DC polarity must be reversed by reversing the test leads.

2.Before reading a DC voltage, always set the meter to a higher voltage scale than the anticipated reading. if in doubt, start at the highest scale and adjust the scale downward until correct readings are obtained.

3.The design of some meters is based on the “current flow” theo- ry while others are based on the “electron flow” theory.

a.The “current flow” theory assumes that direct current flows from the positive (+) to the negative (-).

b.The “electron flow” theory assumes that current flows from negative (-) to positive

(+).

NOTE: When testing generators, the “current flow” theory is applied. That is, current is assumed to flow from positive (+) to negative (-).

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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

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.