Multiquip MQP20P manual Principle of operation, Engine, ElectrONIC Governor System

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general information

principle of operation

This generator is a brushless, self-excited, externally voltage regulated, synchronous AC generator. The generator is made up of six major components: main stator (armature), main rotor (field), exciter stator (field), exciter rotor (armature), rectifier assembly, and voltage regulator.

The generator's exciter consists of a stationary field and a rotating armature. The stationary field (exciter stator) is designed to be the primary source of the generator's residual magnetism. This residual magnetism allows the exciter rotor (armature) to produce AC voltage even when the exciter stator (field) is not powered. This AC voltage is rectified to DC by the rotating rectifier assembly and fed directly to the main rotor (field). As the generator shaft continues to rotate, the main rotor (field) induces a voltage into the generator's main stator (armature). At rated speed, the main stator's voltage produced by the residual magnetism of the exciter allows the automatic voltage regulator to function.

The regulator provides voltage to the exciter resulting in a build-up of generator terminal voltage. This system of using residual magnetism eliminates the need for a special field flashing circuit in the regulator. After the generator has established the initial residual voltage, the regulator provides a controlled DC field voltage to the exciter stator resulting in a controlled generator terminal voltage.

VOLTAGE REGULATION

In the standard configuration (shunt excited), the automatic voltage regulator receives both its input power and voltage sensing from the generator's output terminals.The regulator automatically monitors the generator's output voltage against an internal reference set point and provides the necessary DC output voltage to the exciter field required to maintain constant generator terminal voltage. The generator's terminal voltage is changed by adjusting the regulator's reference set point.

Engine

This standby generator incorporates a Perkins 404D-22 Tier 4 diesel engine.This engine is designed to meet every performance requirement for the generator. Refer to Table 2 for engine specifications.

In keeping with Multiquip’s policy of constantly improving its products, the specifications quoted herein are subject to change without prior notice.

ElectrONIC Governor System

The electronic governor system controls the RPMs of the engine.When the engine demand increases or decreases, the governor system regulates the frequency variation to

± 0.25%.

MQP20P STANDBY GENERATOR • operation and parts manual — rev. #1 (11/28/11) — page 17

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Contents Model MQP20P Diesel engine exhaust and some Proposition 65 warningPage MQP20P Standby Generator Table of ContentsChoose from three easy options SaFeTY MeSSageS Safety InformationGeNeRaTOR SaFeTY GeNeRal SaFeTYRestricted. If the air fl ow is ENgiNe SaFeTYTOWiNg SaFeTY Fuel SaFeTYPower Cord/Cable Safety EleCTRiCal SaFeTYGrounding Safety ENviRONMeNTal SaFeTY BaTTeRY SaFeTYSpecifications Dimensions Typical Generator Grounding Application InstallationIndoor Installation Outdoor InstallationMounting Generator GroundingCamlok outlet box panel General informationGenerator ElectrONIC Governor System Principle of operationEngine Item no Description Major componentsBasic Engine Components Basic engine componentsMicroprocessor Engine Controller MEC Digital controller panelOutlet connectors Connector outlet box and main circuit breakerGenerator Amperage Single Phase LoadLoad application/generator output Refueling Procedure Inspection/setupLubrication Oil Fuel CheckFuel Expands Air Cleaner Fan Belt Tension Cleaning the RadiatorBattery Coolant Antifreeze/summer coolantWiring Battery Cable InstallationAlternator Piping and Hose ConnectionStartup Starting Auto ModeBefore Starting Starting ManualEmergency Shutdown Procedure Normal Shutdown ProcedureBattery Charger and Jacket Water Heater Power Connections JacketWater Heater and Internal Battery ChargerProtective devices Protective devicesTransporting TransportingGeneral Inspection Air Filter MaintenanceAir Filter Dust Indicator Fuel Addition Cleaning Inside the Fuel TankRemoving Water from the Fuel Tank Fuel Tank InspectionVoltage regulator adjustments Radiator CleaningFlushing Out Radiator and Replacing Coolant PotentiometersGenerator Storage Adjustment ProcedureTroubleshooting Generator Troubleshooting GeneratorTroubleshooting Engine Troubleshooting engineTroubleshooting MEC20 Controller Troubleshooting controllerImproper calibration? Troubleshooting Voltage Regulator Troubleshooting Voltage RegulatorMaintenance Parts Locator Control BOX Generator Wiring Diagram single phaseCircuit Breaker BOX Generator Wiring Diagram three phase 505 K1 Explanation of Code in Remarks Column MQP20P with Perkins 404D-22 Diesel Engine 1 to 3 units Suggested Spare PartsHousing assy Part Name Engine and Generator Mounting assy GENERATOR, 30KW Fuel assy Part Name QTY Remarks Electrical assy BOLT, BATTERY, 10.38 Jacket Water HEater assy BRACKET, MOUNTING, Heater Solenoid assy BRACKET, Starter Solenoid Radiator assy Guard Air filter assy Cover Engine exhaust assy Exhaust Flex Engine Oil assy OIL Filler CAP Control panel assy PANEL, FRONT, Control Panel Controller assy MODULE, Output Expan MEC 2/20 W/CABLE Saddlebox assy Phase Units Circuit breaker assy Ground Camlok assy HousingCOVER, HINGED, Black FReigHT pOliCY Terms and Conditions of Sale PartsPage HERE’S HOW to GET Help