Guardian Technologies 4270 manual Test 8- Check Sensing Leads / Power Windings, 159W, 184W

Page 43

Section 7

DIAGNOSTIC TESTS

TEST 8- CHECK SENSING LEADS / POWER

WINDINGS

DISCUSSION:

The Voltage Regulator “regulates” excitation current flow to the Rotor by electronically comparing sensing voltage to a pre-set reference voltage. The sensing voltage is delivered to the Voltage Regulator via Wires 11 and 22.

If an open circuit exists in sensing leads 11S or 22S, the normal reaction of an unprotected Regulator would be to increase the excitation current to the Rotor in an effort to increase the actual AC output voltage. This would result in a “full field” condition and an extremely high AC output voltage.

To protect the system against such a high AC output voltage, the Voltage Regulator will shut down if sens- ing voltage signals are lost.

If the regulator shuts down, the generator's AC output voltage will decrease to a value that is equal to the Rotor's residual magnetism (about 5-12 VAC).

PROCEDURE:

Gain access to the generator control panel interior. Test the Stator power windings, as follows:

1.From main breaker, disconnect Wires 11 and 44.

2.Also disconnect Wires 22 and 33 from the ground terminal.

3.Disconnect Wires 11 and 22 ( sensing leads) from the Voltage Regulator.

4.Set a VOM to its “Rx1” scale and zero the meter.

5.Connect the meter test leads across Stator leads 11 and 22. Normal power winding resistance should be read.

6.Connect the meter test leads across Stator leads 33 and 44. Normal power winding resistance should be read.

7.Connect the meter test leads across Stator sensing leads 11 and 22. Normal Power Winding resistance should be read.

AC POWER WINDING RESISTANCE * QP75D

 

ACROSS WIRES:

OHMS

 

11 & 22

0.159W

 

33 & 44

0.184W

 

 

 

*Resistance values in ohms at 20° C. (68° F.). Actual readings may vary depending on ambient temperature. A tolerance of plus or minus 5% is allowed.

8.Now, set the VOM to its “Rx1 K” or “Rx10,000” scale and zero the meter.

9.Connect the meter test leads across Stator lead 11 and ground. “Infinity” should be read.

10.Connect the meter test leads across Stator lead 33 and ground. The reading should be “Infinity”.

11.Connect the meter test leads across Stator leads Wire 11 and Wire 33. The reading should be “Infinity”.

12.Connect the meter test leads across Stator leads Wire 11 and Wire 66. The reading should be “Infinity”.

13.Connect the meter test leads across Stator leads Wire 33 and Wire 66. The reading should be “Infinity”.

14.Connect the meter test leads across Stator leads Wire 11 and Wire 2. The reading should be “Infinity”.

15.Connect the meter test leads across Stator leads Wire 33 and Wire 2. The reading should be “Infinity”.

RESULTS:

1.If the Stator passes all steps except Step 7, repair, re-connect or replace Sensing leads 11 and 22.

2.Replace the Stator if it’s power windings fail the test. (Note Result No. 1).

3.If the Power Windings test good, perform the “Insulation Resistance Test” on Page 13.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11

22

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

33

44

 

 

 

 

 

 

 

 

 

 

 

 

11

 

22

 

11

 

 

 

 

22

 

 

 

 

 

 

 

 

 

 

 

 

 

11

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

33

44

 

 

 

 

 

 

 

 

 

 

 

 

22

 

 

 

 

 

A. Schematic

 

 

 

 

 

 

B. Pictorial

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 7-5. – Stator Power Winding Leads

TEST 9- CHECK BRUSH LEADS

DISCUSSION:

In Test 4, if application of battery voltage to the Rotor did NOT result in an output of about one-half rated voltage, the brush leads could be one possible cause of the problem. This test will check Wires 4 and 1 for an open circuit condition.

PROCEDURE:

1.Set a VOM to its “Rx1” scale and zero the meter.

2.Disconnect Wire 4 from the Voltage Regulator and from the Rotor brush terminal.

3.Connect the VOM test leads across each end of the wire. The meter should read “Continuity”.

4.Disconnect Wire 1 from the Rotor Brush Terminal. Connect

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Contents Diagnostic Repair Manual Replacement Parts SafetyTable of Contents 57-59 Electromagnetic Fields MagnetismElectromagnetic Induction More Sophisticated AC Generator Simple AC GeneratorGenerator Operating Diagram Generator AC Connection System Field BoostLine Breakers 120 VAC only Connection for 120/240 VAC Dual Voltage LIC Grit or Abrasive to Clean Slip Rings Rotor AssemblyGeneral Battery Charge ComponentsBrush Holder Excitation Circuit ComponentsVoltage Regulator Adjust POT LEDAdjustment Procedure 162Control Panel Components Control Panel Component IdentificationInsulation Resistance Testers Cleaning the GeneratorEffects of Dirt and Moisture Drying the GeneratorStator SHORT-TO-GROUND Tests Brushing and Vacuum CleaningStator Insulation Resistance Cloth or Compressed AIRMegohmmeter Testing Rotor InsulationMeasuring DC Voltage MetersVOM Measuring AC VoltageMeasuring Current Measuring AC FrequencyMeasuring Resistance Ohms LAW Electrical UnitsOperational Analysis IntroductionCircuit CONDITION- OFF Circuit CONDITION- PRE-HEAT Circuit CONDITION- Cranking Circuit CONDITION-RUNNING Circuit CONDITION- Shutdown Circuit CONDITION- Fault Shutdowns Engine Control Circuit Board BatteryAdding Water Effects of TemperatureChecking Battery State of Charge Charging a BatteryStarter Contactor & Motor Preheat SwitchSTART/STOP Switch AMP FuseGlow Plugs Engine GovernorFuel Injection Pump Fuel NOZZLES/INJECTORSOverspeed Protection LOW OIL Pressure Switch High Coolant Temperature SwitchAdapter LOW OIL Pressure Switch Engine Protective DevicesTroubleshooting Flowcharts Troubleshooting Flowcharts Problem 3 No Battery Charge Output Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Test 1- Check NO-LOAD Voltage Frequency Test 2 Check & AdjustTest 4- Fixed Excitation TEST/ROTOR AMP Draw Test 3- Test Excitation Circuit BreakerSet a VOM to its Rx1 scale Test 5- Wire ContinuityRe-connect Wire 11 and Wire 22 to the Voltage Regulator Test 6- Check Field BoostModel QP75D Test 7 Test Stator DPE Winding184W Test 8- Check Sensing Leads / Power WindingsTest 9- Check Brush Leads 159WTance Tests Procedure Test 11- Check Rotor AssemblyTest 10 Check Brushes & Slip Rings Test 14- Check Load Watts & Amperage Test 15 Check Battery Charge OutputTest 12 Check Main Circuit Breaker Test 13- Check Load Voltage FrequencyBattery Charge Rectifier BCR is a full wave rectifier Test 16 Check Battery Charge RectifierShort to Ground Test 20- Check Fuel Pump Test 19- Test PRE-HEAT SwitchSet a VOM to read battery voltage 12 VDC Test 18 TRY Cranking the EngineTest 21- Check 14 AMP Fuse Test 22- Check Battery & CablesTest 23- Check Power Supply to Circuit Board Disconnect the connector from the wires of the fuel pumpNot Activated Test 24 Check START-STOP SwitchTest 27 Check Starter Motor Test 26- Test Starter ContactorConditions Affecting Starter Motor Performance Measuring Current Checking the PinionPinion Tools for Starter Performance TestStarter motor test bracket may be made as shown in Figure Testing Starter MotorTachometer Test BracketTest 28- Check Fuel Supply Test 29 Check Wire 14 Power SupplyTest 30 Check Wire If Wire 18 checks GOOD, proceed to Problem 8 SectionTest 33- Test Glow Plugs Test 32- Test Preheat ContactorTest 34- Test D1 Diode Remove the valve cover from engine Disconnect the battery Test 35- Check Valve AdjustmentTest 36- Fuel Injector Pump Repeat Steps 1 through 8 on remaining cylinder If fuel is noted, proceed to next step in flowchartAdjust the regulated pressure on the gauge to 80 psi Down Test / Compression TestTest 40- Test Water Temperature Switch Test 38 Check OIL Pressure SwitchTest 39- Check Circuit Board for Ground If continuity is measure, replace the switch Test 43 Check Wire 15 for Short to GroundComponents for Short to Ground Major Disassembly Belt Tensioning RE-ASSEMBLYFAN Belt Line Corner UP Between 5˚ to 10˚Section Exploded Views / Part Numbers Bearing Carrier, Front Rotor AssemblyStator Assembly Flywheel AssemblyBase Frame Drawing No D2357-A Slide Latch Flush Door, Service RearDoor, Service Front Base Frame WeldmentEnclosure Drawing No D2358-D Decal, Battery + Cover, Access LiftCover, Access Electrical Gasket, Electrical AccessViews / Part Cover Plate, Scroll Weldment 25 26 Wire Assembly # Assembly, Potted RegulatorAssembly Marine Control Board Rectifier, Battery ChargingIntake and Exhaust System Drawing No D2362-B Hose, Air Inlet Exhaust GasketChamber Air Intake Air FilterViews / Part Numbers Wire Assembly, Black #4 Ground Fuel Pump AssemblyBoot, Battery Cable Cable, BatteryCustomer Controls Assembly Drawing No D2364-D Boot, Circuit Breaker Start / Stop SwitchSwitch, Pushbutton Spst Boot / Nut / Preheat SwitchGear Camshaft AssemblyCamshaft Gear KEY2630 Liter Diesel Cylinder Head Drawing No D2794 Liter Diesel Crankshaft, Piston and Flywheel Drawing No -B OIL Pump Cover Idler Gear AssemblySpring Thrust WasherExhaust Rocker ARM Rocker ARM AssemblyIncludes ALL Components Shown below Intake Rocker ARMLiter Diesel Injector Pump Drawing No -C Tank Return Model 04270 To Injection Pump To Fuel Pump 27 25 19 18 HOUSING, Timing Gear 3114 Liter Diesel Water Pump Drawing No Charts Generator Specifications Engine SpecificationsType Quietpact Model ROTOR/STATOR Resistance ValuesPage Data Data Electrical Data C4945 Schematic Drawing No C4945-A ModelC4946-A ElectricalSheet 2 OF4996 REV. 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