TROUBLESHOOTINGTESTING AND ADJUSTINGPOSSIBLE CAUSESVERIFICATION PROCEDURE27. Voltage Droop Control SettingCorrect voltage at no load but low voltage under load at 0.8 powerToo High (R1)factor, is an indication that voltage droop control (R1) setting istoo high. To make an adjustment, see Operation and MaintenanceInstructions. Check for good contact between the moving brushand the turns of wire on voltage droop control potentiometer(R1). Paint or other material can prevent good electrical contactbetween these components. Bad contact will result in low voltagefrom the generator under load at 0.8 power factor. You will notget an adjustment in the voltage as the droop control is movedfrom maximum to minimum setting.28. Regulator Gain Control SettingCorrect voltage at no load but too low at rated load is anToo Low (R3)indication that regulator gain control (R3) setting is too low. SeeOperation and Maintenance Instructions for adjustment procedures29. Engine RPM Too HighCheck engine rpm with a tachometer of high accuracy or with afrequency meter. Make adjustments as needed to get correctengine rpm.30. Voltage Level Adjustment TooTurn the voltage level rheostat (R2) toward minimum setting. SeeHigh (R2)Operation and Maintenance Instructions for adjustment.31. Reverse Polarity on VoltageCorrect voltage at no-load but too high under load at 0.8 powerDroop Transformer (T1)factor is an indication that the connections on voltage drooptransformer (T1) is wrong. Stop the engine and change theconnections of voltage droop transformer (T1) at terminals (5)and (6). If this gives a correct high voltage under load, change thenumbers on wires from the transformer (T1).32. Regulator Gain Control SettingCorrect voltage at no load but too high at rated load is anToo High (R3)indication that the voltage gain control (R3) setting is too high.See Operation and Maintenance Instructions for adjustment.Check for good contact between the moving brush and the turnsof wire on voltage gain control rheostat (R3). Paint or othermaterial can prevent good electrical contact between thesecomponents. Bad contact will result in high voltage at rated loadand it will not be possible to get an adjustment when the control ismoved from maximum to minimum setting.33. Open Regulator Gain RheostatDisconnect regulator gain rheostat (R3) by removing wire (lb) at(R3)spade terminal (8) of regulator module (A1). Check resistancefrom wire (18) to spade terminal (7) on regulator module (Al).With the regulator gain rheostat setting on maximum gain, theresistance will be approximately 5000 ohms (500 ohms in unitswith Al module that is black in color). When the gain control isturned to minimum position the resistance will become less andwill read a short at the minimum position.34. Open Field Rectifier (CR10)Disconnect field rectifier (CR10) circuit by removing wire (8)from terminal (F1). Use an ohmmeter or continuity checker(8S4627). To check forward resistance of (CR10) put the positivecable on terminal (F2) and the negative cable on wire (8). A lowresistance (10 ohms or less) on ohmmeter scale (RX1) or a lightwith the continuity tester must be seen. If an open circuit(infinity) or no light is seen field rectifier (CR10) is open. Removeand install a new rectifier. For more information, see TESTINGPOWER RECTIFIERS AND CONTROLLED RECTIFIERS.68
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