TROUBLESHOOTINGTESTING AND ADJUSTINGPOSSIBLE CAUSESVERIFICATION PROCEDURE(Continued)voltage. If the stability of the voltage and rpm are the same asbefore, the problem is in the engine (governor).NOTE: The generator name plate shows the maximum excitationvoltage for full load. At no load, the correct excitation voltage isapproximately 25% of the number on the generator nameplate.42. Damping Resistor Open (R5)Disconnect damping resistor (R5) by removing wire (12) betweendamping resistor (R5) and suppression capacitor (C2). Checkresistance of (R5) from wire (12) to terminal (26). Typicalresistance is approximately 10 ohms.43. Temporary Short Circuit in RFIDisconnect the RFI suppression capacitor (C1) by removing theSuppression Capacitor (C1)spade terminal connection of wire (6). Start the engine and lookfor voltage stability. If voltage is not correct, remove (C1) andinstall a new capacitor.44. Temporary Short Circuit inDisconnect suppression capacitor (C2) by removing spade terminalSuppression Capacitor (C2)connection of wire (6). Start the engine and look for voltagestability. If voltage is not correct, remove (C2) and install a newcapacitor.To check suppression capacitor (C2), measure the resistance. Aresistance measurement of anything but infinity shows that thesuppression capacitor (C2) is defective. If the resistance is infinityconnect 120V AC, 60 Hz, across the terminals. Current must beapproximately one amp.NOTE: Install a 10 amp fuse in the 120V AC, 60 Hz, circuit. Thisis to be a safety limit if the capacitor is defective.45. Current in Exciter Field (L3) isWith the engine stopped, disconnect wire F1 from terminal F1.not StableConnect the positive cable from a DC ammeter to terminal Fl.Connect the negative cable to wire F1.NOTE: The DC ammeter must have a capacity of 15 amps or more.Start the engine. The DC current in the exciter field (L3) mustincrease to a value less than 15 amps and remain constant.46. Defect in Voltage LevelWith engine stopped, disconnect wire (7) from spade terminal (4)Rheostat (R2)of module (A1). Measure the resistance between wire (7) andspade terminal (6) of module (A1). This is the resistance of thevoltage level rheostat (R2). The resistance with the voltage levelrheostat (R2) fully clockwise is 0 ohms. The resistance is 500ohms at fully counterclockwise. The resistance must changesmoothly as the adjustment of the voltage level rheostat (R2) ischanged between these points.47. Defect in Voltage DroopWith the engine stopped, disconnect wire (5) from terminal (5) onPotentiometer (R1)module (A1). Measure the resistance between wire (5)andterminal (6) on the module (A1). Resistance with the voltagedroop potentiometer (R1) fully counterclockwise is 0 ohms. Theresistance is 8 ohms at fully clockwise. The resistance must changesmoothly as the adjustment of the voltage droop potentiometer(R1) is changed between these points.70
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