Table 3-1. Troubleshooting. - TM-55-1905-223-24-40127

TM 55-1905-223-24-4

Table 3-1 lists the common fault conditions that may be found during operation or maintenance of the equipment. Look

for causes and do corrective actions in the order listed. This manual cannot list every symptom that may show up, and it

cannot list all of the possible causes and corrective actions. If a symptom is not listed, or if it keeps up after you have

performed the corrective actions, notify your supervisor.

Table 3-1. Troubleshooting.

Malfunction

Test or Inspection

Corrective Action

Low engine oil pressure.

STEP 1. Check to see if regulator valve is stuck open.

Replace valve (para. 3-12).

Engine Will Not Shutdown.

STEP 1. Check to see if fuel shutdown valve inoperative.

Shutdown the engine mechanically with lever on the fuel pump.

Replace sealing washer, piston, and spring (para. 3-12).

Generator Set Output Voltage High or Low.

STEP 1. Check to see if engine speed is incorrect.

Verify/adjust electric governor (para. 3-12).

Generator set output frequency high or low.

STEP 1. Check for correct engine speed.

Adjust the fuel pump high speed screw (para. 3-12).

Fault lights illuminated; overspeed shut down.

STEP 1. Generator output frequency too high.

Measure and adjust frequency between pins V7 and V8 (para. 3-12).

STEP 2. Overspeed potentiometer set too low. Adjust the overspeed potentiometer as follows:

a. Carefully remove the insulating sealant from the overspeed potentiometer on the voltage regulator

board.

b. Rotate the overspeed potentiometer fully clockwise.

c. Connect a frequency meter to terminals VO and V7.

d. Start the generator set.

e. Adjust the engine speed until the frequency meter reads 70 Hz.

f. Slowly rotate the overspeed adjustment counterclockwise until the generator set shuts off.

g. The overspeed fault shut down is now set.

h. Adjust the frequency (para. 3-12).

i. Turn off the generator set.

j. Reset the fault lamp and start the generator set.

k. Adjust the engine speed for proper frequency output (50 to 60 Hz). Refer to paragraph 3-12 for

procedures.

l. Turn off the generator set.

m. Disconnect the frequency meter and reseal the overspeed potentiometer with RTV.

NOTE

Do Not disturb the potentiometer setting when sealing.

3-4