Table 5-1. Troubleshooting (Contd)
TEST OR INSPECTION
Inspect for a cracked or broken rotating rectifier diode.
Replace diode. Refer to paragraph 8-1 or 8-2. If defective diode is not the cause of the
malfunction, go on to step 5.
Inspect for a damaged rotor stator, or field winding as follows:
Inspect the rotor shaft at each end for evidence of nicks, rust, or wear. Inspect the rotor
assembly to be sure all windings are properly pressed into the core slots. Inspect the core
Inspect the field windings and leads for damaged or broken wires. Inspect the main frame
for damage or broken wires. Inspect the main frame for damage and broken welds and for
nicks and burrs around the mounting flanges.
Use a fine file and remove rust, burrs. and fine edges. If damage is beyond
repair, replace defective items. Refer to paragraph 8-1 or 8-2.
GENERATOR VOLTAGE TOO HIGH
Test the voltage regulator to see if it is defective. Refer to paragraph 4-42b.
If the regulator fails to pass the above test, refer to paragraph 7-9c. for test and repair
procedures. If regulator passes above test, go on to step 2.
Inspect exciter. Check for broken or damaged windings and leads.
If damage is evident, replace the exciter. Refer to paragraph 8-1 or 8-2.
GENERATOR FREQUENCY FLUCTUATES OR DROPS UNDER LOAD
Test the frequency converter to determine its condition. Test as follows: a. Model MEP-O18A.
Apply AC input of 120 volts, 60 hertz current across terminals marked "L".
With panel meter (M3) connected to output side meter reading should indicate 60 hertz + 0.5 hertz.
Change 8 5-15