Table 5-1. DS and GS Troubleshooting (Contd)
Test or Inspection
6. GENERATOR FREQUENCY FLUCTUATES OR DROPS UNDER LOAD
Test the frequency converter to determine its condition. Test as follows:
a. Model MEP-017A.
(1) apply AC input of 120 volts, 60 hertz current across terminals marked L.
(2) With panel meter (M3) connected to output side meter reading should indicate 60 hertz + 0.5 hertz.
(3) For test with panel meter disconnected, direct output current of the converter shall be 100
m i c r o a m p e r
+ 10 microampere with 1100 ohm load across positive and negative terminals.
b. Model MEP-022A.
With generator set operating at 3428 rpm, remove screw in the face of the frequency
converter and adjust the potentiometer for a reading of 400 HZ on the frequency meter. If proper reading is not
obtained, proceed as follows:
(1) Disconnect the lead from the positive (+) and negative (-) terminals on the frequency meter.
(2) Attach a multimeter with the scale set to read at least 200 microampere. to the + and terminals on the
(3) Operate generator set at 3428 rpm and turn adjusting screw to obtain a 100 microampere reading on the
multi meter scale.
(4) If reading is accomplished. the frequency meter on the control panel is faulty and must be replaced.
(5) If reading of 100 microamperes cannot be obtained. disconnect the wire leads from the two L terminals
on the frequencv converter. Test the wire leads. If no defect is discovered, replace frequency converter and operate
generator set. Turn adjusting screw to obtain 400 HZ meter reading.
If frequency meter does not pass the above test, replace it. Refer to paragraph 7-2 and replace
the meter in the applicable model generator set.
7. GENERATOR NOISY
Remove the generator, paragraph 6-2 or 6-3, Disassemble the generator, paragraphs 7-13 and 7-14, to the extent
necessary to inspect the bearing, Inspect bearing for leakage, looseness, and smoothness when turned. Inspect for
evidence of wear.
If the bearing does not pass the inspection above, replace it. Assemble the generator, paragraphs 7-
13 and 7-14. Reinstall the generator, paragraph 6-2 or 6-3. If the bearing passes the above inspection,
go on to Step 2.
Remove the generator, paragraph 6-2 or 6-3. Disassemble the generator, paragraph 7-13 and 7-14, to the extent
necessary to inspect the fan and rotor adapter. Inspect for looseness, cracks, wear, and other physical damage.
If the fan and rotor adapter does not pass the above inspection, replace them. Reassemble the gener-
ator, paragraph 7-13 and 7-14. Reinstall the generator, paragraph 6-2 or 6-3.
8. GENERATOR OVERHEATS
Inspect the fan for cracks, breaks, insufficient mounting, and looseness.
If fan condition does not pass the above inspection, replace it. Refer to paragraph 6-2 or 6-3 for re-
moval and installation. If fan passes the inspection, go on to Step 2.
Test the stator as follows:
a. Disconnect the plug connector (P1) at the rear of the control box.
b. Use a multimeter that has been set on the RX1 scale and test for continuity between plug pins A and B, D
and E, and C and F. If continuity is not indicated (full deflection) on any of the tests, remove the plug at the
generator and repeat the tests at the generator.