Table 5-1. Troubleshooting (Contd)
TEST OR INSPECTION
For test with panel meter disconnected, direct output current of the converter shall be 100 microamperes +
10 microamperes with I 100 ohm load across positive and negative terminals.
Model MEP-023A. 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:
Disconnect the lead from the positive ( + ) and the negative (-) terminals on the frequency meter.
Attach a multimeter with the scale set to read at least 200 microamperes, to the + and terminals on the
Operate generator set at 3428 rpm and turn adjusting screw to obtain a 100 microampere reading on the
If reading is accomplished. the frequency meter on the control panel is faulty and must be replaced.
If reading of 100 microamperes cannot be obtained, disconnect the wire leads from the two L terminals on
the frequency converter. Test the wire leads. If no defect is discovered, replace frequency converter (below) and
operate the generator set. Turn adjusting screw to obtain 400 HZ meter reading.
If frequency meter does not pass the above test, replace it. Refer to
figures 4-61 or 4-62 and replace the meter in the applicable model
generator set. If the meter is not defective, go on to step 2.
If the cause of the malfunction is engine lack of power. refer to TM 52805-259-14.
For maintenance correction, refer to TM 5-2805-259-14.
AC AMMETER FAILS TO REGISTER OR CURRENT METER FAILS TO REGISTER
Test the current transformer as follows:
Refer to figure 5-1 1. Disconnect and test resistors with a multimeter. Proper resistance is 150 ohms + 1%.
Test transformer windings for continuity.
Model MEP-023A. To test the current transformer for continuity,. disconnect the six leads
and remove the three resistors from the transformer. Use a multimeter set on the RX 1
ohm scale and test between terminals 1 and 2, 3 and 4, and 5 and 6. If continuity is not
Indicated on all three cases, the transformer is defective. Before reinstalling the resistors
test each to determine if they have a reading within I % of 150 ohms.
If transformer is found to be defective, replace it. Refer to figure 4-61 or 4-62.
Change 8 5-16