GE Industrial Solutions AF-600 FP High Power (460V_575V 150HP and above) User Manual
Page 90
One way to determine if the mains supply is at fault is to swap two of the incoming phases. This assumes that two phases read one current while the
third deviates by more than 5%. If all three phases are different from one another, swap the phase with the highest current with the phase with the
lowest current.
4.
Remove power to frequency converter.
5.
Swap the phase that appears to be incorrect with one of other two phases.
6.
Reapply power to the frequency converter and place it in run.
7.
Repeat the current measurements.
If the imbalance of supply voltage moves with swapping the leads, then the mains supply is suspect. Otherwise, it may indicate a problem with the gating of the
SCR. This may be due to a defective SCR or in the gate signals from the power card to the module, including the possibility of the wire harness from the power
card to the SCR gates. Further tests on the proper gating of the SCRs require an oscilloscope equipped with current probes. Proceed to testing the input waveform
and input SCR in accordance with their procedures.
AF-650 GP and AF-600 FP High Power Service Manual
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