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What is a precharge fault on an ATV66 drive?

Issue:
Display shows "Precharge Fault"

Product Line:
Altivar 66

Environment:
All models and serial numbers

Cause:
Precharge failure: capacitor precharge relay fault

Resolution:

When the unit is powered up, the capacitor charging is monitored. When the capacitor voltage reaches 450 VDC, a 500 msec (for drive controllers ATV66U41N4

through ATV66D12N4) or 1500 msec (for drive controllers ATV66D16N4 through ATV66C19N4) timer is triggered.

While the timer is running, the voltage to the capacitor terminals must remain stable for 100 msec, otherwise a precharge failure fault is triggered

During operation, if the charging relay opens when RUN (LI1) is validated, a precharge failure fault is triggered. The check is made every millisecond.

If a precharge failure occurs, possible causes are:

• Failure of precharge relay/contactor or its associated coil drive circuitry.

• Control card ribbon cable incorrectly connected.

• Excessive mains voltage distortion.

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