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My company (In SoCal) uses a 480 VAC 3-phase Baldor vfd. We have been experiencing a brown out (heatwave/wildfires) and during the night our VFD fails multiple times even though other instrumentation doesn’t fail. The warning sign given is LOW DC Bus Voltage when it fails. However, after resetting it works until the next time it fails. After, the brown out the problem has disappeared.

In my opinion a weak component is leading to failure. What component can that be? Is this an easy fix or should I replace the vfd.

  1. Could the rectifier have a broken diode and not take the peak voltage source?

  2. Could the dc bus filter/capacitor be damaged?

  3. IGBTs for the inverter too slow?