VFD-induced shaft voltages damage motor bearings and shorten motor life
If you’re using variable frequency drives (VFDs) or inverters to control motors, the motors are at risk of electrical bearing damage that can dramatically shorten their lives.
VFDs induce harmful voltages on motor shafts — voltages as 40 volts peak — that can destroy bearings in as little as 3 months!
Through electrical discharge machining, VFD-induced discharges can blast millions of pits in metal bearing surfaces. These discharges burn and contaminate bearing grease, drastically reducing its effectiveness. They also result in fluting, bearing failure, and costly unplanned downtime. And while most motor manufacturers offer “inverter-duty” or “inverter-ready” models, these motors have inverter-rated insulation to protect their windings, but nothing to protect their most vulnerable components — their bearings.
