What can be done when variable speed drives or VFDs are causing motor bearing failures?

FA174066

8/08/2020

Issue:
What can be done when VFDs are causing bearing failures?

Product line:
Altivar All

Environment:
All models, all serial numbers
 
Cause:
Shaft currents causing the motor bearings to weld.

Resolution: 
This phenomena is inherent to VFD use.  On the VFD, try lowering the switching frequency to reduce effects but not resolve it.

Other suggestions include:
installing shaft grounding systems
installing insulated bearings
adding a dv/dt filter to couple less voltage to the rotor
adding a common mode filter
verify good grounding from the motor directly back to the VFD