Motors Running on VFDs Need Shaft Grounding


VFD-Induced Shaft Voltages
Damage Bearings

Motor without Bearing Protection

Variable frequency drives (VFD) on AC and DC motors induce harmful electrical voltages on the motor shaft. Once these voltages exceed the resistance of the bearing lubricant, they discharge through the motor's bearings causing fusion craters, severe pitting, fluting damage. Excessive bearing noise and eventually bearing failure is the result. Current diversion in the form of the patented AEGIS shaft grounding is needed to make these motors sustainable.


AEGIS Shaft Grounding Ring:
Electrical Bearing Protection

Motor with AEGIS Ring

The AEGIS SGR Bearing Protection Ring prevents electrical bearing fluting damage by safely diverting harmful shaft voltages and bearing currents to ground. Using proprietary Electron Transport Technology, the conductive microfibers inside the AEGIS Ring provide the most reliable current diversion technology for shaft grounding with a "path of least resistance" to dramatically extend motor life.

Download our Handbook

AEGIS Bearing Protection Handbook, Edition 3

The Handbook Contains:

  • Bearing Frosting, Fluting, & Inspection
  • VFD Induced Shaft Voltages
    & Bearing Currents
  • High-frequency Bonding
    for VFD-fed Systems
  • AEGIS Shaft Grounding Best Practices
    for AC & DC Motors
  • AEGIS Shaft Voltage Testing
  • AEGIS Selection Guide & Parts List