Maximum Bearing Protection for Large
and Medium Voltage AC and DC Motors

The AEGIS PRO Series design provides reliable shaft grounding for large AC and DC motors, medium voltage applications, generators, and turbines to divert harmful shaft voltages to ground and extend bearing life. Install the AEGIS PRO on the DE and insulate the bearing on the opposite end (NDE) for best results. Large motors and generators often have much higher induced shaft voltages and bearing currents. The six circumferential rows of conductive microfiber provide the extra protection for these high current applications.

Case Studies available for download

AEGIS® Shaft Voltage Tester™

Digital Oscilloscope and Multimeter
with Conductive Microfiber Probe Tips

The AEGIS Shaft Voltage Tester can quickly and easily determine whether a motor is at risk of bearing damage due to shaft voltages.

How do you know if a motor is safe from destructive shaft voltages? For the first time you can get all of the tools you need in one kit. The AEGIS Shaft Voltage Tester Digital Oscilloscope bundle includes the AEGIS-OSC-9100 100 MHz digital oscilloscope, shaft voltage probe tips, and a shaft grounding simulator. Armed with these tools, you can quickly and easily find whether motors are at risk of premature bearing failure due to VFD-produced bearing currents.

Product Description

Download our Handbook...

AEGIS Bearing Protection Handbook, Edition 3

AEGIS Bearing Protection Handbook
(available in several languages)

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

Download now!

AEGIS Rings in Action

Shaft Voltage on a Motor Before and
After AEGIS Installation

AEGIS Decimates Shaft Voltage...
And Then Some

AEGIS Shaft Grounding Rings protect motor bearings from the destructive shaft voltages produced by variable frequency drives (VFDs). This video compares the shaft voltage of a VFD-run pump motor before and after installation of an AEGIS ring. (To see this video in several other languages, see this Youtube playlist.)


VFD Induced Shaft Voltages
Damage Bearings

Motor with No
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 Rings:
Protection Against Electrical Bearing Damage

Motor with AEGIS
Bearing Protection Ring

The AEGIS Shaft Grounding 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.