A Pragma Group Company

Shaft voltage probe


AEGIS SVP™ Shaft Voltage Probe

Hi Amp

High amplitude EDM discharge pattern

lo Amps

Low amplitude voltage discharge pattern


High Peak to Peak common mode voltage


Measuring VFD Induced Shaft Voltages

Stray voltages on shafts and resulting discharge currents can cause serious damage and premature failure to shaft drive trains on motors, generators, turbines and compressors. Bearings, seals, gearboxes, etc are at risk. Motors driven off VSD’s are particularly susceptible. 

Is your machine safe from destructive shaft voltages? For the first time you can easily and more accurately measure the voltage on a rotating shaft. The AEGIS SVP™ Shaft Voltage Probe’s unique design of high density conductive microfibers ensures continuous contact with the rotating shaft. Designed with terminations to suit the Fluke 199C ScopeMeter®, you can determine if your motor is subject to potentially damaging grounding currents. The AEGIS SVP™ may be hand held or used with a magnetic base. Simply contact the rotating shaft with the microfibers and evaluate the voltage waveform on the oscilloscope.

In the event of potentially damaging shaft voltages being present on a shaft a simple and inexpensive solution is the AEGIS SGR™ Bearing Protection Ring.

AEGIS SGR™ Bearing Protection Ring

Use the AEGIS SGR™ or iPRO™ Bearing Protection Ring to prevent electrical current damage to bearings and other components by safely channelling harmful shaft currents to ground. The conductive microfibers provide the path of least resistance and dramatically extend machine life.