Capacitive coupling between windings and rotor can create voltage on a motor's shaft — voltage that can discharge through bearings, damaging them and shortening motor life. For motors powered by sine wave AC power, these voltages are typically 1-2 V. For motors controlled by variable frequency drives, however, these voltages can be as high as 8-15 V. At these higher levels, voltages essentially electric discharge machine (EDM) motor bearings, causing pitting, fusion craters, and fluting, which eventually lead to premature bearing and motor failure.
Until now, there was no convenient way to determine whether a motor was at risk for such bearing damage. By the time bearings began to make noise, the damage was done.
Now, with the AEGIS® SVP Shaft Voltage Test Kit and an oscilloscope, plant maintenance personnel can take readings from motor shafts quickly and easily — readings that confirm or deny the presence of shaft currents that can damage motor bearings.
The following equipment is required to test for damaging shaft currents:
- AEGIS® SVP: A specially-designed shaft voltage probe extends an operator's reach and contacts the motor shaft by means of a conductive microfiber brush, making the process of taking shaft voltage readings safer and easier.
- Oscilloscope: An oscilloscope with a high bandwidth (up to 200 MHz) and fast sampling rate (up to 2.5 gigasamples/second) such as the Fluke 190 Series II ScopeMeter®.
Where to buy AEGIS®: AEGIS® SVP Shaft Voltage Probe Kits and Tips are available through our distribution channels. Please visit the "Where to Buy" section of our website to find a distributor near you.
To buy or learn more about Fluke ScopeMeter portable oscilloscopes visit the Fluke website.
To rent portable oscilloscopes visit TestEquity.
Conductive Microfiber Probe for use with Fluke® 190 Series II ScopeMeters
