Learning Center

Shaft Grounding Rings - The Necessary Accessory for Your Motor and VFD

By Dan Hansen on 15th Jul 2014

Why do you need a shaft grounding ring (SGR)? Motors that are operated with a variable frequency drive (VFD) are more susceptible to bearing failure. In standard generated sine waves, the voltage is balanced; this means that t …

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How to Read a Motor Nameplate

By Paul Rossiter on 21st Mar 2014

Below is a sample nameplate. You can click on the links in the nameplate to learn more. CT:VT: MODEL NO./SERIAL NO. HZ LOW VOLTAGE …

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Bearing Currents

By Craig Hartman on 20th Mar 2014

Courtesy AegisMotor bearings have a higher failure rate when the motor is run with a VFD. This is due to currents in the motor bearings. The classic solution to this problem is insulated bearings. Insulated bearings insulate the b …

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High Voltage Spike (dV/dt) and Motor Protection Methods

By Craig Hartman on 20th Mar 2014

There are two different phenomena that can create high dV/dt and high peak voltages. Reflective Wave Phenomenon Voltage wave reflection is a function of the voltage rise time (dV/dt) and the length of the motor c …

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