Problems that can occur without motor protection filtering:
- Damage to motor bearings
- Unexpected ground fault trips
- Erratic behavior of VFDs and PLCs
- Premature motor insulation failure
- Cable damage
Common Mode Can Cause Motors to Break Down
Three-phase utility power produces three smooth sinusoidal waves which at any point average a sum of zero. This creates an optimal scenario with zero Common Mode. VFDs give off power in a continuous generation of pulses, which on average achieve a sinewave. However, the sum at any point is not always zero, which results in damaging common mode. This can cause motors to break down over time.
Peak Voltages Damage Drives and Motors
The pulse of VFDs is not a clear square pulse. Each rise and fall of the pulse has an over shoot or transient over voltage. This phenomenon is also known as a “reflected wave.” These voltage spikes, especially in long cable leads, can reach dangerous levels and damage drives and motors.
Rise Time Can Reduce Motor Life
Modern VFDs utilize IGBT systems that create extremely fast rise times which can increase motor performance. This can also result in increased motor insulation heating, which can reduce motor life over time.
MTE Motor Protection Products
RL reactors (for cable leads up to approximately 300 ft.)
RL reactors are unequaled in absorbing power line disturbances. They are built to withstand even the most severe power spikes. They reduce nuisance tripping, reduce harmonic distortion, and minimize long lead effects.
dV Sentry™ filters (for cable leads up to approximately 1,000 ft.)
The dV Sentry and its patented Triple Defense Core, is proven reduce common mode, protect against peak
voltage, and reduce rise time – all in one unit.
SineWave Guardian™ filters (for cable leads up to approximately 15,000 ft.)
This best-in-class filter delivers unequaled performance in cleaning the PWM waveforms generated by VFDs. It virtually eliminates high frequency content and voltage peaks, thereby reducing motor heating to provide extended motor life – and less downtime.
