Reduce EMI and Improving Reliability of Servo Motors and VFD
with Motor Filters

Servo motors and VFD have two major EMI-related problems: excessive electromagnetic interference in equipment, and damage to the motor bearings caused by excessive high-frequency currents flowing through them.  Excessive EMI causes problems with measurements and equipment operation.

All pulse-width driven motors suffer deterioration of bearings (often called EDM - electric discharge machining). This article describes the problem in details.

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No Mechanical Fitting, No Wear, No Maintenance

OnFILTER' patented SF-series dedicated dV/dt servo and variable-frequency drives (VFD) filters transform sharp edges of drive pulses into much less "polluting" gradual ramps and also provide additional filtering in motor's ground reducing current through bearings typically 80 to 100 times.  

Reduction of Ground Current with SF Series Motor Filters

No filter

Ground current: 1.72A

SF-Series filter

Ground current: 7.3mA

Measured with Tektronix' CT1 probe 5mV/mA