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.

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

Relevant Products:

No filter

Ground current: 1.72A

SF-Series filter

Ground current: 7.3mA

Measured with Tektronix' CT1 probe 5mV/mA

Questions?  Ask Us:

Technical Article

Interference Technology Magazine' Annual EMC Test and Design Guide, 2016

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What is EMI?  A formal definition of Electromagnetic Interference is that it is a malfunction of equipment caused by excessive high-frequency signals, either radiated (via air), or conducted (via wires).  Often it is also called RFI - Radio Frequency Interference.  Most conventionally, EMI is understood as undesirable high-frequency signals, and EMI filters as devices that suppress such signals while preserving the "good" ones.         

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U.S. Patents 10,263,591; 9,076,806 All specifications are subject to change without notice.

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