Servo Motor / VFD Filters

PWM-driven motors - servo motors and variable frequency drives (VFD) - are a major source of EMI in equipment.  They also cause a number of problems in equipment, including damage to the motor’s bearings due to leakage current causing electrical discharge machining (EDM) and damage to motor’s insulation.  

"We tested the servo filter on another system, this time with Kollmorgen motors. We saw another significant reduction in noise on our signal"  (P.M.,U.K.)

OnFILTER’s patented SF-series filters substantially reduce high-frequency leakage currents in motors and in wiring, assisting in compliance with the requirements of IEC60034-17/-25. They also reduce interfering high-frequency noise within the tool resulting from operation of PWM-driven motors.  

SF series filters greatly reduce high-frequency currents on equipment ground, as well as overall EMI in the tool, lowering risk of EOS and reducing errors in automated equipment and testers.

No Mechanical Fitting, No Wear, No Maintenance

OnFILTER' SF series filters have no mechanical coupling to the motors - all connections are electrical. 
Their cost of ownership is zero.​

  • No mechanical attachments

  • No changes in software

  • No adjustments


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Basic Connection of Motor Filter
Basic Connection of Combo Motor/AC Filter
OnFILTER Servo/VFD Filter Connection Diagram
Application Notes
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Technical Articles

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

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 ©2017-2021 OnFILTER, Inc. CleanSweep is a registered trademark of OnFILTER

U.S. Patents 10,263,591; 9,076,806B1 All specifications are subject to change without notice.

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Servo/VFD Filter Connections