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Motion Control dV/dt EMI Filters

PWM-driven motors - servo motors, stepper motors, and variable frequency drives (VFD) - are a major source of electromagnetic interference (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 offers motor EMI filters for all three types of PWM motors - VFD, servo, and stepper motors.  Patented technology employed in these filters substantially reduce high-frequency leakage currents in motors and in wiring, assisting in compliance with the requirements of IEC61800-3,  IEC60034-17/-25 and NEMA MG 1-2016, as well as with NAMUR recommendations. The filters also reduce interfering high-frequency noise within the tool resulting from operation of PWM-driven motors.  

The motor 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 Adjustments, No Wear, No Maintenance

OnFILTER' motion control filters have no mechanical coupling to the motors - all connections are electrical.  Nothing to adjust, nothing to maintain. Their cost of ownership is zero.​

Click on the filter type suitable for your motor/drive for details:

We have all 3 filters installed on the machine. They seem to be working very well. It really suppresses the noise we were getting on the analog signals from the sensor (Director of Engineering, U.S.)

  • No mechanical attachments

  • No changes in software

  • No adjustments

Servo Motor Drive Waveform
PWM VFD Waveform
Stepper Motor Drive Waveform
Ringing Pulse.jpg
Servo / VFD Filter SF20031
Servo / VFD Filter SF20032
OnFILTER' Stepper Motor Filter TV05101

Drive Pulse Edge Modification by a Filter

OnFILTER' Servo / VFD Drive Modified Waveform

Ground Current Without the Filter

VFD / Servo Ground Current Without Filter

Ground Current With the Filter

VFD / Servo Ground Current With Filter
Application Notes

Filters for Servo Motors and VFD

Practical Aspects of Managing EMI-Caused EOS in IC Handlers and Similar Equipment

Measurements of Conducted Emission in the Manufacturing Environment

EMI-Generated EOS in a Wire Bonder

Mitigating EMI Issues in Servo Motors and Variable Frequency Drives

Dealing with EMI in Semiconductor Device Manufacturing

EOS Sources in Automated Equipment

Managing EMI in Back-End IC Manufacturing, TAP Times

EMI-Caused EOS Exposure of Components and its Mitigation

Origins of EOS in Manufacturing Environment and Its Classification

Technical Articles
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