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Reduce EMI and Improving Reliability of PWM Motors with Motor Filters

Servo/VFD Filters in Motion Control

Servo and stepper 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/SV-series  dedicated dV/dt servo and variable-frequency drives (VFD) filters and and TF/TV-series stepper motor filters and TF/TV-series 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

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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