How to optimize the placement of the MC magnetic ring in motion controllers?

Optimal use of ferrite rings to suppress interference in motion controllers (MCs) requires careful selection of the installation location based on the noise type and path. For power lines, the ferrite ring should be installed close to the noise source, such as the input/output terminals of a switching power supply. For signal lines, the ferrite ring should be close to the interference injection point or sensitive receiver. For common-mode noise, the cable should be wound multiple turns around the ferrite ring to increase inductance; for differential-mode noise, the twisted pairs should pass through together.

The ferrite ring material should be selected based on the noise frequency: manganese-zinc ferrite is suitable for frequencies below 1MHz, and nickel-zinc is suitable for frequencies above 1MHz. During installation, the ferrite ring should be tightly closed and placed as close as possible to the connector. Installing ferrite rings at chassis openings or cable entry/exit points can suppress radiated leakage. For high-frequency noise, multiple ferrite rings can be connected in series. The effectiveness of the ferrite ring can be verified by comparing conducted or radiated test results before and after installation. Note that ferrite rings may saturate under high DC current; therefore, models with high saturation flux density should be selected, or an air-core inductor should be considered. The final location needs to be determined experimentally to achieve the best cost-effective suppression effect.