EMI Suppression Filters(EMC and Noise Suppression)

EMI Suppression Filters (EMC and Noise Suppression)Noise Suppression Product PLT10H (Common Mode Choke Coil)
Cars

Brush motors for automobiles

This page introduces noise problems that often occur with brush motors for automobiles, its mechanism, and the solutions.

Noise problems that often occur with brush motors for automobiles
Reasons why PLT10H is effective at noise suppression
Noise suppression effect of brush motors for automobiles

I have trouble suppressing common normal noise in a broad range from several hundred kHz to several hundred MHz, which is generated from brush motors for automobiles.

I do not have sufficient time to consider noise suppression due to the short design time. I want to clear the CISPR25 noise regulations.

It seems that the noise is generating in the motors for power windows, power slide doors, power seats, door locks, etc.

Reasons why noise is generated in brush motors

Murata's PLT10H solves these problems!

How?

In order to meet the CISPR25 Class 4, use a PLT10H, X capacitor and Y capacitor in combination to solve the problems mentioned above!

Noise suppression with capacitors only (X capacitor and Y capacitor) is not sufficient to realize effective noise suppression, particularly at 30 MHz or more.
This is a hybrid type that suppresses both common mode noise and differential mode noise (normal mode noise).
Adding the PLT10H will improve the noise suppression effectiveness by about 20 dB at 30 MHz or more.

Particularly, the combination shown in the following block diagram is the most effective for noise suppression.

Points of noise suppression of brush motors for automobiles

It is effective to take measures inside a motor (near the noise source).
It is effective to suppress both the normal mode and common mode noise using an X capacitor and Y capacitor in combination.