LC filter for DC motor

[Boris]

Hi everybody!
I built couple drivers for DC motors.(use motors 3-5 V from POLOLU).Works very good,but motor makes noise for RF devices.I know a lot of schematics of filtrs ,but I want to know your opinions and your expiriens in this field.
I 'll appriciative if somebody give me diagrams.
Thank's

 

[dknguyen]

I'd use shorter wiring with more high frequency decoupling capacitors and snubbers before I would try placing anything else in series with the motor- that's expensive and lossy. You can also try increasing the rise and fall times of the MOSFETs in the driver.

 

[Boris]

Iuse driver L298.

 

[Ubergeek63]

HF decoupling caps at the motor.

twist the wires as tight as you can

put ferrite emi beads at both ends

That thing is a bit of a dinosaur. It takes up to 70mA from your main supply and up to 36mA from your logic supply just to steal up to 5V from your motor!

 

[Boris]

Thank You dknguyen!!
Thank You Ubergeek63
I'll try.

 

[dknguyen]

I'd use shorter wiring with more high frequency decoupling capacitors and snubbers before I would try placing anything else in series with the motor- that's expensive and lossy. You can also try increasing the rise and fall times of the MOSFETs in the driver.

Correction. Faster rise and fall times make more RF noise.

 

[Boris]

Thank You.
but I don't use PWM for my driver. I aplay DC voltage to my motor.

 

[Ubergeek63]

Thank You.
but I don't use PWM for my driver. I aplay DC voltage to my motor.

DC? That is terribly inefficient. Not a problem if you are able to get rid of the heat and do not have to worry about battery life.

 

[Boris]

I'll use PWM at finale, but for test my motor driver I use dc voltage.