Thread: Reducing Motor Noise on Speed Controller?

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Hey guys-
I have one of these on my wiper motor-
QKits Electronic Kits: MXA066, PWM DC Motor Speed Control 30 A

Without it, the motor is very quiet. With the speed controller on it, it's pretty loud and noisy. I know that's common with these controllers. Are there any nifty little electrical tricks you know of to reduce that noise (other than muffling the motor itself with batting, cotton, foam, etc etc)???

Thanks!

Anyone have any input?

Wish I did.Mine are a bit noisy,gonna try and hide it with a good sound effect.

Any thoughts on trying this?
http://www.beam-wiki.org/wiki/Reducing_Motor_Noise

A long time ago, at work, we were using PWM modules to control the dimming of lights.

We had a similar problem - when the PWM switches on and off it creates large voltage spikes on the output. We found these to be close to 48V on a 28V system. needless to say It was playing havoc with the rest of the electronics in the system!

The problem was solved by installing filter coils on the output of the PWM, but it wasn't that simple - the filter coil values needed to be picked for each outputs load. so we wound up with 10 or 12 different filter coils in the system (there where a bunch of PWM controllers).

This was so long ago I don't remember what the values were that were used.

You can try some of these:
Toroid Coil Assortment (10-Pack) - RadioShack.com

or you can build your own coil by winding insulated wire around a steel core object.

The coil will go in series with your motor - PWM speed control+ -> Coil -> Motor+

You can also try these, but I don't think they will cut it:
Snap Choke Core - RadioShack.com
Snap-Together Ferrite Choke Core - RadioShack.com
They just snap around the power cable that feeds your motor. I would buy two if you are going to try them and put one on the + and one on the ground. I really think the inline coil will be better though.

Any thoughts on trying this?
http://www.beam-wiki.org/wiki/Reducing_Motor_Noise

The capacitors will try to fill in the off time of the PWM speed controller, so I'm not sure I would go that direction. It depends on the size of the capacitor on how much of the gap will be filled in, the larger (more farads) the more it will fill in the gap.

The coil I previously mentioned will round off the edges of the PWM pulse but not mess with the gap between the pulses.

Ahhh- hey thanks!

BTW - The capacitor method is preferred on non PWM speed controlled motors.

Hmmm iv only heard that relays make extra noise

Originally Posted by Specter

Anyone have any input?

This is no different than cordless dc drills with varialbe pwm speed controls. they make noise. I dont know why you dont adjust the voltage for speed control. Find a variable voltage controller and the noise will be gone. I am doing this with a car window motor and my fcg.