PWM Trouble with PC Fan

Thread Starter

tony48

Joined Jun 11, 2013
4
Hello,

I'm trying to use a PWM controller to control a 12v PC fan. When I wire it up, it controls the fan as expected but there is a loud squealing noise coming from the fan that changes pitch when I change the fan speed. Can anyone help me understand why this is happening and hopefully fix it?

Here's the PWM unit I have:
http://www.amazon.com/LEDwholesalers...1&keywords=Pwm

Thanks very much!
 

shteii01

Joined Feb 19, 2010
4,644
Looking for something?
We're sorry. The Web address you entered is not a functioning page on our site





The blade might be unbalanced. When the speed changes, the blade wobbles and hits the fan frame.
 

spinnaker

Joined Oct 29, 2009
7,830
Hello,

I'm trying to use a PWM controller to control a 12v PC fan. When I wire it up, it controls the fan as expected but there is a loud squealing noise coming from the fan that changes pitch when I change the fan speed. Can anyone help me understand why this is happening and hopefully fix it?

Here's the PWM unit I have:
http://www.amazon.com/LEDwholesalers...1&keywords=Pwm

Thanks very much!
Bad bearing in the fan? Can you take the fan apart and get to the bearings? Perhaps a bit of lubricant will get rid of the squeal for a while.
 

Thread Starter

tony48

Joined Jun 11, 2013
4
The sound is not present when I run the fan without the pwm circuit. It is a distinctly electrical squealing sound
 

BillB3857

Joined Feb 28, 2009
2,570
The base frequency of your PWM circuit may be in resonance with the fan producing the sound. Can you change the base frequency to something higher or lower?
 

#12

Joined Nov 30, 2010
18,224
That's not a chip. It's a completed module. If you're going to change the frequency, you're going to have to dig inside the box and find out how it's made.
 

THE_RB

Joined Feb 11, 2008
5,438
12v PC fans only use about 50mA to 100mA, you can fix this by putting a resistor between the module and the fan. And a large cap (1000uF) across the fan wires. A resistor of 10 ohms should do it.

An inductor can work better than the resistor but is harder to find and can cause other issues.
 
Top