Simple connection brushless motor (fan)

Using Arduino Motors, Mechanics, Power and CNC
#1

Hi,

I have a 5 volt brushless 3 fase motor (fan) from a graphical card. What's the simplest way to make the motor go left right and change the speed.

What worked somewhat is just connecting it like a stepper motor. With the Arduino tutorial. I just can't get the speed controlled nor the direction. What I've also tried is with the L293 H bridge but that didn't do anything.

Is there a simple way to such a thing? I've worked with regular dc motor in the past and then I could do a somewhat equal thing with the pwm output. But that wasn't so accurate, is it possible that it's the same with a brushless?

Kind regards!

#2

First off, computer / brushless fans cannot be reversed. Bummer.

The fan itself contains its own three-phase driver circuit to control its direction and speed and won't work properly if you try to turn it off and on rapidly with PWM. It would be like trying to dim an LED connected to an Arduino by turning on/off the power to the Arduino.

If you're just controlling the speed you need some way to smooth out the power to the fan using something like an RC circuit or by increasing the PWM frequency. I'm sure there are a number of examples to be found if you look around.

#3