After the IC fan controller burned out by a voltage error I pulled it out to see what the motor coils were like.
They are so I think:
4 series coils, but I'm not sure if it's the 4 coils in series.
I was sad because I had burned out the PWM IC of the fan.
I analyzed the 4 coils well, only two filaments are soldered on the PCB, soldered two wires as you can see in the image and plugged in a common 12v 1a power supply, it turned and stopped, so I was making contact and removed quickly it spun a few seconds and stopped.
I try use PWM pulse with the Arduino and a transistor, I can see the pulse in the scope that uses the sound card in my desktop PC but the nothing happens if I connect directly in a source of 12v 1a simply tries to spin and stop.
In the Arduino I tried different intervals for the pulse from 50ms to 2000ms. Possible to use IC 555?
I need help because I do not understand much about electric motors, both dc and ac.