3 wire computer fan won't run continuously
- by Ben
I had an old computer that didn't work anymore, so I took the CPU fan out to see what I could make with it.
The fan is NMB model number BG0903-B044-VTL, like this. It has three wires coming off of it, red, black, and white. I know that the white wire is usually a speed sensor. Does this wire need to be connected to something in order for the fan to run continuously?
Right now when I apply power to the red and black wires (from a 9-volt battery) the fan will spin very briefly, and then slow down until it stops. The fan's motor only spins in the instant that the power is turned on, but doesn't continue, even though the power is still applied. How can I get the fan to spin continuously?