How to control bipolar stepper?

As stated already, it's not a stepper motor, you're just powering one of the phases of a three phase (brushless) motor. Try this out: pull out the spindle motor of a CDROM drive and apply voltage in the same manner as you're doing it for your hard drive. It'll move the bobbin to a position and stay there. Both the hard drive and the CDROM drive use brushless motors.

One way to tell the difference between a stepper motor and a brushless motor is how much each "step" moves. If it's more than 5 degrees it is a brushless motor. No useful stepper motor would have increments that coarse.

On another note, I've tried controlling a 3-phase motor like a galvo, but ended up burning out my H-bridge chip. Literally smoke.

Thanks for the explanation
I trying to controlling the 3-phase motor like a galvo and it is running nice, but i have some troubles.. When i try to make a signal in just one motor, both are moving
They are comparting the DC power source.... What i need to do? I think i need to force the voltaje to go to just one direction and no return.. I was trying to do it with diodes, but didn't worked.. D:

Sourcegeek-

I have a box full of steppers- most harvested from printers or flatbed scanners(all free) some 4 wire and 5 wire too. SOMEDAY I will get around to finishing the stepper laser projector I started. I have one controller in kit form and another I bought complete- not real cheap but not much can be done without one.

Thanks Birock for the link-- that gives me more options.

GL

hak

If any body who cant get free steppers on thier own needs any I am more than happy to provide some in return for the postage and any new knowledge you can give me on this DIY laser project. i need help .

Ha, i want steppers and i can't get them but i don't have knowledges about this projects D:

Good luck