Floppy stepper motors

Discussion in 'General Electronics Chat' started by mrmeval, Jun 29, 2007.

  1. mrmeval

    Thread Starter Distinguished Member

    Jun 30, 2006
    833
    2
    I'll be looking online of course but thought I'd ask here as well.

    I have two floppy stepper motors. Each is from a different manufacturer but both have 4 pins and there are two pair on each that read 25 ohms. Are the pins that read 25 ohms the coils needed to run the stepper in on direction?

    Can these be driven with voltage applied to those pins? Does the voltage have to be a pulse or can it be human pushing button slow?

    Ok, I found a guide here:
    http://www.epanorama.net/circuits/diskstepper.html

    Thanks.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    I can't say for sure about those specific steppers, but steppers generally have current continuously applied - that is what lets them hold in place. The floppy steppers are rated for some level of current in the coils, but it's anybody's guess about that. They may run off five volts, or twelve. I wuld guess twelve, and I would limit current to 100 ma with an external resistor.

    Call one coil A and the other B. If you switch current from one to the next then the stepper should rotate. I'm used to working with 4 coil steppers, where the rotation can be controlled by the sequence you energize coils. I know that floppy steppers should go both ways, but I can't see how with only two coils, unless you have to also reverse the direction of the current.

    You could run the current through a SPDT switch and see what happens when you throw it back and forth. Reverse the polarity and see if it runs backward. Just watch the current so it doesn't cook the coils. It's easy to rig a flip-flop to do the same thing through a couple of FET's.
     
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