Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Stepper motor just vibrates and gets hot

  1. Dec 14, 2009 #1
    I have a 5-wire unipolar J835L. I have not been able to find a data sheet on it, but I have found this diagram:

    293yi5j.jpg

    also, the motor has the following information printed on its label:

    Uni-Polar, Bi-Filar
    120 Ohms
    7.5° per step or 48 full steps per revolution
    JARL J835L PM 24P

    I have connected a ULN2003A ("focus.ti.com/lit/ds/symlink/uln2003a.pdf"[/URL]) between my uC and the motor like this:

    [ATTACH=full]130959[/ATTACH]

    where:
    B = blue wire
    P = purple wire
    Y = yellow wire
    O = orange wire
    W = white wire

    I have tried driving the circuit in these two orders:

    Step POBY and PYBO
    1 1000 1000
    2 0100 0100
    3 0010 0010
    4 0001 0001
    5 1000 1000
    . . .
    . . .

    Where 1 has been verified to be 10v and 0 is 0v. I set each step and then wait for .1ms. The motor then just vibrates. Can anyone give me a pointer?

    Thanks!
    Sam
     
    Last edited by a moderator: Apr 24, 2017
  2. jcsd
  3. Dec 14, 2009 #2

    vk6kro

    User Avatar
    Science Advisor

    That delay of 0.1 mS seems too fast.

    Just for a test, try 500 mS.
     
  4. Dec 14, 2009 #3
    Could be a problem with timings or the run sequence. It could be going forward, then next step makes it go backwards.
     
  5. Dec 15, 2009 #4
    That was it! Thank you :)
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook