8 Wire Stepper

Discussion in 'General Electronics Chat' started by gee_emm, Jul 17, 2009.

  1. gee_emm

    Thread Starter Active Member

    Jan 16, 2008
    Hello all. I have an 8 wire stepper motor, and am trying to figure out the leads. 3 wires (red, white, black) when touched together in any sequence puts resistance on the motor when turning by hand. The other 5 (odd ball colors) do nothing when placed to any of the wires. example.. blue to red white or black or any of the remaining 4. Ive looked online for ohm metering, continuity tests etc. but no luck figuring them out. Any other suggestions are appreciated.
    Thank you
  2. AlainB

    Active Member

    Apr 12, 2009

    A 8 wires (and a 6 wires) motor can be use as bipolar or as unipolar stepper motor. Would be easier to make a simple home made driver for unipolar operation.

    For unipolar connexion, use a Ohms meter to isolate each of the four coils. You should have a reading only when you are measuring the 2 wires of the same coil. Connect together one wire of each coil.

    For testing the sequence, connect one side of a battery (2 - 1,5 volts or a 9 volts battery should be fine unless it is a huge motor) to these connected wires and touch each of the 4 other coil wires with the other side of the battery, one after the other. You should soon find the correct sequence. Putting a piece of scotch tape on the shaft will help to see how the motor behave.

    If 4 wires are solid color and the 4 other are 2 colors, like Red solid and Red/white 2 colors, this should indicate one coil. If so, connect at your choice all solid or all 2 colors wires together.

    Please refer to this link for a more precise way of doing it. 8 wires stepper motors are not the easiest one to investigate.


    Last edited: Jul 17, 2009
  3. russ_hensel

    Distinguished Member

    Jan 11, 2009
  4. SgtWookie


    Jul 17, 2007
    It also might be a 3-phase motor or perhaps a brushless DC motor. The "oddball" colored wires might be a rotary encoder. Hard to say.