9 pin stepper motor challenge

Discussion in 'General Electronics Chat' started by franzschluter, Apr 2, 2010.

  1. franzschluter

    Thread Starter Active Member

    Jun 1, 2009
    Hi guys.

    I'd like to ask some people here if they have ever heard or encountered this problem of mine..It is somewhat strange and very odd to me.

    Task OT:
    Building EDM-Wirecut machine. Bought an old wirecut machine structure with some parts on it for salvage to retrofit. Included is diagrams.

    There are X and Y axis servo motors which seem very strange to me. They have 9pins... How do I identify this type of stepper motor? There is no label no current rating. Absolutely nothing written on it. I would love to use these babies since they are already perfectly fitted into the system and me only needing to make or purchase a driver circuit for it to attach to an Old computer with LPT port.

    My biggest problem here is where to begin with this 9 wire setup. Like knowing what phase angle it will produce in unipolar mode and what stepper driver card I should buy for this stepper motor?

    Below I have included some images.
    In case it is hard to read there are 9 pins.
    Ohmic readings are 18 ohms and 9 ohms.
    There is 1 common which is pin 5 which connects to 1 side of the winding.

    For example pin 2-3,2-4,2-6,2-7,2-8,2-9 is 18 ohms except pin 2-5 which is 9 ohms.

    Best Regards Franz
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    From the last pic, pin 5 has to the common to the other 8 pins. Is there any indication as to voltage applied to the motor? It looks like pin 5 is the voltage source, and the motor is stepped by applying ground to the 8 windings.

    But if 5 only has a reading to pin 2, the motor is probably toast. Each pin should be like 2 - 5, reading 9 ohms.
  3. franzschluter

    Thread Starter Active Member

    Jun 1, 2009
    Sorry I didn't explain it properly.. Any pin measured between 5 and the other 8 pins is 9 ohms... :D

    What I don't understand is the recovery circuit and prom. It is connected to pin 2 and 4. I haven't heard or read any articles on current recovery circuit nor how do they work.

    I am confused which pin to connect to where and how to determine its phase angle and most of all their sequence order. And sadly there is no name plate nor is there nothing engraved written on it to determine typ or any ratings at all. Except on the diagram it says its connected to a REX step motor driver probably custom built for AGIE wirecutters. This stepper motor is responsible in moving a very big and heavy table I reckon 80~100kg. It drives a lead-screw to move each axis in their respective direction. There are even ventilation mounts on the bracket to cool the stepper motor meaning it can get hot.

    Hope this helps on solving this mystery.:confused:
  4. rjenkins

    AAC Fanatic!

    Nov 6, 2005
    The first drawing shows two specific connections, plus the rest of the connections coming from the left and top changing to dotted ...

    This typically means the example shown is repeated.
  5. shortbus

    AAC Fanatic!

    Sep 30, 2009
  6. franzschluter

    Thread Starter Active Member

    Jun 1, 2009
    Giving up.. I'll just buy a new stepper motor for this application.