help on 10 wire stepper motor

Hi,
I have a surplus stepper motor which I plan to use in robot project. Unfortunately I have not been able to understand its wiring. (It has
10 wires coming out of it.). So I dared to open it up to look inside so that it might clear the matter further. I have not had much success after opening it either. There fore this request for help.
This is what it says on the motor:
Model: A2279-9214 Vextra Stepping Motor 4-Phase 0.9DEG/STEP U.S. PAT. NO. 4,385,247 DC 12 V 0.3 A RX7 15859
ORIENTAL MOTOR CO. LTD. MADE IN JAPAN.
I took photos of it in the dis assembled state. Links to those are given below:
        http://s71.photobucket.com/albums/i148/chills_01 /
Please note that:
1. There are 8 poles on the stator. 2. The rotor has been divided into two parts. The "teeth" on each part are not in line, the valley on one, is lined with the peak on the other. 3. There are 10 wires coming out of the motor.
I have scoured the net in detail. The model no. is not mentioned in the "Obsolete" section of the Oriental Motor website of europe/ singapore.
Having exhausted all my resources I have come looking for help here.
Any help is greatly appreciated.
Regards
Zeb
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On 25 May 2007 03:32:18 -0700, the renowned zeb

Have you tried probing it with an ohmmeter?
Best regards, Spehro Pefhany
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I think, if you try a continuity test that you'll find: There are 2 sets of isolated poles i.e. 2, four pole, 5 wire steppers. With a multimeter on Ohms you will probably find very high resistance between any one wire and 5 others - that is they belong to the 'other set' and a fairly low resistance between any particular wire and the other 4 in the same set. If you measure each wire to the other four in a set then one wire will show half the resistance to the other combinations - that is the common for that set and the other 4 are the poles. Pole to Pole measurement will give you the resistance through 2 poles. Pole to common is only 1 pole. you'll just have to find the correct sequence by trail and error then.... It should run with just one set connected - but by using both sets alternately you'll halve the step size. Hope this helps. It's only a (semi) educated guess.
Jon.
zeb wrote:

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The patent itself can be found at this link: http://www.google.com/patents?id=cNo1AAAAEBAJ&dq=4,385,247
As diagrammed, I count only 8 wires for 8 poles, but I'm guessing the "extra" 2 wires are a result of it being wired in 2 sets of 4 poles each, which would give you 5 wires per set. Each 2 poles within a set has a common wire between them. 4 poles within a set are wired in series, with one wire coming out between each 2 pole - giving you a choice of how to wire it - unipolar, bipolar, etc.
Hope that helps and everyone *please* feel free to correct me if I am leading him wrong ! JCD
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If you really want the pinouts for the Motor then you could just send an email to snipped-for-privacy@orientalmotor.com or call them at 1-800-GO-VEXTA (1-800-468-3982).
Just a thought
The Hirudinea
On Fri, 25 May 2007 13:23:29 -0400, "Pogo"

wires are a result of it being wired in 2 sets of 4 poles each, which would give you 5 wires per set. Each 2 poles within a set has a common wire between them. 4 poles within a set are wired in series, with one wire coming out between each 2 pole - giving you a choice of how to wire it - unipolar, bipolar, etc.

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zeb wrote:

Because the plate says it's a four-phase stepper (rather than a five phase stepper, and the pics seem to bear that out), then I'd surprimse two of the wires are for some sense function. The other eight are typical for a four-phase stepper where the wiring does not use commons.
-- Gordon
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(Snip)

(End Snip)
A good deal of understanding on the operation Of stepper motors can be found at http://www.cs.uiowa.edu/~jones/step/
Unfortunately disassembling stepper motors in most cases KILLS the motor or at least severally weakens them see this reference http://www.servorepair.com/servo_talk_sample.htm
A lot more information on why one should NOT disassemble stepper motors (specifically) can be found on 'Do It Yourself CNC' related sites such as http://www.cnczone.com and other CNC discussion forums / groups.
In the future, use a Ohm Reading on a meter to determine what connects to what.
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