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rotate
02-16-2008, 10:11 PM
(after posting this thread, I realized that the title is misleading. It should have read, "using unipolar stepper motor with bipolar driver")

I got some large unipolar (6 wires) stepper motors from a surplus store, but my driver is able to drive only bipolar stepper motor. After looking at the energizing sequence, I figure that I can convert the unipolar to bipolar using 4 diodes.

I haven't seen this being done anywhere, and I was wondering if I'm overlooking something. I'd figure someone here may have done this. Thanks.

mayfieldtm
02-17-2008, 12:40 AM
Rotate:

Ask this on either of these groups.
Both are excellent groups with great people.
Both are orientated towards the home shop.

http://finance.groups.yahoo.com/group/geckodrive/

http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/

Tom M.

Evan
02-17-2008, 02:35 AM
I got some large unipolar (6 wires) stepper motors from a surplus store, but my driver is able to drive only unipolar stepper motor.

You are going to have to clear up this sentence first. The number of wires isn't a certain indicator of the type of stepper.

rotate
02-17-2008, 01:16 PM
You are going to have to clear up this sentence first. The number of wires isn't a certain indicator of the type of stepper.

Yes, that made no sense. It was late and I wasn't thinking straight. I must have subconsciously adverted in using the word bipolar :)
I've made the correction.

studentjim
02-17-2008, 02:41 PM
rotate, if you pm me I can give you the wiring diagrams for the 6 wire motors in unipolar or bipolar. Jim

lenord
02-17-2008, 02:50 PM
Evan,

R U sure ? I have always "known" 5, 6 or 8 wire steppers are unipolar. 4 leads are bipolar.

:confused:
Lenord

studentjim
02-17-2008, 03:22 PM
6 or 8 wire steppers can also be made bipolar

GKman
02-17-2008, 03:57 PM
rotate, if you pm me I can give you the wiring diagrams for the 6 wire motors in unipolar or bipolar. Jim

Can the rest of see it, or is it TOP SECRET?

rotate
02-17-2008, 06:07 PM
Evan,

R U sure ? I have always "known" 5, 6 or 8 wire steppers are unipolar. 4 leads are bipolar.

:confused:
Lenord

To the best of my knowledge:

- 5 or 6 wires is almost always unipolar.

- 4 wires is almost always bipolar.

- 8 wires can also be bipolar or unipolar, but most likely bipolar.

studentjim
02-17-2008, 06:41 PM
Can the rest of see it, or is it TOP SECRET?
I'm sorry for not posting the diagram, it is not top secret, but I'm not sure how to add an attachment on this forum

TGTool
02-17-2008, 07:20 PM
I'm sorry for not posting the diagram, it is not top secret, but I'm not sure how to add an attachment on this forum

Was once in that same position myself. The sticky thread at the top of the list shows how to post pictures in threads or include links to pictures using photobucket.

Dawai
02-17-2008, 11:43 PM
The twelve lead unipolar nema 42 steppers on my bridgeport are running bipolar, the center tap for unipolar connection was just isolated, being in the center of the winding, it serves no purpose for a bipolar drive, just 4 wires from the drive down to the terminal strip, and six wires go out to the motor, then connect to the 12 motor leads inside the motor.

More confusing? the second set of leads inside the motors have polarity dots so cross polarity connection is not done. You can ignore one set of leads altogether and the torque is not reduced significantly. Save the other set for when you burn the first set out.

Evan
02-18-2008, 07:12 AM
- 5 or 6 wires is almost always unipolar.

The bipolar steppers on my mill are six wire. It all depends on how the coils are wired and what wires are brought out.