Determining motor winding wires

Thread Starter

crazybuoy

Joined Sep 19, 2010
77
I have a Unipolar motor (as I think because the motor has five wires) and there is 4 ohm resistance between any two wires. How is it possible?. What may be the common wire?

I don't know how to determine motor common wire and two winding wires. I did not yet apply any voltage to motor.

There is not any sticker on motor to show its specification.
 

Thread Starter

crazybuoy

Joined Sep 19, 2010
77
color of wires - Blue Red Black White Violet

I did not used it ever before, I just bought it from motor market. And I also did not apply voltage to it yet.

Image of motor is attached
 

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MaxHeadRoom

Joined Jul 18, 2013
20,652
Can you feel distinct resistance spots ever couple of degrees when you turn it by hand, if a stepper motor it has an odd number of wires?
Max.
 

Thread Starter

crazybuoy

Joined Sep 19, 2010
77
Yes, I can feel it clearly. I checked it again, the resistance among all wires are still same.

Is it burnt and all wires are short together?

Update: I opened the motor shaft, there was not any burning sign in winding.
 
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Thread Starter

crazybuoy

Joined Sep 19, 2010
77
Got the point. I think my stepper motor is of following type, Please check attached image.

But measurement of resistance is not good. I don't know what to do with this motor.
 

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Last edited:

shortbus

Joined Sep 30, 2009
7,670
Update: I opened the motor shaft, there was not any burning sign in winding
I don't know what to do with this motor.
Usually if you open/take apart a stepper motor you might as well throw it away. They are very touchy to get the parts realigned so that they will work when this is done. When they are manufactured they have fixtures that hold all of the parts in the correct position and it will be just pure luck to do by hand on a work bench.
 

shortbus

Joined Sep 30, 2009
7,670
Another issues some have had, if you remove the rotor without using a 'keeper' you can de-magnetize it.
Max.
A question on this, aren't steppers rotors based on rare earth magnets? I thought the rare earth magnets weren't as prone to "open pole"(best word I could think of) demagnetization, unlike alnico or ceramic type magnets. But do agree that opening a stepper is not a good idea if you plan on using it.
 

MaxHeadRoom

Joined Jul 18, 2013
20,652
A question on this, aren't steppers rotors based on rare earth magnets? I thought the rare earth magnets weren't as prone to "open pole"(best word I could think of) .
I would have thought so, although I have never dismantled a stepper, I have quite a few servo's with no harmful effects without using a keeper, just going by anecdotal reports that mention it, including the Gecko Co personnel.:confused:
Max.
 
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