Bipolar vs. unipolar stepper drive
- Thread starter rdoty
- Start date
Yes, you can drive unipolar stepper motors as bipolar. You can't always do the reverse; but some motors have eight leads.
If you are driving a unipolar as a bipolar motor, you simply don't use the winding center taps. The voltage requirement doubles.
The winding center taps are frequently red and green; the winding "end" colors are frequently yellow, orange (being one pair), black, and brown (being the other pair).
Green is the center tap for black/brown.
Red is the center tap for yellow/orange.
If your wire colors are different, consult your motor's datasheet.
If you are driving a unipolar as a bipolar motor, you simply don't use the winding center taps. The voltage requirement doubles.
The winding center taps are frequently red and green; the winding "end" colors are frequently yellow, orange (being one pair), black, and brown (being the other pair).
Green is the center tap for black/brown.
Red is the center tap for yellow/orange.
If your wire colors are different, consult your motor's datasheet.
This site is about the best for stepper information; http://www.cs.uiowa.edu/~jones/step/
Thanks for the clarification. I'm actually working with a bipolar motor but had some unipolar motors laying around and was curious.
One of the motors I have is listed as Bipolar (series) and has six leads. Obviously one of the leads is a center tap but my question is: presuming you connect the two end leads to the driver output what do you do with the center lead and what is it's purpose?
One of the motors I have is listed as Bipolar (series) and has six leads. Obviously one of the leads is a center tap but my question is: presuming you connect the two end leads to the driver output what do you do with the center lead and what is it's purpose?
Like I stated before go to the Jones site and read, it will explain it all.
A 6 lead motor is a 'hybrid' it can be wired as a bipolar or a unipolar. The center taps are just taped on the end to insulate them when using as a bipolar.
Unipolar steppers are easier to drive because the center tap supplies the +V, and the individual coils are energized by grounding one of the coil ends in a sequential fashion (single stepping). This can be done by using four MOSFETs or Darlington transistors.
With a bipolar stepper motor, you need to reverse the direction of current through the coil. Therefore, each coil must be controlled by an H-bridge configuration; you need two complete H-bridges to drive a bipolar stepper motor.
With a bipolar stepper motor, you need to reverse the direction of current through the coil. Therefore, each coil must be controlled by an H-bridge configuration; you need two complete H-bridges to drive a bipolar stepper motor.
