Re: microstepper drives

[mooney@aps.anl.gov (Tim Mooney)]

Larry, re...

> > (Around a third of the microsteppers in use by SRI-CAT are in
> > applications that really just need bipolar drivers.)
> 
> I am a little puzzled by the above comment.  What is the problem with
> uni-polar drives that can be solved by either a micro-stepper or a
> bipolar drive?   

Bipolar drives can use both windings of each motor phase either in series
or in parallel, while unipolar drives use one winding at a time.  For this
reason they can produce more torque given the same motor and current limit.
Also, because they can be wired differently, you can select high torque at
low speeed (series) or at high speed (parallel).

Tim Mooney