Can anyone tell me if it's OK to use a "unipolar" stepper (i.e. one that
has center-tapped coils) *as* a "bipolar"?   i.e., just ignore the center
tap and use the two series-connected coils as one.  I realize that this
might not be as low of a resistance value as what I might see with an
actual "bipolar" single-coil device, but the question is... will it work?
My instinct is that it should, but perhaps with less startup torque.  What
say you all ?
Thanks!
Jim


Is it OK? Sure.

Are you outside the manufacturers specs? Probably.

Will it void the warrantee? Only if you had one to start with. :-)

If the motor is a 5 wire type, the center tap on the two phases is
connected internally and you'll have problems.

If the motor is a 6 or 8 wire type you should be fine. IIRC I saw one
datasheet for an 8 wire motor that detailed connecting it in unipolar mode,
series bipolar mode and parallel bipolar mode.

There's a lot more details than I can write in an e-mail, but the different
modes have different effects on torque and speed. Basically related to the
inductance of the windings.

-Denny

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