Re: [CAD_CAM_EDM_DRO] Uni-polar or bi-polar, which??

In a message dated 4/2/2007 4:15:42 P.M. Central Daylight Time,
squidsrus85@... writes:

I have found uni-polar and bi-polar stepper driver boards. <<
Dave: These are for the corresponding TWO kinds of stepper motors. The
"unipolar" stepper has two "tapped" windings, only one HALF of each of which
conduct current at any given instant. The "bipolar" has two windings which
conduct current in alternate directions, but "all the time". Thus, the bipolar
motor is inherently more efficient. The newer "square" bipolar motors have
much more torque that "equivalent current-drain" "round" motors. If money is
not an ABSOLUTE factor, go with bipolar! The Gecko and Xylotex drives are
ONLY for bipolar use. It IS possible to wire most unipolar motors in such a way
that, for example, by "using only half the copper", they will work on a
bipolar drive, but inefficiently. Fairly uncommon "eight-wire" motors can be
wired to operate on EITHER type drive, but you have to "know whatcha doin!"

Lotsa luck! Jan Rowland








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