Re: [CAD_CAM_EDM_DRO] RE: Stepper questions

On Wednesday 03 May 2006 11:17 am, Alan Marconett wrote:

> That's an interesting point! I don't recall reading anything like that, I
> could be wrong. Basically the windings do not interact as far as I know.
> Actually, one would think that "turning around" a winding, as in a bipolar
> drive would take longer. The field would have to collapse before it could
> build up in the opposite direction. Therefore wouldn't a unipolar drive,
> with its four windings have the advantage?

Ah, but the key here is "rate of change" -- the faster you can get that
magnetic field to change, the faster that motor is going to respond. And in
a unipolar setup, you're looking at either energizing a winding in one
particular direction or not. In a bipolar setup, on the other hand, you're
effectively looking at reversing the direction of the applied voltage, which
means almost having the effect of twice the applied voltage, therefore
tending to increase how fast those magnetic fields are going to switch
themselves around, since higher _difference_ in voltage gives you more
current flow and a faster rate of change in the magnetic field.

Or at least that's my understanding of it. :-)

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