Well, thanks to scavenging I have both unipolar and bipolar drives. (More unipolar than bipolar, though) My biggest steppers (identical to yours) are unipolar.
HOWEVER...I understand that the unipolar drives are just bipolar drives with an additional center tap on each coil, hence the 6 connections instead of 4. I also understand that they can be driven in bipolar mode, by simply ignoring the center taps.
Since there are single chip solutions for driving both unipolar and bipolar motors, and I'm going to be building my own driver, I just want to know if I should build a unipolar or bipolar unit, first... Which would be the better approach? Would there be any down side to running the unipolar steppers in bipolar mode with a bipolar driver...that sort of thing.
The up side is greater efficiency, and 3 bit microstepping (the unipolar driver chip supports full and half steps, while the bipolar driver chip supports full, half, quarter, and eigth steps). There is usually a down side in decisions such as this...I seem to be overlooking it, somehow.
-- Chuck Knight  |