Ok. I have some 6 wire unipolar motors that I want to run using bipolar drives. There are basically 2 ways to do it. Either use center tap and one end wire from each coil (half-coil), or use the end wires and don't use the center tap (full-coil).

I am wondering about a couple things.

First, the current rating. To start with, I will be using a chopper type bipolar driver. The motor ratings are based on using the motor as a unipolar motor, so with the half-coil option it still remains where only 1/2 of each coil is energized at a time, so the current rating will remain at the 2.9A unipolar rating. Using option 2, the resistance will double and the inductance will be 4x. With double the resistance, it seems that from V=I*R that the current rating should be 1/2 of the unipolar rating, or in my case 1.45A. However, in looking at several 8 wire motor specs and the current rating for different wiring schemes, it appears that the current rating for an 8 wire motor in bipolar series connection has a current rating of 0.7 times the unipolar connection rating. So, if I chose the full-coil option what current rating do I use? 1/2 of the unipolar rating or 0.7 times the unipolar rating?

Second, if I use the full-coil option, the inductance will increase by a factor of 4. This obviously means that the motor would require twice the voltage and would be "slower" due to the inductance increase. I seems that it would also have a higher torque at lower speeds though. Is my thinking here correct?

Finally, is one of these methods preferred over the other, and for what reason.

Thanks in advance.