I thought this was pretty cool. I was reading an article from Machine Design (T connect for steppers 10/26/2006) that highlighted a recent patent from Lin Engineering (~2003) on a new way to hook up those 8 wire stepper motors to any bipolar drive. The performance is approximately half way between a series and parallel connection. They claim the connection causes "the mutual inductance of the two windings now becomes series opposing." Whatever that means. What I see useful is to sacrifice some low end torque for mid range torque. Who wouldn't want a little extra mid-range torque? Well anyway I hooked up a big nema 34 stepper to one of my drives and it happily runs, although I can't comment on the performance differences, still need to get my machine built. Here's a wiring diagram:
P.S. anyone know why the image attachment tag isn't working in this subforum?