Ok, I've hurt my head thinking about this. I am trying to determin the Maximum power usage of my Stepper motors. They are current limited at 3 amps per phase, wired bipolar parrallel. Since there are two phases does that mean the motor will be using 6 amps total, or is only one phase energized at a time (in full step mode). I have a 48V supply I'd like to use but it's only 400 watt. I can tweak the voltage down further but if the steppers are using 6 amps each then thats a peak of 864 watts as is and I need a bigger supply. I am currently using a 500 watt 25V supply which is plenty either way. I did find some 48V server power supplies rated at 1300 watt for only $60 or so, but I don't want to spend any money if I can get away with it.

So, to reask the question. In full step mode, are one or both of the coils of a stepper running at maximum current?


I realize that the effective power is much lower when the stepper is idle, since it only has the DC coil resistance to deal with and the chopper circuit will limit the power sent to the coils to limit the current.

 

Never mind, I figured it out when I stopped trying to think about it. In full step mode only one phase is energized at time and in a half step or better mode the phases will be energized at lower currents so that it equals out to the max current per phase in total. I still might get that 1300watt supply if I get a chance but I'll just tweak my 48v supply down to 42V and will have plenty of power.