the specs on the back of the stepper are 4.0v/phase,1.6A/phase,2.5 ohm/ phase1.8 deg step. i can't believe that it only runs on 4 volts. the power to the control board of the equipment it came off of runs on 24 volts.so i thought it would run on 24 volts. i started out with zero volts and brought the voltage up until it started stepping and it was way over four volts before it started to step. unless i have too much load on it? i will have to try with a fresh motor. right now i have to stop and clean up my lab. i can't move around and my bench has too much stuff on it.