I am having a problem in a Gear Shaving machine(HURTH), after every 4-5 cycles there was a warning of infeed position not reached. and after 15-20 minutes the m/c use to work efficiently.I checked for all the possible conditions but I did not reach to any conclusion. When there was warning of infeed position not reached except vertical feed all the axes could be moved. So I checked the vertical axis stepper motor(brake),it was very hot,I want to know that how can be current measured of a stepper motor?