I dunno.. you've kind of exhausted my repertoire of stepping motor
knowledge.

Is it perhaps a five-wire motor? If the two windings are tied together
at a center tap then your controller might be getting confused. Such a
motor would work if you only drive one winding, but when you drive
both, you'll be bypassing some windings.

wrote:
firstly,thanks for your response.i am not using pulse width modulation
for generating micro-stepping currents(that option in my drive stands
disabled...after your mail i tried enabling it and tried to run my
motor at maximum frequency of 40khz all the way down to 1.25khz...there
was no difference.same old story).could you think of any other
solutions to this problem.for ur info my stepper motor is of 0.16 amp
peak,5volt 1kg torque,1.8degree step angle,30mm diameter rating.
also another motor of 0.65 amp peak,24volt,1.8degree
step angle,80mm dia worked fine with the same drive(ofcourse with
different current settings).help me out on this please