simple stepper power question.

is there a formula to determine power of a stepper ?

I have a Slo-Syn NEMA 34, 1.7 volt, 4.5 amp
single stack.


Also, has anyone put together a simple test
for stepper power ? Seems like a weight,
and a long crank arm with holes drilled
each inch would allow one to keep moving
the wieght farther out until the motor
started missing steps.

Dave