Specs for an unknown stepper

[millman52]

Is there a way to calculate V & A on a stepper motor of unknown origin?

[pminmo]

Is there any information on the nameplate of the motor? Manufacturer, or anything? If not you can partially start with physical size, you can count the number of wires, you can measure coil resistance.

[millman52]

They are square black cased NEMA 34 steppers, 4 wire, they read 1-1.1 resistance. There are no markings what so ever on the cases.

This reading was taken at the end of 25' of 16 ga fine stranded wire with soldered connections at the motor.

[pminmo]

What is the depth of the stepper? Compare the size to the nema 34's here: http://www.kelinginc.net/SMotorstock.html

That will give you a starting point, beyond that it becomes trial and error to most people. Start with a lower safe current, monitor the motor temperature, and adjust the current upward.