# Stepper Motor Current

I have rescued a stepper motor from the trash heap by tearing down an old(1999) laser printer. I can't seem to find any info on it on the internet though I did look. The label on the motor says:

Rotory Digital Actuator 2x22
TYPE MSDE048C51 RH7-1098 01
PHASE 4 VOLT 24 OHM 14
Sankyo JAPAN

If anyone can point me to a datasheet or other info on this thing, I would really appreciate it. Among other things, I'm wondering if I can I use ohms law and divide the 24 Volts by the 14 Ohms to get 1.7Amps as the current that this will draw?
This is my first foray into steppers and I'm just learning about electricity too so please forgive the ignorance. Hopefully it's a temporary malady! I did pull the power supply from the printer too so my plan is to use that to power the motor so this is just more for my understanding than anything.

Thanks for any help.

Sam

if I can I use ohms law and divide the 24 Volts by the 14 Ohms to get 1.7Amps

Yes, that's correct. Remember that this is an inductive load, and you must fit back-EMF protection diodes to the driver circuit.

Does that(1.7Amps) apply per winding or is that the overall max the motor will draw or are these values one and the same? I tested the resistance between wires and discovered that the resistance between what I guess you would call the center tap of a winding and either end tap is about 14.5Ohms. I suppose this comes down to the question of does there ever arise an occasion when more than one winding is energized at the same time? Perhaps to hold a position or something?

Back to the tutorial for me...

Does that(1.7Amps) apply per winding or is that the overall max the motor will draw

Per winding, I'd say. But if you only ever energise one winding at a time, that's the same as the overall current draw. If you energise two windings at the same time, for half-stepping, you'll get double the current draw. You must energise at least one winding all the time, for the stepper motor to hold a stationary position.

Oh, that's great information.

Thanks a bunch!

Yes, you can have two coils energized at once, if you want (it's your choice). Here's a quick intro for you:

http://www.doc.ic.ac.uk/~ih/doc/stepper/control2/sequence.html

Ran