Stepper Motor Rating

[moki]

I hope someone can help me! I have 2 stepper motors from an Epson Stylus Color 400 printer. The motors have 17PM-K212-P17 and P/N EM-257 on the label. I have visited the Minebea website. They list a 17PM-K249B bipolar motor in the pdf files. According to the website 17 is the size of motor, P is type of motor, M is the step angle, K is type of lamin, 2 is motor length, and 12 electrical variation. The website is :

Hybrid Stepping Motors - Custom-made

The Epson manual says: Drive Voltage - 42v. 7.8 ohms 4 phase /200 pole stepping motor. What is the current rating? Can I simply divide 42v by 7.8 oms? This will give me a current of 5.3A. Seems a little too high to me.

Will appreciate any help.

Thanks

[H500]

5.3a is definitely too high. I would guess 500ma for a motor that size, with that resistance.

[moki]

Thanks for the reply. Managed to find some info on the net. It is rated for 700mA. Now, will I have supply full 42v to achieve a current of 700mA?

[H500]

The voltage rating is suspicious, but 42 volts would be reasonably good regardless of its rating. Of course you should use a chopper drive, or you might burn out your motors. Keep in mind that those are very weak motors. For cnc, motors usually take 3-6 amps.

[moki]

Want to build a light machine for PCBs, plastic and maybe wood. Will try them out when I am ready. I will more than likely try and get unipolar motors. I am busy putting together a 3 axis controller from Chromationsystems.