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View Full Version : current ratings of an arbit stepper motor



DceRobo
08-22-2006, 03:35 PM
i have a pair of SANYO DENKI NEMA 17 motors 41mmX41mm. (code:103-548-0250). i brought them from a scrap market in delhi for Rs. 100 each. the problem is there is no mention of ratings on it. all it says at the back is 3ohm/winding and 1.8degrees /step. i tried looking on net for a long time to find the rarings, but cud not get it. sanyo denki did not reply either. Since it is the 1st time i m working with steppers, cud somebody who has used these pairs before please help me with the voltage and current ratings for the same? i am using them for a maze solving robot.

a photo of it is on tha site: http://www.kapaza.be/detail/3006176/3_stuks_SANYO_stappenmotoren.html

thanx

ppppking04
08-22-2006, 07:22 PM
Generally 3 ohm steppers are for 5 volts...

As far as i know...

DceRobo
08-23-2006, 12:00 PM
thanx.........

which wud mean a current consumption of around 1.67 A per motor, i guess.... i planned using ULN2803 before but as they have a max cureent rating through one darlington pair to be around 500mA, what do u suggest i use??? also what voltage should i drive them at?? should 12 V DC be good enough? i need to make a mobile robot....

ppppking04
08-23-2006, 03:08 PM
I have not used 3ohm stepper motor but have friends who do so...
So trust at your own risk...

Nevertheless the way to drive a higher current rating motor is usually chopper drive...(Google for it...lots of resources)
This circuit restricts the current through the stepper to a settable value using a higher voltage than rated...So it should work fine for your case...

Btw what IC u using...my suggestion is you use L297/298 Check its datasheet...

DceRobo
08-24-2006, 12:55 PM
i have unipolar stepper motors, instead of going for L298, i plan to go for UCN5804. its datasheet says it will be pefectly fine. although i am also looking at UDN2544 as an option. seems to be a pretty good IC, as its datasheet says. but then probably vikas has used 5804s earlier, so i think i can rely on them. (the brilliant micromouse tutorial mentions it.). i think current limiting resistance with 5804 might do a good job for me.