Sunday, 21 August 2011

My Parts List: Stepper Motors

Mendel Prusa needs 5 no. NEMA 17 bi-polar stepper motors. These seem to be easy enough to find, and can be bought super-cheap on eBay from a  number of Chinese sellers, but I found the ones I contacted were not too responsive about realistic postage costs when you ordered more than one. (The quoted cost of postage for 5 steppers was 5 times the cost of posting one - I don't think so!)

In the end, I bought them from my regular Australian supplier of all things Arduino, Little Bird Electronics for $17.19 each http://littlebirdelectronics.com/products/stepper-motor-with-cable

They arrived about a week after I ordered them - very nice units!
I have played with stepper motors before, but I had never had two (or more!) identical units to play with, nor have I used steppers with this much torque. Interesting to test them out by joining the ends of each set of coils together to feel the inductive load, and how when you close BOTH coils the inductive load gets even higher, but the stepper motor action becomes quite smooth (instead of "jumpy"). Also fun to hook two steppers together so that when you turn the shaft on one, the other follows with identical rotation as a "slave" unit - without any power hook up. (The motor you are turning effectively becomes a stepper driver for the "slave".)

Oh well - as they say - "little things amuse little minds"!