Stepper Motor Help

No problem. We'll get you going.

1) How many wires are there coming out of the motor? 2) What is the resistance between each pair of wires? (Make a little chart and post it) From that, we can make some guesses as to the internal wiring, and get you going.

Do you want to build your own controller or do you want to buy one?

Do you want smaller than 1.8 degree steps?

Do you want a LOT smaller than 1.8 degree steps?

These answers will help us help you choose a controller.

Hi Alan, Thanks for your help.

There are six wires from the motor. They are attached to a connector in this order : black, red, r/w, white, green, g/w.

Ignoring polarity, which was found to be unimportant, there are 14 combinations.

Disregarding the opens the resistances are: green to white -3.6 Ohms g/w to white - 3.6 Ohms green to g/w - 7.2 Ohms

black to red - 3.6 Ohms black to r/w - 3.6 Ohms red to r/w - 7.2 Ohms

Seems to me that white is the ct for one phase and black is the ct for the other phase. Black's phases are red and r/w, white's phases are green and g/w. My assumptions could be wrong. I can build the controller, or buy one. I would like to see a schematic and decide. Very Best Regards, Tom

---------------------- Keep track of that, and which end is which.

---------------------------- White is common/center-tap.

------------------------------ Black is common/center-tap.

Yup, this is a unipolar stepper, and it needs the common positive supply connected to black and white, and then each arm needs an NPN or else an N-channel MOSFET to ground. Then the base or else gate to ground is the control for the motor. Only with red and one with green should be activated at the same time. The four states of this will operate according to the typical quardrature truth-table.

-------------------- Here:

-Steve

Snip my original

If the black and white wires are insulated from one another, the OP could probably leave the black and white wires disconnected and just use it as a bipolar stepper.

---------------- True, but who wants to? Unipolar's are easier to control, precisely because you don't NEED H-Bridges!

-Steve

Hey, I was just sayin'. I suppose that someone that wanted more output torque might want to drive it as a bipolar. You still NEED output drivers, it's not like H-bridges are a whole order of magnitude more complicated.

----------------- Okay, but a unipolar's coils are typically higher resistance than a decent bipolar, and have less torque when treated as bipolar.

-Steve