stepper motor wire identification

Thread Starter

raidermanz

Joined Aug 14, 2007
32
I am trying to configure a stepper motor and create my own driver, more as a learning experience than anything. I mean, I know I could buy a driver relatively cheap, but then I wouldn't learn anything. And heaven knows if there is one thing I could use, it is to learn something. Anyway, I have a stepper motor (selected blindly), and a pic microcontroller, some transistors, and some diodes. I understand how to identify the wires as to which ones are connected to each common through the resistance method. However, I am still scratching my head about which order to energize them. I am not needing a lot of speed, or torque, but rather, would like to feel comfortable when I proudly declare that I know how to build a driver for a stepper motor. Could anyone offer assistance? I know that the yellow and brown wires are common with the white wire, and the blue and red wires are common to the black wire. Beyond that, I might as well be a 10 year old looking at boobies...I think I should know what to do next, I just can't bring my self to touch anything!!
 

Thread Starter

raidermanz

Joined Aug 14, 2007
32
but, (referring to the link), how do I know which wire is A, or A-. If I energize A- and B- as the first step it will work, but will it still work if I energize A and B-, then A- and B-, then A- and B, then B and A. I don't know if it makes a difference, but it boils down to I know the difference between A wires and B wires, but not the difference between A and A-, or B and B-. Will it work either way?
 

shortbus

Joined Sep 30, 2009
10,045
While I'm all for learning, doing a stepper driver with a PIC generally isn't something that allows it to be used in something like a CNC machine. Or with other software.
As a stand alone driver just to make a motor turn you would be OK. But when it has to interact with existing programs its easier to use a real driver.
 

Kermit2

Joined Feb 5, 2010
4,162
get a battery about 1/2 the voltage of the motor. A single cell (1.5V) if its a low voltage motor.

Put the negative lead on the center tap and touch the positive to each of the two coil ends one at a time and tag the end which makes the motor turn clockwise.

Then do the same for the other coils.

Now you will have the wires identified to work together as a motor. If you find the motor turns the wrong way when you connect up your circuit, simply reverse the motor leads of each coil and leave the center taps alone.

Edit: let me be clear. the motor won't 'motor' as traditional motors do, but it will try to move in one direction or another, although you may have to observe closely to see it.
 

Thread Starter

raidermanz

Joined Aug 14, 2007
32
Thanks to everyone for all the help. Sequencing the wires independently helped me identify the "firing" order to make the motor move. I am now armed with enough knowledge to do harm. I am sure with every puff of smoke I will get smarterer and smarterer. Again, thanks to everyone for their help.
 

John P

Joined Oct 14, 2008
2,026
Now you will have the wires identified to work together as a motor. If you find the motor turns the wrong way when you connect up your circuit, simply reverse the motor leads of each coil and leave the center taps alone.
No, that won't work. Reverse only ONE pair of leads.

If you reverse 12341234, you get 34123412, which is just 1234 again, shifted 2 steps.

But 12341234 changed to 32143214 actually reverses the order of the coil excitation (only reversing 1 and 3, not 2 and 4).
 
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