Very General ? 4-Wire/6-Wire

[cwoodall]

I ran across some stepper motors the other day that were $9.95 each. I can't remember the exact details, but they were about 3V, 3A, 1.8deg/step, NEMA 23. Looked to be single stack. These had 4-wires, not 6. I'm curious about drivers for 4-wire steppers as opposed to 6-wire steppers. I see a lot of driver "kits" that will handle 5, 6, and 8-wire motors, but I don't see much on 4-wire motors. What's up with this?


Thanks,

Curtis

[drk]

4 wire steppers are bipolar stepper motors while 5 and 6 wire ones are unipolar.
8 wire steppers can be connected as bipolar or unipolar.
And if you dont see much of bipolar stepper driver kits, u need to see more in the forums here.

u can make a lot of small bipolar drives and a lot of free circuits are available aswell.

[ger21]

If you want a kit, check out http://www.embeddedtronics.com They sell bare boards and parts lists.

[cwoodall]

Hmmmmmmmmmmm, just found the info. EAD (Eastern Air Devices) 2.58V, 3.0 A, 1.8deg, 140 oz.-in., 4-wire bipolar (.25" shaft out of each end x .75" long)..........They appear to be brand new.

I'm planning on buying the 200 oz.-in. package from HobbyCNC, but thought I'd take these, build my own driver board and have something to play/test with until I procure all of my serious stuff for a 3-axis router.

Just for curiosity, how big of a performance difference would there be between 140 oz.-in. as opposed to 200 oz.-in. in a 3-axis machine that mainly does wood (with a bit of very light aluminum/delrin)....?


Curtis

[drk]

Hi Curtis,

I dont know if I can answer correctly, but personally, I have never found 1Nm stepper motors useful. The prices of these motors are not very high and I would really suggest that you go for the 2Nm (approx.) steppers available in plenty on ebay or from automation direct if you have to stick to NEMA 23 size. Be sure to get the current ratings of the motors you plan on buy and look for bipolar drives which have microstepping and can handle those currents.
I had posted a link for such drives a few days back. You might wanna search.

But first find drives that can provide the current for the motors you choose.

Or you could just stick to the hobbycnc package.

Best of luck.



Dev

[buscht]

Curtis, the 140 oz-in will work, but stronger is better. I built my first machine with 110 oz-in motors and continually lost steps. I wasn't very happy, but upgraded to 269 oz-in motors and have been very satisfied.

http://www.xylotex.com/

[Evodyne]

Curtis,

Whichever motors you choose note that you'll get stronger performance with a chopper type drive vs. a non-chopper type. The chopper drives will typically have a higher supply voltage. They modulate this voltage to the motor so as to get a constant current. Because they initially apply a higher voltage than a standard drive, the current rises to a given value quicker. More current equals more magnetic flux and better performance.

Evodyne

[DukerX]

Correct me if I'm wrong here, but aren't unipolar (6 wire) steppers simply bipolar (4 wire) steppers whit a center "tap" on each coil?