Hello Guys!
I was looking a lot for a bipolar driver for my cnc.
I couldn't find any good ones.
What i need is full pcb(of the driver for 3 motors) with lpt port(dosen't have to be). It would be great if the ic was l298. Got a few of them laying around my workshop.
Thank you!
ps. Don't worry about my motors, they're compatible with l298 . 
Assuming your motors are stepper motors, the L298 is a poor choice for driving them in a CNC machine. Use a modern stepper motor driver chip instead, that way you can step them faster without them overheating. Also the driver chip will run much cooler. If your motors need 1.5A per winding or less (which I guess is probably the case if you were going to use L298), then I suggest a board based on the A4988 chip. You can get these boards inexpensively from Pololu or eBay.
bartuss12:
ps. Don't worry about my motors, they're compatible with l298 .
That's not the issue, what sort of performance are you expecting (rpm) and what motors have
you got? If they have high-inductance windings you'll have difficulty(*) and you'll not get
much performance anyway without a chopper driver. I think there's a chopper pre-driver
for the L298 you can get, which might be a good option.
Sorry for adding such a low info. :~
The motors are:
Minebea 23lm-co33-05V
1.8deg/step
3.0A (I know that l298 is rated for 2A)
Spreadsheet(page 17 of the pdf):
http://cnc25.free.fr/documentation/moteurs%20pap/pap_nmb.pdf
The main problem now is that they have 6 wires and acording to spreadsheet(I think) they should be unipolar.
But they aren't.
I connect voltage from the psu. Whenever its connected to : black-red or white-orange (look pdf) it moves, but with other wires it dosen't.
I know how to run unipolar motor. My small CNC is running fine (on diffrient way smaller unipolar motors).
So is that motor broken (somehow) and it can't be driven by unipolar driver?
~Thank you for both of your answers . I think I may consider just buying unipolar driver as dc42 said.
Sorry for double posting but:
-A4988 has max. current output of 2A
Six wires means it can be wired either unipolar or bipolar. In bipolar mode you would leave the black and white wires disconnected. In unipolar mode you would connect the black and white to your motor power and switch the four other wires.
~$50 can get you a 3 axis board with a lpt connector, connections for limit switches, optoisolation, etc. Search eBay for "3 axis TB6560".
I know how to connect unipolar motor. The thing is that blue and yellow wire dosen't move the motor at all(while red and orange move normally, with voltage + connected to white and black).
Is my motor broken or something?
Yeah I saw those boards already. They're pretty good. (U can connect screen, keypad etc.)
But I wanted to do something by myself. In the name of opensource!
(I created unipolar driver, so why not bipolar )
EDIT:
So what I did is I removed the cover of the motor. Now I can see whany unipolar dosen't work.
Here is the image:
So what I can see is that motor dosen't have the middle pin connected. I think that it may be done. How should i connect it?
Thank you!
There's no centre-tap to the windings to connect to.
Measure the resistance between the different connections and let us see the results.
...R
1.3ohm both
1.3ohm - that's definitely a good high performance motor - but it will need those 3A to get max
performance and the A4988 isn't upto 2A (despite what you read) let alone 3, so you'll need a
proper stepper motor driver for this. For good speed you'll be looking at 36V or more supply too.
(The A4988 can theoretically take 2A if on an infinite heatsink, which it isn't, overwise you'll find 1.5A is
pushing it thermally).
Yeah I was experiencing a lot of heating with l298. I think buying a cnc (All in one) driver is an only way (they have 4A max and big heatsink with fan).
Do you guys know where can I buy that driver (TB6560) for a best price?
On ebay they cost about 45 dollars-
http://www.ebay.com/itm/CNC-Router-3-Axis-TB6560-3-5A-Stepper-Motor-Driver-Board-For-Engraving-Machine-/271187134909?pt=LH_DefaultDomain_0&hash=item3f240349bd
Anywhere cheaper?
Thank you!
If there are 6 wires there have to be a lot more than 2 places to read resistance. Can you list them all?
...R
bartuss12:
1.3ohm both
Look at the pictrue, as I said I have only 4 wires soldered to the pcb. I can only measure the resistance of both coils (not half coil and full coil as it would be in unipolar)
Sorry, I was going on the datasheet you posted, but it seems the actual motor you have is not the same. The motors in the datasheet list a max current of 2 amps but for all we know your motor could be completely different.
Perhaps you could rig up a test circuit with a couple of transistors or mosfets driven by the Arduino to give one-way motion. That would allow you to measure currents and learn a bit more about the motor you have. Then you should know what sort of driver to buy.
...R
