Noob...Power Supply question?

[andyfive]

Hello everyone. First off, I would like to thank everyone for sharing their knowledge. I have learned alot from this forum, about CNC. I knew nothing about CNC before.
Now, my question.
I'm planning on building a machine. If I were to use 3 (XYZ) 3.6v, 2a steppers, with a chopper driver, would a 12v, 4a power supply work? Does the driver only fire one coil, on one stepper at a time, or does it drive all 3 steppers at the same time?

Any help is appreciated.
Thank You,
Andy Five.

[10bulls]

Your drivers are independant and the controller can drive all steppers simulataneously.
Most drivers, unless full stepping can drive both coils at the same time. So worst case you could draw 12A.
However, chances are unless you are driving a very heavy or stiff load, the current will be drawn in small spikes which will average out a lot less so you may just get away with 4A.
BTW old PC power supplies usually can do 12V @ 8A or more and are pretty easy to find.
On the other hand, you would probably want to go to a higher voltage anyway, to get better performance from the steppers.

[ger21]

It depends on the drive. For Geckos and the bipolar Xylotex, a 4a supply would work, but that would be the minimum. You should have 2/3 of the rated motor current per motor, or 2/3 * 2 * 3 = 3.99a. You really should use at least a 24V supply, though. You can usually find them on Ebay for under $20, and you'll get twice the speed you'd get using 12V. If you start with 12V, there's probably a 99% chance you'll swith to something bigger anyway, so just do it from the start.