View Full Version : New Machine Build CRP4848 CNC Router build....(need electronics advice)

06-08-2014, 11:39 PM
Hey everyone,
Glad to finally start my own CRP 48x48 CNC router build.
Got all the extrusions from Ahren at CNC router parts, everything looks good so far!

Motors & Electronics:
Bought a Nema34 set from longsmotor on eBay:
4 x 1232oz Nema 34 bipolar motors (3.08V, 5.6A, 0.55Ohm/phase, 8.4Nm (torque)
4 x DM860 stepper driver (7.8A, 256 Microsteps)
4 x 350W / 60V / 5.6A power supplies (don't ask why there are 4 of them??!! . Gonna get one to handle all motors.
1 x cheap breakout board that doesn't deserve to be called a breakout board basically.

My experience with electronics is still at the beginner stages, I would truly appreciate any advice from the experts' on this forum!
My question is about the power supply. I have done a bit of research and hopefully have calculated the V and amps needed correctly:

Voltage required: 3.08 x 20 (need 10 to 20 times the voltage of the motor) = 61.6V
Amps required: 5.6 x 4 x 0.66 = 14.8A. (Sum of all motors' amps times 4 times 2/3)
If my calculations are correct, I'll need a 60V power supply with at least 15A
Please correct me if I'm wrong.

Here's my question: should I get a 56V x 20Amps (KL5620) or 60V x 20Amps (KL6020) power supply?
Here's the link to the supplies: Toroidal Power Supplies | Automation Technology Inc (http://www.automationtechnologiesinc.com/products-page/torroidal-power-supplies)
The difference is significant in terms of size - the 60V one 2 in longer and 1in wider (no clue the height, but probably much taller also!)
If 56V will be plenty for my application - I'll definitely like to go with that one rather.

Next steps:
- order for PMDX-126 Board and PMDX-107 (VFD spindle controller)
- order 220V air spindle
- order VFD (will probably go with the cheaper version to save money for now ...Huangyang VFD)

I will be posting pics and the process/updates of my next steps of my build in next post shortly!

- Dex