Hi, all;
I'm reworking the electronics on a CNC system. The original system used small stepper motors but was obviously designed for a range of motion hardware - I suspect the "high end" model would have used servos instead of steppers. So, I'm refitting it with servos since it doesn't work right now anyway. I'm using slightly oversize (ok, a lot oversize) servos so I can directly drive the ball screws... that way I get no backlash from belts, gear drives, etc. So, oversize servos and servo drives to match... each axis servo (X, Y and Z) needs about 3 amps continuous at 230VDC, peak is about 10A each. I'm going to (approximately) size the power supply to handle normal continuous load on all three axes. With the draw from the servo drives' electronics added, call it 10 amps at 230VDC, or about 2.3KVA. I've done this before on a milling machine and helped other folks with CNC machines using similar power supplies - basically, a linear supply with a large step down transformer feeding a rectifier and enough capacitors to smooth out ripple. I feed this to a DC bus with a clamping regulator on it to avoid overvolt conditions. Linear supplies have been recommended to me a lot for CNC use because they tolerate the braking voltages and noise associated with driving servos.
So, where I'm at right now is building another supply. I have all the parts except the transformer in my stockpile. The problem is coming up with the proper voltage - 230VDC means I need a transformer with a 240V single phase primary and a 160 volt secondary. Not a terribly common item, especially sized for 2.5KVA.
Here's my question - I'm getting set to disassemble and rewind a transformer to produce the voltage I need for rectification, and before I get started with all that work I wanted to see if anyone could think of a better way to build this power supply. For example, does someone out there sell a CNC supply this size for a decent price? Maybe 3x supplies of 750VA instead?
Does anyone know of an easier way to get a solid 230VDC from 245VAC mains current @10 amps?