building power supply

[heilcnc]

if i use 2 28 volt 6 amp transformers in my power supply wired in parallel will i get 12 amps if i can were can i find more info on building this kind of power supply for my cnc mill i will be using hobby cnc board and 3 3amp step motors thanks

[NC Cams]

Theoretically, yes.

I'd be more inclined NOT to parallel transformers unless they were identical and even then I'd feel uncomfortable doing so.

Check out these;

http://www.cnczone.com/forums/showth...015#post142015

http://forums.bit-tech.net/showthread.php?t=108208

[rippersoft]

You can build 2 separate powersupplies with identical parts and tie the positive ends of the capacitors together for + DC and tie the negative ends together for - DC or ground. Be sure to also tie the - end to chasis ground in your case. Eliminates ground loops.

I have done this with 4 transformers, rectifiers, and capacitors to create a 32VDC 16Amp powersupply all in the same case with plenty of fans. Works great, no overheating.

RipperSoftware

[rippersoft]

An add-on to the above. The transformers are NOT tied together. The output at the capacitor end or DC voltage is tied together. That eliminates the problem of matching transformers and other AC stuff.

RipperSoftware

[H500]

If you're using nema23 size motors, I would be very surprised if you need more than a single 6 amp transformer. Don't forget that the supply deliver the current at a higher voltage that what is at the motor, so less current is needed.

[rippersoft]

The machine is really an experiment. The powersupply needs to be able to run bigger motors if I move it to another rig with say, nema 34 motors. Sometimes it is good to over engineer.

RipperSoftware

[smarbaga]

i parelled 6, 24v 10 amp transfo's once, no prob.
hung them together with threaded rod.
i used 100 amp diodes, stud mount.
i have replaced 600 and 1000 amp puck scr's and triac's in motor drives
when they kick on at near full load you can almost see the electrons flowing through them, you sure can hear them.

[ViperTX]

smarbaga.....that must have been a helacious large bridge rectifier.....