Power Supply Help

[SteinAir]

Hi Guys,

I posted this over in another forum but couldn't get a response, so I'm REALLY hoping someone can help me out.

Anyway, I'm currently building a CNC router and have juts about finished gathering all my "stuff" to get it built. I am however having a brain freeze when it comes to power supplies. I need some help here.

I'm using Servos for all axis, here's the details I have.
X&Y Axis: Reliance E660's, 120V
Z Axis: Pittman 14xx, 38.0V
Using Rutex 990H drives.

So, I'm wondering, can it get by with one large power supply, or do I need 2 because of the differing power requirements of my servos?? What should the power supply rating be in Volts & AMPS?? I realize the rutex drives are only good to 100V and that should be more than plenty for the Reliance servos. They are rated at 10Amp max, and I have no idea what the pittman is rated at, but I think it's around 5 amps based on loose research.

I'm not intersted in building a power supply myself, so any pointers towards where to purchase one would be great....-or- if you're interested in building one for me, I have more money than time right now.

Any help would be MUCH appreciated.

Here's my basic design overview. My Moving Gantry Router is loosely based on the Data-Cut router plans, modified to my scrounging abilities, etc.. Will probably use Mach 2, still trying to decide on CAD/CAM software, leaning towards sheetcam for 2D work with TurboCAD, or Rhino, or Visual Mill, or.....

Have a happy new year,
Stein Bruch

[Bubba]

Stein,
I definately would go with TWO power supplies due to the vast difference in the voltages.
For the Reliance, I would tend to limit the voltage to about 90 volts to be sure the drives would not pop under back emf conditions which could cause an overvoltage condition. If as you say, the Reliance motors are rated at 10amp max, that would be a total of 20 for the two and I would design for about 2/3 of that or ~13-15 amp max. The chances of you seeing the need for 40 amp total at one time should be very slim.
For the small servo, it is real easy to achieve the full 5 amp rating and I would shoot for that unless the transformer I used was rated again at the 2/3 rating or ~3 amp.
As for transformers, I "roll my own" using transformers out of old microwaves. I cut the HV (~2000V) winding out and wind my own using magnet wire that can be found at places like MPJA.com or surplussales.com. In my testing, I get about .9 to 1.0 V per turn and the one that I made last week took about 4 hours from start to finish. This one happen to be for a 50V (DC) supply [~39V AC] and a secondary winding for my 12V control voltage.
Of course the usual disclaimers apply and YMMV

Bubba

[trubleshtr]

There is a member on this forum, I believe his name is jfiery or fieryj, anyways if you contact him(from "member list" above) he might be able to build a power supply to your requirements, I bought some stuff through him and he is nice to deal with.

[ViperTX]

Steinair,

You can have 2 supplies at different voltages (90 VDC and 38 VDC) this would be the best option, but this is a custom power supply.

Or you could also run the 3 servos at 35 to 28 VDC at 25 to 30 amps, which is the option that will get you up and running the quickest. Check out ebay for a linear power supply with these ratings.