Newbie- Dual Output PSU

[holyjewsus]

I'm looking at one of these power supplies....(it's a 56v 1500watt psu with 2 56volt 13 amp outputs) for a 5 axis build I'm involved in. We're using 5 gecko 201x's under various amount of current consumption.

3 from 5-6 amps each and 2 around 2.8 amps each


How do I go about wiring the dual 56v outputs from the psu to the geckos... I want to avoid ground loops. The data sheet says to wire the outputs in parallel to double the current to 26...

Does it make sense to wire one outputs to some geckos and use the other output for two other dedicated geckos?

thanks!

http://www.antekinc.com/pdf/PS-15N56R.pdf

[doorknob]

I've tried to think through this a bit, but I do not see how keeping the two 56-volt outputs isolated from each other (vs. wiring them in parallel) would help you to avoid ground loops. If it were me, I would wire them in parallel.

But YMMV. Maybe someone sees something that I'm overlooking.

[Al_The_Man]

It is simple, as the PDF states, the two 15a DC outputs are wired in parallel to double their capacity, they are then treated as one supply, I too am not sure what you mean by ground loops in this context?
Al.

[holyjewsus]

Hey guys, thanks for the help, you probably don't know what I mean by ground loops, because I'm not really sure what I mean... haha

I've just read lots on being aware of creating differentials in voltage and I wasn't sure how the two outputs from the psu worked... if it was like trying to tie together two physically different power supplies together... which I've not read good things regarding...

anyway, thanks again for the quick help.

[Al_The_Man]

If they are fairly well balanced as these appear to be it should not be a problem, especially as they both originate from the same transformer.
Al.

[holyjewsus]

I have another question concerning the same power supply and fusing.

What kind of fuse is recommended for the power supply and how is it wired? circuit breaker?


if anyone has experience with this board: PMDX.COM - Products for CNC and motion control applications

we'll be using the 126 breakout and two of the 133 boards connected with ribbon cables, is it possible to fuse each gecko with this setup, theres only one motor power in connector for each motherboard.

Is there anything wrong with fusing 3 geckos and 2 geckos with 1 fuse each?

[Al_The_Man]

If you are using the supply with 240 in then you need a suitably rated fuse in each primary leg, or a suitably rated breaker.
If using 120v in, then you only require a fuse or breaker in the hot leg.
I usually also fuse the AC secondary before the bridge, but that may prove difficult with these as I believe the AC is fed to the bridge through a PCT board.
Al.

[holyjewsus]

Al, I really appreciate all your responses, thanks for taking the time,

http://www.pmdx.com/Doc/AN125-1_MachinePower_02.pdf

We're using the pmdx 126 as our breakout motherboard,(apparently this applies to the 126 and 125) this board requires AC power, we're using 110 for both this board and the psu for the steppers.

In the document I linked the contactor carries power to the spindle and steppers.

If you had to guess, would you assume this meant to the AC - DC psu that powers the steppers?

[Al_The_Man]

Yes, I would assume they mean the AC supply to both spindle and stepper supply, it shows this as the output of the DP relay or contactor.
You should cut power to both in the event of an E-Stop.
Al.

[holyjewsus]

and now for the rub!

the spindle is a 220v 3 phase, do we use another contactor rated for the 220v?

[Al_The_Man]

Is it fed from true 3ph or is this a VFD with 220v 1ph input?
Either way you should have a contactor or HD relay on the input side controlled by the E-Stop condition.
A 3 phase contactor coil could be fed parallel with the relay coil shown, if necessary.
Or off of an auxiliary contact on the E-stop relay.
Al.

[holyjewsus]

Originally Posted by Al_The_Man Is it fed from true 3ph or is this a VFD with 220v 1ph input? Either way you should have a contactor or HD relay on the input side controlled by the E-Stop condition. A 3 phase contactor coil could be fed parallel with the relay coil shown, if necessary. Or off of an auxiliary contact on the E-stop relay. Al.

That is undecided at this time, we are searching for the VFD now, multiple persons are involved in the project, any advice?

Also, Al, you rock, thanks for all the help, hopefully someday I can return the favor somehow.