Re: CNC retrofit using Bridgeport Power Supply?

I have done the exact thing you are attempting. at 56 volts, you
are good to about 70-75ipm, I ran the geckos at the 86 volts at our
old shop and they had rapids above the stock 120ipm. There are four
ways to wire that transformer, parallel, series, and high/low tap.
With the power configuration at our new shop, I had to run the lower
voltage setting, because the higher setting gave me around 100v (too
high) According to Mariss, the parts in the gecko go to 100vdc, but
running them above the recommended 80v makes good heat sinking even
more critical, plus you have less lee-way in the event of a spike on
your mains. I don't know if anyone has brought this up, but in
order to interface with the gecko, you need a +5 supply lead from
your pc. A super easy way to do this on newer pcs, is to get a USB
extension cable at your local office supply store, cut the end off
it, and you will find a red and a black heavy wire, plus two light
gauge wires. The red and black are +5 and GND, disregard the
lighter serial lines. Be sure to ground the black wire to your
grounding system for the Geckos. BTW, my machine was a BOSS 5
Series1 CNC circa '79 - '80. It works great and we use it almost
every day in production.


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "rberryman2"
<rberryman2@y...> wrote:

> I'm upgrading a BOSS controller to EMC using Gecko 210's
> to drive the steppers. I was wondering about using the
> existing DC power supplies to drive them.
>
> They put out about 84VDC (60VAC) on the lowest voltage tap.
> This is apparently too high for the Geckos which I
> understand to be limited to 80V (will have to ask Gecko).
>
> One option would be to wire the 3-phase transformer to power
> the 440V tap with 220V which gives 40VAC on the output
> and 56VDC rectified.
>
> Do you think that 56V is sufficient to power the steppers?
>
> Thanks in advance for any advice.