Re: [CAD_CAM_EDM_DRO] Re: Clarifications needed -

On Saturday 13 September 2003 12:24 am, Jon Elson spake:

> Weyland wrote:
> >Ah, yesssss... okay.
> >Don't wanna let the smoke out.
> >They usually don't work after they lose the smoke.
> >
> >How could I limit the voltage to 79, then?
>
> Why do you need it so high? What is to be gained by this? Are you having
> performance problems with the motors as it is now?

<shrug>
Dunno.
This is the Alpha build, so I have no benchmark to go by.

Would you and others recommend I have it lower?

I'm not sure at this point if it makes a difference, but all
three motors ( with a fourth later) run off of this voltage.
I'm guessing, but it seems possible to have all three axis' drawing
off of the output voltage at once, making each get 1/3 available...
Or am I thinking of this incorrectly?

> There are autotransformers used to run 230 V air conditioners and similar
> equipment in buildings where only 120/208 V is available. They can be
> used to either step up or down the voltage by roughly 10%. If you are
> getting
> 82 V now, you should be able to step it down to 74 V or so, which should
> be saver for the Gecko drives.

I'll have to go Google "autotranformers", because I've no idea wha that is.

> >I'm not so much looking for "...30 seconds of run-time..." as much
> >as I'm thinking to try and overcome the *NOTORIOUS* and _frequent_
> >brown-outs around South Florida.
> >The half of a second of free spin on the spindle won't really
> >be horrible, but I'd like to not lose steps and such during one.
>
> OK, the capacitor bank on the power supply should ride through that.
> I had a power fail here while machining, and it went completely dark.
> I was reaching behind me for a flashlight when the power came back on.
> I saw to my amazement that the machine was still chugging away.
> The VFD on the 1 Hp spindle motor rode through the outage, supplying
> power all the time, the servo amps, axis motor supply and everything
> continued without noticing the power dip. I was pretty amazed.
> If you use a somewhat oversized PC power supply, it will have longer
> ride-through. And, I do have a LOT of capacitors in my servo motor
> power supply.

Heh. No sh|t...
And wouldn'tcha know it... I tried it.
You are right.
I pulled the plug on the controller box, and watched as the Geckos stayed lit.
I put a meter on the output of the power supply,
and watched as it *SLOWLY* dropped down.
It sure seems like you're on the mark.

Thanks, I learned something.

Weyland