Re: [CAD_CAM_EDM_DRO] Re:Power supply questions

Something like this can be easily handled by an old electronic tube diod.
I wonder if these are still produced.
Alex

----- Original Message -----
From: Andrew Werby <drewid@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Saturday, December 07, 2002 7:25 PM
Subject: [CAD_CAM_EDM_DRO] Re:Power supply questions


> [While we're on the subject of power supplies, are there any
> reasonably-priced power supplies appropriate for this purpose that are
> available for purchase all set up and ready to go? I'd really like to find
> one in a box, with a fan installed, and (preferably) with a UL sticker
> attached. Ideally it would take 110v AC input and convert it to about
60vDC
> at 20 amps or so. The rest of the circuitry would be at a (relatively) low
> voltage, which doesn't seem all that dangerous to play with (and probably
> won't require a UL sticker), but power supplies can bite you if you're not
> careful.
>
> I can find "wall warts" that put out (nearly) enough voltage but not
enough
> amps (or vice versa), and also switching power supplies built for
> computers, but apparently the switching function, while it reduces the
> amount of wire necessary and thus the expense, can interfere with the
pulse
> train. (The Gecko site indicates they can be used, though, if one fits the
> drives with capacitors to filter the current.) The other problem with
> computer supplies is that they are meant to be mounted to the DIN rails
> inside a computer, and not to be free-standing.
>
> A third class of supplies I've looked at- bench-type laboratory power
> supplies- seem ideal: they come mounted in a box, and they can be found
with
> sufficient voltage and amp capacity, but they're hideously expensive, and
> seem fancier that what's needed, with multiple outputs and extraneous
meters
> and knobs, etc. Has anybody out there powered a Gecko-based servo setup
> (like the one Thomas wants to build) with an off-the-shelf unit? It seems
> like a major stumbling block would be removed if we didn't have to "roll
our
> own".]
>
> Andrew Werby
> www.computersculpture.com
>
> "Tom Murray <thomasm923@...>" <thomasm923@...>
> Subject: Power supply questions
>
> I hate repost my recent questions, but I really need some help in
> building a power supply.
>
> Questions below:
>
> My Taig mill is ordered, and one of the things that I have to do
> while I wait the 6 to 8 weeks for delivery is make a power supply.
>
> There's a few things that I'd like to ask the group to get me
> started...
>
> First, I am wondering if my choice of caps is correct. I will be
> using a 30 volt transformer to supply power to three 24 volt servos
> rated at 6 amps peak. I doubt that it will ever need to supply more
> than 12 amps at once, if that much, but let's assume that the maximum
> current is 15 amps. I am looking at some surplus capacitors rated at
> 17,000 MFD, 75 VDC. Would a pair of these in parallel be sufficient?
>
> Second, I wonder if it is ok to attach a smaller transformer to the
> same AC input that is hooked up to the main transformer to supply 5
> volts to the Geckos?
>
> [I thought the new edition of the G-320s didn't need the extra 5v input.
Am
> I wrong here?]
>
> Third, how does one calculate the rating of the fuse that is needed?
> I assume that it should be a slow-blow type, but what would the
> correct amperage rating be? A little over the maximum current, a
> little under, or dead on?
>
> Thanks,
> Tom Murray
>
>
>
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