Re: What does everybody use...

In a message dated 5/17/99 4:14:44 PM Eastern Daylight Time,
garfield@... writes:

<< On Mon, 17 May 1999 13:00:40 -0600, "Tim Goldstein"
<timg@...> wrote:

>For a controller I am using a Camtronics 5 amp Bi-polar Chopper unit. The
>power supply I am using with it is a surplus unit that puts out 24 VDC 20
>amp with a 10 VDC 15 amp tap that I don't use.

eXactamunod what I've done (nice box w/24VDC@25A). Just chimin in, to
emphasize that if ANYONE runs across a nice whopper 24VDC with largo
AMPS like this, SNAG it post haste. I got one for my router, and meant
to go back and pick up a few others for other machines or axis', but
alas they were gone within days, and I missed out. Argh.

>>

I scrounge power supply components at the recycling center/metal salvage
yard. The transformer and the capacitors are the most expensive parts to come
by for a big DC power supply. Rat Shack sells a 25 amp bridge rectifier diode
that is adequate for turning the AC from the output of your transformer into
pulsating DC. Do keep in mind that the rectifier must be heatsinked
adequately for multi-ampere use.

Currently ;-) I'm using a scrounged 1kVA "buck-boost" transformer wired to
provide 24 VAC out from 120 VAC in, one of the Rat Shack diodes I mentioned
and some big caps scrounged from an old mainframe power supply. "Buck Boost"
transformers are available from WW Grainger and other electrical supply
houses. They are nice because of their flexibility in wiring. They can be
used with either 120 or 240 volt input and can produce either 12 V or 24 V
out at a pretty hefty ampere rating. I think the one I'm using is capable of
around 40 A at 24 VAC, much more than my requirements.

One of the big improvements that I made to my system was putting my
Camtronics driver board in a "wind tunnel" enclosure that I made from
plywood. The driver chips used on the board have a thermal protection circuit
built in and if they get too hot the current drive to the motors is reduced
to protect the chips. Getting a really good flow of cooling air over the heat
sinks on the board allows you to get the maximum that the power driver chips
can deliver.

Jon Croad