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Re: Dimmer as a Variac.
Original poster: "Luc by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ludev-at-videotron.ca>
This is a good link about dimmer:
Tesla list wrote:
> Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> As it happens, the dimmers (or fan speed controllers, which might actually
> work better, since they drive a somewhat inductive load) made by Lutron are
> typically better than those from Leviton. In a former job a few years ago,
> we were looking for replacements for 5A variacs to control a 1/3 HP PSC
> motor. We went through many, many commercially available dimmers. As you
> noted though, the construction quality is a bit iffy, although, to be fair,
> we never had one (out of hundreds) fail because of construction or
> workmanship defects.
> The slightly more expensive units (i.e. more than $5) also usually have an
> inductive snubber/RFI filter in them, which the cheaper ones don't.
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Friday, July 06, 2001 7:32 PM
> Subject: Dimmer as a Variac.
> > Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
> > Hi All,
> > Today I got a Leviton No. 6681 600 watt dimmer switch at the hardware
> > store. It cost me about $7. I imagine these are available everywhere at
> > least in the USA. I pulled the back cover off to expose the electronics:
> > http://hot-streamer-dot-com/temp/P7060004.jpg
> > Wow! They sure are cheap!! :-)) All hand tack soldered. Many
> > opportunities for shorting and such...
> > The main power electronic device does not have heat sink compound under
> > I think drilling out the rivet and adding a little thermal grease will
> > increase it's short term power handling about 200%!
> > Not enough room inside to add internal MOVs but a little thermal grease
> > some "adjustment" of the guts should help them to survive considerably.
> > I am thinking that MOVs and a good line filter will complete the poor
> > variac and I can do a little testing to see if the idea is worth while.
> > Still have to check what the output wave forms look like and see how that
> > will affect the rest of the coil...
> > Stay tuned...
> > Cheers,
> > Terry