[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Yes, yes...nice....but what can you do with it?



on that fateful day 8/7/00 5:17 PM, Tesla list uttered:

> Original poster: "Christopher Boden" <chrisboden-at-hotmail-dot-com>
> 
> After a recreational afternoon of dumpster diving....er.....creative
> resource allocation and recycling...yeah. We found a massive toroid core for
> a large Variac.
> It's about 1' in diameter, and about 2X3" in cross section. There are 3
> wires coming off. The wire gauge is about 12 or 14 and it weighs about 15-20
> pounds.
> There is ONLY the core and coil. No wiper, or mounts or anything.
> What can we do with it? Ideas?

Ballast.  Are you sure it's not a toroidal transformer?  ie; is there a
milled-down bare place on the windings where the wiper _used_ to go?

> We also found a very nice motor driven Variac rated for 2500Watts at 120VAC.
> The motor control looks bent and destroyed, but the variac should be fine.

Now that's a score.

> Another toy we found *might* be usefull. It's another lighting control
> module, but this one is solid-state.

Solid state dimmers tend to be rather unforgiving.  For one thing, most of
them are _not designed to handle inductive loads such as transformers.  For
another, they are notoriously sensitive to spikes coming back from the load.
I would not attempt to use my dimming equipment to run even a small Tesla
coil, not even on a bet.

> We can identify almost all the parts
> with one exception. There is a 6" dia, 2"thick black disk shaped potted
> thingy (yes, that's a technical term) with 2 wires of about 18AWG coming out
> of the top. 

It sounds like a toroidal filter, except that it's _huge_, even for a high
powered dimmer.  All solid state dimmers include an inductive filter to
reduce the rise time of the spike which occurs when the triac (on cheap
dimmers) or back-to-back SCR's (on pro dimmers) turn on.  That spike can
play merry heck with sound systems radios, show controls systems, and even
the dimmer control signals themselves.  I've never heard of a filter toroid
that big, tho.

> What is it? I'll try to dig up a part# if possible. Given it's
> application we may be able to make a few of these (there are at least 6 in
> the dumpster, we're making another trip) into a solid state TC control panel
> for the SAM upgrade to a 10kVA PIG system.

Good luck, you're going to need it.  If it wasn't useful to the theatrical
department, chances are it's not a dimmer any more, but a collection of
dimmer parts.  You might want to price high current dual SCR modules before
you venture into solid state control territory- the sticker shock may turn
your hair white!

- Gomez

..............................................................
"The most fundamental human right is ownership of your body.
If you cannot do with it as you please, you are not yet free."
                                 - W. A. Lemieux