On Tue, 5 Feb 2008 14:49:32 -0800 (PST), Mark
wrote:

On Feb 5, 5:19*pm, default wrote:
On Tue, 05 Feb 2008 18:08:12 GMT, "James Sweet"





wrote:

The lash up works. *I can control a 120 VAC lamp with the dimmer
triggering the external triac. *So at least it triggers on 120.

Before it goes into the range, I need some mounting washers for the
triac. *These are bolted to a bare heatsink and I'd rather insulate
the triac than insulate the heatsink.

Still want to tinker a bit to see if the bare, out of the box, dimmer
can be made to work the triac with only the two wires they supply.
--

Wire it up on 240 powering a couple of 200-300W incandescent bulbs in
series, if that works then it should work fine with the burner.

The idea of getting a hardware store lamp dimmer and mating it to a
higher voltage higher power triac could have some commercial
implications. *Especially if it can be done without additional
circuitry.

Most of the old stage lighting and centrifuge (industrial) stuff I've
seen. *A: they want you to buy the carbon pile/rheostat or variac to
"fix it" and that costs hundreds or thousands of dollars. *Or their
"updated" controller that only cost hundreds++.

I'm guessing but the one or two theater's left with rheostat controls
belong to Catholic schools or very old theaters.

Oh. Forget that stuff, I just want an option for my range. *

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I'd worry about 2 things..

1)lots of EMI generated from 50 Amp pulses floating around

2) if the triac shorts your burnner will be on full tilt and may be
dangerous if you are not there, may want to include a mechanical
overtemp saftey device. The triac could decide to short even when
the burner is not in use when you are not home etc......

Maybe triac + mechanical overtemp saftey + mechanical on/off


The other failure mode I have seen is that the burner shorts to its
outer shell and this is very bad becasue you can't turn it off
because the burner stays activated by one side of the 240 line unless
you have both sides of the line switched...

take care

Mark

Thanks

The EMI seems to be nothing . . . but a few years ago I found the
range burners were causing my computer modem to slow way down due to
EMI. Took me years to figure out the stove was causing the problem .
.. . but I built a common mode filter for the incoming power (all 20+
amps or so). The filter is still in there.

It wouldn't be the first time the mechanical range controls shorted
and caused the burner to stay full on, so the triac is no worse in
that respect.

The idea that the triac, just sitting there, could decide to short has
me worried too. I have a lamp dimmer in my bedroom that is one of
those push on/off. I leave it on, and just turn it down all the way
and it hasn't shorted in 20 years.

But there's more to lose if the range shorts so I want a double
make/break switch for that.
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