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Old May 31st, 2004, 11:16 PM
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A reply from a friend of Wolf and I in response.

Hello Brian;

Re: The 12 volt lamp with the transformer.

The dimmer won't care but the transformer will.
This is a large part of what got Colortran's ENR dimmers in trouble in
Florida and 'Vegas.

The transformer depends upon it's inductive reactance to limit it's current
to safe values.
When the dimmer is set to less than full, it's chopping out pieces of the
normally complete sine wave.
This is what drives the transformers nuts as they can no longer properly
develop their inductive reactance and thus end up consuming far more power
than they were ever intended to.
Most of the more modern state of the art dimmers have various control curve
options designed to work with cold cathode loads, transformer loads, yada,
yada, etcetera.

Some transformers are rated as "impedance protected", many are not.
In many theatres operators turn off their control consoles at night but
leave the power for their dimmer racks on. In these situations there is
often enough trickle current still available to smoke some of these little
non-impedance protected transformers.
One of our local road houses smoked several rain light transformers over
night for just this reason.

Best McGiver work around:
Add a dummy load in parallel with the transformer's primary.
This will normally save you from smoking the transformers.
With the 1990 Strand CD80 racks, I was successfully utilizing dummy loads as
small as 120-S-6's, little 6 watt, 120 volt lamps although 40 and 60 watt
lamps are more commonly utilized.

Toodleoo Brian!
Ron
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