Jinx wrote:
>Halogens came up last time there was a long talk about dimming.
>Don't recall anything said about life-time as such, but I have this
>vague recollection of if you run them too cold for the evaporate-
>condense cycle to work properly it can affect long-term operation.
>And dimming is off the menu because of the temperature drop

I followed this thread too. Had a good talk to a friend in the lighting
control business & he said that although running halogens at low
levels for extended periods does upset the cycle, they will recover
quite OK if you run them up at 100% every so often. Some of the
lighting control systems are programmed to do this by themselves
during out-of-business hours. He also said that the cycle problem
is mainly confined to lamps where the glass envelope is far away
(in relative terms) from the filament. Dicroic lamps don't seem to be
in this category. So the upshot is that dimming is OK for them. One
thing he did mention is running electronic transformers from standard
phase control dimmers. They don't always behave correctly. Seems
that the iron-cored transformer types work best with those dimmers.
Sorry to ramble on, but it may clear things up for a lot of people.
Regards...

___________________________________________
David Duffy        Audio Visual Devices P/L
U8, 9-11 Trade St, Cleveland 4163 Australia
Ph: +61 7 38210362   Fax: +61 7 38210281
New Web: www.audiovisualdevices.com.au
New email: avd@audiovisualdevices.com.au
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