On Wed, 09 Feb 2005 17:01:14 GMT, "Vaughn Simon"
wrote:


"Ed Angell" edangellatcomcastdotnet wrote in message
...
Sorry for the OT post, but I don't know a better group of knowledgeable
folks to ask.

As long as a triac is run within it's published temperature limits, is
there
any shortening of their life due to running warm ??

I can't give you a scientific answer, but I used to run thousands of
triacs in outdoor traffic control boxes in south Florida. We seldom had a
failure that could not be explained by lightning or a short circuit.

Triacs used in traffic control loadswitchs are very conservatively
applied, or at least they were in the '70s. Lamp loads are tough
because of the arc that occurs when a lamp burns out. Most of the
triacs were at least 20 amp parts and some were bigger.

Lightning in South Florida was a problem. We got some controllers
back from Dade County that looked like they'd been dipped in a
volcano! I think some of the 8-phase dual-ring controllers I
designed back then are still in service in MN.