Over Wattage & Over Voltage

I had the same problem with the 500W workers in one of our theatres, the lamps were lasting about a month before popping, relamping with 300W solved it.

I think the problem was the lamps overheating.

Cheers

Richard

Any chance that the client had somebody with greasy fingers doing the relamping?  Given that it was a "school system," what are the chances that somebody who didn't know better (such as the janatorial staff) did the relamping with their bare hands?  Our clients regularly run 1K lamps of this type in 'mini-10' type fixtures with no problems.  The added heat of the 1K lamp is only going to hasten the problem happening.

Also, I am confused.  First you say that the lamps were on different dimmers but the same phase.  Then, you say that they were all on the same dimmer.

The lamps pictured show how they blew out, classic over voltage flash-out. The striping is where the filament supports caught the tungsten and shielded the glass. Fingerprint blowouts show a fairly obvious print location and don't usually have the tungsten coating the tube. There were only 4 lamps left in the fixtures (3 were empty) so they might have had other reasons. By the time it got to me it was far bigger than a stray student with leather gloves.

As for the numbers; there are 9 fixtures total, 3 each on 3 dimmers.

Over heating is unlikely to be the issue. These units have screen shields rather than glass so they aren't sealed up. Now when they closed the barn doors, thats another story. They also were burning out in seconds, so there wasn't time to heat up.

I think I've covered the obvious, but it's always good to double check.