Thought everyone was doing a great job on the subject thus I didn't want to step in, plus attempting to spend less time on-line given there are a lot of very good lamp people now on this forum. All FEL lamps at least for the like last ten to 15 years have been of any burn position so sag should not be any problem no matter how the lamp is mounted. Up or down that
filament support
wire is there to prevent sag and slipping off. Initial thought would be that where the
filament support
wire is located on the 575w lamp is at a cooler spot on the
filament grid and it is less likely to stretch and sag there unless bumped thus the hook of the support is sufficient. (This without looking at one) On the FEL lamp, it's located at the hot spot but wraps around the
filament sufficiently to prevent slippage at any position.
On the other
hand rotating them isn't a bad idea, perhapsfor any lamp. Perhaps DR.
Bulb from Ushio or another engineer could answer the question, "Given the universal support of burn position to the
filament is concern about sag during the life of the lamp valid?" At very least, during this 180 degree swap of the lamp, it's
base and
bi-post should be examined to see if the
base is going bad. So if nothing else you have examined the lamp
socket which is always a good part of
preventative maintenance. I Always hate those sockets that weld themself to the
lampholder due to just leaving them alone. Beyond the spring steel lamp poppers I make for
HPL lamps, I found recently that my mini pry-bar (about 4") works well in popping welded lamps.
On the other
hand, why is anyone still using FEL lamps?
The
filament support
wire is hooked to support the
filament for any position so it shouldn't matter what position the lamp is at. I donated all of that type of lamp to my local theater, once I sold off all my more modern Lekos. I'll have a look at the concept in the morning at work and perhaps it's theoretically possible that a modern 575w lamp's
filament might slip off the hanger. I'll
throw the question to one or two manufacturer's engineers to answer. I'm sure they would love such a question as opposed to my more normal, "Why are these moving light lamps failing so soon questions".
At times filaments from CYX to FEL do slip off a
filament support. Its common for the
filament to burn right
thru the outer
globe and even keep working while mostly encased in glass - kind of cool for wall of shame type lamps. But on the other
hand it is rare for a
filament to slip off its hanger no matter what burn position, unless given a good bump while in use. On some lamps the
filament support
grid (often made of glass on higher wattage
filament)breaks and allows the
filament and hangers to go flopping. This is often from
shock say in a
road case bounced onto a truck dock plate or as I read on a moving light lamp tag today "
Truss fell" as reason why the lamp broke. That was a first for me in "reason for lamp replacement" and the only lamp that broke so I expect it must have just been some form of pre-rig
truss cart that's top heavy that fell over.
At least
filament lamps don't have the
filament support
wire sag or bending problems that many moving light lamps have. They can burn through with heat due to proximity to the lamp capsule. If bounced while being moved, that
filament lower or higher lead in
wire/support
wire, can
bend ( if not carbonizing or melting) and allowing the inner
HID capsule to either get too close to the upper support
wire or in the case of a lower capsule bending allowing it to get too close to the above or outer
globe of the lamp. Also the support wires can scratch the outer
globe of a HR lamps and cause cracking.
Moving light lamps.... again I'm sure the lamp manufacturers would much rather discuss a
filament lamp question with me over moving light lamp problems which I mostly deal with these days. I wouldn't even have to involve a
fixture manufacturer or two- in which I have found that the cooling of the lamp is just plain insufficient for the operating temperature of the lamp, causing lamp and
base failure (very expensive in replacing all these lamps and bases plus heat fuses and fans, wiring
etc). More than one brand of "high tech"
fixture that beyond having heat causing problems, is also using a lamp that doesn't support the inner capsule well enough... but is the only lamp on the market with a high enough fill pressure within the lamp to work. Lots of modern moving light
fixture problems out there with lamps not living up to their expected lamp life.
