Make Lamps Last Longer


In our drama wing at school we have another lighting rig. At the start of year I unplugged the board ect. and still saw all the filaments glowing a dull orange. The dimmers had been left on but the lights do not go completely out, they just glow. Most of the lams are rated at 400 hours but these have lasted about 17,500+ hours.

Saying that it might be a possible fire hazard, I'm not sure but they've been on for a couple of years.
This is the reason dimmers should be turned off when not in use. The glow is part of the design to make the lights last longer. It is known as pre-heat .

A low voltage is sent to each dimmer channel to keep the filament warm so that it never gets cold when it is off. When the filament is cold the resistance is less so when the lamp is switched on there is a higher in-rush of current then when the filament is warm. It is this sudden inrush of current that can literally shake the filament to pieces. Some dimmer packs have an adjustment in them to do this. Your packs probably have this feature. On a lot of modern lighting control boards you can actually set this level so that even if you have the channel set to zero the board will send a level of a few percent to keep the light warm.

This shouldn't be a fire hazard as the light fittings will never get very hot. But leaving them on day in day out will shorten their life.
Good to see that your dimmers did not go to full when the light board was off. On the other hand, why in turning off the light board is it necessry to leave the dimmers on?

In having a very good explination above, the lamps are still on. While it if they are still glowing need some trimmer adjustment, it still does not make much sense to leve the dimmers on when board is off. This unless there is remote stations as to why it's left on.

As for life, not much of a problem once dimmed.
At the end of each lesson we have to put the lighting desk away. :(

LOL Schools...

We leave the dimmers on though. Dunno why but it's not up to me.
While I have worked in places that don't turn off their dimmers - last time it was a surprise to me in the circuit tested not to be live yet suddenly I felt a slight shock. After that I had to use a ghost light load while verifying the circuits I was working on were dead.

On the other hand, it's been my tradition no matter where I work that goes back to school, that even in my work area, when I go home for the day, all power goes out in the work area. This ensures that should a heat gun get it's switch depressed or I leave on the soldering iron, battery charger has a problem or what ever, the power is off.

The same on stage with the dimmers. When I was in school we had Kliegl dimmers which like many other types of dimmer go nuts when control is removed from them. First you turn off the dimmers, than the light board and you simply do not reverse this process. Your light board turned off means the dimmers are already off.

No matter if the more modern dimmers are not effected by loosing signal or not, should something arc the data cable, it's plugged into something it should not be ect, there is no telling what your dimmers that are still on might do.

Also, since they are resorting back to a badly trimmed warmer current to the lamps, you do still have dimming and heat from it going on, and potential in the system. What happens if one night the fan on your dimmer stops? In addition to your lamps having a huge amount of hours on them - even while dimmed, other parts such as the dimmer's fan while it might be rated for constant use, will tend to wear out faster when always on.

Next what happens during a lightning storm or power serge, or brown out? Nobody there to save the dimmers could be costly.

I know lots of places leave on their dimmers, others and I think most others do shut them down for the night when they go home. Granted most places I have been are using the smaller portable or older technology.

I think it's a good idea to shut them down for the night. Probably much a similar debate to turning off your computer when done verses leaving it constantly on.
We leave our on (not even sure how to turn them off actually... never really looked...) but we couldnt really turn them off as a big set b/c the house lights are on same big set of dimmers and the janators and alot of other people come in at random times during the night and want light. Ya, it probably shouldnt have been setup that way but it is (luckly whoever setup the dimmers was smart to put the house light ones on top so the heat goes out right up and out the top of the stack b/c they are closest to the fans)

My computer is almost always on or in hybernate mode, I restart maybe 2 times a week....
Our dimmers also control our house lights, so turning them off is out of the question. But, whenever our board stops sending a signal, nornmally because it's off, the dimmer rack goes into hibernate mode and the fans shut down and all the dimmers are cut off of power.
I know very few places that leave power to the dimmers on. At my school we shut down the power to our dimmers when they are not in use, assuming they will not be used within the next 12 hours.

I know of one theater where power is left on to the dimmers, and that is mostly because everyone there is to lazy to kill power.
Ship has some good points about power surges and lightning strikes and how they can damage the electronics if the dimmer racks are left on. I saw a theater in Norfolk, VA. that went thru 3 ETC Sensor Control Electronic Modules this way. I believe they finally started shutting down the main service.

However. ETC and Strand, as examplle and AFAIK, do not recommend shutting down the racks in a permanent install. In general, the main breakers/switches are not designed for constant On/Off, though a fused switch handles it better then a main CB. The Sensor racks also do not like having power repeatadly lost to the CEM's. and I know for sure that the new CEM+'s on ethernet should NOT be powered off. They want to see the net all the time, which is why my system has a UPS in the ethernet rack with the switchers.

Which brings up the point about surges and strikes. In general, the CEM's are vulnerable. No doubt about it. I've also been told it's rare, mostly as lot of theaters have power disto into the building from undergound feeds, which are less vulnerable to strikes. I'm also told that the ETC CEM's are fairly robust and can tolerate a wide range of voltages and temperatures.

Somthing to consider as well is that the racks are often used (in big installations) for stuff other then console related usage, such as work lights, running lights, direct relay power to stuff needing constant power, house lights, lobby lighting, etc... You can open a whole can of worms shutting down stuff that needs to be left on.

Obviously, it's a case by case basis, with smaller installs wanting to shutdown if the breaker/switches are designed for it, as well as if the situation warrents it.

I leave my stuff on, though


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