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Lights burning alot

Discussion in 'Lighting and Electrics' started by thebikingtechie, Dec 18, 2006.

  1. thebikingtechie

    thebikingtechie Active Member

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    We have recently had lights burning left and right. Is there any reason they would do this. We are really careful putting them in and we always wipe off the bulb with alcohol if we even brush it with our fingers. We think it might be power surges because our school gets a lot of them.

    Thanks for any incite
     
  2. Footer

    Footer Senior Team Senior Team Premium Member

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    What kind of dimmers, what kind of lamps, what kind of fixtures, how much use, etc... It could be you are running 115v lamps with 120v dimmers... could be you are bumping the lights often (as in 0 to 100% in a 0 count), could be ton of things. Also, how are they blowing?
     
  3. thebikingtechie

    thebikingtechie Active Member

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    575w 750v Source 4s and 2.4 kw dimmers. HPL bulbs I don't know any more specific info on the bulbs. We really don't bump them at all but we use black out a lot.
     
  4. Footer

    Footer Senior Team Senior Team Premium Member

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    What kind of dimmers/what voltage? and the voltage of the lamps? a 750v lamp at 575w in a 115v dimmer would burn very dim.....
     
  5. TechiGoz

    TechiGoz Active Member

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    Knowing the voltage/capacity of the dimmers is pretty crucial when problem solving these sorts of issues. Bit more information on the dimmers, power in the school (what are the surges that you speak of?).

    I dont think using quick black outs should blow them as quickly as you are saying, but you may be overloading the dimmers. The lights are easier to blow than a circuit breaker.
     
  6. Footer

    Footer Senior Team Senior Team Premium Member

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    No, The breaker will only blow if too much current is being drawn over the circuit. If you are pulling 25 amps (4 750w lamps) over a 2.4k dimmer the breaker will blow because the current being pulled exceeds the working load of the dimmer, the wiring, and everything in between. A lamp will not go out because you are pulling too much power. Circuit breakers blow alot easier then you think.

    Also, power "surges" should not make it past your dimmers, and if they are you have a few more problems then just bad lamps.
     
  7. thebikingtechie

    thebikingtechie Active Member

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    I don't know what the voltage of the dimmers is. We have EDI MX dimmers if that helps. Thanks for all the advice.
     
  8. SteveB

    SteveB Well-Known Member

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    Did you install these fixtures all about the same time ?.

    I've found this happening on a batch of new S4's as a group of lamps would all reach their avg. life span about the same time.

    SB
     
  9. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    It's not near as exciting as some of the theories other people are working on in this thread but I've had that happen too. How old are the lamps themselves? How much burn time? Were they all installed at once? Is it only one type of fixture that is burning out?
     
  10. highschooltech

    highschooltech Active Member

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    The power surges shouldn't be effecting the lights because they would be stopped at the dimmer. I really don't know what to say to that.
     
  11. Footer

    Footer Senior Team Senior Team Premium Member

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    Most dimmers have some sort of power conditioning, so "surges" should not make it past the dimmer. If you are really having power surges odds are your control modules and other electronic gear will blow way before your lamps will. Put a meter on your dimmers at full with a fixture running and see what the voltage is, if it is 120v and you have 115v lamps you have your answer.
     
  12. Jezza

    Jezza Active Member

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    Just to clarify, I think we are talking about 750w S4 Lekos lamped with 575w/115v HPL bulbs. As most of the other posters have mentioned, more information would be preferable but here are my suggestions. First, issolate the issue. Is it only in the Lekos? Is it only on certain dimmers or is it all over your stage? Have the electrics been recently redone? I am leaning heavily towards the "all the bulbs bowing @ the same time due to simillar install dates" idea but I rarely ever have that happen with my rigs. Running 115v bulbs off 120v dimmers can shorten the life span, although they will run a little brighter (and cooler in terms of color temperature if I'm not mistaken). If your capable/able, try meetering you voltage coming out of one of your dimmers @ 100% and that will give you the most accurate reading (remember, do this while loading up all the other phases in the system ie turn a bunch of other lights on so the rack is balanaced out). You could have some faulty wirirng that might be feeding the lamps 240v at certain instances causing them to blow. What kind of "blow" is it? A sort of sputter and die? A bright flash? Does the bulb physically explode?
     
    Last edited: Dec 19, 2006
  13. fosstech

    fosstech Active Member

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    Make sure you load the dimmer with some sort of fixture when metering to get an accurate measurement. Use a twofer if you only have one receptacle for that dimmer.

    Your voltage probably won't be 120V at the raceway because of voltage drop over the wire from the dimmer to the fixture itself. But if the voltage is a little high coming into the dimmers, you might actually be getting 120V at the fixture. The only way to find out is to meter it. That's the principle behind 115V lamps; they compensate for that voltage drop by hitting the rated output at 115V.

    Here at college we have six racks of ETC Sensor dimmers, with 560-some odd dimmers available in the space. When they installed the system ten years ago, they put in a big step up transformer in the dimmer room that bumped the line voltage into the racks up to I believe 130V. That was done solely to compensate for the voltage drop over the hundreds of feet of 12ga wire to each fixture.
     
  14. thebikingtechie

    thebikingtechie Active Member

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    The fixtures were installed at the same time but we have been going through multiple lamps on the same lights suggesting that the lights are burning very quickly.
     
  15. Footer

    Footer Senior Team Senior Team Premium Member

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    Meter it. That should do it.
     
  16. dbn

    dbn Member

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    Well, that depends on the dimmers. ETC Sensor racks with the advanced control module have output voltage limiting. Sensors with the basic control module don't. Many other SCR / SSR dimmers fall into this category, and don't have output voltage limiting. One the SCR is in the conducting state, for the AC waveform half-cycle, the output voltage follows the input voltage, less one forward-baised diode drop (about 1 volt).

    We had a consistent problem with early lamp failure on our 115v lamps. It turned out to be power line issues. We had the local untility come in to perform a power quality analysis. They determined that at certain times of day the line voltage would rise as high as 125 to 128 volts. This is at the upper limit of the power standard allowed by our state's public utilties commission, but are withn spec. We're not talking about surges here, but periodic fluctuations in voltage measured in minutes or 10's on minutes. The utility company offered us no solution. Since our dimmers do not have the output voltage limiting feature, we decided to take precautionary measures in the soft-patch of the console. All dimmers feeding 115v lamps are proportionally patched at 80%, which with the aid of a true RMS voltmeter, we determined would limit the highest voltage we see on the line (128v) to 115 v at the lamp socket.

    Regards,
     
  17. Chris15

    Chris15 CBMod CB Mods Premium Member

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    In case people were not aware, the above mentioned voltage fluctuations are due to changes in load on the grid. This can also occur on a local scale, if, for instance, all the ovens are on in the kitchen, then I would expect a lower mains voltage. As a general rule the voltage will be low: on a hot day (people have the airconditioning on), on a cold day (electric heating) and in the evening (people cooking dinner). Middle of the night I would expect a high voltage, but the off peak electricity system helps to counteract that by switching on all the hot water systems etc to use up the power which is being generated anyway (it takes MANY hours to start up a coal power station.)
     
  18. Jezza

    Jezza Active Member

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    dbn, patching your dimmers in at 80% on the console didn't affect your color temperature? During off peak usage i can see that as being useful and your lights should be compensated down to a 115 like voltage however when the main voltage was lower, 80% has a considerably warmer quality than 100% on a tungsten bulb. How did you deal with that issue?
     
  19. zac850

    zac850 Well-Known Member

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    dbn, What type of dimmers do you have? Most (well, basically all dimmers now a days) work by turning on and off the power 120 times a second, NOT by limiting the voltage. When your fixtures are on at 80% the lamp sees whatever your voltage may be 80% as often as if it were on full.


    As for the original post, my one suggestion would be to create a warmup cue or sub that you run before any show. Manually or otherwise SLOWLY turn on all the fixtures in the theater to about 25% or 35% for 30 seconds or so, then SLOWLY turn them off. This will slowly warm up all the lamps, so that they don't get immediately turned on with the first cue in the show. Lamps more often fail right as their being turned on, not after hours and hours of use.

    On an ETC Express, you can create a warmup sub simply:
    Code:
    [Channel] [1] [thru] [last channel number] [at] [30] [record] [sub] [press bump button on desired sub] [time] [15] [30][10] [enter] 
    What that does is let you hit the bump button on the lighting console. Walk downstairs, visually inspect that every lamp is working, and then the console turns all the lights off its self. There are many similar ways to accomplish this, that is my way.

    That should help. Other then that you may be wanting to call an electrician and see what he thinks of power on the mains.

    Having said that, lamps fail. If you put the lamps in at around the same time, or you flash the lamps a lot (chases kill lamps), don't be surprised that they die. I've seen people play with the bump buttons just for fun, while no one was in the theater, and wonder why the lamp suddenly died. Bump on and bump outs have a similar effect.

    Good luck,
    Zac Spitzer
     
  20. Grog12

    Grog12 CBMod CB Mods Premium Member

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    How quickly is "burning left and right"?

    Are the lamps burning out within seconds? minutes? hours? weeks?
    Everyone else has offered several valid solutions but as to which one
    is your issue kind of depends on how quickly the lamps are burning...

    The other question is the dead lamps that you're pulling...what do they look like? Do the base pins have any carbon burns on them? Do the envelopes have black marks? Or do they look like any other lamps and they just don't work?
     

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