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Automated Fixtures Moving light lamp cool-down

Discussion in 'Lighting and Electrics' started by Radiant, Nov 30, 2008.

  1. Radiant

    Radiant Active Member

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    How long should I allow moving lights to cool down, before shutting off their power? I was taught (by someone who honestly wouldn't know) that a minute or two is all that is necessary. We use Coemar ProSpot 250 LXs and Martin MAC 600s. I read both manuals just now, and saw no reference to a cool down period. I think I read somewhere here on CB that 20 minutes is required. Both manuals recommend 10 to 15 minutes minimum cool down before changing a lamp.
     
  2. len

    len Well-Known Member

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    Cool down is something I've never seen in a manual (not that I look). But my suspicion is that it doesn't do any good unless you shut off the lamp and leave the power on. When concluding a show, I try and do that first (from the console), then pack up the FOH, and by the time I'm ready to start directing tearing down the deck, lamps would be cool to touch, so it's ok to power them down. But sometimes the crew will start disconnecting multi-pins, which shuts off the fans, which makes the whole process moot anyway.
     
  3. Footer

    Footer Senior Team Senior Team Premium Member

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    My feeling is this... the fixture will never be hotter then it is when the lamp is on. Therefore, the fixture can only get cooler when the power gets cut, no matter what. Now, I would let the fixture cool before dropping it into a case, and I always 50/50 the fixture before I power it down, but all in all, I think you should be OK just cutting the power.
     
  4. sparky_vision

    sparky_vision Member

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    Radiant,

    As far as I know, shutting the fixtures completely off won't hurt the lamps unless there's a sudden, extreme temperture change involved. (Like, saying attempting to replace a hot lamp, which you should obviously never do.) The MAC 600s particularly have the huge cooling fins which take care of a lot of heat. (The fan in the head blows on the glass, not the lamp.)

    Letting them cool won't hurt at all, of course, but it isn't stricly necessary unless you're pulling the lamp out.
     
  5. Grog12

    Grog12 CBMod CB Mods Premium Member

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    The problem isn't the lamps sparky, its the electronics inside the moving light.

    If a fixture has a fan I don't power them off for 5-10 minutes after lamp off. If it has a heat sink I'm a little more leinant as heat sinks work even when the fixture is powered down.
     
  6. Sony

    Sony Active Member

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    I have to agree wih Grog, the fans aren't only to cool the lamps but also to cool the electronics inside the fixture. Running the fans after shutting down the fixture keeps the still VERY HOT lamp from overheating the nearby electronics and possibly damaging something. Since the lamp even though not at operating temperature is still MUCH hotter than the operating temperature of the electronics that control it.
     
  7. Radiant

    Radiant Active Member

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    I'm sorry, I should've been more clear. I indeed do shut off the lamp before turning off the breakers. The interval that I'm pondering is the time between when the lamp is doused and when the fans turn off (when the breakers are turned off).

    Our Coemar LXs and MAC 600s both have fans. Additionally, the MAC has a heat sink. The Coemars all have stepper motor failures, save the one that my friend at the PAC serviced for us. All of the motors in it were sticking or seized, which he said is caused by heat. It is too cost prohibitive at this point to replace all the motors for the other three instruments. The MACs thus far have no such issues, and I'd like to ensure they never do. It would be an inconvenience to wait 20 minutes before shutting off the power, but I'll do it if it increases their lifespan.
     
  8. sparky_vision

    sparky_vision Member

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    You're right, Grog, it's not just the lamp that the fans are protecting. At least in the 600s though, the PCB interconnect and motors are in the arm, far away from the lamp. And the fact that Martin made the fixture head a giant heatsink certainly helps matters.

    That being said, I can't speak for the Coemars. The only Coemar light I've ever teched was the iWash Halo - so there's every chance your motors were damaged by heat. I know the Halos have heat issues - the first piece of glass to go is almost always the magenta flag, which is closest to the lamp. (If memory serves)

    If you've the time, by all means, let them cool, it's probably better. At least for the MACs though, if they were my fixtures I wouldn't be terribly concerned about yanking the power right after I doused the lamp if I didn't have the time to let them cool. Motors always eventually wear out and need to be replaced, though overheating will certainly speed them on their way.
     
  9. TimMiller

    TimMiller Well-Known Member

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    if the fixture is convection cooled such as a mac 600 or studio spot/color i just kill the power. Cyberlights i kill the power (it is much easier than trying to get them to lamp off). Mac 500's and especially the pals, i let them cool down until i have to kill power for whatever reason. The main reason why there is a fan in the head of the mac600 was to get around a lawsuit from highend over convection cooling (anyone remember the mess between studio color and mac600) That little fan is pretty much worthless.
     

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