Lycian Spotlight Cool Down Time

[WooferHound]

Our theater has 3 Lycian 1290xlt spotlights. Looking at the manual it has a page worth of stuff written about turning it on and lamp life, but it does not say anything about turning it off or cooling it down. A senior member of our crew will turn off the lamp and then turn off the fan a few moments later. I can't say anything different to him because there isn't anything in the user manual to back me up. Also I can't think of how any harm can come to the spotlight if you don't cool it down.
What do you guys think ?

 

[derekleffew]

As the Lycian 1290's lamp is virtually identical (maybe the exact same lamp?) to the Strong Xenon 2K Super Trouper, see http://www.controlbooth.com/forums/lighting-electrics/7785-strong-super-trouper.html .

EDIT: Hmm, Alabama!?

 

[Pie4Weebl]

Here is my logic with arc lamps, and I realize many people feel differently about the topic, but this is my opinion. The purpose of a fan is to prevent the light from exceeding its operating temperature and over heating right? Well then, it isn't going to get any hotter after its turned off, so the fan doesn't really do anything but cool it down faster. That can be good if you have to pack it up, but otherwise isn't a huge deal for a house spot.

.02

 

[derekleffew]

...Well then, it isn't going to get any hotter after its turned off, ...

Don't you ever watch the Food channel?

From Carry-Over Cooking: Cooking Terms: RecipeTips.com :

Referred to as the resting time or the resting period, Carry-Over Cooking is a length of time during which the temperature in the food continues to rise 10ºF to 20ºF once the food is removed from the oven or cooking area.

Perhaps not a big deal for most discharge lamps, but for Xenon lamps which operate at up to 30 atmospheres of pressure when lit, not a good idea.

 

[aemeeich]

Don't you ever watch the Food channel?

"From Carry-Over Cooking: Cooking Terms: RecipeTips.com :
Referred to as the resting time or the resting period, Carry-Over Cooking is a length of time during which the temperature in the food continues to rise 10ºF to 20ºF once the food is removed from the oven or cooking area."

Perhaps not a big deal for most discharge lamps, but for Xenon lamps which operate at up to 30 atmospheres of pressure when lit, not a good idea.

The science behind carry over cooking doesn't apply to a discharge lamp. The reason food heats up an additional 10-20° is because that measurement is taken in the center of the food. When cooking, the center is always cooler than the outer surface. It is this heat migration from the outer surface of the food to the center that creates the 10-20° rise. The outer surface will not rise any higher than it was the instant it was removed from the oven - in fact it will start falling due to the migration of heat to the center and also losses to the air.

So in the case of a discharge fixture, the lamp itself will not rise any higher than it was the instant it was turned off, however, the surrounding housing will heat up higher than it was when it was being cooled by the fan. Depending on the materials in the housing, it could possibly get to a temperature that could be damaging. IE - the reflector might not like the increase in heat.

 

[Pie4Weebl]

The science behind carry over cooking doesn't apply to a discharge lamp. The reason food heats up an additional 10-20° is because that measurement is taken in the center of the food. When cooking, the center is always cooler than the outer surface. It is this heat migration from the outer surface of the food to the center that creates the 10-20° rise. The outer surface will not rise any higher than it was the instant it was removed from the oven - in fact it will start falling due to the migration of heat to the center and also losses to the air.

So in the case of a discharge fixture, the lamp itself will not rise any higher than it was the instant it was turned off, however, the surrounding housing will heat up higher than it was when it was being cooled by the fan. Depending on the materials in the housing, it could possibly get to a temperature that could be damaging. IE - the reflector might not like the increase in heat.

I was going to say touche to derek, but it seems you have one upped him! Good point about the reflector.

 

[hobbsies]

I had one of these lamps explode on me once and destroy the reflector. Turned the spotlight on at the start of tech and 3 minutes later BOOM!

Are the lamps in Moving lights and projectors arc lamps, and why is there a limit on some lamps on how long the lamp can be re-struck after turning it off?

 

[mstaylor]

I turn both Lycians and Supers off without really cooling them with the fan is they are staying in place. If they are being packed for transport or rolled to storage, I will cool them down with the fan so the movement doesn't rattle a hot bulb. Is that the correct thing to do, don't know but it has worked for me for at least 30 yrs.

 

[JD]

I had one of these lamps explode on me once and destroy the reflector. Turned the spotlight on at the start of tech and 3 minutes later BOOM!

Are the lamps in Moving lights and projectors arc lamps, and why is there a limit on some lamps on how long the lamp can be re-struck after turning it off?

Many movers use HMI which works like a mercury vapor lamp. (Technically Metal Halide.) Xenon does not use any metals or halides, and always requires quite a kick voltage to get them going. HMI uses metals, and when cold strike at a more reasonable voltage. When hot, however, they require a lot higher of a voltage, so many ballasts can not hot re-strike them. Some can.

 

[ship]

As a general policy, before you remove the lamp for transport (as you should in the 1290XLT) or turn the fixture fan off, stick your hand up towards it's cooling vent. If cool enough that it's heated some but not burning or substantially hot, it's safe to do work on it. Better yet cooler than heated. By the time you remove the cover screws and apply your safety gear, the lamp should be cool enough.

Simple policy I learned for dealing with such lamps and in almost 12 years, I have never exploded one. Sorry, never exploded one.

We are talking about how much $$$ per lamp? What's your time in pay grade in waiting a few more minutes to remove it - this even if instructed to rush. Your instructor is wrong and lucky so far. Want's to play his game, hope you are not the person playing it for him.

Beyond the Manual, Steve from Lycian is a very useful person to contact. Contact them and have them send these specifications you need.

 

[derekleffew]

Admittedly, the 1290 Manual.pdf is not as clear as it could be, and certainly not as clear as Strong's. However, page 10, under Troubleshooting...

indicates that the fan should be operated for a period of time after the lamp has been extinguished.

I really fail to see how this continues to be a debatable topic. I can think of very few instances where disregarding a manufacturer's printed instructions results in any actual benefit.

 

[WooferHound]

I had not actually seen that bit in the Lycian manual. But it says not to cut off the fan without a sufficient cool down time, while never specifying the length of the cool down time. How can I possibly follow the manufacturer's instructions?

 

[ship]

I had not actually seen that bit in the Lycian manual. But it says not to cut off the fan without a sufficient cool down time, while never specifying the length of the cool down time. How can I possibly follow the manufacturer's instructions?

Urr. is it -20F or +130F where you are working? Might be a bit of a difference in operating temperatures for say that fan either heating the lamp sufficiently to cool down properly without shock, or or in cooling it down sufficiently.

Assuming that concept of operating conditions, either manual could be written better in advice but has to follow legal stuff also. That's where proper training comes in. Your instructor is clearly incorrect which than leaves you with a problem of concept for cool down, verses his own concept in policy. Doing what you are told by your superviser, or in knowing better perhaps getting laid off at some point due to a certain shortfall in budget - this in part say from a weeks worth of pay for one lamp that went "bad". This in no part due to turning off the fan's too soon of course and I'm sure the person instructing you in being lucky has never found a problem with - and it won't be him that gets laid off during that budget fall.

Expense of the lamp, time to clean if not even replace the reflector if you can without sending it back to the factory for that - I do at many times the cost of a lamp. If your boss would stand up for you in following policy and a problem with it, and this won't in any way reflect on the amount of time you might get laid off later.... sure if presented other more sensible concepts, go with what the boss says.

Otherwise you have a problem in following or asking about his policy given other info. Asking perhaps about the concept of cool enough you can put your hand next to the vent and it's warm and not hot as a concept.

Assuming an XBO 2000HS.ofr lamp, one could also search out the instructions for the lamp you are using in advice it could give from the website. Could also search out Mark from Osram from this website for advice on this concept for the main lamp used in the fixture.

In the end, where you work and your boss in policy might not always be correct, than a question of changing policy or living with it.

Sub note... I did once explode one of these lamps and it was loud. This was at room temperature and while inserting it into a 55gal. drum for disposal I hit the fill pinch in bumping it and it did explode. Luckily it was in felt wrapping and didn't injure people - the noise alone set people on edge. Even if cool, the concussion of a hand grenade and yes I have thrown them before. Even if cool... such lamps are dangerous to work with. Concept possible that negative verses positive pressure in cooling in possibly when at a mid-point, it's not explosive in a concept... possible, I would not attempt to measure what that level is. Such lamps are dangerous.

 

[derekleffew]

...Sub note... I did once explode one of these lamps and it was loud. This was at room temperature and while inserting it into a 55gal. drum for disposal I hit the fill pinch in bumping it and it did explode. Luckily it was in felt wrapping and didn't injure people - the noise alone set people on edge. Even if cool, the concussion of a hand grenade and yes I have thrown them before. Even if cool... such lamps are dangerous to work with. ...

I hope you've changed your ways since then.

From Ushio's Lamp Safety - Support

XENON ARC LAMP DISPOSAL
* Xenon arc lamps must be disposed of in a careful and proper manner in order to prevent injury.

1. Wear a protective mask, leather gloves and protective clothing when handling a spent lamp.
2. Place the used lamp in its original protective case and original cardboard packaging (box) that was provided when the lamp was new.
3. Firmly attach tape around the original cardboard box to seal the lamp securely.
4. From approximately three (3) feet in height, drop the cardboard box, with the lamp and protective case inside, onto a hard floor to break the lamp.

However, I can see dropping a packaged lamp all day long and not have it break.

Here's what I was told by Strong:
1. Don all appropriate PPE.
2. Place lamp inside its protective covering.
3. Wrap in a bath towel.
4. Outside, hit it with a hammer.
5. Discard all appropriately. The tungsten cathode and anode may have some recyclable value.

From the same site as cited above is this sight:

Never touch the lamp when it is on, or soon after it has been turned off, as it is hot and will cause serious burns. Lamps should be allowed to cool for a minimum of ten (10) minutes after the lamp is turned off.

One can, and probably should, interpret that to mean forced air cooling for ten minutes.

...How can I possibly follow the manufacturer's instructions?

Interpret the manufacturer's "cooled sufficiently" to mean "reach approximate ambient temperature." As ship noted, the manufacturer has no way of knowing what your room temperature is. One wonders why manufacturers don't simply put in a thermostatically-controlled fan, like overhead projector s used to have.

 

[ship]

I hope you've changed your ways since then.

From Ushio's Lamp Safety - Support

However, I can see dropping a packaged lamp all day long and not have it break.

Here's what I was told by Strong:
1. Don all appropriate PPE.
2. Place lamp inside its protective covering.
3. Wrap in a bath towel.
4. Outside, hit it with a hammer.
5. Discard all appropriately. The tungsten cathode and anode may have some recyclable value.

Something for my boys to work on I think than for disposal. Almost 20 years since I thru a hand grenade and I have no wish of throwing more if asking about such a thing.

On the othere hand, if asking about the above breaking the envelope instructions... no I have not in the past followed that above from a big huge MVR1500/U/Sports lighter lamp to even outer globes to MSR 250/2 lamps in saving space at $1K per 55gal. drum to recycle. Might be a good thing to do for me. Enough of them in safely contained have exploded on my work table in having to clean up after it than I would wish.

Still though, thanks for the info in crushing outer globes to some lamps. This with protection... my guys are searching for a project this week anyway, time to give them something to do that would be loud enough to be fun. I'll provide supervision but be glad for the space savings on the drum and not having to approach it with another load of lamps with caution should some bad lamp under explode.

None the less, that's disposal and not working lamp cooling temp. and I stand by it. What's Ushio say about lamp removal for say the UXL-20SC which could work fine in the fixture, for lamp removal?

 

[PeteEngel]

The Xenon Lamp is a single element arc lamp that operates at over 30 atmospheres of pressure while operating and is under about +1 atmosphere of pressure cold. that means it will explode if broken cold, unless the ceramic seal has failed.
the fill pinch on a lamp is designed to keep the envelope closed and the internal fill inside up to a specific temperature. the forced air cooling keeps the lamp envelope and housing below a specific temp. it is a misnomer to think that because a lamp is extinguished, that it then goes down right away. without forced air cooling the arc has been extinguished, but the fan is not cooling the arc, it is cooling the quartz envelope, and once that fan turns off, there is a rise in temp on that envelope. a safe presumption would be a rise of at least 10% for as long as 5 minutes, though that time might be a bit long. i think all Xenon fixtures require a fan to operate while the lamp is off, while only some HMI fixtures require that. that is based on the safe temp rating of the fill pinch/envelope.
as a matter of course, running the fan for 5 minutes after lamp off should be enough to cool the envelope to a point where the fan could be turned off (in a house situation, not a touring/pack it up situation). i haven't read the Lycian requirement for cooling but that should be the first step. my rule of thumb for followspots is if i can put my hand on the top of the lamphouse and it is not hot to the touch (i can keep my hand on it) then it is cool enough.
We all have done things for years without harm that in hind sight (or with further information) we found was incorrect, even if nothing untoward happened.
i'm reminded of a class in explosives i took back in college (WAAAYYYY BACK). we were out at a strip mine during the final phase of a 1/4 mile shoot of a seam of coal. the lead shooter told us they had a 50 year experienced explosives expert on site. he was the go to guy for decades. they used electric ignition for the cap and used a resistance meter to make sure everything was good to the first cap. its quite an impressive site seeing 20' thick seam of coal and knowing that they've done the math on it to make sure that once the shoot is done all of the coal is broken to a point that all the pieces are no bigger than your fist. anyway, one day a sales man came in to show them the newest resistance meter available. everyone was around the sales man oooing and aahhing and when he said "and now even the battery compartment is easily accessed to you can change your batteryquicker than in your old model", the lead shooter said....

"what battery?"

he retired soon after. at least that was the story we were told. then they blew up about 4000 lbs of explosives. i guess you can see the moral of the story so i won't linger on it.

also, please note that HMI/MSR/USR etc lamps are not really under pressure cold, but they do contain, among other elements, Mercury. at room temp it is a liquid. it is a gas under operating temps. please don't dispose of in your normal garbage. (a 2500w lamp will have about a gram (? maybe a half gram, i've forgotten) of mercury in it. contact your sanitation company to find out about the local hazardous waste instructions.

 

[Les]

I'm reminded of this video, involving a movie projector lamp:

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YouTube - Exploding Projector Bulb