Film-Tech Forum ARCHIVE: Xenon Bulb Life Time

This is topic Xenon Bulb Life Time in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Marin Zorica (Member # 1716) on 12-05-2005, 10:55 AM:

Ok, xenon bulb average service time is between 1500 and 2000 uhrs, but what is the average time for exchanging bulb?

Normally is it operate at recommended conditions?

How often do you exchange xenon bulbs?

Posted by Dominic Espinosa (Member # 2122) on 12-05-2005, 01:05 PM:

The warranty period is usually between 2000 and 2800 hours. After which if it blows up in your lamphouse and damages your reflector or other parts the lamp company won't pay for the repairs.

Most theaters don't change them based on hours used however.
Most rely on light output and try to squeeze the most out of every lamp.
Since every lamp is different some will last less than warranty, others will last for two, three, or four times the warranty period before they start getting too dim.
I say as long as it's still bright and not flickering you're in good shape.

We rotate our lamps ever 500 hours as per our lamphouse manual's instructions. Apparantly it helps.

Hope that helped.
Good luck.

Posted by Monte L Fullmer (Member # 2797) on 12-05-2005, 01:58 PM:

Interesting. What breed of bulb that has a 2800 hr warranty posted on it, per any chance?

Good rule of thumb is the 50 percent over warranty hours of any bulb size to achieve the maximum usefulness of the bulb. (example: a 2k bulb should be pulled out at 3000 to 3200 hrs after the install hours..). But the real sad thing is that bulbs start to lose their light efficency 25 to 50 percent after install hours

Any hours over is when the bulb's efficency and output begins to lessen.

Plus, with bulbs that has moogoo hours on it, the light output has gone muddy due to the gas inside has seen better days, the quartz has begun to weaken, or even have begun to darken for chance of explosion, gas loss, weaken end seals,et.al. , arc points inside the envelope are shot, have widen causing increased igniton pulses, amperage and voltage use which could tax the rectifier(s).

Some theatres worry about the dollar sign instead of quality presentation with recommended bulb changouts when needed.

-Monte

Posted by Robert E. Allen (Member # 1351) on 12-05-2005, 03:04 PM:

Just before I left Regal my GM told me he had been instructed by the home office to change his 4500w lamps every 1200 hours.

Posted by Louis Bornwasser (Member # 3063) on 12-05-2005, 03:36 PM:

With everything perfect I can reliably get 4500 hours on 2000 watt Osram. Naturally I overlamp. Other wattages are about what Monte suggested.

Osram's warranty is based on the point where 20% light loss is expected. Hence 2400 hrs at 2000 watts is where 20% of the light is expected to be gone. Naturally, if you start slightly low, you can reduce your light loss by increasing current. Louis

Posted by Brad Miller (Member # 2) on 12-05-2005, 04:19 PM:

quote: Dominic Espinosa
The warranty period is usually between 2000 and 2800 hours.

Lamp sizes are different. You must have small wattage lamps burning in your theater.

Posted by Monte L Fullmer (Member # 2797) on 12-05-2005, 05:25 PM:

quote: Robert E. Allen
GM told me he had been instructed by the home office to change his 4500w lamps every 1200 hours.

..the same here when I was with EDWARDS in our Christie SLC nd Refrence consoles - to pull these bigger lamps (4k, 4.5k and 6k) with no more than 1400 hrs on them since these big bulbs loses their light brilliance so quickly.

Kinda sad to had to bust these bulbs that looked so new, but with this required replacement hours on these big bulbs, they had to go no matter what.

..but I heard that LTi's (especially the Helios) have a greater endurance of light output in these larger sizes that they can stay in longer in consoles..

thx-monte

Posted by Brad Miller (Member # 2) on 12-05-2005, 05:45 PM:

That's not what I've heard from techs I know who have used them. No matter how you slice it, you cannot beat the usable lifespan on a Christie lamp in a Christie console. Some of the money crunchers making purchasing decisions should really do the math on this, as theaters could save a lot of money in operating costs.

Posted by Mike Spaeth (Member # 524) on 12-05-2005, 05:48 PM:

I have Strong consoles and have seen 2k Christies run in excess of 7k-8k hours with no noticeable flicker. That's all I needed to see to start buying the $50 more expensive Christie bulb!

Posted by Monte L Fullmer (Member # 2797) on 12-05-2005, 06:11 PM:

Gee, Mike - I bet when you pull them 2k Christies bulbs with that many hours on them, I bet when you pop these, they don't pop-just shatter (from the weakened quartz) since the gas pressure inside of them is so low from being all worn out.

Must be newer X-90 consoles with those compact "switchers" inside then to keep bulbs in them that long with excellent exhaust pulling through them-in as well as pretty "clean" power going into the building.

-Monte

Posted by Dominic Espinosa (Member # 2122) on 12-06-2005, 12:01 AM:

quote: Brad Miller
You must have small wattage lamps burning in your theater.

Indeed we do, Brad.

I failed to mention that.

Posted by Marin Zorica (Member # 1716) on 12-06-2005, 05:23 AM:

Hmmm, on mine opinion for lamps to 2500W i think 3000 uhrs is working period, here we widely use vertical xenon lamps is single screen theatres.

Also one thing is very interesting, what is about mirrors?

I and most people heer use Meopta cold mirrors for vertical lamphouses.

They are pretty good, and i exchange some what are been in projector for over 15 to 20 years.

Posted by Monte L Fullmer (Member # 2797) on 12-06-2005, 01:09 PM:

Oh Shoot! Verticals - danged things will burn forever then. I've seen 2k's in ORC/CFS consoles run 12k hours and still have some life in them...even though the envelope is blacker than pitch by this time... [Wink]

-Monte

Posted by Jack Ondracek (Member # 1466) on 12-06-2005, 01:19 PM:

Hmmmm.... that would make the lamp about as efficient as the mirrors in those things, right?

Posted by Marin Zorica (Member # 1716) on 12-07-2005, 07:19 AM:

quote: Jack Ondracek
that would make the lamp about as efficient as the mirrors in those things

I've seen couples get 5000-10000 and still burning!

Even there are situation with poor mirrors that bulb over lived mirror life time!

So what you thing for vertical xenon bulb of 2,5KW what are time for changing?

Also how if bulb rotation effective in vertical and horizontal lamp house, and how many time needs it?

Posted by Christos Mitsakis (Member # 143) on 12-07-2005, 11:10 AM:

Marin,
In vertical configuration lamphouses the bulbs don't need rotation since the plasma burns steadier. Also from experience, a horizontal burning bulb doesn't need rotation if steady burning is acomplished by a well controled magnet. If the quartz begins to darken then rotation is needed and it is time also to check the magnetic stabilization.

Christos

Posted by Monte L Fullmer (Member # 2797) on 12-07-2005, 01:00 PM:

Even with verticals - use the recommended changeout period listed with the bulbs.

Rotation isn't needed with the verticals.

Why bulbs get rotated is so the deposits doesn't gather on one place in the envelope, plus with bulbs in the horizontal position, the electrodes will sag over time is another reason to prevent this sagging with rotation.

Yet, some consoles cannot have their bulbs rotated - like the Christies due to the bulb's cathode end is a threaded pin (HTP) and the threaded end must be secure and fit snug to the collector nut that the pin threads into.

Posted by John Pytlak (Member # 331) on 12-08-2005, 10:45 AM:

quote: Monte L Fullmer
Yet, some consoles cannot have their bulbs rotated - like the Christies due to the bulb's cathode end is a threaded pin (HTP) and the threaded end must be secure and fit snug to the collector nut that the pin threads into.

For those who prefer to rotate lamps, don't some use a "spacer washer" that is just thick enough to have the lamp tighten into the cathode mount to rotate 180 degrees?

Posted by Daryl C. W. O'Shea (Member # 1303) on 12-08-2005, 12:45 PM:

Yes.

Posted by Monte L Fullmer (Member # 2797) on 12-08-2005, 02:21 PM:

True, but the last time I did a HTP bulb the washers weren't included in the box and found out that bulb rotation for the HTP bulbs wasn't necessary since the insertion of the washer brought the focus to the aperture in tighter and most theatres weren't backing the bulb slightly to compensate for the slight forward placement of the bulb with the washer insertion.

Posted by Louis Bornwasser (Member # 3063) on 12-08-2005, 04:31 PM:

Osram no longer requires rotation for warranty purposes. I sometimes rotate anyway to extend the life. (3500 hours and am little darkening has occured...moves the darkening to another spot on the bulb.)

Posted by Phil Blake (Member # 2012) on 12-11-2005, 12:35 AM:

I have experienced the same as Louis Bornwasser stated , getting 4500 hours from 2K Osram . Light is still good at those hours , just lamp striking difficulties become a problem so we change at 4500hrs.

Posted by Richard Hamilton (Member # 321) on 12-11-2005, 05:25 AM:

quote: Monte L Fullmer
True, but the last time I did a HTP bulb the washers weren't included in the box and found out that bulb rotation for the HTP bulbs wasn't necessary since the insertion of the washer brought the focus to the aperture in tighter and most theatres weren't backing the bulb slightly to compensate for the slight forward placement of the bulb with the washer insertion.

That doesn't make sense, just because people don't change the focus of the bulb, a bulb manufacturer suddenly says that it isn't necessary? That would be like a projector company saying "because people don't check the oil, it is no longer necesarry, just wait until the machine starts to act up, then change the oil".

If someone changes a bulb, but doesnt know how to check the light on the screen afterwards, they have no business changing bulbs. If they are too lazy, then they shouldn't even be in the booth.

Rick

Posted by Mark Gulbrandsen (Member # 72) on 12-11-2005, 08:25 AM:

You guys are only getting 4500 hours [Roll Eyes]

.... Not that I promote it but we have many customers that run their Christie Lamps past 10,000 hours... a few make 15,000 hours and these lamps come out clear but become hard to ignite! At one small plex in a smallish town I was the first tech to change lamps after the plex had been open for 7 years [Eek!]

. I've come to the conclusion that any other brand really is false economy.

Mark

Posted by Steven J Hart (Member # 2340) on 12-13-2005, 07:02 PM:

quote: Mark Gulbrandsen
You guys are only getting 4500 hours .... Not that I promote it but we have many customers that run their Christie Lamps past 10,000 hours... a few make 15,000 hours and these lamps come out clear but become hard to ignite! At one small plex in a smallish town I was the first tech to change lamps after the plex had been open for 7 years . I've come to the conclusion that any other brand really is false economy.

Mark

Do you recomend Christie lamps for all brands of consoles and lamphouses, or do you get these great results from Christie bulbs installed in Christie equipment?
Steve

Posted by Frank Dubrois (Member # 3042) on 12-16-2005, 01:34 PM:

We use Christie and Strong lamphouses. No matter what watt bulb we use, 2000-4000, we seem to get mearly 2000 hours. I thought we were supposed to get close to 3200 on the 2000 watts, and about 1800 on the 4000 watt. I'm not one to run bulbs over 50% pas their warranty, however, with the 2000 watt bulbs, we basically get warranty life out of them before they get too dim.

What is the final word on rotating bulbs inside Christies? We also have the screw in type, and found the washers needed to rotate are only about $1. To me, its worth the $1, to my company, it apparently isnt. Do they know something I dont?? or would the $1 spent per washer be worth it in bulb hours??

Posted by Louis Bornwasser (Member # 3063) on 12-16-2005, 01:40 PM:

Osram does not require rotating. However, others may require it to activate warranty. The washer should not be needed on -htp bulbs, since you can loosen the clamp, unscrew what you need, then retighten. (Other Christie lamps use the nut supplied with the bulb so there is no problem in rotating.

Anything done to lengthen the useful life is probably worth it If in doubt, do the math: Cost divided by useful life= cost per hour. Louis

Posted by Frank Dubrois (Member # 3042) on 12-16-2005, 06:44 PM:

Well, I tried to get one washer ordered in able to show whether or not it would actually extend the life of our bulbs, but no good. Not needed aparently. Oh well.