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Author Topic: Lamp Question Tristan Lane Master Film Handler Posts: 444 From: Nampa, Idaho Registered: Feb 2002 posted 04-27-2007 01:20 AM                     Monte's pictures provide a good example of the darkening that occurs on a Helios bulb after full warranty hours. I used to think this was a quality issue related to the tungsten used in the lamp. I changed my thinking after pulling an Osram 4200 watt helios style lamp @ warranty hours and it had exactly the same type of darkening directly above the gap. The darkening appears on the LTI 4200 helios as well. The Osram lamp was operated well within specifications, with adequate exhaust. The darkened envelope is probably due to how much closer the quartz is to the arc when compared to a traditional lamp. I'm willing to overlook this due to the increased light these lamps provide. My experience with Helios lamps has been great. I began using them shortly after they were introduced. I don't recall any major issues, or catastrophic failures. The occasional flicker happened on a few, but only after warranty hours were used. Company policy was to run lamps to a certain percentage over warranty, and then change the lamp. The lamps were changed regardless of whether they were still in good shape. Some of the houses I installed them in (which Monte is very familiar with) yielded light increases up to 30% on screen, and never dropped below the light level provided by the previously used lamps. This proved to be very economical in 5 houses where CXL-60 lamps were replaced with LTI 4200 lamps, with an increased light output, and more warranty-hours. The LTI lamp also costs considerably less than the CXL-60. In roughly 60 other screens that I serviced, we replaced the CXL-40/45 lamps with 3000 watt helios lamps with similar results. I suppose the opinion of the lamp depends on the user's expectations and needs. If you are looking for a lamp that will perform well long after warranty is up, stick with Christie. Their track record is hard to dispute. But the Helios lamps have their advantages, and LTI's quality and and track record has improved greatly in the past few years.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 04-27-2007 04:19 AM                     Course, I really can't blame LTI completely for their bulbs - be it poor manufacturing or QA situations. I do believe it all depends of what lamphouse/console one is using as well (it take two to tango in a lot of situations..) The two bulb examples that I presented in my earlier post came out of STRONG X-90 consoles (c) 1989 having the original switcher rectifiers (the big extinct suitcase variety) which by chance, are still plugging away quite nicely outside of the reports that STRONG switchers are lucky to last this long of 19 years. Yet, I have managed to gather 3800 hours out of an LTI LTIX-2000w standard bulb that was operated in a lot newer X-90 console with the newer compact suitcase switcher. So we see, it's not all LTI's fault My theory is that the LTI bulbs we did burn were more sensitive to aging switchers than with either OSRAMs or CHRISTIES, which could be more forgiving to high ripple situations that these older switchers could be emitting during operation. I do believe in Tristian's statement above on his testimony of the LTI's (in which these complexes that he mentions still uses the LTI Helios and have proven very successful in their operations) that they are a good bulb in certain aspects (which the light output is a definite winner with LTI's), but wonder if this make of bulb is more suitable for reactance (diode and transformer) rectifiers instead of switching rectifiers... It all works out in the wash somehow ... thx - Monte  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 04-27-2007 08:04 AM                     quote: Jon Miller but why would they want to hang onto a lamp some 14,000 hours past the Russian-roulette stage? Just to see how long its possible for a lamp to last. Envelope is still clear and the arc is stable. Years ago Marble lamps used to last this long and I can remember theor ads in Box Office mag listing the hours many locations went with them. quote: Tristan Lane LTI's quality and and track record has improved greatly in the past few years. Well, I don't quite agree its improved over the last few years... more like over the last year or so. Three years ago we were selling quite a few LTI lamps and none of them were even making rated hours except the odd one now and then. After they lost many customers they had to do something about the reliability problems... not referring to Helios here just LTI in general. The AMC's we service use them exclusively and thats where I've seen them begin to last longer and longer... now they at least make it past rated warranty hours on a regular basis. FWIW: We quit selling LTI because of reliability issues and because OSRAM gave us pricing that was consideraby better than LTI's... but we still sell Christie at the rate of about 20 to 1 vs. Osram. Mark  |  IP: Logged Jon Miller Jedi Master Film Handler Posts: 973 From: San Diego, CA, USA Registered: Sep 1999 posted 04-27-2007 10:32 AM                     Mark, that reminds me...a long time ago I read something (where I found it, I've long since forgotten) about a theatre getting astounding lamp life from their xenons powered by the pure DC from a motor-generator set from their carbon-arc days. No ripple, no electrode erosion. Maybe that is where Marble got their lamp longevity figures?  |  IP: Logged Dan Reiter Film Handler Posts: 74 From: Easton PA Registered: Jul 2002 posted 04-30-2007 12:42 PM                     We at SUPERIOR QUARTZ have been following this thread with a lot of interest, and wanted to interject our thoughts. First, Bulb Construction – The internal vessel pressures and arc length are the determining factors in the power level of any bulb. When changing the size and volume of the envelope, the pressure ratio of gas:volume must be maintained to meet lamp performance goals. Thickness of the envelope wall is a construction factors to ensure vessel strength. Seal designs, electrode design, seal placement, and so many design issues get mixed in. Tungsten quality was mentioned a few times. Gordon is accurate in the source and quality issues with Tungsten. There are very few reputable sources. We at SQP make sure we only use the highest quality Tungsten and Xenon available, and then use the most stringent processing methods to remove all contamination. In addition, our use of the foil seals, and our individual attention to every bulb makes ours the most labor-intensive bulbs available, yet we keep our prices competitive. This alone is one of the most critical factors in bulb life and performance, and is in reality very hard to replicate thousands of times, as each bulb burns in it’s own unique way. In addition, basic lamp construction techniques can affect the purity during the process. Internal quality control during the manufacturing process, as well as stringent QC methods is another critical factor in manufacturing good bulbs. And then throw in types of seals, electrode design, electrode support, material purity, and a billion other factors, and you can see how hard it is to make a bulb. There is a LOT more going on with construction than just how the bulb appears to the user. The other HUGE factor in bulb life is the equipment the bulb is in. Probably the most important. All aspects of the lamp section come into play. Cooling, as touched on previously, is critical. Is the blower clogged with dirt? Is there good airflow though the lamphouse, so you do not get a “hot Box”? Where the bulb is in the reflector even comes into play. Bulb mounting fixtures and stresses while in operation can come into play. Does the douser re-focus back on the bulb when it is closed? That’s a major bulb-killer. Then you look at the electrical side of things. Power supplies are a big factor. Magnetic or electronic, how much ripple is present. Is there a shorted or open diode the operator does not know about? Magnetic stabilization – Is there any, and is it still effective? DC cabling connections – is there a bad point? That will change the current and meter readings. Are the lamphouse meters accurate, so the operator is not either over-driving, or under-driving the bulb? Igniter – Is the spark-gap still within spec, so the ignition pulse is not destructive? Then you toss in the theater operators themselves. Do they rotate and/or maintain the bulbs? Do they allow auto-strike, or do they manually strike the bulb with long ignition periods? How many shows a day? There are so many factors involved with this, the best way to make ANY bulb last is to have a properly functioning system. Many opinions on this thread have shown that, and there are some very old bulbs still running. We formally invite all to visit our facility, and see how our bulbs are made. Thank You. If we can help in any way at SQP, please contact us.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 04-30-2007 03:56 PM                     Dan, Do you guys use any radioactive substance(Thorium)mixed in with your electrode tungsten? I've heard that some manufacturers do this in attempt to get longer lamp life. I suppose there may also be other resasons for doing this though. Thanks, Mark  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 04-30-2007 05:49 PM                     quote: Dan Reiter We formally invite all to visit our facility, and see how our bulbs are made. Is there any possibility of you posting some photographs of the production process?  |  IP: Logged Dan Reiter Film Handler Posts: 74 From: Easton PA Registered: Jul 2002 posted 05-01-2007 07:19 AM                     Mark, Most manufacturers use Thorium on the electrodes of Xenon, and other lamps, to aid ignition, stabilize the Tungsten, and yes, increase lamp life. Happily, the amount used is extremely small, less than in an average wrist-watch. I'll find some pics of the lamp process and post them shortly.  |  IP: Logged Tim Reed Better Projection Pays Posts: 5246 From: Northampton, PA Registered: Sep 1999 posted 05-01-2007 08:51 AM                       quote: Monte L Fullmer the anode plug Monte, what is this anode plug you keep referring to? You mean the cable? quote: Dan Reiter We formally invite all to visit our facility, and see how our bulbs are made. Thanks, Dan! I'll definitely take you up on that.  |  IP: Logged Dan Reiter Film Handler Posts: 74 From: Easton PA Registered: Jul 2002 posted 05-01-2007 11:03 AM                     Here are two pics of making a lamp, as well as the Xenon Lathe area...  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 05-01-2007 12:26 PM                     quote: Tim Reed what is this anode plug (lol) the big anode tungsten thingey in the bulb..Don't ask me how I came up with that name, just something I came up with when I began dealing with xenon bulbs back in the late 70's.  |  IP: Logged Tim Reed Better Projection Pays Posts: 5246 From: Northampton, PA Registered: Sep 1999 posted 05-01-2007 09:23 PM                       Monte! Haha! Okay, that IS the anode.  |  IP: Logged Justin West Master Film Handler Posts: 271 From: Peoria, IL, USA Registered: Jul 2001 posted 05-02-2007 10:54 AM                     quote: Dan Reiter Do they rotate and/or maintain the bulbs? Is rotating the bulb necessary, today?  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 05-02-2007 11:01 AM                        quote: Justin West Is rotating the bulb necessary, today? That's sure a good question, Justin. Opinions on this board are all over the place. My experience out here is that these bulbs seem to work best if you just keep them clean, check the connections once in awhile, and leave them alone. These things almost always go unstable on me if I rotate them. After that, it's just a matter of a short time before I get tired of looking at them & just put in new ones. "Your results may vary", but I seem to get the best life by leaving them in-place until I change them out. 4,000 to 7,000 watt bulbs... Christie, Superior Quartz, Osram... it doesn't seem to matter. In the past 5 years, I've installed new lamphouses, power supplies and blowers, with no change in performance from the bulbs. My screens look a lot better, though!  |  IP: Logged Dan Reiter Film Handler Posts: 74 From: Easton PA Registered: Jul 2002 posted 05-02-2007 01:02 PM                     Arc stability seems to be much more of an issue of the equipment the bulb is operating in. If the arc is steady and straight throughout the bulbs' lifetime, it will burn straight, and not damage or dis-figure the electrodes, and provide long, trouble-free life. If the magnetic stabilization is incorrect, the equipment is operating at enough of an angle to induce off-centered flame travel, there are excessive heating/cooling issues, or the DC curent is not smooth, the electrodes will suffer. Once an irregularity forms on the Annode & Cathode, then bulb roating is the only method available to try to "force" the arc to re-establish a straight path again, form a uniform pattern on the annode, and then regular maintenance, checking, and rotations become needed for the rest of that particular bulb's service life in order to obtain best and even light. Jack is also correct in his notes about the electrical connections. As soon as a major DC connection loosens up, it will both burn the DC cable at the point of the problem, and induce a problem with the lamp's performance. We at SQP have seen the specrum of lamp probems, and they can usually be traced to lamphouse issues.  |  IP: Logged

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