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Author Topic: Xenon Bulbs Exploding after about 1200 Hours Cary Neumann Film Handler Posts: 2 From: Cloquet, MN, USA Registered: Apr 2003 posted 06-11-2003 03:17 AM                     I have had problems the last few months with Xenon bulbs( 2 different manufacturers) exploding after about 1200 hours in 2 of our 6 lamphouses. 2 Bulbs in each of the 2 lamphouses. Any ideas on what might be happening? Thanks, CARY  |  IP: Logged Mike Pennell Expert Film Handler Posts: 150 From: Tucson, AZ, USA Registered: Apr 2003 posted 06-11-2003 03:49 AM                     Are the blowers and the exhaust working properly? The squirrel cages get pretty cruddy sometimes. Fingerprints on bulbs? Are you letting the bulbs cool down long enough at the end of the nite before the power is turned off?  |  IP: Logged Andrew Duggan Expert Film Handler Posts: 127 From: Albany, NY, USA Registered: Jun 2002 posted 06-11-2003 03:53 AM                        Hey Cary. Do you have any more information about this problem that you can provide? What kind of lamphouses and power supplies are being used? What kind of bulbs were these, both manufacturer and power rating (1600 watts, 2000 watts, etc.)? Did you take any actions since then, like opening the lamphouse with a multimeter to check and see if maybe you're running too much power to the bulb(s)? Any more info you can throw out there will probably help a lot in figuring out the problem. It's a bit of a shot in the dark right now, but I'm going to go out on a limb and say that either A)You are running too much current to the bulb (you should open up your lamphouse and test this manually with a decent ammeter, since many of the built-in meters on lamphouses are notorious for being horribly, terribly wrong....Lumex...I am looking in your direction...) or B) The ventilation on your lamphouses is inadequate (Another baleful stare at Lumex...). These are both easy problems to remedy, but like I said they are both just blind assumptions, and as we all know, assumption is the mother of all f*ckups... Hope this helps a bit.  |  IP: Logged Dick Vaughan Phenomenal Film Handler Posts: 1032 From: Bradford, West Yorkshire, UK Registered: Jul 2000 posted 06-11-2003 05:48 AM                        More importantly what type of lamp are they and what are the manufacturers recommended maximum hours? Is 1200 hours greater than 25% over this figure?  |  IP: Logged German Marin Expert Film Handler Posts: 227 From: Verbania (VB), Italy Registered: Jul 2001 posted 06-11-2003 07:05 AM                     Important: The way it were handling before and during its installation. I've seen bulbs horrible shipping and it cause the quarz break. One day my workmate took a lamp because he'd go to a booth to change it and sudendly it explode (It was lying on the desk). The bulbs explodes during it were running? or at night while nobody's there?  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 06-11-2003 10:58 AM                     Let's assume that nothing visible has changed in your lamphouse. Nobody had tinkered with the current taps. Nobody is mis-installing or mis-handling the lamps. You do everything the way you used to do it, only now the lamps explode. The VERY first thing I would do is check ALL of your ventillation pipes, inlets and outlets to make sure everything's working correctly. Check out your roof ventillator to see if it's running. Check the blower inside (or that blows inside) the lamphouse. Make sure all the duct work isn't clogged up with dust bunnies. Make sure that no birds have come along and built a nest in your ventillation pipes that go up to the roof. Check the air flow to see if there is an air stream blowing right on (or right near) the lamp itself. Compare the results of the "suspect" lamphouse with the results of a test on an identical "known-good" lamphouse if you can. I KNOW somebody is going to holler for this suggestion but here goes... A lit cigarette makes a good "air flow tracker". When held near the exhaust duct, the smoke should almost instantly get sucked out and none of it should linger inside the cavity. If you don't like the idea of cigarettes in your booth, even for the short time it takes you to do this test (then you put the cigarette out and throw it in the trash) you can use a candle or a wooden match. Just light it and let it burn for a short time then blow it out. It will produce 10 - 15 seconds worth of smoke that you can do the test with. One dead give away that your lamps are overheating is when you look at the metal ends of the lamp that are left over after the explosion. IF they are darkened or even "rainbow" colored (Blue and yellow and orange, etc.) you KNOW that the lamp it getting too hot. The first likely cause of that is lack of ventillation. The second likely cause of that is putting too much current through them. Like I said, though, I'm assuming that everything in your equipment looks the same as it was before and nobody has been tinkering. That puts the "too much current" theory into second place. Check your ventillation first and then check other things.  |  IP: Logged Tom Sauter Expert Film Handler Posts: 163 From: Buffalo, NY, USA Registered: Sep 2000 posted 06-13-2003 10:31 AM                        A third cause of overheating discoloration on the lamp ends is a poor electrical connection at the lamp. You may notice discoloration on the anode/cathode lead insulation.  |  IP: Logged Cary Neumann Film Handler Posts: 2 From: Cloquet, MN, USA Registered: Apr 2003 posted 06-17-2003 12:23 AM                     We are using; Perkin Elmer: XM 2000H/VC/G and LTI: LTIX 2000W-H XENON short arc lamps. in Lamphouse Strong Lume-x; Model: 65001-1 I will check all your suggestions to check if we can see what's going on. Everything appears to be working properly, and we always allow 20 minutes to cool down before shut down. Thanks to all for your suggestions talk to you later, Cary  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 06-17-2003 10:16 PM                     The blower in the SLX is prone to clogging. If the rotor vanes are coated with grease and dust (the normal situation) take the blower right out and disassemble it, remove the rotor and then the motor. I usually use gunk and then hot soapy water plus a lot of scrubbing to get the rotor and housing clean. Oil the motor's bearings (don't wash the motor!) while you have it out out and the oil holes are accessible. You need an exhaust fan, not just the internal blower. The internal fan should freewheel (without power) on the suction from your exhaust fan. The quartz glass envelope of the lamp is happy at ridiculous temperatures, but the seal - the area where the glass attaches to the metal electrodes - must be kept relatively cool. Overheating the seal area can cause either a leak (which is boring but still kills the lamp) or an explosion. The problem is the difference in thermal expansion rates between quartz and metal. The seal is made of a special glass that has an expansion rate that's supposed to compensate but it only compensates up to a certain temperature, at which point something gives. The cathode seal is usually not a problem, it's right in the airflow through the mirror hole and not in the light beam. The anode seal is not directly air-cooled and it's right out there in the centre of the light beam. If the alignment is correct it should be in a cone of low intensity light though. Misaligning the lamp can focus a LOT of heat on the anode end of the lamp. If the whole lamphouse is misaligned to the projector, the odd lamp alignment required to get decent light on the screen can do the same thing. If you use heat filters make sure the glass is at a slight angle, the heat gets sent straight back to the lamp otherwise. Most likely problems: either the cooling is insufficient or you are overdriving the lamp. Check the accuracy of the ammeter. The rectifier you have is sensitive to input voltage fluctuations. Possibly your line voltage goes up occasionally and thus increases the current too much? This is fairly common where a major power user is nearby - industrial areas or entertainment districts, also in rural locations where a single power feed covers a large area. I've run into this where setting the lamp current during the day when a nearby industry is running led to very high operating current at night when the factory is shut down.  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 06-18-2003 12:43 AM                        I got an email from one of my suppliers last night. He specifically mentioned Perkin Elmer bulbs, saying that they were getting their bulbs made in China and "they're popping like popcorn".  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 06-21-2003 03:54 PM                     I was told the PE has sold the xenon lamp division to a chineese business concern  |  IP: Logged Aaron Mehocic Jedi Master Film Handler Posts: 804 From: New Castle, PA, USA Registered: Jun 99 posted 06-21-2003 10:09 PM                     Mark Gulbrandsen has mentioned this in a few of his posts in other threads. Once again quality goes down the shit shoot due to corporate sell outs and "realignments". ORC made a good lamp, but since Perkin-Elmer took over, there have been noticible shortcomings in their product to say the least. The Soviets sold a lamp that would often explode prematurely. I wonder if this is the ChiCom's version. Lets hope not.  |  IP: Logged Gracia L. Babbidge Jedi Master Film Handler Posts: 709 From: Bowdoin, Maine Registered: Aug 2000 posted 06-23-2003 11:56 AM                        One theatre I was at once purchased a few xenon lamps from a newer company that had 'Hollywood' in their name. And I'd advise against getting xenons from them. We had one of the Hollywood lamps running on screen 9, and an Osram lamp on screen 8, and not only did the Osram put about twice as much light on-screen, it long out-lived the Hollywood piece of - which blew up in the lamphouse somewhere between 800 and 1000 hours, whereas the Osram was at 5000+ hours when it got swapped out. I know, I know, it should have been changed sooner, but things didn't work out that way...  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 09-05-2003 07:03 AM                        I just had my first bulb explosion last night. It was more of a "crash" (like a big plate glass window breaking) than a "boom." This was one of our kick-ass (not) LTI 2000 W/H bulbs--running at 75 amps and with a whopping (not) 1200 or so hours--in a Strong Highlight II lamphouse, and it happened mid-show. I was maybe twenty feet away (working at the rewind bench) when it happened. The explosion was violent enough to crack the green window in the shutter guard (Simplex X-L PR1014 projector). It also caused visible damage to the (metal) reflector and left bits of quartz all of the lamphouse and shutter guard area of the projector. The weird thing is that the positive (anode?) end of the dead lamp almost looked burned--not melted. Not sure if this happened as a result of the explosion or if it caused it. There wasn't any visible damage or charring to other parts of the bulb, and all connections appeared to be tight. Obviously, we'll be sending the bulb (what's left of it, anyway) back to LTI to see what they say, but my current thinking is that this was a defective bulb. The lamphouse/rectifier is fairly new (five years old) and we were getting 4000+ hours with Osram bulbs and 2500 or so hours with LTI bulbs. I suppose that the ammeter might be defective, but that seems unlikely given the lifetimes that we were seeing with other bulbs and given that we have never run 2k bulbs at more than 80 amps. We lost the rest of that show (platter house with one machine per screen), but the second show (with new LTI bulb) ran fine, and the damaged reflector didn't seem to affect image quality. As a side note: are there any automation systems which use a photocell (or other device) inside the lamphouse and will kill the show if there is no light? If there hadn't been someone in the booth when this happened, the audience could easily have been left sitting in the dark until someone complained to an usher.  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 09-05-2003 07:22 AM                     The "burned" anode definitely points to a problem. There's no heat made after the explosion so either the heating caused the failure, or possibly the anode managed to short to ground after the explosion but that would show some arcing damage to the metal. Automation-wise, I'm only familiar with the Strong CNA automation that has a lamp fail shutoff. They attach a magnetic sensor - identical to their newer door switch sensor that uses the little magnet on the door - to a lamp DC cable. This switches in the magnetic field from the lamp current in the wire. Undoubtedly some other automations have a similar feature.  |  IP: Logged

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