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Author Topic: Xenon lamp question David Rigby Expert Film Handler Posts: 134 From: Chorlton, Manchester, UK Registered: May 2002 posted 12-14-2004 12:08 PM                     Maybe a dumb one Is there any reason I can't use a horizontal bulb in a vertical lamphouse? What are the physical differences between horizontal and vertical lamps, other than length? David  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 12-14-2004 12:59 PM                        Xenon lamps were originally designed for vertical operation, which tends to produce a more stable arc plasma. The Osram publication "Technology and Applications of XBO Theatre Lamps" details the transition to horizontal operation, where "Not until 1970 were lamps successfully forced into the horizontal position, albeit with a resulting reduction in lamp life...". Horizontal operation was made possible by "firstly introducing magnetic arc stabilization and secondly by developing lamps with very short electrode gaps, high currents, and a new bulb geometry". Tilting a horizontal lamp "will result in markedly greater arc instability".  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 12-14-2004 07:57 PM                     Many verticle xenon systems were designed around using horizontal lamps such as the ORC and CFS styled consoles You will need to get the correct adapters to place the catode tip at the right point of the reflector  |  IP: Logged Barry Martin Expert Film Handler Posts: 203 From: Newington, CT USA Registered: Jul 2002 posted 12-14-2004 10:08 PM                        John, what are the PROS to horizontal operation? Or the CONS to vertical? It would seem to me that vertical lamphouses have all the benefits. And all the verticals I've seen have smaller houses too so they take up less space. Why did they convert?  |  IP: Logged David Rigby Expert Film Handler Posts: 134 From: Chorlton, Manchester, UK Registered: May 2002 posted 12-15-2004 08:55 AM                     Thanks for the info. I'm aware of the shorter length of horizontal bulbs but before I rush out to get adapters made to centre the arc in the mirror I figured it worth asking whether it's even sensible to try this. Lamphouse is a Cinemeccanica CX1600...is this one viable for use with horizontal lamps? David  |  IP: Logged Ray Kaufman Film Handler Posts: 16 From: San Pedro, CA, USA Registered: Apr 2004 posted 12-15-2004 09:37 AM                        Correct me if I'm ... But, aren't vertical lamphouses entirely different from horizontal. The few vertical I've seen incorporate a slotted reflector, wherein horizontal have a hole thru the 'bottom' or bsck of the bowl. Also, The houses themselves are quite a bit smaller. and the distance from the back of the reflector to the film is much shorter. I'd think that alone would make conversion difficult if not impossible. Sort'a like fitting a full sized car interior into a Mini.  |  IP: Logged Aaron Sisemore Flaming Ribs beat Reeses Peanut Butter Cups any day! Posts: 3061 From: Rockwall TX USA Registered: Sep 1999 posted 12-15-2004 09:53 AM                     Ray, the older vertical lamphouses are as you describe. Most of the 'newer' ones (ORC, CFS/LIT) are basically a horizontal lamphouse turned 90 degrees (so the light points 'up') with a 45 degree diagonal mirror to aim the light forward. This design is not very good for light efficiency, but the bulbs do last longer than on most comparable horixontal lamphouses. -Aaron  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 12-15-2004 10:10 AM                        quote: Barry Martin John, what are the PROS to horizontal operation? Or the CONS to vertical? The Osram publication states: quote: This (horizontal) burning position enabled the use of lighting systems with deep-dish elliptical reflectors such as were usual in the carbon arc era, which give an approximately 30% increase in utilization factor. In other words, horizontal lamphouses tend to be more efficient. As noted before, horizontal lamps require more effort to achieve a stable arc plasma, and lamp life may not be as long.  |  IP: Logged Mattias Ohlson Expert Film Handler Posts: 180 From: Falun, Sweden Registered: Mar 2003 posted 12-15-2004 12:14 PM                     Can someone point my in the direction of estimation of normal xenon lamp life for a 5kW bulb working pretty hard to light up a big screen under normal conditions?  |  IP: Logged Jason Miller Expert Film Handler Posts: 241 From: Little Rock, AR, Registered: Mar 2004 posted 12-15-2004 03:47 PM                    it really depends on who made the bulb.. LTI bulbs warranty to 800-1000 (model) Osram 1000 Christie 500 Superior 1000 ORC 800 REG burns bulbs to 125% warranty (horiz) and 200% (vert). burning bulbs to get the last flicker of light out of them just to save money isnt a good thing.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 12-15-2004 04:37 PM                     Jason your numbers are way off. The Christie bulb will outlast all others.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 12-15-2004 06:03 PM                     Yay Christie-comes through again. I worked in a theatre that had the complete Cinemeccanica V8/V88 setup (big 13k reel transport on the back, 10k reel arms on the front) with the side shooting 2.5K xenon vertical lamphouses and IREM "steering wheel" rectifiers. The lamphouses had the prefocus mirrors that were positioned in front of the bulb to prefocus the bulb to the big amber tint glass mirror,before hitting the coated flat mirror, then onto the aperture opening. Without the prefocus mirrors, there was a lot of light lost in these lamphouses before it would exit out the "snood." Now, that was some serious alignment factors for the bulbs with these lamphouses. But was nice that the bulb can be encased in the carrier when installing/uninstalling these bulbs. It seems like the verticals can last many times more than the horizontals, mainly due to the vertical positions of the arc ends to eliminate the sagging syndrome of the horizontal-reason due to the rotation factor of the horizontals, outside of the darkening of the quartz. I've seen 2.5K's run over 10K hours in these vertical lamphouses, but I get mighty leery of a changeout on thinking of the quartz being weakened due to these extensive hours, but the light output is still great. -thx Monte  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 12-15-2004 07:05 PM                     One local chain typically gets 10,000 to 15,000 hours from their 2kw Christie lamps. Last Summer I changed a 2kw Christie lamp out in Elko, NV. that had been in since the threatre opened 8 years ago. Thats good service life! Proper cooling also helps one achieve this number of hours.... if you want to go that far with the lamp.... I don't personally reccomnend it though. Mark  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 12-15-2004 08:01 PM                     I have several customers that use the xbo2000H in there vertical cinemecanica lamphouses A twin reflector vertical system was capable of good light and very flat field of illumination if aligned correctly but they were a pain to do and took a long time  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 12-15-2004 08:41 PM                        Regarding bulb life: assuming that cost is not an issue (ha!), and assuming that there is no visible flicker and that the image is bright enough to meet SMPTE specs, when should one change out a xenon? At warranty hours? At some point past warranty hours? Before the bulb reaches warranty hours? My own usual policy with 2kw lamps is to keep using them up to 3500-4000 hours, unless the image is dark or flickers before then, at which point I'll change the bulb. I've seen Osrams that gave perfect light to 4000 hours before being pulled due to age. I've also seen LTIs that barely make it to warranty hours before starting to flicker (and one that blew up at 1200 hours).  |  IP: Logged

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