Film-Tech Forum ARCHIVE: Xenon lamp question

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Posted by David Rigby (Member # 1301) on 12-14-2004, 12:08 PM:

Maybe a dumb one [Smile]

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

Posted by John Pytlak (Member # 331) on 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".

Posted by Gordon McLeod (Member # 33) on 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

Posted by Barry Martin (Member # 1376) on 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?

Posted by David Rigby (Member # 1301) on 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

Posted by Ray Kaufman (Member # 2351) on 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.

Posted by Aaron Sisemore (Member # 145) on 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

Posted by John Pytlak (Member # 331) on 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.

Posted by Mattias Ohlson (Member # 1662) on 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?

Posted by Jason Miller (Member # 2341) on 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.

Posted by Brad Miller (Member # 2) on 12-15-2004, 04:37 PM:

Jason your numbers are way off. The Christie bulb will outlast all others.

Posted by Monte L Fullmer (Member # 2797) on 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

Posted by Mark Gulbrandsen (Member # 72) on 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

Posted by Gordon McLeod (Member # 33) on 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

Posted by Scott Norwood (Member # 30) on 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).

Posted by Monte L Fullmer (Member # 2797) on 12-15-2004, 09:00 PM:

Course, isn't LTI who bought out PerkinElmer (and also CFS), where PE was ORCON, whom took over Hanovia? We were never so glad to get rid of our last PE bulbs when the last one, which didn't give me any trouble and went to almost 4k hrs before dying. Only good thing that I did notice about PE bulbs is that the voltage run against the amperage was the lowest against the CHR and the OSRAM-and Osram/Sylvania being the highest using a 2kw bulb. I can crank up the amps to the maximun run on a PE and the value between volts and amps was still under the wattage output when they get the age on them.

Marko, remember Larry from Elko, NV? He's with us now at the Nampa. - thx Monte

Posted by Mark Gulbrandsen (Member # 72) on 12-15-2004, 09:18 PM:

quote: Monte L Fullmer
Course, isn't LTI who bought out PerkinElmer

No, LTI is its own entity. Strong distributes theor lamps which have been ok for us. Just a few returns. Christie continues to be our largest seller though, with Osram third.

quote: Monte L Fullmer
Marko, remember Larry from Elko, NV? He's with us now at the Nampa.

Larry's a top notch guy... he's being wasted working for Real and he has my sympathy.

Mark

Posted by Jason Miller (Member # 2341) on 12-15-2004, 09:33 PM:

quote: Brad Miller
Jason your numbers are way off. The Christie bulb will outlast all others.

I got the pro-rated warranty info fromChristie's website:

ChristieCXL50SC

and as I said.. these are just warranty numbers. performance is different. I agree that Christie bulbs usually outperform other bulbs.

Posted by Matthew Bailey (Member # 601) on 12-15-2004, 09:57 PM:

Can they design xenon bulbs with safety envelopes that contain glass fragments in case they explode? I remember looking at a labware catalog that had flasks & beakers that would contain glass & liquids if they shattered.

Posted by Ever Gonzalez (Member # 2794) on 12-15-2004, 10:55 PM:

We had a 2K LTI blow up at 31 hours I beleive. It was some rediculous small number like that.

That was fun to clean up.

Posted by Monte L Fullmer (Member # 2797) on 12-15-2004, 11:58 PM:

Be grand if they did develop some sort of containment device to capture the quartz when a bulb blows, but it would have to be a containment device that would allow all of the light go through, handle the extreme heat, adaptable for all consoles..et.al. like a digital projector's lamp system - all contained within a shielded containment device.

It's just something that we all projectionist's have to live with- being scared out of our wits when a bulb blows and we're standing next to the console checking the focus, or watching the movie.

I've had two of them blow while standing next to the console. One was in an old Xetron console (the spider that holds the front of the bulb didn't allow for expansion when the bulb got hot,causing a great amount of tweaking), the other was in a Reference console using a CXL-60. That big 6kw blew, yet didn't harm the mirror too much-just a scrape here and there. That 6k only had 900 hrs on it.

quote: Mark Gulbrandsen
Larry's a top notch guy... he's being wasted working for Real and he has my sympathy.

True. He's already noticing that - the micromanagement syndrome that Nampa likes to operate with. He left NV for that theatre owner's moral tactics of operations. He'll tough if out though and play these stupid "games", but don't know right off how long.

He's really going to turn around Nampa though, for this theatre was getting some bad heat from the plaza owners on getting a better management staff here, for we've had some pretty serious issues over here: gang shootings, parking lot break-ins, extremely unprofessional management operations here and what have you.

It was time to get this place in order and Nampa feels that Larry can do the job....thx-Monte

[ 12-16-2004, 01:54 AM: Message edited by: Monte L Fullmer ]

Posted by Mattias Ohlson (Member # 1662) on 12-16-2004, 05:11 AM:

How much overcapacity do you buy into your bulb. As the bulb ages it looses light output to perhaps 50 percent with xenon? In that case do you buy a bulb the initally can light up a bigger screen than you have so that it can meet standards at the end of its life. In doing so you run it light in the beginning and tougher at the end or?

Posted by Samuel Hynds (Member # 2610) on 12-16-2004, 09:09 AM:

David,

To get back to your question about the CX1600 - Can this lamphouse handle a horizonal lamp? Don't think so; there is not enough room inside this box to handle a horizonal system. This lamphouse should have a bowtie looking mirror, which is glass in nature.

To convert this lamphouse from vertical to horizonal would require complete removal of everything inside (mirror holder and lamp holder, and to install a horizonal lampholder (with a reflector holder as well).

You do get better life from you lamps when you burn them vertically, plus having not to rotate you lamp at half life. [Roll Eyes]

Posted by Peter Hall (Member # 695) on 12-16-2004, 10:13 AM:

Does anyone in the US know whats happening with Superior Quartz - I know they have signed a deal to supply in the US under the MIT brand. We really like their lamps but are concerned on long term supply and support ..

Posted by Mark Gulbrandsen (Member # 72) on 12-16-2004, 05:40 PM:

The bigger question is will MIT be around to supply those lamps from Superior [Confused]

? Posts from and about MIT are non-existant lately which leads me to wonder..... I don't know anyone buying their equipment yet either......

Mark

Posted by Gordon McLeod (Member # 33) on 12-16-2004, 08:19 PM:

Sam the question wasn't to convert it to a horizontal system but to mount a horizontal lamp vertically and that is simple and fairly common solution

Posted by Aaron Sisemore (Member # 145) on 12-19-2004, 11:09 PM:

quote: Monte L Fullmer
Course, isn't LTI who bought out PerkinElmer (and also CFS)...

You are confusing LTI (Lighting Technologies, International, the lamp mnanufacturer) with LIT (Lighting Images Technology, the current owner of what's left of CFS).

-Aaron

Posted by David Rigby (Member # 1301) on 12-23-2004, 12:58 PM:

This turned into quite an educational discussion [Smile]

Thanks for all the info guys - everything I've ever read about vertical lamphouses suggests they're great for lamp life. I had wondered about changing to horizontal for ease of lamp availability but I really rather like my Cinemec lamphouse with its butterfly mirror, hence my thoughts on using horizontal lamps in it...my only conern besides feasibility was efficiency. Spoke to Robert at Robertfilm in Montreal and he seemed to think the good ol CX1600 was a decent enough lamphouse anyway and not horribly inefficient. Does Robert post on here at all? He's a knowledegable and very helpful guy [Smile]

David

Posted by Gordon McLeod (Member # 33) on 12-23-2004, 02:30 PM:

"he seemed to think the good ol CX1600 was a decent enough lamphouse anyway and not horribly inefficient"
That should have a smiley at the end of that comment those lamphouses are very inefficient and definetly produce a very uneven light distribution

Posted by Darryl Spicer (Member # 711) on 05-04-2005, 09:01 PM:

I have a question? We have been using Osram bulbs here (2500 and 3000 watt). My question is why does the 2500 watt bulbs have the funny looking wire leads coming off of both ends of the bulbs and the 3000's have the normal posative end lead for bolting down coming off one end?

Posted by Gordon McLeod (Member # 33) on 05-04-2005, 11:41 PM:

the xbo2500 has a set of leads with what looks like two bullets on the end they are for vertical operation only
the xbo2500hs has the same ends as a 3000hsc

Posted by Darryl Spicer (Member # 711) on 05-05-2005, 12:30 AM:

Well, we use them in a vertical position. I was more so curious as to what lamphouse those particular connections went to. Ours is a CFS console but do not require those connections. Gordon, I am guessing that the ones you mentioned would most likely work in a CFS?

Posted by Monte L Fullmer (Member # 2797) on 05-05-2005, 03:36 AM:

quote: Gordon McLeod
....what looks like two bullets on the end they are for vertical operation only...

ORC consoles also had verticals, and as with the "Charlie Consoles" (CFS) - the two almost had the same lamp frame and recifier design.

These 2.5Kw vertical "bullet connector cable" bulbs were used in these Cinemeccanica V-18 13k reel to reel setups. The lamphouse was a "side shooter" lamphouse by which the lamphouse was positioned on the side of the unit and fired the light to a flat optical coated mirror which bent the light 90 degrees to the aperture opening.

Here are a couple of picts of the Cinemeccanica. The first one is the actual bulb frame and mirror assembly that is taken out of the lamphouse.

One will notice the pre-focus mirror positioned in front of the bulb to aid in containing the light from the front of the bulb and refocus it back to the large balcore glass mirror.

Here is a picture of one of these beasts in operation below. This machine was using either platter, or the big reels. Once can notice the angled cover plate which behind it was that flat optical mirror, which we took out at times to clean. It just slid out of a slot when this cover was removed.

Focusing this form of lamphouse was actually a trick to do, since one had to separately align the bulb-both vertically and horizonally and to focus both mirrors, one at a time. Then one had to align the flat optical mirror to align with the aperture opening. This had to be done at each bulb change. The nice thing about the V-18 lamphouse, with the bulbs being vertical, that the lamphouse can be left on at all times (the dowser plate was quite a thick plate to really take the heat), and with verticals, the life on these bulbs can last a whole lot longer than the horizontals.

I've seen 9000hrs on an Osram 2500XBO and still give out great light, and the envelope never was dark in these lamphouses.

-Monte

Posted by Gordon McLeod (Member # 33) on 05-05-2005, 08:30 AM:

That lamp was first used in the zies Ikon Xenosol lamphouse and then in almost all the other vertical lamphouse most also had the auxilary front spherical mirror

Posted by John Pytlak (Member # 331) on 05-05-2005, 01:56 PM:

First xenon lamphouse I ever saw was a Zeiss Ikon Xenosol at the old Amherst University Theatre across from the south campus of SUNY Buffalo, in the late 1960's. Of course, xenon lamps were introduced in Germany during the mid 1950's by Osram.