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Author Topic: Need Advice Converting Carbon Arc Lamphouse to Xenon Luciano Brigite Master Film Handler Posts: 277 From: Sao Paulo, SP, Brazil Registered: Jan 2002 posted 07-13-2003 12:19 AM                     The bulb used was an Osram HMI 1200W/GS. I don't have the tech data for it in hand ( it's all in a binder somewhere else) It's available in the Osram's website. Lamp life is around 1500Hours ( also have to check the tech data for it)The screen used in both cases was about 5 X 3 meters, the HMI setup ( bulb, ballast and ignitor) was cheaper than a Xenon setup. ( the ballast and Ignitor was made by myself, the bulb was around $180.00 USD)Same cooling requirements for Xenon was applied with the HMI. Since it wasn't used in a permanent setup ( like, for a real theatrical use)the results were very good, a bit more that what I was expecting to get from it .I strongly suggest further testing with the HMI setup in order to see if problems won't develop with larger screens and/or different distances ( in the setup it was ~17 meters from projector to screen) Shutter in the projector was the drum type, not the blade ones (Erneman IV projector was used)  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 07-13-2003 03:20 AM                        Over the past year I've seen several comments about the product output of the Big Sky company. Their early product had some glaring flaws, but they've fixed most of them, as far as I can see. After buying one unit to see if it performed as advertised, I'm replacing all of my old 4kW X-60 lamphouses with their product. They've taken the chassis that they use on many of their current consoles and have adapted it to a pedestal-mounted cabinet. The reflector (glass dichroic) is great... none of the hotspots that the comparable Strong product is putting out, and the projectors stay cold to the touch. Cooling seems adequate up to the 7kW range, so it's probably good for whatever you'd want to do. I'd bet they'd probably sell you the "innards", and you could find a way to adapt it to the Magnarc. You will have to make sure there are enough openings in the Magnarc cabinet to allow for the increased airflow you'll need for a xenon lamp. Otherwise, this is a design that lends itself well to Irem, Strong and ORC power supplies.  |  IP: Logged Paul Trimboli Master Film Handler Posts: 274 From: Perth Western Australia Registered: Dec 2002 posted 07-13-2003 08:30 AM                     Hmm must have been very bright with 110 000 lumens on a 5 meter screen, it life is 750hours, but for the price is very good, I will have to look and see how much they are in Australia. Will give it a try, maybe I can find one that has a lower colour temp, which will last longer? SMPTE states 5200k is the lowest colour temp for 35mm.  |  IP: Logged Luciano Brigite Master Film Handler Posts: 277 From: Sao Paulo, SP, Brazil Registered: Jan 2002 posted 07-13-2003 10:28 AM                     Ooops.. my bad about the bulb life. FWIK.. the HMI bulbs are all in the 6000°K range. some will go to 6500°K ( there are differences in color temp. depending on bulb wattage and even more from one brand to another, even if their tech. data says 6000°K . I noticed it between Osram and Ushio bulbs, both of 1200W.) Forgot to say that the same care in handling for Xenon bulbs apply to HMI, they're smaller than Xenons and doesn't seem to have all that pressure inside but they will fail about the same way if you leave finger prints, etc on it and the cooling isn't enough. Also.. they'll take some 5 minutes to reach the full output and if you shut it off, you'll be able to re-strike it only after 12 minutes or so.  |  IP: Logged Robert Throop Master Film Handler Posts: 412 From: Vernon, NY USA Registered: Jun 99 posted 07-13-2003 07:18 PM                     The Cyclex was made by Ashcraft and used a special 96 cycle motor generator to avoid flicker.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 07-14-2003 08:10 AM                     Any bet if you are not getting a beat flicker it is becasue you are on a 50 Hz power source and the projector is probably running very close to 25 FPS. therefore no beat can't be done though on 60 hz mains with 24fps without square wave powersupplies as are used for northamerican film production Also the cost per hour of operation is much higher with HMI than with xenon and as they age the colour temp actually rises  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 07-14-2003 02:08 PM                        quote: If it was 1200watts, that would be around the 110 000 lumen mark No Way! Even the largest 7000-watt xenon lamps used for film projection today put only about 20,000 lumens on the screen.  |  IP: Logged Michael Harlow Expert Film Handler Posts: 170 From: Faversham, Kent, UK Registered: Jul 2002 posted 07-14-2003 04:57 PM                     John P. I will check for sure but i am sure that the Philips 1200w MSR lamp reaches nearly 110,000 lumen. I have these in some lighting effects in my club. They are similar to HMI but more rugged. I'll checkk the tech data. sorry, just checked. 110,000 max luminous flux, peak 20,000 cdl.  |  IP: Logged Luciano Brigite Master Film Handler Posts: 277 From: Sao Paulo, SP, Brazil Registered: Jan 2002 posted 07-14-2003 09:19 PM                     Frequency here where I am is 60 Hz. I can't say anything about the speed the projector was running since it wasn't me who set it up. If I remember it right, the HMI bulbs are around the 11.000 lumens.. not 110.000 ( I sure need to organize my tech papers a lot better..couldn't find the tech sheets for the HMI bulbs)  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 07-14-2003 09:22 PM                        The discrepancy is that you have to focus that light through the aperture, shutter, and onto the screen. Your 110,000 lumen number is TOTAL output, not focused.  |  IP: Logged Luciano Brigite Master Film Handler Posts: 277 From: Sao Paulo, SP, Brazil Registered: Jan 2002 posted 07-14-2003 11:18 PM                     I need to make a note to myself to not post anything when I'm tired and nearly falling asleep.. i'll end posting things a bit out of the way or forgetting things. Now I have a question about the Magnarcs. A few months ago I received a lamphouse, it's not the real Magnarc, but it's a clone of it on everything save fora few minor differences in one thing or another. Well, the curious thing is, it was "converted" by it's previous owner to use an HMI bulb and about everything inside of it is gone, even the positive clamps. I'm working on it now (rebuilding it) and making it ready for xenon.while de- assembling the thing I noticed that the magnet is gone and it's used with the xenon for arc stabilization (sp?) My question is: What I can use in place of that magnet? ( the original Magnarc has a permanent magnet, this one I believe had one the same way and not the high current cable coiled around a iron bar behind the mirror)  |  IP: Logged Paul Trimboli Master Film Handler Posts: 274 From: Perth Western Australia Registered: Dec 2002 posted 07-15-2003 03:10 AM                     Hmm so that lamp produces 110 000 lumens, so after it goes through the projector what would be the lumen output? How many lumens does it take to say illuminate say a 10meter screen?  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 07-15-2003 04:56 AM                        Stupid question: why does require more light than film for the same size screen? With film, 50% of the light from the lamp would be lost at the shutter, while DLP has only the DLP chip and the lens (and port glass and screen) to suck up light. Is the DLP chip itself that much denser than film? Or is there some other reason that I'm missing?  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 07-15-2003 06:08 AM                        It's a matter of optical efficiency. The chips are only part of the optical path. Remember, you have the reflector, heat filters, integrating bar, dichroics to split the light into red, green and blue, the lens, etc. With film, you just have the reflector, the shutter, the film, and the lens. Approximate lumens required to illuminate a matte white screen to 16 footlamberts is (area in square feet) x 16  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 07-15-2003 10:25 AM                     D cinemas big light eater is the fact that there is polarization used in the beam spliting system  |  IP: Logged

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