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Author Topic: Welder's inverters for lamphouses? Matthew Taylor Expert Film Handler Posts: 186 From: Essex, UK Registered: Mar 2004 posted 03-09-2007 01:53 PM                     Is it possible to use welding PSU's on lamphouses? Looking at the specs of some of them, it looks like they can produce the current output required but I'm not sure whether the output would be smooth enough.  |  IP: Logged William T. Parr Jedi Master Film Handler Posts: 823 From: Cedar Park, TX Registered: Nov 2000 posted 03-09-2007 02:07 PM                     Matthew, It can be and has been done. We used a Miller's Welding unit as the power supply for a 3000W Peerless Mac Arc conversion at the Centre Theatre n Corpus Christi. Works very well.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-09-2007 03:10 PM                     IN fact Imax uses Millers at almost all theor installations.... but.... with an extra box out in front that contains filtration and other stuff to mark the DC clean enough. Take a look at some of the Imax booth photos and you will see the Millers and Imax "box mod" that mounts in front. Mark  |  IP: Logged Adam Martin I'm not even gonna point out the irony. Posts: 3686 From: Dallas, TX Registered: Nov 2000 posted 03-09-2007 07:10 PM                     The box on the front of the Miller rectifiers in the Imax booths only provide easy-service-access for connections. There is a circuit board added inside the main body behind the control panel to interface with the PLC so that there is data communication that allows for remote control, remote meter readings, and the ability to reduce power when the dowsers are closed. Unless the theater provides some other external unit, there is no power conditioning on the GT systems. The SR system sort-of has conditioning, but it's more for providing emergency power to the control console and does not feed the rectifiers. Some theaters spend extra for an electronics-grade panel to supply the audio system. See photos here and here.  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 03-09-2007 07:24 PM                  Assuming the "Standard" welding supply as implied, where does IMAX develop the boost voltage and place the Tesla coil, (and auto strike ckt) for the HV necessary to start the xenon arc? The systems I've built for 15kW water-cooled lamps where specifically designed for the function and didn't use "arc welders"...I always thought that a bit cheesy for an otherwise good product!  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-09-2007 07:30 PM                     Somewhere I have the schematic of what they do to to those rectifiers that was sent by an anynoumous Imax tech years ago. It does include filtration and I believe the boost circuit as well. I will try to dig it up and send it to BRad. Its pretty interesting. Phil, Your 15kw switching rectifier bank design ALWAYS works like a champ and never gives any problems. Lamp life with it is exactly the same as it is with the modified Millers. Price out a Miller sometime as I once did to replace a single 7kw switcher on a Megasystems machine... they are dirt cheap even with the mods you have to do to them. If you call Miller and tell them Imax they know which ones are used. Mark  |  IP: Logged Richard Hamilton Phenomenal Film Handler Posts: 1341 From: Evansville, Indiana Registered: Jan 2000 posted 03-09-2007 09:23 PM                     Mark, Was that at Jordan Commons? I didn't do the install there, but I did replace the Strong power supply with an Irem Rick  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 03-09-2007 09:35 PM                  The thing that always bothered me about an IREM is the LOUD vibration of the transformers AND the crappy HIGH DC ripple! I ALWAYS had to use isolation pads for mounting and the external choke to help eliminate the shitty ripple. I cannot recommend them for anything other than a boat anchor.  |  IP: Logged Paul Mayer Oh get out of it Melvin, before it pulls you under! Posts: 3836 From: Albuquerque, NM Registered: Feb 2000 posted 03-09-2007 09:43 PM                        quote: Phil Hill I cannot recommend them for anything other than a boat anchor. How 'bout as chocks? I'm always running out of chocks for my MD-83s these days...  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 03-09-2007 09:51 PM                  hahahahahaha! Thanks for your comment, Paul. But I thought YOU would have said something about "shitty ripple"... you know like the wine... HA!  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-09-2007 10:07 PM                     quote: Richard Hamilton Mark, Was that at Jordan Commons? Yea. quote: Paul Mayer How 'bout as chocks? I'm always running out of chocks for my MD-83s these days... I agree with Phil... Irems are absolute crap! Paul... You could use em as chocks but your back wouod eventuially give out yankin em out from the tires with a rope attached.....  |  IP: Logged Tim Reed Better Projection Pays Posts: 5246 From: Northampton, PA Registered: Sep 1999 posted 03-09-2007 10:14 PM                       Doesn't an "inverter" convert DC to AC?  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-10-2007 02:59 AM                        quote: Tim Reed Doesn't an "inverter" convert DC to AC? Yeah, that's where the Irems come in. They're sort of like a double conversion UPS.  |  IP: Logged Matthew Taylor Expert Film Handler Posts: 186 From: Essex, UK Registered: Mar 2004 posted 03-10-2007 03:48 AM                     So if I got an 'off the shelf' welding psu, would it need modification to run a normal ....say...1600w lamphouse?  |  IP: Logged Robert Minichino Master Film Handler Posts: 350 From: Haskell, NJ, USA Registered: Dec 2005 posted 03-10-2007 08:38 AM                        Assuming it was up to supplying the current you need at 100% duty cycle, you'd also need a boost supply to generate a higher voltage for striking.  |  IP: Logged

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