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Author Topic: Rebuild IREM rectifier Sigurd Wik Film Handler Posts: 37 From: Bergen, Hordaland, Norway Registered: Feb 2011 posted 02-12-2014 06:20 AM                     I have a couple of IREM EX-170GM/3-E with input volt range 360-460V. Do any of you know if it is possible to rebuild this to input volt range 230V? Hard to find info on this, so I suspect it is not possible. Sigurd  |  IP: Logged Edgar Prass Film Handler Posts: 32 From: Tartu, Tartu county, Estonia Registered: Mar 2013 posted 02-12-2014 06:27 AM                     3-phase rectifier can't be rebuilt to single phase.  |  IP: Logged Jim Cassedy Phenomenal Film Handler Posts: 1661 From: San Francisco, CA Registered: Dec 2006 posted 02-12-2014 10:14 AM                     It is true, as Edgar says, that it's almost impossible to re-build a 3-hase rectifer to work on single phase- - HOWEVER, there is a "work around": I know of at least half-a-dozen old theaters that are running both Irem and Christie 3-Phase rectifiers on single phase by using a bank of large capactors to create a "phantom" 3rd phase. I used to have a wiring diagram on how to do this, but I can't seem to find it at the moment. You might be able to find info online since trick also works with certain types of 3phase motors too. You should be aware that: 1) This method is slightly electrically inefficent and so it will will "downsize" your rectifer capacity, but I'm not sure by what percantage. So, You won't be able to run a 4K bulb on a 4K rectifier. I think it cuts the rating by appx 25%, but I couldn't swear to that in court. 2)The rectifers converted this way will often a make loud, very annoying, buzzing sound at appx 120hz when you use this trick. I find the buzz so annoying that I can't stand to be in the same room for more than a few minutes where one of these 'converted' rectifiers is running. But it doesn't seem to do the rectifer any harm- - One theater I know has been running their capacitor-converted rectifier for over 25 years now, and has never had any problems with it. Not even a burned out diode, since I think they're running well below their rated current specs. At the theaters I've seen this done at, the buzzing seems to be worse with Chrisite rectifiers than with the IREM units. I might be able to take a look at one of the rectifiers and make a wiring diagram of how the conversion was done, but I'm tied up for the next two weeks in another part of town doing some work for the Academy Awards, so it would have to wait. Perhaps somone else on the forums has done this 'trick' and can give you info on how to do it.  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 02-12-2014 10:44 AM                       I don't think single phase was mentioned. Perhaps he just wants to run on 220 3 Phase. Maybe I missed something?  |  IP: Logged Jim Cassedy Phenomenal Film Handler Posts: 1661 From: San Francisco, CA Registered: Dec 2006 posted 02-12-2014 11:01 AM                     D'oh! I think you're right, Sam. I read & wrote that reply before I had my morning coffee so my mind wasn't fully 'firing on all cylinders' yet & I misinterpreted the question. "sometimes the mouse is quicker than the mind"  |  IP: Logged Sigurd Wik Film Handler Posts: 37 From: Bergen, Hordaland, Norway Registered: Feb 2011 posted 02-12-2014 01:32 PM                     Thanks for quick replies. Yes, I just want to run 230V on three phase. I'm in the process of changing lamphouses and rectifiers and I can have these for free, that is why I wonder if it is at all possible without installing a transformator, which would cost a great deal as I understand from my electrician. Come to think of it, I also lack these Kinoton xenon bulb adapters for attaching the cathode to the xenon unit of the lamp house. Am happy to buy a couple if anyone have these. The lamp houses are the Kinoton Universal 2-7 kW. I can supply pictures if needed. Sigurd  |  IP: Logged Jonathan Wood Expert Film Handler Posts: 206 From: Oxfordshire, United kingdom Registered: Jan 2008 posted 02-12-2014 01:36 PM                     I think he meant 3/230 too but out of interest and this might be a stupid question but wouldn't the 3 ph rec have all the components in to make a single phase rectifier ? Jon  |  IP: Logged Ian Freer Expert Film Handler Posts: 135 From: Wellington, New Zealand Registered: Oct 2003 posted 02-12-2014 02:52 PM                     Hi Sigurd I may be making some assumptions here, but a quick search online says Norway utilises 230/240AC single phase electrical supply, so this would mean 3-ph power is already in the 360-460VAC range and no modification should be necessary? If your power supply is typically 110/120VAC single phase then that is a different story and I should stop making assumptions... Ian  |  IP: Logged Jonathan Wood Expert Film Handler Posts: 206 From: Oxfordshire, United kingdom Registered: Jan 2008 posted 02-12-2014 03:22 PM                     As I understand it he already has it running from 3/400 and wants to run it from 3/230, 3 phase comes in both 230v and 400 v  |  IP: Logged Sigurd Wik Film Handler Posts: 37 From: Bergen, Hordaland, Norway Registered: Feb 2011 posted 02-12-2014 03:38 PM                     Yes, Jonathan is correct. It has been installed in a cinema running on 3/400, while I have 3/230 in my cinema.  |  IP: Logged Jonathan Wood Expert Film Handler Posts: 206 From: Oxfordshire, United kingdom Registered: Jan 2008 posted 02-12-2014 04:05 PM                     Hi Sigurd, I also have a 3 phase Irem rec, its not being used right now but I always thought it was a bit like a dual voltage 3 ph motor in that it could be wired to run off 3/230 or 3/400 ?Maybe not , Im not sure but it must have been easier to make a rectifier that could run from both sources rather than have to build two different models ? Jon  |  IP: Logged Sigurd Wik Film Handler Posts: 37 From: Bergen, Hordaland, Norway Registered: Feb 2011 posted 02-12-2014 04:22 PM                     Hi Jonathan, Yes, it would seem so. In IREM's info sheet they state them as two different models, EX-170GM/3-E and EX-170GM/3-US, the difference being input volt range 360-460 vs 187-230 and max input current 18 vs 23. Hard to say anything from that.  |  IP: Logged Jonathan Wood Expert Film Handler Posts: 206 From: Oxfordshire, United kingdom Registered: Jan 2008 posted 02-12-2014 04:28 PM                     Just had a look at the plate on mine and its input is only listed as 400v and looking at Irem's website it doesn't look like its possible to change the input without a transformer, which as you say, would be expensive. Good luck with that !  |  IP: Logged Sigurd Wik Film Handler Posts: 37 From: Bergen, Hordaland, Norway Registered: Feb 2011 posted 02-12-2014 04:37 PM                     I see. Thanks for checking, appreciate it.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 02-12-2014 05:53 PM                     The only European item I can absolutely say this can be done on is the 3-Phase motor on the Phillips FP-56 projector. Although the taps to do this are not brought out anywhere in the connection box one can find them by dismantling the motor itself and re-arranging the internal windings themselves. Takes a little doing but can be done. Irem is still around and they have been very helpful to me in the past on older rectifiers. I suggest you contact them directly to see how the main transformers are wound and if reconfiguration is at all possible. 360 volt three phase seems to be the norm in Europe... Mark  |  IP: Logged

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