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Author Topic: Problems with xps-45s power supply output Justin Frakes Film Handler Posts: 20 From: New Boston, IL, USA Registered: May 2018 posted 05-25-2019 11:29 AM                     Hey guys I was hoping to pick your brain here for a minute. I've got a xps45s ORC power supply. I've rebuilt this thing a few times over the years from lightning strikes and various things. About a week before we opened for the season we had an issue with the 3 phase with the wild leg missing the power company brought a new transformer and put it out on the pole well I never checked the voltage and fired up the projector opening night and before the 30 amp breaker popped the power supply decided to let the smoke out of most of the rectifier diodes and they were glowing red. Turns out the power company hooked up the wrong tap and we weren't getting the 240 3 phase but instead 170v because they forgot to tighten a ground wire on the transformer so it was pulling high amps and the time delay breaker let it smoke the diodes. So I replaced them all and I'm afraid the transformer windings got hot enough to possibly melt the old enamel off and possibly short. I cant get it to put out 32v and 140amps and I'm on the highighest tap(which I've never used) I can get the watts I want but only 25 vdc and then the amps are 160 plus. I've got 240 going in on all 3 phases. 25vdc out and by changing the taps I can get 80 amps-200amps out of it. I have a lapmhouse rated for 140amp max and I'm running a 4500w lamp. I've got 4100w at 25vdc and 165 amps. I'm not wanting to run it that way because the heat from the high amp draw. I have 1000cfm of cooling fans hooked to the lapmhouse also so it can handle a little more and I upsized all the wires a couple years ago so everything can handle the amps safely but something isn't right. Let me know what you guys think, thanks so much! Justin.  |  IP: Logged Paul Finn Film Handler Posts: 41 From: Bay City, MI Registered: Jan 2019 posted 05-27-2019 01:06 PM                     The power company information and actions given in the OP does not make sense to me. With low voltage into a transformer, any transformer, 170v in this case into the transformer in the power supply looking for 240v, the result should be low voltage output - both AC to the diodes from the transformer and rectified low DC output. The 170 volts on all three phase input legs certainly would not have caused the dramatic diode failures indicated. Did the power company supply 277 volts or 480 volts between any of the three phase legs by mistake until the damage was done and corrections made?? A couple suggestions: C1 and C2 in the power supply charge up to the peak voltage and filter/smooth the ripple voltage and current in the rectified DC. If the rectified DC is the 25 volts that is being seen, good C1 & C2 capacitors would raise that to near the peak voltage level of about 35vDC which is in the range that is being sought. Also, contacts on relay K2 which normally bypass R3, may be burned and are not placing C1 & C2 directly across the power supply DC output lines. R3 should have 0vDC drop across it (be shorted) with the PS in normal operation. Also, if abnormal high voltages were present and the lamp house meter(s) were exposed, they may no longer be accurate. Short of these beginning possibilities, detailed resistance and voltage measurements of the transformer windings would be needed. Transformer secondary voltage measurements both unloaded and loaded. Loaded DC voltage ripple measurements would also be in order. If the power supply was subjected to high voltage, all of the circuit components are suspect until determined ok. One last thought: The electrode condition(s) in a xenon lamp determine the voltage drop across the elements. I have seen xenon lamps which create lower than normal voltage drops and require correspondingly higher than normal current to operate at the design wattage. If everything else checks out here, try a different lamp. Paul Finn  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 05-29-2019 07:31 PM                     Depending on the era of the XPS-45 there were a certain range that had alumnium main transformer windings. I guess this was to save weight, but they are still extremely heavy. At any rate, if you have one of those versions then kiss it good bye, because every single one of those fails at some point. They become a really good boat anchor. Over 40+ years, I had to replace about a half dozen of them for that reason in various parts of the USA. Yes, it could still be something else, but not that many people are aware of the version with alumnium windings, so I wanted to bring that up. Mark  |  IP: Logged Justin Frakes Film Handler Posts: 20 From: New Boston, IL, USA Registered: May 2018 posted 06-01-2019 01:48 AM                     Good to know about the aluminium windings, but this has all copper windings. So I took some readings while I could before having some sound issues abruptly. Under load with the lamp lit I had 248vac (pulling 36 amps on a 30 amp breaker supposedly I suspect the meter might not be correct I'm going to use a different one tomorrow) on all three phases when measured phase to phase. Between the transformer secondary outputs I was reading 20vac. At the filter caps 25.5vdc and 25.5vdc to lapmhouse. I'll get some ohm readings. I an using the Z tap for the primaries. In the manual it says W tap for 240 and X tap for 208 and it doesnt say anything about about the Y or Z tap in my manual. If I wire the primaries W I only get 15vac out of the secondary and 20vdc to lapmhouse. Thanks guys I appreciate it.  |  IP: Logged Sean McKinnon Phenomenal Film Handler Posts: 1712 From: Peabody Massachusetts Registered: Sep 2000 posted 06-02-2019 08:39 AM                        You should be getting 208 V phase to phase not 248.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 06-02-2019 04:06 PM                     quote: Sean McKinnon You should be getting 208 V phase to phase not 248. Some locations still have high legs, rare, but they do still exist. That could be the cause of his odd radings. Mark  |  IP: Logged Sean McKinnon Phenomenal Film Handler Posts: 1712 From: Peabody Massachusetts Registered: Sep 2000 posted 06-03-2019 06:48 PM                        You're right mark maybe the reason for his lower current reading.  |  IP: Logged Justin Frakes Film Handler Posts: 20 From: New Boston, IL, USA Registered: May 2018 posted 06-05-2019 11:37 AM                     We have the delta 3 phase with the high leg. I was an inside electrician for 6 years. Anyway the place was built in 1921 so it's always had the delta 3 phase and when I was a kid we had delta at the farm with a 360v wild leg. It was a 4 or 5 wire system if I remember correctly. Something they quit doing years ago.  |  IP: Logged Justin Frakes Film Handler Posts: 20 From: New Boston, IL, USA Registered: May 2018 posted 06-22-2019 03:48 PM                     Where can I get one of these power supplies? I got this one working but I'd like to have a backup on hand. Thanks, Justin.  |  IP: Logged Paul Finn Film Handler Posts: 41 From: Bay City, MI Registered: Jan 2019 posted 06-23-2019 01:09 PM                     For the benefit of all, please provide the information on the resolution of the power supply problem(s)? Thanks, Paul Finn  |  IP: Logged Justin Frakes Film Handler Posts: 20 From: New Boston, IL, USA Registered: May 2018 posted 06-28-2019 10:31 PM                     No problem, the windings on the transformers were shorted, I unwound them by hand which was very time consuming and rewound them after coating the copper with new enamel and replaced the parchment paper between the windings. Now I've got 32vdc 140 amps and everything has been replaced in the power supply. I still would like to get a backup incase this happens again, where can I get one? Thanks all, I always appreciate your help and sorry for not replying with what I did to repair it, I've been battling some health problems so I haven't had much time to get online.  |  IP: Logged Sean McKinnon Phenomenal Film Handler Posts: 1712 From: Peabody Massachusetts Registered: Sep 2000 posted 06-29-2019 09:13 AM                        Wow! Commited! We have a few in our old rental inventory that have been replaced with electronic irems or newer LP rectifiers. I imagine we may be willing to sell one but I think shipping to you would be expensive.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 06-30-2019 03:24 PM                     I am not surprised at this finding... Sean... LP Associates made ORC's rectifiers. A better bet for him is a used 5kw Compact Strong switcher (Link Below). Those are field or factory repairable too. I have repaired hundreds of the 2.5 kw compact switcher over the years. New transistors, diodes a couple of zeners some times and alays 2-15 amp uses ad you are good to go. About 75 screws to disassemble though. This is the most reliable Stromg unit... And they are light enough to ship. https://www.ebay.com/itm/STRONG-6200000-SWITCHING-POWER-SUPPLY-SERIES-V2-CONT-DUTY-30A-IN- 100-150A-OUT/332997262469?hash=item4d882efc85:g:cvEAAOSw8DpcMFgB Mark  |  IP: Logged Justin Frakes Film Handler Posts: 20 From: New Boston, IL, USA Registered: May 2018 posted 06-30-2019 07:48 PM                     I cant thank you guys enough. I will try to be more active on the forum so I can give back in my knowledgeable areas. I think that is the way to go with the newer switching power supply. I really appreciate it.  |  IP: Logged Sean McKinnon Phenomenal Film Handler Posts: 1712 From: Peabody Massachusetts Registered: Sep 2000 posted 07-02-2019 08:10 AM                        up until a year or so ago you could still buy new LP Associates supplies but I think we got the last run when they were sold. I've had mixed luck with the newer strong switchers however strong lighting in Texas (I think) will repair them for a flat fee which is more economical than doing it in house I have found.  |  IP: Logged

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