Film-Tech Forum ARCHIVE: Problems with xps-45s power supply output

This is topic Problems with xps-45s power supply output in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=012434

Posted by Justin Frakes (Member # 10491) on 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.

Posted by Paul Finn (Member # 10726) on 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

Posted by Mark Gulbrandsen (Member # 72) on 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

Posted by Justin Frakes (Member # 10491) on 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.

Posted by Sean McKinnon (Member # 612) on 06-02-2019, 08:39 AM:

You should be getting 208 V phase to phase not 248.

Posted by Mark Gulbrandsen (Member # 72) on 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

Posted by Sean McKinnon (Member # 612) on 06-03-2019, 06:48 PM:

You're right mark maybe the reason for his lower current reading.

Posted by Justin Frakes (Member # 10491) on 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.

Posted by Justin Frakes (Member # 10491) on 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.

Posted by Paul Finn (Member # 10726) on 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

Posted by Justin Frakes (Member # 10491) on 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.

Posted by Sean McKinnon (Member # 612) on 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.

Posted by Mark Gulbrandsen (Member # 72) on 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

Posted by Justin Frakes (Member # 10491) on 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.

Posted by Sean McKinnon (Member # 612) on 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.

Posted by Mark Gulbrandsen (Member # 72) on 07-03-2019, 04:40 PM:

No need to send a switcher to Strong lighting. They are actually a very easy repair.... I called them gravy jobs. The parts to repair a 2.5KW switcher cost less than 50 bucks. 4-High Speed Transistors, 4-High Speed diodes, two 15 amp fast blow fuses and occasionally a couple zener diodes. The only down side of repairing them is the sheer number of screws to remove and replace. I repaired several hundred of them over a ten year period.

The secret to NOT having them fail is to have surge protection on every electrical panel in the booth. Locations we did that saw zero switcher failures. Most of my repair business on those came from other states. Not our own installs...

This is an example of a whole panel surge protector. This example is pretty pricy, they typically run in the $300 to $400 range from an electrical supply. They DO require a three phase breaker of their owwn to meet code.

[URL=https://www.graybar.com/store/en/gb/type-2-panel-mount-surge-protection-92047441#{Protection%20Type:Type%202%20Surge%20Protection}&{Voltage%20Configuration:120/240V,%20Single%20(Split)%20Phase}&{Max.%20Surge%20Current:80kA}&{Additional%20Feature s:Home%20Control%20and%20X10%20Compatible}&{Mount%20Type:Panel%20Mount}&{Material:Steel}&{Amperage%20Rating:20A}]Whole Panel Surge Protector[/URL]

Posted by Sean McKinnon (Member # 612) on 07-09-2019, 12:40 PM:

While I agree they are pretty easy to repair for what they charge versus what my labor rate per hour is it is far better to let them do it and get their warranty as well.

Posted by Justin Frakes (Member # 10491) on 07-20-2019, 10:14 PM:

I'm not worried about repairing it if it breaks, does anyone know where I can get the muti pin plug? Also does anyone have a schematic of the strong 62-70028 control board? Or pictures of one, or where I could buy one? I'm confident I could make one of I cant find one somewhere. Thanks again guys I really appreciate the help. Justin.

Posted by Sean McKinnon (Member # 612) on 07-25-2019, 01:43 PM:

Strong Lighting has the parts for these and the current adjust PCB that is needed to make the supply work (you can also solder a pot onto it but the little board is more elegant and fits on the supply with supplies standoffs.