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Removing Power Cords.


James Shelby
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I would like to remove the two power cords from my controlers and replace them with one longer cord of 12AWG SOOW three conductor with ground. I see 120volt connectors on the board can I use these to jumper the white wire so I will have two hots and one white? Looks like I can I just want to make sure before I cut up all my cords.

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James,

Yes and no. First off you need to be very careful running a single cable to the controller that is sharing the common, or else you could overheat it. Now you can do it. But you need to be very careful to make sure when plug it into the wall outlets that you make sure that those outlets are not on the same breaker and those breakers are not on the same bus.

I was actually going to do the same thing last year with our controllers because I have several rolls of 12/3 SJEOW wire but decided not too just for the simple fact I would rather have one extra plug then to have the possibility of overheating the wire.

So my recomendation would be to just go ahead and add a second line. And yes after you hook it in make sure you remove the jumpers.

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Thanks for the answer BUT I'm working with another issue related to this issue of shareing the neutral. I'm running three phase on a massive display and it might be a problem with phaseing and shared neutrals. When a few of us run some test we will post our findings, should be by next week at the latest.

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  • 2 weeks later...
James Shelby

Well from looking at it very closely it looks like you can share the neutral. You have two hots and one neutral in your distrabution panel anyway. We plug one cord into one outlet and the second cord into the other outlet, two hots one neutral. So far I can't see any problems as long as you keep the one side on a different hot than the other. By doing this you ballance the load and won't overload the neutral. Three phase has some funny problems, if you need to know what they are let me know.

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Three phase Wye (208/120) and three phase Delta are going to have totally different behaviors and issues, and sub flavors of both systems exist.

Most of the three phase I have seen in commercial buildings is 208/120 Y, where neutral is centered between all three phases. Not only are the three phases 120 degrees away from each other, but in all cases phase to neutral will always be 120 degrees from phase to neutral on the other legs.

From what I understand, your system is a three phase delta 240/120 system where neutral is bonded to the center tap between the A and B phases. This gives the phase angel between A-N and B-N as 180 degrees as is typical in a 120/240 split phase application. You just also happen to have the B-C and C-A phases in your panel, where each full leg (A-B, B-C, C-A) is 120 degrees apart. Also, C is 190 to neutral, and not really useful for loads to neutral.

Not sure about any code issues here, but technically, you can probably find large transformers (240V:240V CT) to take one of these other legs (B-C or C-A) and isolate it from its original neutral reference, and shift it to be a split phase centered around neutral... This would allow you to take better advantage of the service you have, and if repeated for the remaining phase, would allow you to take full advantage of the three phase service.

- Kevin

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James Shelby

For testing I'm in a warehouse with the Delta system but the show will be built around a WYE system in a park. In two weeks I will be finished with the building of the trees and bridge, we will back then to let you know if everything works ok. I've heard of a system in Texas has been built this way for two years and he has had no problems. I'll keep you updated.

P.S. My big issue has been; the LOR has been designed around the left and right banks must have power inputs 180 degrees out of phase for channels 1-8 to work correctly. Some three phase users have seen the problem and some have not, I'm tring to make sure I'm one of the have nots.

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James Shelby wrote:

My big issue has been; the LOR has been designed around the left and right banks must have power inputs 180 degrees out of phase for channels 1-8 to work correctly. Some three phase users have seen the problem and some have not, I'm tring to make sure I'm one of the have nots.
I hadn't thought about it before, but this sounds like a valid issue. Someone from LOR should answer this one, but here's my guess: There is a 100K resistor that feeds the 60-Hz powerline signal to the processor. I assume the firmware uses this signal to time the triac switching. If this assumption is correct, and this powerline timing signal is 120 degrees out of phase with the actual power input on channels 1-8, then the dimming levels will be wrong.

If this is the case, the best solution would be simply to connect both sides of the LOR controller to the same circuit. I assume you can organize your lights so that you won't have more than 20 amps on 16 channels. If you can't do that, perhaps you could use 8-channel units.

Of course, I would be wrong if the triac switching circuit uses a RC circuit tied to the powerline. Would someone from LOR answer this?
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James Shelby

Steven,
What has came down from Dan is;
"We have a zero cross dector that is feed from the right bank (cannels 9-16). If you connect to two phases then channels 9-16 work fine but channels 1-8 will act erratically because they will be 120 degrees out of sync."
Like I said I've talked to a few people with this three phase set-up using two hots and shareing the neutral and they have not seen this problem. Last year I ran 128 channels this way with no problems. I'm hoping now that I've moved this display and it's twice the size I won't see the problem this year. Dan also said that if we did see the problem the fix , like you said, is to have both cords receiving it's power from the same phase.
For you running LOR at your homes you souldn't see this problem because your power comes into your home 180 degrees out of sync for with LOR was designed. This post is only for those of us running three phase and it's just something for us to look out for if a problem does come up with erratic behavior.

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  • 1 month later...

James Shelby wrote:

Steven,
What has came down from Dan is;
"We have a zero cross dector that is feed from the right bank (cannels 9-16). If you connect to two phases then channels 9-16 work fine but channels 1-8 will act erratically because they will be 120 degrees out of sync."
Like I said I've talked to a few people with this three phase set-up using two hots and shareing the neutral and they have not seen this problem. Last year I ran 128 channels this way with no problems. I'm hoping now that I've moved this display and it's twice the size I won't see the problem this year. Dan also said that if we did see the problem the fix , like you said, is to have both cords receiving it's power from the same phase.
For you running LOR at your homes you souldn't see this problem because your power comes into your home 180 degrees out of sync for with LOR was designed. This post is only for those of us running three phase and it's just something for us to look out for if a problem does come up with erratic behavior.




I'm having this three phase issue at our church still. Does anyone know how I can determine which circuits are on the "same phase"? I have access to the power panel, but from my trials so far - it doesn't seem that there is any order as I move down the breaker panel.

Thanks for any ideas.
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Donald Puryear

In a three phase panel the breakers alternate phases.



1,2 A phase

3,4 B phase

5,6 C phase

7,8 A Phase

9,10 B phase

11,12 C phase ETC....

If you have access to a meter you can always check your plugs.

Run cords from the two Recpt. You want to use. Take a volt meter and measure the voltage from the two small slots of the two cords. 0-volts same phase. 208 (240) your on two diffrent phases. Here is a pic.. (I'm no artist)


Attached files 144991=8568-pic1.bmp

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James,

In your situation if you run 2 hots and one neutral to your controller and each hot is powered by seperate phases then you should not have a problem. Except for the 120 degree phase issue as mentioned.

By definition the neutral carries unbalanced current. Meaning if your sharing a neutral and have your hots on 2 phases, side A of LOR pulling 15 amps and the side B of LOR pulling 18 amps then effectively your SHARED neutral is only be carrying 3 amps to complete the circuit.

On the other hand. If you have both hots tied to the same phase, with the current on side A and Side B of the LOR board would be additive. Meaning if side A is pulling 15 amps and side B is pulling 18 amps then your neutral would be seeing 33 amps to complete the path back to the panel. 33 amps would definately overload your 12 ga wire. You would need an 8ga. neutral to be safe.

Chuck

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"I'm having this three phase issue at our church still. Does anyone know how I can determine which circuits are on the "same phase"? I have access to the power panel, but from my trials so far - it doesn't seem that there is any order as I move down the breaker panel.

Thanks for any ideas."

Hey Tom my display is dead for this year. A year of work and something in our setup will not allow LOR to work for us. I should rephase that it works but channels stick on, flicker, shimmer, won't come on, at different times and in different songs, it looks really bad to me but most people around here think it's part of the show, it just looks like I really didn't know what I was doing when I sequenced my songs.
To answer your queston what I did to phase my boxes, (by the way I built the 3000amp three phase system myself so I know it's three phase) was to turn off all B phase and C phase breakers leaving only A phase breakers on. I pluged both cords of one controller into the two outlets I found with power, when I ran out of outlets I repeated the process for B phase, ( turning off A phase breakers and C phase breakers finding those B phase outlets until I ran out of outlets). Then I repeated the process for C phase.
What did I do when I ran out of two outlets of the same phase, lets say I had one A phase and one C phase outlet, I ran temp power cords back to the panel and picked up one more A phase breaker and one more C phase breaker. Next year I'm going to rewire the whole thing that way I don't need to mess with all this. Did all this work? I'm not sure because it looks so bad anyway but I do know each controller is on the same phase. Also we found we need to swap power cords from one outlet to the next two or three times a week and that seems to help our problem but did not fix all our problems. LOR thinks we have a comm problem but I think it is that plus this three phase issue. We have spent a lot of long hours and money on this and nothing has fixed it YET. If you need anything let me know I have tried it all. James

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cmoore60 wrote:

James,

In your situation if you run 2 hots and one neutral to your controller and each hot is powered by seperate phases then you should not have a problem. Except for the 120 degree phase issue as mentioned.

By definition the neutral carries unbalanced current. Meaning if your sharing a neutral and have your hots on 2 phases, side A of LOR pulling 15 amps and the side B of LOR pulling 18 amps then effectively your SHARED neutral is only be carrying 3 amps to complete the circuit.

On the other hand. If you have both hots tied to the same phase, with the current on side A and Side B of the LOR board would be additive. Meaning if side A is pulling 15 amps and side B is pulling 18 amps then your neutral would be seeing 33 amps to complete the path back to the panel. 33 amps would definately overload your 12 ga wire. You would need an 8ga. neutral to be safe.

Chuck
Chuck
Very very good point. I know all that, I've been a contractor for 20+ years and that is what blew me away when LOR needed ALL three phase users to connect both hots to one phase. You will over load the neutral every time and burn the screws out of the neutral bar in the panel, if not the wire, we check ours every week. Again very good point I wish LOR was aware of that when the page was blank in the very begaining.
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James,

The situation I pointed out would only be a problem if you used ONE power cord to the controller that contained your 2 hots, 1 neutral and 1 ground.

If you used the controllers with 2 power inputs as LOR ships them, then you would just plug each male plug into a circuits on one phase, but 2 circuits.

Chuck

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James Shelby wrote:

"I'm having this three phase issue at our church still. Does anyone know how I can determine which circuits are on the "same phase"? I have access to the power panel, but from my trials so far - it doesn't seem that there is any order as I move down the breaker panel.

Thanks for any ideas."

Hey Tom my display is dead for this year. A year of work and something in our setup will not allow LOR to work for us. I should rephase that it works but channels stick on, flicker, shimmer, won't come on, at different times and in different songs, it looks really bad to me but most people around here think it's part of the show, it just looks like I really didn't know what I was doing when I sequenced my songs.
To answer your queston what I did to phase my boxes, (by the way I built the 3000amp three phase system myself so I know it's three phase) was to turn off all B phase and C phase breakers leaving only A phase breakers on. I pluged both cords of one controller into the two outlets I found with power, when I ran out of outlets I repeated the process for B phase, ( turning off A phase breakers and C phase breakers finding those B phase outlets until I ran out of outlets). Then I repeated the process for C phase.
What did I do when I ran out of two outlets of the same phase, lets say I had one A phase and one C phase outlet, I ran temp power cords back to the panel and picked up one more A phase breaker and one more C phase breaker. Next year I'm going to rewire the whole thing that way I don't need to mess with all this. Did all this work? I'm not sure because it looks so bad anyway but I do know each controller is on the same phase. Also we found we need to swap power cords from one outlet to the next two or three times a week and that seems to help our problem but did not fix all our problems. LOR thinks we have a comm problem but I think it is that plus this three phase issue. We have spent a lot of long hours and money on this and nothing has fixed it YET. If you need anything let me know I have tried it all. James


James,



I'm so sorry about your syncronized show this year. :) I saw your web site, and it looks awesome. This is our church's first year (second actually - but last year was a small 16 channel/4 tree display) with a big sync'd display.

I am going to get a volt meter tomorrow.

With trial & error, I thought I had isolated the phases, and connected appropriately. The first "show" went great (or maybe I just wasn't paying close enough attention). The second, and subsequent showings I see light "pops" during the fades and now even a channel blinking on without any reason.

This is frustrating, as I had to scale back the show already to keep it under 30A per controller. I don't think I could get it down to 20A per controller. :(

Thanks for the pic and suggestion, Donald. I'll post tomorrow after I try it.

Tom
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Donald Puryear

Tom :

You can still load your boards to 30 amps. just plug both power cords into two diffrent circuits that are on the same Phase. everything should run fine.

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Another thing I had to do was to uninstall LOR, last night. It looks like to me an upgrade here and an upgrade there has caused some of my problems. I've reloaded everything, drivers and all, and that helped a lot but not 100%. Also check your RJ45 jacks on the boards to make sure they have not been pulled off the board. Cat5 can become damaged just setting there, have you replaced your cables? Here is some very good information http://www.lightorama.com/SoftwareUpgrade.html. Good luck talk to you soon.

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