# Suddenly, the Three Phase died.



## gafftapegreenia (Apr 19, 2007)

So, my highschool doesn't have a theatre. Instead, we have a large room that has been made into what we call the Commons. It was once the schools original gym, before the new one was built in the 50's. The space today was last renovated in the 90's, when three phase power was wired in the ceiling and five, 6 channel Rosco hanging dimmers installed. We only use the dimmers to their max for the fall play, which is usually in November, and we last used them in February for a convention. Well, yesterday I was focusing a few PAR's for a Revival being held in the commons, and only four channels on one of the packs worked. So, I made a few cable runs and was fine. Well, that night when we went to turn on the lights for the revival, nothing came on. Luckily the Revival wasn't dependant on theatrical lighting, but I want to know what happened to thew power.

I talked with maintenance today. They first tried resetting all the circuit breakers, which did nothing to help. Maintenance said that they believe the three phase power has shorted out and are going to call in an electrician. I don't see how in two months between use an entire system can suddenly short out when no one has touched it. 

If the school ever does get a theatre, which is doubtful, or even a blackbox, which is also unlikely, then they might want to consider getting an actual dimmer rack and then wiring some distribution boxes and such in the ceiling. The Commons could be a very viable performance space, if only the school had put more long term planning into it. As it is now, we need at least two dimmers packs for every play we do. However, it is a private school, so I know that they could eventually find the money for such a project, but there is one major obstacle: the Michigan economy. 

However, it's my senior year. I have thirteen class days left. I have been one of "those people" who have a passion for what they do and have done what I can to learn what I can in my highschool experience. They won't have someone like me next year, who knows the difference between a 360Q and a Source 4. I am setting up a sort of guide to help introduce them to the equiopment that will be passing into their care and the common setups that we have done over the years. I've been teaching my replacements, but the thing I have to keep telling them is I didn't become Lighting Head over night. I had to start out reading all I could, in a sense teaching my self and learning by doing. Unless they take the time to really learn, it will just be illumination.


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## Mayhem (Apr 19, 2007)

gafftapegreenia said:


> I don't see how in two months between use an entire system can suddenly short out when no one has touched it.



Ever seen the result of a mouse or rat crawling over the bus bars?


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## gafftapegreenia (Apr 19, 2007)

Yes, I had that thought. It just sucks to think that could have killed the entire system.


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## Van (Apr 20, 2007)

Sounds like you only lost one leg of your three phase, if it's a 6 channel dimmer and you had 4 working. Could be a ton of things depending on how that leg is loaded. I have a HVAC uit on the roof of our building, I've had it tested multiple times with no abnormalities observed, however I have to replace the 2nd phase fuse about every three months. There are also things like corosion, or a loose lug on the feeder lines to be considered.


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## SHARYNF (Apr 20, 2007)

I agree with Van, you probably lost a leg of the three phase, happens a lot more than you would think. I usually suggest that coming out of the main breaker or disconnect that there is a indication for each leg. Since most use fuses, it is pretty much impossible to tell, without checking the fuse. Also it is not out of the question to have one of the legs coming into the panel to be out, I have seen on systems that are fed from over head wires where there can be a problem with the connection, dropping one leg.

Causes all sorts of problems with motors that need all three phases, and takes a bit of debugging, since we usually expect all on or all off, not two legs on one off

Sharyn


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## gafftapegreenia (Apr 20, 2007)

Whatever happened to the wiring it's a mess, becuse now not only are those four remaining dimmers not working, but the four other 6 channel hanging packs don't work either. This is one beyond my or the school's knowledge. I'll let an electrician figure this one out. I would look into it,but I don't want to kill myself.


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## Van (Apr 20, 2007)

That's one of the most honest and smartest things I've ever heard on here!


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## avkid (Apr 20, 2007)

gafftapegreenia said:


> This is one beyond my or the school's knowledge. I'll let an electrician figure this one out. I would look into it,but I don't want to kill myself.


If you can, be there when the electrician is,you may learn something.


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