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Running your entire rig at full

Discussion in 'Lighting and Electrics' started by photoatdv, Mar 9, 2009.

  1. photoatdv

    photoatdv Active Member

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    Just a thought... somebody was talking about that we do not use our dmmers to capacity. Often when I'm troubleshooting or doing a check at the beginning of a show I'll throw everything to full. Generally it's just that I don't want to figure out what dimmer (s) I need, but lately I do it so if there are any issues with loading or dying lamps I'll find out then, not in dress or show. All of our dimmers are not used, if fact probably only half are used. Is that a bad idea in terms of upstream breakers? If need be I could accomplish the same ends by doing half the system at a time. I do put some very dynamic loads on the system even in show (I come pretty close to flashing the full system at full on effects sometimes).
     
  2. TimMiller

    TimMiller Well-Known Member

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    Re: Questions about 3 phase - 1 phase load

    I will do the same thing, i will flash the load on, let my meter (to the best of its ability) attempt to catch an inrush current rating (for a ball park amount), I will leave the entire rig on for a while, to let everything get a little toasty, and meter my feeder to see how balanced i am, along with making sure i'm not about to pop anything. I worry more about being balaced across all 3 legs of power when i am running off of generators, they really dont like it when you are pulling hard on 2 legs but not the 3rd.
     
    Last edited by a moderator: Mar 9, 2009
  3. icewolf08

    icewolf08 CBMod CB Mods

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    Re: Questions about 3 phase - 1 phase load

    Well, chances are you don't actually load your racks to full capacity. Consider that if you actually were to put one Source 4 on every dimmer then you are only drawing a total of 460A (96 x 575W = 55200W 55200W/120V=460A) which is well under what the standard feeder for an ETC SR48 rack with 96 dimmers would be fed with (generally a 400A 3ø). So, figure in some 2-fers, 1k fixtures, and such, and you are probably still well under your max, especially if you aren't loading every dimmer.

    As for whether or not turning everything on at once is a good idea, probably not. I also don't really understand from your post why it is necessary. You put a lot of strain on the equipment when you run everything at full. Even though the odds are that you won't trip brakers based on "steady state" theoretical "perfect world" math, consider that if you just pop everything up to full you have a huge inrush current which could cause brakers to trip. You are also heating cables and raceways and other gear more than you would under "normal usage."

    I am sure that there are people who could give you a more detailed and specific answer, but I have always been taught that you should never run an entire rig at full all at once. However, if you are trying to meter power like Tim was talking about, running your rig at full is a necessity.
     
  4. photoatdv

    photoatdv Active Member

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    Re: Questions about 3 phase - 1 phase load

    There are 2 reasons I do the full on;
    1. So I can see what isn't working that needs to go on the electrician's to do list(granted that may be me as well, but I know it is a physical problem-- putting everything at full takes patch, programming and console settings out of the equation). This I could accomplish by bringing the dimmers up a few at a time and therefore avoiding the inrush current.
    2. I often flash over 50% of my rig at a time during shows, so this builds in a margin of error to test that nothing will trip. However I could figgure out what the actual max I will flash and flash if with the stuff that will already be on on plus a couple of extra instruments if it really makes a difference.
     
  5. sk8rsdad

    sk8rsdad Well-Known Member Premium Member Fight Leukemia

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    I won't intentionally do a Full On test. It would push our peak load over a threshold and trigger a $600 premium on our monthly electricity bill.
     
  6. Footer

    Footer Senior Team Senior Team Premium Member

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    Re: Questions about 3 phase - 1 phase load

    You need to do a Lamp Check, Channel Check, Dimmer Check... call it what you will. I would highly advise to not walking into your theatre cold and turning everything on at full. Your lamps will hate you for that. I would suggest writing cue .1 that over a period of about 2 minutes takes all the lights to 50% or even 80%. This is called a warmer cue. It will heat up your lamps and get them ready to go. Added to that you need to check more things then is the instrument turning on. If I am a P.E. on a show I go through every channel individually, checking it for color, focus, and if it is working or not.

    Also, you should be OK to run every dimmer full loaded at full. Most installed systems are specked for this. Electrical Engineers like to enough power going to every circuit.
     
  7. icewolf08

    icewolf08 CBMod CB Mods

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    Re: Questions about 3 phase - 1 phase load

    Personally, I find it very hard to tell when one fixture is out if you have every fixture on, especially at full. I find that unless I know exactly how many lights are supposed to be on a batten or in a position then I still need to drag out the paperwork and count fixtures. I seem to do this even if I really do know the entire rig cold. This is the biggest reason that I do a full channel check before every performance and step through each channel one at a time. it allows me to check for all kinds of issues from blown lamps to dropped focus.

    Also, if you are using your console to bring every dimmer up to full then you are not eliminating all the factors you claim to. Consider that even if you bring every dimmer up by dimmer on the console, it still has to send the data out to the dimmers and devices. So you can still have data distribution errors or be sending bad data right from the console. If you waned to eliminate any programming, softpatching, or other data related issues you would have to bring everything up from your rack controller, which is doable.

    As for flashing 50% of your rig. Say you loaded a full ETC SR48 rack to capacity. If you turn on 50% of the dimmers, 48 total, at 2400W each you theoretically wouldn't max out a 3ø 400A service. However, if you were only on 3ø 300A service you would be over. So, I suppose the moral is that you need to know the limitations of your system.
     
  8. icewolf08

    icewolf08 CBMod CB Mods

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    Re: Questions about 3 phase - 1 phase load

    To run a full rack of 2.4kW dimmers (96 total) at full you theoretically need 640A per phase (96x2400=230400W 230400W/120V=1920A 1920A/3=640A/ø. Which means in reality that you would probably have a minimum of a 700A disconnect. However I think that it is more common to see installed racks put on 400A service, because as with all things, electricians assume that you won't be using all 96 dimmers at full load at 100% at the same time.
     
  9. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Re: Questions about 3 phase - 1 phase load

    Absolutely untrue. See this article: Power play: Considerations for feeding permanent dimmer-per-circuit systems in theatres and similar locations, written by one of our own, whom many/most consider to be an expert in the industry. It is wasteful and impractical to feed every dimmer rack with its total possible potential.
     
  10. Esoteric

    Esoteric Well-Known Member

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    Re: Questions about 3 phase - 1 phase load

    I will usually glow everything at about 5% to do a line check.

    Past that it is hard to tell individual units.

    Then I will do a 20 minute warm up to full, leave them there for 5 minutes to warm them up, and then kill them and wait until preshow.

    Mike

    PS In all my installs the racks could be loaded to full and still run at full. My ME won't let me install it any other way. At the PAC we had enough power to run our 288 2.4kW dimmers fully loaded at full.
     
  11. JD

    JD Well-Known Member

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    Don't think a full on will tell you much. If anything, the lamps are getting a lower than usual voltage. I agree that a warm up (very debated) does help, but its easier to call channels and stand on stage and watch. Even 90 channels should only take about 90 seconds to run through at a second a channel. Intels take a bit longer if you want to step through features, but a full on just turns into a bright blur. Doesn't make Al Gore happy either. :rolleyes:
     
  12. Footer

    Footer Senior Team Senior Team Premium Member

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    Re: Questions about 3 phase - 1 phase load

    I have had many an argument about the de-rating thing. I know of some people who swear against it, and some that are all for it. My theatre is a pretty old CD-80 install, and we have 1200 amps available for use. My newer blackbox is a Sensor install and is sitting at 800 amps. Both have about the same number of dimmers, around a rack and a half. I had not seen that article, I find the house light thing interesting. I knew it was code to run de-rated, but I also know there are plenty of older installs that have the power there anyway. It just depends
     
  13. TimMiller

    TimMiller Well-Known Member

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    Re: Questions about 3 phase - 1 phase load

    You theater guys, in the good outdoor shows, with the big generators, you kick the rig up to full for more smoke :D. They ask for more smoke you give them more light and they get more smoke, the yummy black stuff.
     
  14. avkid

    avkid Not a New User Fight Leukemia

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    Re: Questions about 3 phase - 1 phase load

    There's nothing like the smell of Diesel in the morning.
    ;)
     
  15. TimMiller

    TimMiller Well-Known Member

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    Re: Questions about 3 phase - 1 phase load

    Yep. Esp when i leave the truck running in the morning to get it warmed up and then get in with the heater or ac on. ahh.. the smell....
     
  16. mrtrudeau23

    mrtrudeau23 Active Member

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    The year before I came to college, my school did Pirates of Penzance. The plot included 300+ ETC source 4 brand lights. Someone decided to put all of the lights at full one day, and blew the breaker for the dimmer rack. It also resulted in a call from an angry electric company because of the power surge through their system. Depending on how large the plot is, it probably isn't a good idea to run everything at full. The story is one that we frequently laugh about now, but we definitely learned our lesson with large light plots.
     
  17. Esoteric

    Esoteric Well-Known Member

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    We used to turn our 500+ unit plots up to full (including 1k units) for fun. :mrgreen:

    Mike
     
  18. zuixro

    zuixro Active Member

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    In high school, we used to run our rig at 100% for about 20 minutes to check that we wouldn't trip any breakers. All of our lights were on portable dimmer packs, so we tried to spread them out across the circuits in the building.

    Now, in college I just do it for fun. (36 1k PAR64, ~ 2 dozen 575w S-4's, the stage heats up pretty fast)
     
  19. iLightTheStage

    iLightTheStage Active Member

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    I have to agree with others: you have to know that your system can handle it.

    Sometimes, you have to set up a system where, if all used at full, will blow your service, in order to meet the demands of the show/design.

    And, sometimes, you have to run everything at full so you know that nothing will go wrong during your event. I was working at a ballroom of a boston hotel once, and we were told that each quadbox on the wall was on their own 20amp breaker. After setting up plasmas, and uplights, and a couple movers, I happened to be standing next to the breaker panel and heard *clunk*. Turns out that we were entirely told wrong... the entire room was on two 20amp breakers... that's it!

    Had we not been running everything at full during the time, we might not have found out about the problem until the event was already happening. Especially since an over-loaded breaker can take minutes to trip.
     
  20. JD

    JD Well-Known Member

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    Did an outdoor gig for Hall & Oats once. It was so cold that the band asked me to just turn everything on to full and leave it there for the whole show. I told them I would do one better and pull all the gels. (Yea, I know, doesn't affect the temperature one bit, but it preserved my stock of gels!) Good stress test, I guess. Gives all those little quartz tubes a chance to go through their complete halogen cycle. :)
     

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