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balancing a load

Discussion in 'Lighting and Electrics' started by techienerd07, Feb 11, 2008.

  1. techienerd07

    techienerd07 Member

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    I need to find out how to balance a load across 3 phases in the dimmer rack. I can do the math all myself if someone can tell me how or what the formulas are to be able to do it. Even just a friendly link to a web site that explains it would be fine with me. Thanks!:)
     
  2. STEVETERRY

    STEVETERRY Well-Known Member

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    Actually, this is something that you, as an entertainment technician, should not be worrying about too much! A properly designed electrical system can tolerate big imbalances in phase current. In fact, if we're worried about reducing neutral current due to imbalances, the highest neutral current on a feeder to a phase-control dimming system occurs with all channels set at 50%, with all phases in total balance. Thus, we're fighting a losing battle!

    I suggest that in a normal dimming system, distribution of circuits will get you close to a balance without you having to actively intervene by modifying your show hookup.

    ST
     
  3. JD

    JD Well-Known Member

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    Really not that hard and no need for a formula. You just need to know the layout of your dimmer rack (what channels are on which of the three phase legs.) The object is to end up with equal wattage loads on each of the legs. Close is good. Closer is better.

    For example, lets say you had 24k of lights being used on a show (make it simple, 24 1k lights) and channels 1,4,7,10 were on one leg, 2,5,8,11 were on the second, and 3,6,9,12 on the third. Putting 2 lights on each channel would give you a balanced load.

    If you had 6 k to balance and your layout was 1,2,3,4 / 5,6,7,8 / 9,10,11,12 then you would put 2k in the first group, skip a couple of channels, put 2k in the second group, skip a couple, and 2k in the last group.
     
  4. Footer

    Footer Senior Team Senior Team Premium Member

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    Also, Lightwright will do this for you if you do your show setup/dimming system set up correctly.
     
  5. digitaltec

    digitaltec Active Member

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    I would be more the happy to help. Let me know how many channels are on your rack and the fixtures you are using and I would be more then happy to send you the information you need along with an example.

    Send me the info in a e-mail so I can respond with the correct information and a spreadsheet.
     

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