effects of loading 2 phases of 3 phase power

Discussion in 'General Electronics Chat' started by strantor, Mar 18, 2011.

  1. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
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    1,988
    If I install a 120V stepdown transformer on phases A and B of a 480V 3 phase system & put a large load on the transformer, what will happen to the rest of the components on the 480V system?
    What will happen to the power source?

    I have read someone mentioning that you need to load the C phase to balance the load, but how do you do that? If you have a higher load between A & B, so you put a load between C & B to balance it out, didn't you just equalize A & C and double the load on B?
     
  2. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    3 phase system are implemented because of their efficiency in power transmission/utilization. Unbalancing a 3 phase system moves you away from those desirable qualities.

    The same can be said for your residential supply where you have two hots and a neutral (the two hots are actually 2 of 3 phases that your share with others in your neighbourhood). What happens if you place all your breakers on one hot to neutrual and none on the other. Notice how breaker panels divide the breakers evenly from side to side in an attempt to 'balance' you as a load.

    if you sit down and do some math based around a balanced/unbalanced 3 phase systems, you'll see what the fuss is all about.
     
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