Discussion in 'Homework Help' started by cpleng7, Jan 4, 2011.

  1. cpleng7

    Thread Starter Active Member

    Dec 18, 2008
    I have a three phase power source which 415V line to line .
    and I have three transfomer 240 - 12V.
    Now I have a task to step down the three phase system to 12V each phase.
    How I can do?
  2. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    You could take 2 transformers and put the primaries in series. Two 220 volt primaries add up 440 volt. The secondaries can be placed in parallel for 12 volts out.

    You would need 6 transformers to do this for all three phases.

    Otherwise you need the proper voltage step down transformer.
  3. Adjuster

    Late Member

    Dec 26, 2010
    415V line to line. How many volts line to neutral? Or if you don't have a neutral, from line to a star point?
  4. edgetrigger


    Dec 19, 2010
    How many wires your three phase has. If it has 4 wires marked RGB and N then it is a star connection. The voltage between any of R,G,B wrt N is called the phase voltage and will be around 240V for 415v 3 phase system.

    Connect the primary of the transofrmer between
    R & N
    Y & N
    B & N

    now the load is also distributed equally. The output of each 240-12 step down will give you 12 v as desired.

    If you dont have a star connection then you have to have a star-delta tranformer.