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3 phase calculations

Johno12345
it might just be too early in the morning but I'm getting really confused.


On a 3 phase circuit, I measure 6a 6a and 6a on L1 L2 and L3


I want to work out how many watts it is, so I use rapid tables, set it as 3 phase, 400v line to line and it asks for the amps, is that 6, or is it 18?


The results don't make sense. 


If the loading wasn't equal, is it the sum of all three readings, or an average, or, even, do I clamp all three phases together?


so, using the formula P = √3 × pf × I × V which is fine, but again, is I the total amps per phase, 18, or 6? 



Any help is appreciated
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  • 0
    that's where I was getting confused


    If I treat it as three separate single-phase circuits then I get


    6a x pf (1) x231 = 1386w x 3


    oh wait, that's right


    That is the way I always used to do it, obviously, I really confused myself this morning, I had a terrible feeling I had done some calculations wrong, but I haven't. 


    I'm making an excel sheet to calculate it out, ill add it here when it's complete.


    I am determined to understand things that I put together as proposals, rather than just blindly trusting people and the results they produce.



    Thanks A
Reply
  • 0
    that's where I was getting confused


    If I treat it as three separate single-phase circuits then I get


    6a x pf (1) x231 = 1386w x 3


    oh wait, that's right


    That is the way I always used to do it, obviously, I really confused myself this morning, I had a terrible feeling I had done some calculations wrong, but I haven't. 


    I'm making an excel sheet to calculate it out, ill add it here when it's complete.


    I am determined to understand things that I put together as proposals, rather than just blindly trusting people and the results they produce.



    Thanks A
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