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Old 03-02-2015, 07:38 PM   #1
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If you have 10 amps on A-phase and 10 amps on B-phase, are the amps cancelled due to each phase being 180* out on the sine wave? What if you were to add another 12 amps on C phase? Would you now have 2 amps on your neutral?
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Old 03-02-2015, 07:39 PM   #2
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If you have 10 amps on A-phase and 10 amps on B-phase, are the amps cancelled due to each phase being 180* out on the sine wave? What if you were to add another 12 amps on C phase? Would you now have 2 amps on your neutral?
Yes, and Yes...
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Old 03-02-2015, 07:43 PM   #3
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If it's three phase, A and B are not 180 degrees. They are 120 degrees and you would have to calculate current accordly. So I would say no to both questions.
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Old 03-02-2015, 07:47 PM   #4
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In 3 phase if you only have 2 phase sharing a neutral the neutral becomes a current carrying conductor.
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Old 03-02-2015, 07:59 PM   #5
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Originally Posted by travis13 View Post
If you have 10 amps on A-phase and 10 amps on B-phase, are the amps cancelled due to each phase being 180* out on the sine wave? What if you were to add another 12 amps on C phase? Would you now have 2 amps on your neutral?
If you have 10 amps on phase A and 10 amps on Phase B and 0 amps on Phase C then you have 10 amps on the neutral. Now when you add 12 amps to Phase C you have 2 amps on the neutral

If you have single phase and you have 10 amps on Phases A and B then there is 0 amps on the neutral. The formula for single phase is N=A-B

For 3 phase it is more complicated. Here is an excel formula for it using cells A5, B5 and C5 as the input amps for the phases

=SQRT(((A5*A5)+(B5*B5)+(C5*C5))-((A5*B5)+(B5*C5)+(A5*C5)))

This is the formula

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Old 03-02-2015, 08:04 PM   #6
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Post #33 may help:

http://forums.mikeholt.com/showthrea...=167171&page=4
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Old 03-02-2015, 08:17 PM   #7
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Meadow if you want someone to see post 33 then click on the post number-- this will bring the post to the top of the screen and the url will take you write there so copy it.

Here it is

http://forums.mikeholt.com/showthrea...20#post1624520
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Old 03-02-2015, 08:33 PM   #8
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I did not know that, Thanks!
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