Trick, the A,B,C are the currents in phase A, Phase B, and Phase C.
So for a split(single)phase service, the nuetral current is the unbalnced current flowing between phase A and phase B.
So if 30 amps were flowing on phase A, and 15 amps were flowing on Phase B, the nuetral current would be: Yes it is a minus...
A-B=N
30-15=15
On a wye service, if we had 150amps on A, 110amps on B, and 75amps on C.
N= Sq root of (A^+B^+C^)-(AB+AC+CB)
N=Sq root of (150^+110^+75^)-((150*110)+(150*75)+(75*110)
N=Sq root of
(22500+12100+5625)-((16500)+(11250)+(8250))
N=Sq root of
(40225)-(36000)
N=Sq root of
(4225)
N=65 amps
How does that look?
[This message has been edited by Dnkldorf (edited 07-28-2006).]
