fAAP¼
m 0
2 p
IAln
DAP
GMRA
ðÞWb=m (13:41)
fABP¼
m 0
2 p
IBln
DBP
DAB
ðÞWb=m (13:42)
fACP¼
m 0
2 p
ICln
DCP
DAC
ðÞWb=m (13:43)
The corresponding flux linkage of conductor A at pointP(Fig. 13.12) is evaluated as
lAP¼lAAPþlABPþlACP (13:44)
having
lAAP¼
m 0
2 p
IAln
DAP
GMRA
ðÞWb=m (13:45)
A B C
fA f (^) B f (^) C
DAB DBC
DCA
X X X
FIGURE 13.11 Magnetic flux produced by each conductor in a three-phase system.
C
DAP
B
P
lAAP
lABP lACP
PP
DAC
DAP DAP DCP
DBP
A A
B B
C C
(a) (b) (c)
A
DAB
FIGURE 13.12 Flux linkage of (a) conductor A at pointP, (b) conductor B on conductor A at pointP, and (c)
conductor C on conductor A at pointP. Three-phase system.