Page 270 - Solutions Manual to accompany Electric Machinery Fundamentals

(b) If the armature current is 20 A, then the effective field current contribution from the armature
current
N SE I 25   20 A  0.5 A
N F A 1000

I
and the I A R  R S  voltage drop is R  A A R S  20 A   0.21    4.2 V . The location where the
A
N
triangle formed by SE I and IR exactly fits between the E and V lines corresponds to a terminal
N F A A A A T
voltage of 121 V, as shown below.

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