Page 637 - Basic Electrical Engineering
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E = KϕN
b
E = V − I R a
b
a
Figure 7.20 (a) DC shunt motor; (b) characteristics of a dc shunt motor
For a shunt motor flux produced by the field current is directly proportional
to the field current.
Hence,
ϕ ∝ I f
From Fig. 7.20 (a),
As can be seen from Fig. 7.20 (a), when V and R are constant, I will be
f
f
constant.
Since I is constant, ϕ is constant. Then
f
T = KϕI = K I where Kϕ = K 1
1 a
a
∴ T ∝ I a
Torque T versus current I characteristic has been shown in Fig. 7.20 (bi).
a
