Question

a)Explain the shunt excitation and compound excitation of DC generator. b)A 240V compound DC motor has...

a)Explain the shunt excitation and compound excitation of DC generator.

b)A 240V compound DC motor has the armature, series field and shunt field resistances are
0.22 Ω, 0.04 Ω and 200 Ω respectively. On full load, the line current is 17.5 A and the motor runs at 1800 rpm. (short shunt)
i) Draw the diagram and the power flow of the motor.
ii) Find the back EMF of the motor.
iii) Find the mechanical power developed.
iv) Find the output power if the rotational losses are 250W.
v) Find the output torque.
vi) Determine the overall efficiency.

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