218. At the instant of starting when a D.C. motor is put on supply, it behaves like
A. a highly resistive circuit
B. a low resistance circuit
C. a capacitive circuit
D. none of the above

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219. The speed of a D.C. motor can be varied by varying
A. field current
B. applied voltage
C. resistance in series with armatu
D. any of the above

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220. Which one of the following is not necessarily the advantage of D.C. motors over A.C. motors?
A. Low cost
B. Wide speed range
C. Stability
D. High starting torque

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221. For a D.C. shunt motor if the excitation is changed
A. torque will remain constant
B. torque will change but power will remain constant
C. torque and power both will change
D. torque, power and speed, all will change

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222. Which motor has the poorest speed control?
A. Differentially compounded motor
B. Cumulatively compounded motor
C. Shunt motor
D. Series motor

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223. The plugging gives the
A. zero torque braking
B. smallest torque braking
C. highest torque braking
D. none of the above

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224. The armature voltage control of D.C. motor provides
A. constant voltage drive
B. constant current drive
C. constant torque drive
D. none of the above

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