134. An over-excited synchronous motor behaves as
A. a resistor
B. an inductor
C. a capacitor
D. none of the above
135. At full-load, the rotor poles of a synchronous motor are displaced by a mechanical angle of 1? from their no-load position. If the machine has 40 poles, then torque angle is
A. 40? electrical
B. 20? electrical
C. 100 electrical
D. none of the above
136. The mechanical power developed by a synchronous motor is independent of
A. applied stator voltage
B. torque angle
C. field excitation
D. speed
137. When a synchronous motor is pulled out of synchronism, the stator current
A. becomes zero
B. is increased too much
C. is decreased too much
D. remains unchanged
138. A synchronous capacitor is an over-excited motor running at
A. full-load
B. half full load
C. no-load
D.pone of the above
139. A synchronous motor delivers reactive power when
A. over-excited
B. under-excited
C. normally excited
D. none of the above
140. When a unity p.f. synchronous motor is operated at a leading p.f., it results in
A. more than rated horsepower output
B. more than rated stator current
C. less than rated horsepower output
D. none of the above
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