MULTIPLE CHOICE QUESTIONS
Q.1 Which of the following d.c. motor would be
suitable for drives requiring high starting torque but only fairly constant
speed such as crushers ?
(A) shunt
(B) series
(C) compound
(D) permanent magnet
Q.2 A d.c. shunt motor is found suitable to drive fans
because they require
(A) small torque at start up
(B) large torque at high speeds
(C) practically constant voltage
(D) both (a) and (b)
Q.3 Which of the following load would be best driven
by a d.c. compound motor ?
(A) reciprocating pump
(B) centrifugal pump
(C) electric locomotive
(D) fan
Q.4 As the load is increased, the speed of a d.c.
shunt motor
(A) increases proportionately
(B) remains constant
(C) increases slightly
(D) reduces slightly
Q.5 Between no-load and full-load, .......... motor
develops the least torque
(A) series
(B) shunt
(C) cumulative compound
(D) differential compound
Q.6 The Ta/Ia graph of a d.c. series motor is a
(A) parabola from no-load to overload
(B) straight line throughout
(C) parabola throughout
(D) parabola upto full-load and a straight line at
overloads.
Q.7 As compared to shunt and compound motors, series
motor has the highest torque because of its comparatively .......... at the
start.
(A) lower armature resistance
(B) stronger series field
(C) fewer series turns
(D) larger armature current
Q.8 Unlike a shunt motor, it is difficult for a series
motor to stall under heavy loading because
(A) it develops high overload torque
(B) its flux remains constant
(C) it slows down considerably
(D) its back e.m.f. is reduced to almost zero.
Q.9 When load is removed, .......... motor will run at
the highest speed.
(A) shunt
(B) cumulative-compound
(C) differential compound
(D) series
Q.10 A series motor is best suited for driving
(A) lathes
(B) cranes and hoists
(C) shears and punches
(D) machine tools
