Questions on Synchronous Motors Multiple choice Questions and Answers pdf

111.    The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as
(a)     pull-up torque
(b)     pull-in torque
(c)    pull-out torque
(d)    none of the above
Ans: b

112.    A synchronous machine with low value of short-circuit ratio has
(a)     lower stability limit
(6)     high stability limit
(c)    good speed regulation
(d)    good voltage regulation
(e)    none of the above
Ans: a

113.    The construction of a synchronous motor resembles
(a)    a series motor
(b)    an induction motor
(c)    an alternator
(d)    a rotary converter
Ans: c

114.    If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will
(a)     stop
(b)     run as induction motor
(c)    function as static condenser
(d)    burn with dense smoke
Ans: a

1    For power factor correction, synchronous motors operate at
(a)    no-load and greatly over-excited fields
(b)    no-load and under-excited fields
(c)    normal load with minimum excitation
(d)    normal load with zero excitation
Ans: a

116.    The maximum torque which a synchronous motor will develop at rest for any angular position of the rotor, at rated stator supply voltage and frequency, is known as
(a)    locked-rotor torque
(b)    synchronous torque
(c)    pull up torque
(d)     reluctance torque
Ans: a

117.    Exciters of synchronous machines are
(a)     d.c. shunt machines
(b)     d.c. series machines
(c)    d.c. compound machines
(d)    any of the above
Ans: a

118.    The coupling angle or load angle of synchronous motor is defined as the angle between the
(a)    rotor and stator teeth
(b)    rotor and the stator poles of opposite polarity
(c)    rotor and the stator poles of the same polarity
(d)    none of the above
Ans: b

119.    If the synchronous motor, properly synchronised to the supply is running on no load and is having negligible loss then
(a) the stator current will be zero
(b) the stator current will be very small
(c) the stator current will be very high
(d) the back e.m.f. will be more than the supply voltage
(e) none of the above
Ans: a

120 The armature current of the synchronous motor
(a)     has large values for low excitation i niy
(b)    has large values for high excitation only
(c)    has large values for low and high excitation
(d)    any of the above
Ans: c

121.    The maximum power developed in a synchronous motor will depend on
(a)     the rotor excitation only
(b)     the supply voltage only
(c)    the rotor excitation and supply volt-age both
(d)    the rotor excitation, supply voltage and maximum value of coupling angle (90°)
(e)    none of the above
Ans: d

122.    A synchronous motor which works on a leading power factor and does not drive a mechanical load is called as
(a)    static condenser
(b)    condenser
(c)    synchronous condenser
(d)    none of the above
Ans: c

Read More Questions:
Synchronous Motors MCQs Part1
Synchronous Motors MCQs Part2
Synchronous Motors MCQs Part3
Synchronous Motors MCQs Part4
Synchronous Motors MCQs Part5
Synchronous Motors MCQs Part6
Synchronous Motors MCQs Part7
Synchronous Motors MCQs Part8
Synchronous Motors MCQs Part9
Synchronous Motors MCQs Part10
Synchronous Motors MCQs Part11
Synchronous Motors MCQs Part12