Synchronous Motors — Part 2 MCQs with Explanations

the direction of instantaneous torque reverses after half cycle is the correct answer to “Synchronous motors are generally not self-starting because”. This question is standard in competitive examination syllabi for Synchronous Motors.

the force required to accelerate the rotor to the synchronous speed in an instant is absent is the correct answer to “The synchronous motor is not inherently self-starting because”. This question is standard in competitive examination syllabi for Synchronous Motors.

90° is the correct answer to “The power developed by a synchronous motor will be maximum when the load angle is”. This question is standard in competitive examination syllabi for Synchronous Motors.

armature current and field current is the correct answer to “In a synchronous motor, V-curves represent relation between”. This question is standard in competitive examination syllabi for Synchronous Motors.

locked-rotor torque is the correct answer to “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”. This question is standard in competitive examination syllabi for Synchronous Motors.

both high and low excitation is the correct answer to “In a synchronous motor, the armature current has large values for”. This question is standard in competitive examination syllabi for Synchronous Motors.

rotor and the stator poles of opposite polarity is the correct answer to “The coupling angle or load angle of synchronous motor is defined as the angle between the”. This question is standard in competitive examination syllabi for Synchronous Motors.

has large values for low and high excitation is the correct answer to “The armature current of the synchronous motor”. This question is standard in competitive examination syllabi for Synchronous Motors.

become less is the correct answer to “If in a synchronous motor, driving mechanical load and drawing current at lagging power factor from constant voltage supply, its field excitation is increased, then its power factor”. This question is standard in competitive examination syllabi for Synchronous Motors.

synchronising torque is the correct answer to “The maximum value of torque that a synchronous motor can develop without losing its synchronism, is known as”. This question is standard in competitive examination syllabi for Synchronous Motors.

d.c. shunt machines is the correct answer to “Exciters of synchronous machines are”. This question is standard in competitive examination syllabi for Synchronous Motors.

armature current is the correct answer to “A synchronous motor running with normal excitation adjusts to load increases essentially by increase in”. This question is standard in competitive examination syllabi for Synchronous Motors.

excitation winding gets disconnected is the correct answer to “A synchronous motor will always stop when”. This question is standard in competitive examination syllabi for Synchronous Motors.

A.C. synchronous motor is the correct answer to “Which of the following motors will be used in electric clocks”. This question is standard in competitive examination syllabi for Synchronous Motors.

directly opposes it is the correct answer to “When a 3-phase synchronous generator is supplying a zero power factor lagging load, the armature field affects the main field in the following way”. This question is standard in competitive examination syllabi for Synchronous Motors.

pole faces is the correct answer to “In a synchronous motor, damper windings are provided on”. This question is standard in competitive examination syllabi for Synchronous Motors.

prevent hunting and provide the starting torque is the correct answer to “In a synchronous motor, the damping winding is generally used to”. This question is standard in competitive examination syllabi for Synchronous Motors.

stator supply is not required to produce magnetic field is the correct answer to “A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is mainly because”. This question is standard in competitive examination syllabi for Synchronous Motors.

Periodic variation of load is the correct answer to “Under which of the following conditions hunting of synchronous motor is likely to occur”. This question is standard in competitive examination syllabi for Synchronous Motors.

the rotating stator flux and rotor poles is the correct answer to “The torque angle, in a synchronous motor, is the angle between”. This question is standard in competitive examination syllabi for Synchronous Motors.

Er (net resultant voltage) in armature is increased is the correct answer to “A synchronous motor is running with normal excitation. When the load is increased, the armature current drawn by it increases because”. This question is standard in competitive examination syllabi for Synchronous Motors.

stop is the correct answer to “If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will”. This question is standard in competitive examination syllabi for Synchronous Motors.

None of the above is the correct answer to “When the voltage applied to a synchronous motor is increased, which of the following will reduce”. This question is standard in competitive examination syllabi for Synchronous Motors.

increase armature current but decrease power factor is the correct answer to “The effect of increasing the load on a synchronous motor running with normal excitation is to”. This question is standard in competitive examination syllabi for Synchronous Motors.

the synchronous speed is the correct answer to “Synchronous motor always runs at”. This question is standard in competitive examination syllabi for Synchronous Motors.

lagging, leading and unity power factors is the correct answer to “A synchronous motor can operate at”. This question is standard in competitive examination syllabi for Synchronous Motors.

small induction motor is the correct answer to “A pony motor is basically a”. This question is standard in competitive examination syllabi for Synchronous Motors.

the rotor excitation, supply voltage and maximum value of coupling angle (90°) is the correct answer to “The maximum power developed in a synchronous motor will depend on”. This question is standard in competitive examination syllabi for Synchronous Motors.

All of the above reasons is the correct answer to “Armature of a synchronous machine is”. This question is standard in competitive examination syllabi for Synchronous Motors.

inversely proportional to the synchronous reactance is the correct answer to “Synchronsizingpower of a synchronous machine is”. This question is standard in competitive examination syllabi for Synchronous Motors.

improve is the correct answer to “A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will”. This question is standard in competitive examination syllabi for Synchronous Motors.

Not-self starting is the correct answer to “Synchronous motors are”. This question is standard in competitive examination syllabi for Synchronous Motors.

unity or 0.8 leading is the correct answer to “The standard full-load power factor ratings for synchronous motors are”. This question is standard in competitive examination syllabi for Synchronous Motors.

the stator current will be zero is the correct answer to “If the synchronous motor, properly synchronised to the supply is running on no load and is having negligible loss then”. This question is standard in competitive examination syllabi for Synchronous Motors.

zero is the correct answer to “The speed regulation of a synchronous motor is always”. This question is standard in competitive examination syllabi for Synchronous Motors.

an alternator is the correct answer to “The construction of a synchronous motor resembles”. This question is standard in competitive examination syllabi for Synchronous Motors.

two slip-rings is the correct answer to “A three-phase synchronous motor will have”. This question is standard in competitive examination syllabi for Synchronous Motors.

changing frequency is the correct answer to “The operating speed of a synchronous motor can be changed to new fixed value by”. This question is standard in competitive examination syllabi for Synchronous Motors.

unity power factor is the correct answer to “The minimum armature current of the synchronous motor corresponds to operation at”. This question is standard in competitive examination syllabi for Synchronous Motors.

the motor stops is the correct answer to “If the field circuit of an unloaded salientpole synchronous motor gets suddenly open-circuited, then”. This question is standard in competitive examination syllabi for Synchronous Motors.