## Hi all

Important questions of induction motor and synchronous machine

Que-01 With neat sketch explain construction of 3-phase Induction Motor
Que-02 Explain how rotating magnetic field is produced in 3-phase induction motor
Que-03 Derive the Expression for developed Torque in a 3 – phase induction motor and find the condition for
maximum torque?
Que-04 For an induction motor, derive a relationship between the starting torque and maximum torque
explaining clearly the symbols used.
Que-05 Neatly Sketch and explain the Torque – Speed Characteristics of a 3 – phase induction motor
indicating there in the starting torque, maximum torque and the operating region? What will be the
effect of change in rotor resistance on Torque-Speed characteristic?
Que-06 Develop the equivalent circuit for a 3 – phase induction motor and explain the how the mechanical
power developed is taken care in the equivalent circuit?
Que-07 Explain the procedure to construct the circle diagram for induction motor and how various quantities
are measured from circle diagram?
Que-09 Why a starter is necessary to start an induction motor? Explain following starters and their
comparison
(i) Direct On Line (ii) Star Delta (iii) Auto Transformer (iv) Rotor Resistance
Que-10 Enlist various Speed control methods for 3 phase induction motor and explain following methods
(i) Volt/Hz or V/f control (ii) Consequent Pole (iii) Slip Energy Recovery (iv) Cascade Control
Que-11 Explain the phenomenon of “Crawling and Cogging” in three phase induction motor with their
remedies
Que-12 Give comparison between single cage and double cage rotor induction motor
Que-13 Explain why 1-phase induction motor is not self starting? Explain any one method to make it self
starting
Que-14 Explain double revolving field theory for 1-phase induction motor
Que-15 Derive an EMF equation of an alternator
Que-16 With neat sketch, Explain detailed construction of 3-phase synchronous machine
Que-17 Explain the concept of pitch factor and distribution factor in an alternator. How these values change
with harmonics?
Que-18 Explain armature reaction and its effect at different power factor in an alternator
Que-19 Explain the two reaction theory of salient pole synchronous machine
Que-20 List different methods for finding voltage regulation of an alternator and explain potier method.
Que-21 State the conditions necessary for paralleling the alternator. Explain one dark and two birght lamp
method with necessary electrical circuit diagram
Que-22 Why synchronous motor is not self starting? Explain methods of starting of synchronous motor.
Que-23 Explain V-curves and inverted V-curves of synchronous motor
Que-24 Explain the hunting of synchronous machine and method of its prevention
Que-25 Explain the effect of varying excitation at constant load on synchronous motor