ELECTRICAL DEPARTMENT NOTICE BOARD

	Question bank  (4Th semester)
	A C Machines [ subject code : 2140906]
1	Explain the construction and working principle of  Polyphase Induction Motor
2	Explain OC & SC test of  Polyphase Induction Motor
3	Explain the losses & power stage of  Polyphase Induction Motor
4	Draw the phasor diagram and equivalent circuit of a 3-phase induction motor.
5	Explain the importance of Circle diagram of Polyphase Induction Motor.
6	Explain the need of starter for AC motor. Draw and Explain the circuit diagram of any one Starter for 3-Phase Induction Motor.
7	Explain the effect of unbalance voltage and variation in frequency on the performance of 3-Phase Induction Motor.
8	Explain the Rotating magnetic field in three phase induction motor.
9	State the difference between DOL starter and Star-delta starter.
10	Explain how by inserting resistance in the rotor circuit of a slipring induction motor the starting current of the motor can be limited.
11	Explain the phenomenon of cogging and crawling in induction motor.
12	State different methods of speed control of 3- Induction motor. Explain an one method of speed control of 3-   slip ring induction motor from the rotorside.
13	Explain performance of 3-phase I.M. for change in supply frequency with constant supply voltage.
14	Derive the equation of  torque of three phase Induction Motor at starting & under running condition.
15	Derive the condition of max. torque of three phase Induction Motor at starting & under running condition.
16	Draw & explain power angle characteristics of synchronous machine.
17	Derive the equation of synchronizing power & condition for maximum power.
18	What are the different excitation systems used in synchronous machine
19	What is  SCR in synchronou machine ?, explain in detail.
20	Compare the methods for finding voltage regulation of Alternator.
21	Explain the different effect for failour in synchronizing the alternators.
22	Explain the different methods for synchronizing the alternators.
23	Explain the slip test for finding voltage regulation of three phase alternator by measuring direct axis & quadrater axis reactance.
24	List different methods for finding voltage regulation of an alternator and explain any one method.
25	State the conditions necessary for paralleling alternators. Explain one dark and two bright lamp method with necessary electrical circuit diagram.
26	Explain concept of pitch factor and distribution factor in case of an alternator. How these values change with harmonics.
27	What is armature reaction? Explain the effect of armature reaction at different power factor on the terminal voltage of an alternator.
28	Derive emf equation of alternator. Explain distribution factor with effect of harmonics.
29	Explain the construction and working principle of synchronous Generator.
30	Explain the direct load test for finding voltage regulation of three phase alternator .