ELECTRICAL DEPARTMENT NOTICE BOARD

	Question bank ( 7Th  Semester- Electrical)
	Design of A C Machines[ subject code : 2170909]
1	Derive an output equation for 3-ф induction motor with usual notation.
2	Explain the points to be considered for the selection of number of stator slots of an 3-phase induction motor.
3	Explain the factors that effects the choice of specific magnetic & electric  loading in case of a induction machine.
4	Discuss the effect of air gap length on the performance of a 3-phase induction motor.
5	Discuss how the magnetizing current can be estimated from the design data in a three phase induction motor.
6	Discuss the effect of variation of main dimension(D&L) on performance (Rating, losses & efficiency) of  3-ф induction motor
7	Discuss the Harmonic  torque in 3-ф induction motor
8	Prove that torque produce by 5TH harmonics is in backward direction & 7TH harmonics is in forward direction.
9	State the rules for the selection of rotor slots. Describe the methods for reducing the effect of harmonics torque.
10	Explain the deciding factor for stator slots and state the equation for 1) Area of stator slots 2) Stator winding resistance 3) Stator copper losses
11	Explain steps of design of field winding of alternator.
12
13	Explain importance of damper winding in synchronous machine.
14	Explain the terms “critical speed” and “run away speed” with reference to synchronous machine.
15	Define and explain the term “short circuit ratio” of a synchronous generator and discuss its influences on the machine performance.
16	Explain the effect of skewing the rotor slots in a squirrel cage induction motor.
17	What is the role of damper winding in (i) synchronous generator and (ii)synchronous motor? Derive the equation of MMF of damper winding.
18	Explain the factors that effects the choice of specific magnetic & electric  loading in case of a synchronous machine.
19	Write the steps and necessary equations for rotor design of an synchronous machine
20	Explain the factors which are to be considered while selecting the armature slots of a synchronous machine.
21	Explain briefly the methods for improving e.m.f. wave form of an alternator.
22	Discuss in steps the design of field winding of a salient pole synchronous machine.
23	Discuss the design differences of a salient pole and non salient pole synchronous machines.
24	Explain the factors to be considered while selecting number of armature slots in the design of a synchronous machine.
25	Explain the design of salient pole rotor in a synchronous machine.