ELECTRICAL DEPARTMENT NOTICE BOARD

MID-SEMESTER TEST ,  SYLLABUS Design of A C Machines(7Th Semester- Electrical)

[ subject code : 2170909] (1)DESIGN OF THREE PHASE INDUCTION MOTOR: MAIN DIMENSIONS: Output equation, choice of specific loadings, separation of D and L. STATOR DESIGN: Stator winding design, Calculation of no. of turns per phase, Conductor’s area, Shape of the stator slots, Area of stator slots, Stator teeth design, Depth of the stator core, Length of air gap, Numerical problems related to above topics. ROTOR DESIGN: A. Squirrel cage rotor – Selection of no. of rotor slots, Effect of harmonics and choice of rotor slots to minimize harmonics, vibration, noise and voltage ripples, Rules for selecting no. of rotor slots, Methods for reducing harmonic torque, Design of rotor bars and rotor slots. Design of end rings and rotor core. B. Wound rotor - Calculation of number of rotor slots, Number of turns, Cross sectional area of rotor conductors, Types of rotor windings, Check for rotor tooth density, Design of rotor slot and rotor core. (2)DESIGN OF SINGLE PHASE INDUCTION MOTOR: Design of main dimensions, Design of stator, Design of rotor, Design of auxiliary winding. PERFORMANCE PARAMETERS EVALUATION: Rotor resistance, Stator resistance, Iron loss, Friction and Windage loss, Starting torque, Circle diagram, Calculation of capacitance for maximum torque. (3)DESIGN OF SYNCHRONOUS MACHINE: Output equation and design of main dimensions, Short Circuit Ratio (SCR) and its significance, Length of air gap and shape of pole face. ARMATURE DESIGN: Armature winding (Single layer and double layer), Number of armature slots, Slot dimensions, Length of mean turn, Calculation of armature resistance and reactance. DESIGN OF FIELD SYSTEM: Design of magnetic circuit, Open circuit characteristic, Determination of full load field MMF, Design of field winding, Determination of direct and quadrature axis synchronous reactance, Short circuit characteristics.

	Question bank                                                ( 7Th  Semester- Electrical)
	Design of A C Machines[ subject code : 2170909]
	Three phase induction motor design
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 a 3-phase induction motor.
3	Explain the factors that affect 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 the current distribution in the bars and the end rings of a squirrel cage induction motor. Also derive the relation for the current in the end ring.
12	Derive the equation of rotor resistance referred to stator side, for a squirrel cage induction motor.
13	Explain the design procedure of rotor for3-ф induction motor with usual notation.
14	Explain the design procedure of stator for3-ф induction motor with usual notation.
	single phase induction motor design
15	Derive an output equation for 1-ф induction motor with usual notation.
16	Explain the design procedure of rotor for1-ф induction motor with usual notation.
17	Explain the design procedure of stator for1-ф induction motor with usual notation.
18	Explain the design procedure of an auxiliary winding in case of resistance split phase 1-ф induction motor with usual notation.
19	Explain the design procedure of an auxiliary winding in case of capacitor split phase 1-ф induction motor with usual notation.
20	Explain the importance of circle diagram in designing auxiliary winding for 1-ф induction motor.
	Synchronous machine design
21	Derive an output equation for 3-ф Synchronous machines with usual notation.
22	Explain steps of design of field winding of alternator.
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 terms “critical speed” and “run away speed” with reference to synchronous machine.
26	Define and explain the term “short circuit ratio” of a synchronous generator and discuss its influences on the machine performance.
27	Explain the design of armature resistance & leakage reactance of alternator
28	What is the role of damper winding in (i) synchronous generator and (ii)synchronous motor? Derive the equation of MMF of damper winding.
30	Explain the factors that affect the choice of specific magnetic & electric loading in case of a synchronous machine.
31	Write the steps and necessary equations for rotor design of an synchronous machine
32	Explain the factors which are to be considered while selecting the armature slots of a synchronous machine.
33	Explain steps of designing damper winding of alternator.
34	Explain the harmonics effect & their elimination efforts.
35	Explain different types of excitation systems used for alternator.