B.TECH - Semester 6 induction machines and special electrical machines Question Paper 2020 (jan)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- Derive the expression for frequency of rotor induced emf of a 3 phase induction motor.
- Write short note on crawling of induction motors.
- What is the necessity of short circuited rotor conductors in a squirrel cage induction motor?
- Mention the applications of induction generator.
- Compare star delta starter with DOL starter.
- Write short notes on plugging in an induction motor.
- Briefly explain the principle of operation of a universal motor.
- What is the purpose of shading coil in a shaded pole motor?
- What is a stepper motor? What are the different types of stepper motors?
- What are the application of reluctance motor? ( $\mathbf{1 0} \boldsymbol{\times} \mathbf{2} \boldsymbol{=} \mathbf{2 0}$ Marks) Answer any one full question from each Module.
- (a) With neat diagram explain the constructional details of a 3 phase induction motor. Also explain different types of induction motors according to rotor construction.
- (b) A 3- phase, 50 Hz , 6- pole induction motor runs at 940 r.p.m. and delivers 7 kW output. What starting torque will the motor develop when switched directly on to the supply, if maximum torque is developed at 800 rpm . The total friction and winda...
- (a) Explain from basics the working principle of a 3 phase induction motor.
- (b) A 6 - pole, $50 \mathrm{~Hz}, 3$ - phase induction motor runs at 960 r.p.m. When the torque on the shaft is $200 \mathrm{~N}-\mathrm{m}$. If the stator losses are 1500 W and friction and windage losses are and 500 W , find
- (i) rotor Cu loss and (ii) efficiency of the motor.
- (a) Explain with suitable diagram, the speed control of induction motor by cascade connection. Mention the advantages and disadvantages of this method.
- (b) Explain the working of a self-excited induction generator. Or
- (a) Draw and explain the connections of stator windings of 3 phase induction motor for Dynamic braking. What are the advantages of this method?
- (b) What is a synchronous induction motor? Explain the characteristics and advantages of a synchronous induction motor.