B.TECH - Semester 8 special electrical machines Question Paper 2021 (feb)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- Discuss the role of servomotors in automation systems. List out few applications.
- A stepper motor is operating at a pulse rate of 5000 pulses per second. It travels $100^{\circ}$ in 0.02 sec . Find its resolution.
- Explain the steady state and dynamic characteristics of stepper motors.
- What is meant by hybrid stepping motors?
- What are the types of rotor position sensors used in switched reluctance motors?
- Compare electronic commutation and mechanical commutation.
- Derive the torque equation of reluctance motors.
- Compare conventional DC motor with BLDC motor.
- Draw the equivalent circuit of linear induction motor and explain.
- Discuss the use of Hall sensors for position sensing in PMBLDC motor. $$ (10 \times 4=40 \text { Marks }) $$ (Answer one full question from each module)
- (a) Explain with neat sketches the working of a DC servomotor. What modifications are made to operate it as a series split field DC servomotor?
- (b) Discuss the various excitation modes of stepper motors.
- (a) Explain with figures, the construction and working of $A C$ servomotors.
- (b) Explain with figures and timing diagrams, the working of multi-stack variable reluctance stepper motors.
- (a) Derive the torque equation of switched reluctance motor. Draw he torque slip characteristics and explain.
- (b) Explain with figures, the construction and working principle of reluctance motors.
- (a) Explain with figures, the principle of operation of hysteresis motor. Draw the torque - slip characteristics and explain.
- (b) Explain different types of switched reluctance motors.
- (a) Analyse the operation of electronic commutation in BLDC motor with necessary diagrams. Explain the operation. 10
- (b) Explain different types of linear motors. List out the applications. 10
- (a) Derive the expressions for the EMF and torque of a BLDC motor. Draw and explain the torque-speed characteristics.
- (b) Explain with neat figures, the construction and principle of operation of linear induction motors. Derive the expression for linear force.