Special Machine (EX-802 (B)) - Important Questions

Explain the different types of stepper motors, including single-stack and multi-stack, with a neat schematic diagram and working operation.

Describe the different ways in which stepper motors can be used.

What are the different driver circuits used in stepper motors? Explain any one with schematic diagram.

Explain micro-stepping in stepper motors.

List the important features of stepper motors.

Explain how to control load angle in a stepper motor.

Discuss speed control methods of stepper motor.

Differentiate between permanent magnet and hybrid stepper motor.

Explain the construction and working principle of hybrid stepper motor with neat diagrams.

Draw and explain in detail the static and dynamic characteristics of stepper motor.

Explain the dual voltage driver circuit for two-phase-on drive of a four-phase stepper motor and the nature of current build-up.

Calculate the stepping angle of a hybrid / variable reluctance stepper motor from stator and rotor teeth.

Explain the principle of operation of a switched reluctance motor with cross-sectional diagram and state its advantages.

Explain briefly how torque is produced in a switched reluctance motor with expression, and explain shaft position sensing.

Explain advantages and disadvantages of Solid Rotor.

Calculate instantaneous torque, maximum energy conversion per stroke and average torque for a given SRM with aligned/unaligned inductances.

Explain the operating principle of a switched reluctance motor and torque development with angle-torque characteristics.

Explain the shaft position sensor in the Switched Reluctance Motor.

Explain the construction and working principle of a brushless DC motor.

Explain the torque production in brushless DC motor.

Explain how the speed of a brushless DC motor is controlled?

Explain commutation and armature reaction in a PMBLDC motor.

Explain series and parallel winding pattern of brushless DC motor.

Derive an expression for permeance coefficient of PMBLDC motor.

State the advantages of a BLDC motor over a conventional DC motor.

Discuss the use of Hall sensors for position sensing in a PMBLDC motor with necessary block diagram.

Discuss B-H relationship, leakage flux, fringing and stacking factor.

Discuss the construction and working principle of a permanent magnet brushless DC motor and draw its torque-speed characteristics.

What are the different applications of permanent magnet DC motors?

Compare between soft and hard ferromagnetic materials.

Draw and explain the constructional details of a permanent magnet DC motor.

Write a short note on any two:

Write short notes on motors suitable for electric vehicles and PV-fed water pumping systems and related motor topics

Explain the construction and operation of a PM synchronous motor.

Differentiate between permanent magnet BLDC motor and permanent magnet synchronous motor.

Explain the speed control methods and power controllers used for PMSM with necessary diagrams.

Explain sensorless control of PM synchronous motor.

Give applications of permanent magnet synchronous motor

Derive the EMF equation of a Permanent Magnet Synchronous Motor (PMSM).

Describe the torque-speed characteristics of PMSM with phasor diagram and circle diagram.

Describe the methods to reduce the torque pulsation in the PM synchronous motor.

With a neat sketch explain the torque-speed characteristics of AC servomotor.

Explain the methods of energy conversion via Electric field with examples of Electrical Machines.