1. Write short notes on any two of the following

Single phasing of 3-phase Induction Motor

Hysteresis Motors

Brushless D.C. Motor

Derive the steady state voltage and current equations for a 1-phase induction motor from fundamentals.

Explain the steady state behaviour of a d.c. machine.

Deduce Park's transformations relating the 3-phase currents of a synchronous machine to the corresponding d-q axes currents.

Draw and explain the power angle characteristics of a 3-phase synchronous machine.

Draw the basic two-pole schematic diagram of a separately excited d.c. generator. Derive the expressions for generated emf and motional inductance.

A separately excited d.c. motor is applied with a sudden inertial load. Obtain the expression for the motor speed as a function of time.

Enumerate the assumptions pertaining to the use of generalised mathematical model of d.c. machine.

Using transient analysis for an alternator, ignoring all resistances, derive the expression for transient field current.

Discuss the effect on electromagnetic torque developed in a 3-phase induction motor due to

variable voltage, constant frequency and

constant voltage, variable frequency, using torque slip characteristics.

Draw the equivalent circuit of an induction motor, for

positive sequence voltage and

negative sequence voltage

Explain the principle of operation of a linear induction motor. Derive the expression for linear force developed.

Explain the construction and working of a Schrage motor.