1. Write short notes on any two of the following:

Single-phase Reluctance Motor

Hysteresis Motor

Two-phase Servomotor

Hybrid Stepper Motor

Draw a labelled diagram of Kron's Primitive Machine and its basic two pole representation. Write down the voltage equations for vds, vqs, vdr and vqr in matrix form.

Consider transformation from 3-phases to 2-phases 0). Draw a schematic diagram of balanced 3-phase windings and 2-phase windings on the motor. Determine the two phase currents.

For a separately excited dc generator, derive the expressions for steady state.and transient armature generated emf.

A separately excited dc generator running at 4500/n rpm has the following parameters:

rf= 80 ohm; Lf= 40H; ra 0·1 ohm;
La 0·3 mH; Md= 0·8
Kg=120 volts/field amp.

The field is unexcited and the armature is open. Determine the armature voltage as a function of time, if a constant voltage of 160 volts is suddenly impressed across the field terminals.

Derive the transfer function for a separately excited dc generator on-load operation.

Derive the expression for armature current in case of dc shunt motor.

Derive the expression for synchronizing power in terms of Vt Ef, Xd, Xq and o.

Derive the expression for terminal voltage of a synchronous generator in case of sudden capacitive unloading.

Explain 'single phasing' of a 3-phase induction motor.

For a 3-phase induction motor driven by a constant current and. constant frequency source of supply, derive the expression for maximum torque and starting torque.

Draw the equivalent circuit of a poly phase induction motor.

Derive the expression for air-gap power in a three-phase induction motor.