




ADVANCED ASPECTS OF ELECTRICAL MACHINES
Group A
Synchronous motor analysis taking armature resistance into account, vector diagrams, power
circle and excitation circle—diagrams. Performance calculations under various operating
conditions.
The equation of motion or 'swing' equation for synchronous motors and generators. Solutions
of linearized swing equation, small oscillations of synchronous machines. Hunting of
synchronous motors, elements of large oscillation of synchronous machines, concept oftransient stability.
Starting of synchronous motors with the help of damper windings, George's phenomenon.
Brushless excitation of synchronous generators and motors.
Synchronousinduction motor: Slipring induction motor run as synchronous motor.Different
types of motor excitation. Starting and running characteristicscombined synchronous motor
and induction motor circle diagrams, performance calculation, design features.
Concept of negative sequence and zero sequence reactances of synchronous machines.



Group B
IInverter operation of induction motors, space and time harmonies and their effects on the
performance of induction motors.
Induction generators; Operation from busbars, selfexcitation equivalent circuits and
performance—its utility in wind power generation.
A.C. commutator machines: General construction. Derivation of generalized expressions: (a)
Transformer e.m.f. and rotational e.m.f's in phase windings; (b) Transformer and rotational
e.m.f's in commutator windings, uncompensated and compensated series motor: vector
diagrams, circle diagram, operational characteristics and design features.
Variable reluctance and fractional and subfractional h.p. motors: Different types of
reluctance and stepper motors, permanent magnet motors, derivation of performance
equations. Control schemes and performance.







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