GENERAL: ISI specifications for conductors, Transformer, transformer oil and
induction motors. Standard specifications for rotating electrical machinery as per
IEC publications.Temperature Rise Calculations and Measurement Sources and
position of heat generation, Solid body heating, Heating and cooling processes.
Calculation of steady temperature rise of induction motor armature and
transformer core. Machine ratings based on thermal considerations. Typical
temperature gradients in transformers and three phase induction motors.
Methods of measuring temperature in Electrical machines.
Ventilation :
Methods of cooling transformer. design of tank. Types of ventilation methods of
cooling 3-phase induction motors, cooling circuits and type of enclosures.
Quantity of cooling medium, Air,Hydrogen, water and Oil.
Magnetic Circuits:
Magnetic circuits of transformers and three phase induction motor. Specific slot
permeance and slot leakage reactance of a three phase induction motor leakage
reactance of cylindrical coils and equal length and sandwich coils of equal width
in a transformer. Variation in magnetic losses with changes with changes in
supply voltage frequency of a transformer.
Electric Circuits:
Types of low voltage and high voltage winding transformer. Calculation of
resultant mechanical forces in transformer under normal and abnormal
conditions. Characteristics of an armature windings. Types of windings used for
induction motors, winding factors.
Transformers:
Design of single phase and three phase core type poser and distribution
transformers, single phase shell type transformer, Magnetic and electric circuit,
leakage reactance, regulation, no load current, cooling system, overall
dimensions and weight. Recent advances in design of transformer.
Induction Motors:
Design of squirrel cage and wound rotor type of three phase induction motors.
Stator and its winding, slot and its insulation, squirrel cage and slip ring rotors,
no load current, short circuit current, efficiency, circle diagram, Stator
temperature rise, weight. Recent advances in the design of induction motors.