EE8301 Electrical Machines 1 Previous Year Question Paper
UNIT I MAGNETIC CIRCUITS AND MAGNETIC MATERIALS
Magnetic circuits –Laws governing magnetic circuits – Flux linkage, Inductance and energy – Statically and Dynamically induced EMF – Torque – Properties of magnetic materials, Hysteresis and Eddy Current losses – AC excitation, introduction to permanent magnets- Transformer as a magnetically coupled circuit.
UNIT II TRANSFORMERS
Construction – principle of operation – equivalent circuit parameters – phasor diagrams, losses – testing – efficiency and voltage regulation-all day efficiency-Sumpner’s test, per unit representation – inrush current – three phase transformers-connections – Scott Connection – Phasing of transformer– parallel operation of three phase transformers-auto transformer – tap changing transformers- tertiary winding.
UNIT III ELECTROMECHANICAL ENERGY CONVERSION AND CONCEPTS IN ROTATING MACHINES
Energy in magnetic system – Field energy and co energy-force and torque equations – singly and multiply excited magnetic field systems-mmf of distributed windings – Winding Inductances-, magnetic fields in rotating machines – rotating mmf waves – magnetic saturation and leakage fluxes.
UNIT IV DC GENERATORS
Construction and components of DC Machine – Principle of operation – Lap and wave windings-EMF equations– circuit model – armature reaction –methods of excitationcommutation – interpoles compensating winding –characteristics of DC generators.
UNIT V DC MOTORS
Principle and operations – types of DC Motors – Speed Torque Characteristics of DC Motorsstarting and speed control of DC motors –Plugging, dynamic and regenerative brakingtesting and efficiency – Retardation test- Swinburne’s test and Hopkinson’s test – Permanent Magnet DC (PMDC)motors-applications of DC Motor
EE8301 Electrical Machines 1 Previous Year Question Paper Regulation 2017 question paper