electrical machines 18

   After carefully studying this lecture notes you should be able to:
? Distinguish between the function of a d.c motor and d.c generator.
? Describe the action of a commutator.
? Describe the construction of a d.c machine.
? Distinguish between wave and lap armature windings, advantages uses of lap and wave windings.
? Understand shunt, series and compound windings of a d.c machine.
? Understand armature reaction.
? Calculate generated e.m.f in an armature using   .
? Describe types of d.c generator and their characteristics.
? Calculate generated e.m.f for  shunt generator using  .
? State typical application of d.c generators.
? List d.c machine losses and calculate efficiency .
? Calculate back e.m.f for a d.c shunt motor using  .
? Calculate the torque of a d.c motor using  .
? Describe types of d.c motor and their characteristics .
? State typical applications of d.c motor.
? Describe a d.c motor starter.
? Describe method of speed control of d.c motor.
? Describe of a stepping motors.
? Describe of a solenoids.
? Understand the principle of operation of transformer.
? Understand term "rating" of a transformer
? Use   in calculations on transformer.
? Construct a transformer no-load phaser diagram and calculate magnetizing and core loss components of the no-load current.
? State the e.m.f equation for a transformer   and use it in calculations.
? Describe transformer construction.
? Derive the equivalent resistance, reactance and impedance referred to primary of a transformer.
? Understand voltage regulation.
? Describe losses in transformers and calculate efficiency.
? Describe a three-phase transformer.
? Describe three-phase voltage generation.
? Represent three-phase voltage and currents in phasor form.
? Describe standard three-phase load connections.
? Analyze balanced three-phase circuits
? Compute active power, reactive power and apparent power in a three-phase system.