Sem-III

• General concept of rotating electrical machines. Principle of DC generator. Use of Armature, Field Coil, Polarity, Yoke, Cooling Fan, Commutator, slip ring and Brushes, Laminated core etc. E.M.F. equation Separately excited and self excited generators. Series, shunt and compound generators.
• Armature reaction, Commutation, inter poles and connection of inter poles. Parallel Operation of DC Generators. Load characteristics of DC generators. Application, losses & efficiency of DC Generators. Routine & maintenance.
• Principle and types of DC motor.

• Identify terminals, parts and connections of different types of DC machines.
• Measure field and armature resistance of DC machines.
• Determine build up voltage of DC shunt generator with varying field excitation and performance analysis on load.
• Test for continuity and insulation resistance of DC machine.
• Start, run and reverse direction of rotation of DC series, shunt and compound motors.
• Perform no load and load test and determine characteristics of series and shunt generators.

1 Sign & Symbol Trade related
Alternating Current
Drawing of simple electrical circuit using electrical symbols.
Drawing of sine square & triangular waves.
Diagram of battery charging circuit.
Practice in reading typical example of circuit containing R, L & C.
Reading of electrical drawing.