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DC motors: E.M.F.
equation, back emf of motors, torque equations, methodof excitation,
characteristics of DC shunt, series and compound motors. Speed - torque
characteristics of DC motors. Starters, principles of speed control and braking. Three phase Induction Motors : Rotating
magnetic field, construction and principle of operation, slip, rotor frequency,
development of equivalent circuit, torque equation, maximum torque, torque-speed
characteristics, speed control, starting methods, motor ratings. Single Phase Motors : Principles of
operation and characteristics of single phase induction motor, capacitor, shaded
pole, reluctance, hysteresis types, stepper motor. Measuring Instruments: Principles of moving
iron, moving coil, rectifier ammeters and voltmeters, principles of dynamometer-
wattmeter and induction type energy meters, principles of p.f. meter and
frequency meter, use of current and potential transformers. Measurement of R,L,C : Measurement of low,
medium and high resistance. Wheatstone and Kelvin bridge method. Ohm meters,
Megohm bridge and megger. AC bridge circuits for measurement of inductance,
capacitance and Q- factor. Schering Bridge. Potentiometer : Principles of simple DC and
AC potentiometers and their applications, DC vernier potentiometer. |
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