Electrical technology by Uday A Bakshi; Varsha U BakshiCall Number: TK146 B170 2007
ISBN: 9788184311501
Publication Date: 2007
D.C. MachinesWorking principle of d.c. machines, constructional features, and types of d.c. machines, d.c. generator action, emf equation .Motoring action, torque equation for d.c. motor, characteristics of d.c. motor, back e.m.f. in d.c. motor, starters, conventional methods for speed control of d.c. motors.Electrical Power Measurement and IlluminationA) Measurement of active and reactive power in three phase balanced circuits by using one, two and three voltmeter methods; measurement of energy in three phase balanced circuits; Tariffs for LT and HT consumers (Descriptive treatment only); Power factor improvement.B) llumination laws; different terms and factors used in context with illumination; requirement of good lighting scheme; industrial lighting, street lighting and flood lighting; design of a simple indoor lighting scheme.Synchronous Machines and TransformerA) Synchronous MachinesWorking principle, constructional features, emf equation, winding factors, synchronous speed of an alternator, concept of synchronous impedance, regulation of an alternator by synchronous impedance and direct loading method.B)TransformersEquivalent circuit of a single phase transformer; open circuit and short circuit test to determine transformer efficiency, regulation and equivalent circuit; welding transformers, current transformers and potential transformers; three phase transformers; star / star, star / delta, delta/star, and delta / delta connections with concept of phasor group; study of typical distribution transformer substation.Three Phase Induction MotorsConcept of rotating magnetic field ; working principle of three phase induction motors; constructional feature; types; torque equation; torque slip characteristics; torque ratios; power stages; efficiency; types of starters; conventional methods of speed control; braking and applications of these motors.Single Phase Motors & Special Purpose MachinesWorking principle, constructional features, applications and characteristics of:a) Single phase induction motors : Split phase and shaded pole types;b) Special purpose motors : Stepper motors, servomotors, hysteresis motors, reluctance motors, a.c. series motors, universal motors and synchronous motors.Electrical Drives, Heating and Weldinga) Selection, ratings, applications and maintenance of electrical drives :1. Selection - Factors to be considered, duty cycles, enclosures, class of insulation.2. Ratings - Current rating, torque rating and temperature rating.3. Applications - Typical industrial applications and meters suitable for different loads.4. Maintenance - Maintenance of electrical equipment such as transformers and motors.b) Electrical heating and welding :1. Resistance welding - Properties of good heating elements, heating element materials, design of simple heating elements with an application to ovens.2. Induction heating - Principle and typical applications to core and coreless furnaces.3. Dielectric heating - Principle and application to typical heating processes.4. Resistance and arc welding - Principles and typical applications in industry.