EM (Diploma Electronics and Communication Engineering 3rd)

1. Three Phase Supply

a) Advantages of 3 phase system over single phase system

b) Star delta connections

c) Relation between phase voltage and line voltage, phase current and line

current in a 3 phase system

d) Power and power factor(p.f.) in 3 phase system and their measurements,

importance of p.f. (simple problems)

(06 hrs)

2. Transformer

Principle of transformer, construction, voltage and current transformation.

Methods of connection in 3 phase transformers, current and voltage relationship,

auto transformer and its uses, instrument transformer, voltage regulation and its

significance, need for isolation, electrical and transients suppression, principles

of isolation transformer, specifications of all types of transformers. Losses in a

transformer

(08 hrs)former

3. DC Motor

Principle, significance of back emf, types of motors and their construction, motor

characteristics for shunt and series, speed control of DC motors and factors

controlling the speed. Starting methods, construction and working of 3 point

starter, applications (simple problems)

(08 hrs)

4. Three Phase Induction Motors

Principle, construction, concept of slip, torque and characteristics, effect of motor

resistance on torque (running and starting), rotor current, output power, different

(08 hrs)

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methods of speed control. Starting methods and constructional and working of

3 point starter, applications (simple problems)

5. Synchronous Motors

Principle, construction and working, effect of load and excitation on synchronous

motor. Starting of motor and their applications

(06 hrs)

6. Single Phase Motors

Principle, construction, working speed, control, starting and applications of the

following motors:

a) Induction motor

c) Universal motor

(06 hrs)

7. Stepper Motor and Servo Motor

Types, construction, working and their applications