Previous year question paper for ET (Diploma Mechanical Engineering 3rd)

 1. General Introduction:- (05 hrs)

1.1 Types of elect. Engg. materials; conducting semi-conducting &

 insulating materials and their application.

1.2 Applications for electricity and Advantages of Elect. Energy over

 other types of energy.

1.3 Concept of voltage current power and energy and their units

2. DC Circuits:- (05 hrs)

2.1 Resistance factors affecting the resistance of conducting metals

 resistivity and their units.

2.2 Resistances in series & parallel.

2.3 Ohm’s Law,

2.4 Faraday’s Laws,

2.5 Len’s Law.

3. Principles of AC Circuits:- (12 hrs)

3.1 Concept of voltage generation advantages of three phase generation

over single phase generation. Three phase star & delta connections

voltage & current relationship (no derivation)

3.2 Def of cycle, frequency time period instantaneous value rms & max

value of sinusoidal wave (relation between rms & max value), form

factor & peak factor.

3.3 Concept of phase & phase difference.

3.4 Concept of resistance, inductance, capacitance and impedance in

 ac circuits.

3.5 Power factor(concept of lead, lag & unity p.f.),its importance and

 improvement.

3.6 Measurement of three phase power using two voltmeter method.

3.7 Determination of true power, current & p. f. in simple ac series

 circuits (simple problems)

4. DC Machines:- (08 hrs)

1.1 Construction & principle of working of dc motor & generator.

1.2 Flaming’s Rules

1.3 Starting of dc motors ( three-point starter) & speed control.

1.4 Reversing the direction of rotation of dc motors. 

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5. AC Machines:- (10 hrs)

5.1 Types of AC motors and their applications

5.2 Construction of three phase induction motors, comparison of sq.

 cage and slip-ring induction motors

5.3 Working principle of single phase & three-phase induction motors.

5.4 Reversing the direction of rotation of single phase & three phase

 induction motors.

5.5 Starting of three phase induction motors using star/delta & DOI,

 starters, starting single phase split phase motors.

6. Transformer:- (06 hrs)

6.1 Construction & working principle.

6.2 Transformation ratio, emf equation, losses & efficiency.

6.3 Auto transformer,

6.4 Cooling of transformers.

7. Basic Electronics:- (10 hrs)

7.1 Basic idea of semiconductor products, diode, Zener diode,

 Transistor, SCR and their applications