Previous year question paper for EEEM (Diploma Electrical Engineering 4th)

1. Classification: (5 Hrs)

 Classification of materials into conducting, semi conducting and insulating

materials through a brief reference to their atomic structure and energy

bands

2. Conducting Materials (15 Hrs)

 2.1 Introduction

 2.2 Resistance and factors affecting it such as alloying and temperature

etc

2.3 Classification of conducting material as low resistivity and high

resistivity materials, Low resistance materials

2.3.1 Copper:

General properties as conductor: Resistivity, temperature

coefficient, density, mechanical properties of hard-drawn and

annealed copper, corrosion, contact resistance. Application

in the field of electrical engineering.

 2.3.2 Aluminium:

 General properties as conductor: Rresistivity, temperature

coefficient, density, mechanical properties of hard and

annealed aluminium, solderability, contact resistance.

Applications in the field of electrical engineering.

 2.3.3 Steel:

 General properties as conductor: Resistivity, corrosion,

temperature coefficient, density, mechanical properties,

solderability, Applications in the field of electrical

engineering.

2.3.4. Introduction to bundle conductors and its applications.

2.3.5. Low resistivity copper alloys: Brass, Bronze (cadmium and

Beryllium), their practical applications with reasons for the

same

 2.4 Applications of special metals e.g. Silver, Gold, Platinum etc.

2.5 High resistivity materials and their applications e.g., manganin,

constantin, Nichrome, mercury, platinum, carbon and tungsten

2.6 Superconductors and their applications 

99

3. Review of Semi-conducting Materials (5 Hrs)

 Semi-conductors and their properties, Materials used for electronic

components like resistors, capacitors, diodes, transistors and inductors

etc.

4. Insulating materials; General Properties: (15 Hrs)

 4.1 Electrical Properties:

Volume resistivity, surface resistance, dielectric loss, dielectric

strength (breakdown voltage) dielectric constant

 4.2 Physical Properties:

 Hygroscopicity, tensile and compressive strength, abrasive

resistance, brittleness

 4.3 Thermal Properties:

Heat resistance, classification according to permissible temperature

rise. Effect of overloading on the life of an electrical appliance,

increase in rating with the use of insulating materials having higher

thermal stability, Thermal conductivity, Electro-thermal

breakdown in solid dielectrics

 4.4 Chemical Properties:

 Solubility, chemical resistance, weatherability

4.5 Mechanical properties, mechanical structure, tensile structure

5. Insulating Materials and their applications: (18 Hrs)

 5.1 Plastics

5.1.1 Definition and classification

 5.1.2 Thermosetting materials:

 Phenol-formaldehyde resins (i.e. Bakelite) amino resins

(urea formaldehyde and Malamine-formaldehyde), epoxy

resins - their important properties and applications

 5.1.3 Thermo-plastic materials:

 Polyvinyl chloride (PVC), polyethelene, silicons, their

important properties and applications

 5.2 Natural insulating materials, properties and their applications

 - Mica and Mica products

 - Asbestos and asbestos products

 - Ceramic materials (porcelain and steatite)

 - Glass and glass products

 - Cotton

 - Silk

 - Jute

 - Paper (dry and impregnated)

 - Rubber, Bitumen

 - Mineral and insulating oil for transformers switchgear

capacitors, high voltage insulated cables, insulating

varnishes for coating and impregnation

- Enamels for winding wires

- Glass fibre sleeves

 5.3 Gaseous materials; Air, Hydrogen, Nitrogen, SF6 their

properties and applications 

100

6. Magnetic Materials: (12 Hrs)

6.1 Introduction - ferromagnetic materials, permeability, B-H curve,

magnetic saturation, hysteresis loop including coercive force and

residual magnetism, concept of eddy current and hysteresis loss,

curie temperature, magnetostriction effect.

 6.2 Soft Magnetic Materials:

6.2.1 Alloyed steels with silicon: High silicon, alloy steel for

transformers, low silicon alloy steel for electric rotating

machines

6.2.2 Cold rolled grain oriented steels for transformer, Nonoriented

steels for rotating machine

 6.2.3 Nickel-iron alloys

 6.2.4 Soft Ferrites

 6.3 Hard magnetic materials

Tungsten steel, chrome steel, hard ferrites and cobalt steel, their

applications

7. Special Materials (5 hrs)

 Thermocouple, bimetals, leads soldering and fuse material, mention their

applications

8. Introduction of various engineering materials necessary for fabrication of

electrical machines such as motors, generators, transformers etc.(5 hrs)