Utilization of Electrical Energy & Electric Traction

Describe in brief the following electric arc welding process:

i. Carbon arc welding

ii. Shielded metal arc welding

iii. Gas metal arc welding 

Describe the construction and principle of operation of Sodium vapour lamp and mercury vapour lamp.

Enumerate the various factors to be considered while designing street lighting. Also discuss various types of lighting schemes.

Define the following terms:

i Luminous flux

ii. Lumen

iii. Lamp efficiency

iv. Solid angle 

Derive the relations for the following with the help of simplified speedtime curve-

i. Maximum speed attained by a train

ii. time of acceleration

iii. time of retardation

Draw speed time curve for a train running on main line. Identify various parts of the curve. State the modifications to be done in the curve to make the calculations of various parameters associated with the speed time curve simple and resulting in minimum error.

Write short notes on the following:

i) Electrodeposition

ii) Basic principles of electrolytic process arc furnaces. 

Discuss the relative merits and demerits of direct and indirect electric arc furnaces. Mention the advantages of dielectric heating. 

What are the essential requirements of satisfactory braking?

Describe in brief the following types of electric welding processes and their applications:

i) Seam welding 

ii) Butt welding

iii) Submerged arc welding

A wooden board 30 cms x 15 cms x 2 cms is to be heated from 20°C to 180° in 10 minutes by dielectric heating using 40MHz supply. The specific heat of wood is 0.35 and density 0.55 gm/cm³,  and p.f. is 0.05. Estimate the voltage across the specimen and current during heating. Assume loss of energy by conduction, convection and radiation as 10%.

Explain the resistance heating, with suitable diagram.

A lamp has a uniform power of 300 in all directions and is provided with a reflector which directs 60% of total emitted light uniformly to a fiat circular disc of 6 m diameter place 6 m vertically below the lamp.

Determine the illumination: 

i) at the center of disc with and without reflection

ii) at the edge of surface with and without reflection

iii) what is average illumination over the disc without reflection

Compare fluorescent and filament lamps on the basis of quality of light, working principle, capital cost and running cost. 

Attempt all of the following:

(a) Compare A.C and D.C welding

(b) Discuss the advantages of electric heating over the other methods of heating.

(c) Explain the working principle of induction furnance.

(d) State the important factors on which the selection of electric drives depends. Name the motors which are generally used for an electric drive

(e) Describe the construction and functioning of Nickel cadmium batteries.