10 questions
Q.1. (a) Describe with the help of neat sketch, the working of a vertical core type Induction furnace. Give the applications of high frequency Eddy current heating. [8]
(b) Compare in detail, electric arc welding with resistance welding. Explain with the help of a neat sketch the process of spot welding. [8]
Q.1. (a) Calculate the efficiency of a high frequency induction furnace which takes 15 minutes to melt 2kg of aluminium. Input to the furnace using 5kW and initial temperature 20 degC. Specific heat of aluminium = 0.88 kJ/kg degC; Melting point of aluminium = 660 degC; Latent heat of fusion of aluminium = 32 kJ/kg; 1 kJ = 2.78 x 10^-4 kWh. [8]
(b) Explain welding transformer with a suitable diagram. [8]
Q.2. (a) Discuss the law of illumination and its limitations. [8]
(b) Describe with the help of a neat diagram the construction and working of a high pressure mercury vapour lamp. [8]
Q.2. (a) What is photometry? Describe photovoltaic method of photometry and discuss its limitations. [8]
(b) Write a short note on street lighting and flood lighting. [8]
Q.3. (a) Explain the extraction process of Aluminium with a suitable diagram. [8]
(b) What is meant by 'anodizing'? Explain process of 'anodizing' and describe the equipments used for it. [8]
Q.3. (a) Explain "reverse current process" in electroplating? Discuss its advantages. [8]
(b) Calculate ampere-hours required to deposit a coating of silver 0.06mm thick on a sphere of 10cm radius. Assume electrochemical equivalent of Silver = 0.001118 and density of Silver to be 10.5. [8]
Q.4. (a) Compare DC and AC system of railway electrification from the point of main line and suburban line railway service. [8]
(b) Write a short note on overhead equipment including current collectors for overhead systems and conductor rail system. [8]
Q.4. (a) Discuss Merits and Demerits of DC system track electrification. [8]
(b) Describe the suitability of DC series Motor for its application in electric locomotive for traction duty. [8]
Q.5. (a) What is tractive effort of a train and what are its functions? Derive an expression for tractive effort developed by a train unit. [8]
(b) Discuss the advantage of series-parallel starting against the ordinary rheostatic for a pair of DC traction motors. [8]
Q.5. (a) What are the advantages and disadvantages of the regenerative braking of electric traction Motor? [8]
(b) Explain the terms 'adhesive weight' and coefficient of adhesion and what do you understand by train resistance? [8]