Utilization of Electrical Energy 2018 Question Paper — Government Col…
The 2018 Utilization of Electrical Energy previous year question paper (Government College of Engineering and Technology, Jammu), with every question and its marks.
- University: Government College of Engineering and Technology, Jammu
- Subject: Utilization of Electrical Energy
- Course: Electrical Utilization
- Branch: Electrical Engg
- Year: 2018
- Paper: end-term
- Duration: 180 minutes
- Total marks: 100
Instructions
- Attempt five questions in all, selecting at least two questions from each Section.
- Each question carries equal marks.
- Assume missing data wherever missing.
- Use of calculator is allowed.
Questions
Section - A
- Q1. (a) Discuss the factors which affect the selection of motor for a particular drive. (b) What are the essential requirements for satisfactory braking? Compare the performance of electrical and mechanical braking. [20 marks]
- Q2. (a) Explain the dc dynamic braking of 3-phase induction motor. (b) A 220 V, 20 kW dc shunt motor running at its rated speed of 1200 rpm is to be braked by plugging. The armature resistance is 0.1 ohm and the rated efficiency of motor is 88%. Determine: (i) The armature resistance to be connected in series with armature to limit the initial braking current to twice the rated current. (ii) The initial braking torque. [20 marks]
- Q3. (a) Explain different systems of track electrification. (b) Sketch the typical speed-time curves for main line service and Suburban service with electric traction. (c) Explain why a D.C. series motor is ideally suited for traction purposes. [20 marks]
- Q4. (a) Explain various methods of speed control of series motors. (b) An electric train is to have acceleration and braking retardation of 0.8 km/h/s and 3.2 km/h/s respectively. If the ratio of maximum to average speddi is 1.3 and time for stops 26 seconds, find schedule speed for a run of 1.5 km. Assume simplified trapezoidal speed-time curve. [20 marks]
Section - B
- Q5. (a) What are different methods of electric heating? Describe briefly the methods of direct and indirect resistance heating. List the applications of these two methods. (b) Explain the design procedure of the heating elements when the power and voltage of oven are known. [20 marks]
- Q6. (a) Explain different arc welding processes. What is meant by negative resistance characteristics of an arc? (b) Explain the advantages of flash butt welding over simple butt welding. [20 marks]
- Q7. (a) Explain the various factors to be taken into account for designing schemes for: (i) Street lighting (ii) Flood lighting (b) Explain the working of fluorescent and filament lamps. [20 marks]
- Q8. (a) Define the terms: (i) Solid angle (ii) luminous flux (iii) Lumen (iv) Candle power (v) Luminous intensity (vi) Luminous efficiency (b) State and prove the laws of illumination. [20 marks]