Examinations for Electrical Engineering Students: Electrical Power Systems (ELEC6005), Exams of Electrical Engineering

Download Examinations for Electrical Engineering Students: Electrical Power Systems (ELEC6005) and more Exams Electrical Engineering in PDF only on Docsity! Page 1 of 5 CORK INSTITUTE OF TECHNOLOGY INSTITIÚID TEICNEOLAÍOCHTA CHORCAÍ Semester 1 Examinations 2009/10 Module Title: Electrical Power Systems Module Code: ELEC6005 School: School of Electrical & Electronic Engineering Programme Title: Bachelor of Engineering in Electrical Engineering – Stage 1 Programme Code: EELEC_7_Y1 External Examiner(s): Mr. G. Beecher, Dr. M. Duffy Internal Examiner(s): Mr. J.C. Duggan Instructions: Answer EIGHT questions. All questions carry equal marks. Not more than 15 minutes should be devoted to each question. Duration: 2 HOURS Sitting: Winter 2009 Requirements for this examination: Note to Candidates: Please check the Programme Title and the Module Title to ensure that you have received the correct examination. If in doubt please contact an Invigilator. Page 2 of 5 Q1. (a) Explain why power transformers are an essential part of our public supply network. (5 marks) (b) Why are only voltages in the range 10V to 250V used in single phase supply systems? (5 marks) (c) What is meant by the frequency of a supply? (2.5marks) Q2. (a) Distinguish between a circuit diagram and a wiring diagram. (5 marks) (b) Draw a circuit diagram to show how two lights may be controlled together from three switch positions include cable names and colours. (7.5 marks) Q3. (a) Name three practical wiring methods employed in the wiring of lighting circuits. (5 marks) (b) State the factors which influence the choice of the methods in (a) above for one particular installation. (5 marks) (c) What is meant by wrong polarity? (2.5 marks) Q4. (a) The name plate on a certain cooker indicates a total loading of 10kW at a supply voltage of 230V. Determine the rated current. (2.5 marks) (b) The cooker in (a) above is wired using a cable rated at 36 amp fuse/MCB. Explain why this arrangement is acceptable. (8 marks) (c) Distinguish between a 2 pole switch and a 2 position switch. (2 marks)