This preview shows pages 1–13. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: G. Rizzoni, Principles and Applications of Electrical Engineering Problem solutions, Chapter 7 7.1 Chapter 7 Instructor Notes Chapter 7 surveys all important aspects of electric power. Coverage of Chapter 7 can take place immediately following Chapter 4, or as part of a later course on energy systems or electric machines. The material in this chapter will be of particular importance to Aerospace, Civil, Industrial, and Mechanical engineers, who are concerned with the utilization of electric power. The chapter permits very flexible coverage, with sections 7.1 and 7.2 describing basic singlephase AC power ideas. A survey course might only use this introductory material. The next two sections discuss transformers and threephase power. Two descriptive sections are also provided to introduce the ideas of residential wiring, grounding and safety, and the generation and distribution of AC power. These sections can be covered independent of the transformer and threephase material. The section Focus on Measurements: The wattmeter provides a practical look at the measurement of power. The section Focus on Measurements: How Halleffect current transducers work may be useful in the context of a power systems course, while Focus on Measurements: Power factor correction proposes a more applied look at the problem of improving the power factor of an industrial load. The homework problems present a few simple applications in addition to the usual exercises meant to reinforce the understanding of the fundamentals. Problems 7.19, 20, 2225 present a variety of power factor correction problems. Two advanced problems (7.35, 7.36) discuss transformer test methods; these problems may be suitable in a second course in energy systems. Problem 7.48 illustrates the billing penalties incurred when electric loads have insufficient power factors (this problem is based on actual data supplied by Detroit Edison). Those instructors who plan to integrate the threephase material into a course on power systems and electric machines, will find that problems 7.47 and 7.4951 can be assigned in conjunction with the material covered in Chapter 17, as part of a more indepth look at threephase machines. G. Rizzoni, Principles and Applications of Electrical Engineering Problem solutions, Chapter 7 7.2 Problem 7.1 Solution: Known quantities: Resistance value, 30 = R , and the voltage across the soldering iron, V 117 = V ~ . Find: The power dissipated in the soldering iron. Analysis: The power dissipated in the soldering iron is: W 3 456 30 117 2 2 . R V ~ P = = = ______________________________________________________________________________________ Problem 7.2 Solution: Known quantities: Rated power, W 1000 = P , and the voltage across the heating element, V 240 = V ~ ....
View
Full
Document
This note was uploaded on 04/08/2009 for the course ELE ELE1403 taught by Professor Khaled during the Spring '09 term at NYU Poly.
 Spring '09
 Khaled

Click to edit the document details