Thursday, June 23, 2011
3:01 PM | Posted by
Anonymous |
Benjamin Franklin is famous for his discovery of electricity.
He started studying electricity in the early 1750s. His observations, including his kite experimentation, verified the nature of electricity. He knew that lightning was very powerful and hazardous. The famous 1752 kite experiment featured a pointed metal bit on the top of the kite and a metal key at the base end of the kite row. The row went through the key and attached to a Leyden Jar. (A Leyden jar consists of two metal conductors separated by an insulator.)
He held the row with a short section of dry silk as insulation from the lightning energy. He flew the kite in a thunderstorm. He initially noticed that various loose strands of the hemp row stood erect, avoiding one another. (Hemp is a perennial American plant used in rope making by the indians.) He proceeded to feel the key with his knuckle and received a little electrical shock.
Between 1750 and 1850 there were many great discoveries in the principles of electricity and magnetism by Volta, Coulomb, Gauss, Henry, Faraday, and others. It was found that electric current produces a magnetic field and that a moving magnetic field produces electricity in a wire. This led to many inventions such as the battery (1800), generator (1831), electric motor(1831), telegraph (1837), and telephone (1876), plus many other intriguing inventions.
In 1879, Thomas Edison invented a more efficient lightbulb, similar to those in use today.
In 1882, he placed into operation the historic Pearl Street steam–electric plant and the first direct current (DC) distribution system in New York City, powering over 10,000 electric lightbulbs. By the late 1880s,
Power demand for electric motors required 24-hour service and dramatically raised electricity demand for transportation and other industry needs. By the end of the 1880s, small, centralized areas of electrical power distribution were spread across U.S. Cities. Each distribution center was limited to a service range of a few blocks because of the inefficiencies of transmitting Direct current. Voltage could not be increased or decreased using direct current systems, and a way to to transport power longer distances was needed.
To solve the problem of transporting electrical power over long distances, George Westinghouse developed a device called the “transformer”.
The transformer allowed electrical energy to be transported over long distances efficiently. This made it possible to supply electric power to homes and businesses located far from the electric generating plants. The application of transformers required the distribution system to be of the alternatingcurrent (AC) type as opposed to direct current (DC) type.
Since the early 1900s alternating current power systems began appearing throughout the United States. These power systems became interconnected to form what we know today as the three major power grids in the United States and Canada. The remainder of this chapter discusses the fundamental terms used in today’s electric power systems based on this history.
Do you feel confused confused about this lesson? Leave your question now in a comment.
Do you feel confused confused about this lesson? Leave your question now in a comment.
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