What is an electric motor?
An electric motor is is a device used to convert electrical energy to mechanical energy. It takes an electric current and uses it to spin a rod therefore generating mechanical power to push, pull and do all sorts of everyday actions that we think are just second nature. For example electric motors are used in vacuum cleaners, dishwashers, computer printers, fax machines, video cassette recorders, machine tools, printing presses, automobiles, subway systems, sewage treatment plants, water pumping stations and more and are among the most important inventions of all time.
How Does It Work?
The principle on which motors operate is Ampere's law, named after "The link between electricity, magnetism, and movement was originally discovered in 1820 by French physicist André-Marie Ampère (1775–1867)." This law states that a wire carrying an electric current produces a magnetic field around itself. As shown below, when a wire carries a current therefore producing an magnetic field, you can use that magnetic field to generate mechanical energy through setting up a loop for rotation. One side will be attracted to the north pole and one to the south but when set opposite they will begin to constantly rotate creating power.
The inventors that applied this principle were "Englishmen Michael Faraday (1791–1867) and William Sturgeon (1783–1850) and American Joseph Henry (1797–1878)" First in 1820, a Danish physicist, Orsted, confirmed the connection between electricity and magnetism, followed by the discoveries of Ampere. Faraday then progressed the foundation of the electric motor through his 1821 experiment followed by Barlow’s wheel using electromagnetism. Finally a german scientist, Jacobi, created the first electric motor. The first patent however went to Thomas Davenport in 1837.
Types of Current
alternating current (AC): An alternating current does exactly what you would expect, alternates or periodically switches direction. In an AC motor you add a communicator which is a metal ring divided into two separate halves and its job is to reverse the electric current in the coil each time the coil rotates through half a turn. At one instant, one part of the loop is attracted by the north pole of the magnet, and at the next instant, it is attracted by the south pole of the magnet. As the current changes directions, the loop is forced to spin on its axis therefore creating a motor.
direct current (DC): Electric currents in DC motors move in one direction
- For more information of electric motors this video will explain:
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