Chapter 5. What Is an Electric Motor?

An electric motor is a device that turns electrical energy into mechanical energy. In 1821, Michael Faraday demonstrated what was perhaps the first example of an electromagnetic motor (see Figure 5-1). A wire was dangled into a pool of mercury and placed next to a permanent magnet. When a voltage was applied between the mercury and the top of the wire, current flowed. It created a magnetic field, and the end of the wire started orbiting the magnet.

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Figure 5-1. Faraday’s electric motor

Do not try to build this motor. Mercury is extremely toxic, and even exposure to the vapor can cause long-lasting ...

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