How Do Electric Motors and Generators Work?

How are Electric Generators Built?

An electrical generator is built with two primary parts in mind. The rotor is best described as the portion which rotates or moves in an electrical generator, while the stator is the portion of the generator which remains stationary. In most cases, the rotor is a piece of conductive metal wrapped with conductive wire attached to a battery or power outlet. This rotor is attached to a crank. The stator is typically a set of magnets set outside of the rotor, but which are close enough to cast a magnetic field through it.

How Do Electric Generators Work?

Depending on the type of generator, the crank may be turned by a turbine or the crankshaft of an engine. The result is all the same. When the crank turns, so does the rotor. The rotor continuously passes through the magnetic field of the stator. It was first discovered by Michael Faraday in 1831 that by moving wires through a magnetic field, an electrical current would be generated and flow through the wire. Each time one end of the rotor passes through the field, an electrical current is created and travels through the wires attached to the rotor. From the wires, the current can be moved into a battery for storage, or in the case of portable generators, pass directly into any electrical appliance plugged into the outlet of the generator.

How Do Electric Motors Work?

An electric motor works in just the opposite fashion. The magnetic field created by the stator is still present, but the rotor is a little more advanced. A metal armature or axle is threaded through the center of a metal rod. The rod is wrapped at either end with copper wire, making it something called a commutator. Altogether, this makes the rotor. The commutator is placed directly between the magnets of the stator and allowed to spin freely. Because of the magnetic field which it sits in, its ends will be pulled to either of the magnets, eventually reaching equilibrium between the two. An electric current is passed through the wires attached to the commutator, turning it into an electromagnet. The poles of the electromagnet are not static, they will switch. As the poles shift in the magnetic field of the stator, the commutator will spin continuously. This will turn the axle of the rotor and create mechanical energy, which can be harnessed for any number of uses.