The Physics of an Electric Motor An electric motor is a device used to convert electrical energy into rotational kinetic energy. There are two different types of electric motors and each has its own use. The different types are DC and AC motors. Each of these engines will be analyzed below. To understand how this motor works, we must understand the relationship between electricity and magnetism or simply electromagnetism. Direct electric current in a simple description: There are two requirements for current flow. The first is a source of electrical potential energy or EMF (electromotive force). The second is a conductor that provides a complete circuit to carry the current. The reason why a conductor conducts lies at the atomic level. The valance shell of a conductive atom is not completely filled, so electrons will flow from one atom to another. When these electrons move from one atom to another, electric current is formed (a brief description). A magnet can be made from different materials, but magnetic stone is the natural form. The most important part of magnetism to make electric motors work is: A magnet has two different ends, or poles, a north pole and a south pole. These poles behave like electric charges, like poles they repel and unlike poles they attract although magnets have no effect on immobile charges. The relationship between electricity and magnetism is that each phenomenon generates a field. Electric fields can be represented by thinking in terms of gravitational forces. Where any two objects have a gravitational force on each other. Any two electric charges have a force between them (which repels or attracts depending on the polarity). This electric field... at the center of the card... degrees, increases in the opposite or negative direction until it reaches its maximum negative value at 270 degrees, and finally decreases again to zero at 360 degrees. It follows, therefore, that the induced emf can be fully described by the relation.v+Vmaxsin(angular position of the coil)” (cookeadamsdellmoore pg 509) This hopefully adds some insight into the use of electric motors and the principles that make them work these engines. Such as electromagnetism, binary switches for DC motors, and selecting the operating frequency of a motor through the use of an oscillator. Wheeler; copyright 1992Basic Mathematics for Electronics Seventh Edition: Nelson M. Cooke, Herbert F. R. Adams, Peter B. Dell, T. Adair Moore; Copyright 1960