generator

A generator is a device or process that produces energy or material, or a mathematical or computational construct that produces a sequence or structure. In electrical engineering, a generator is a machine that converts mechanical energy into electrical energy by electromagnetic induction. Most electrical generators are AC machines, called alternators, but DC machines—dynamos—also exist. A generator consists of a stator and a rotor, with a magnetic field and windings that induce current as the rotor moves. They can be driven by steam turbines, hydro turbines, internal combustion engines, waterwheels, or wind turbines, and range from portable units to large power stations. They may be connected to the electrical grid or used as standalone backup power sources.

Synchronous generators require control systems to regulate voltage and frequency; excitation systems control the magnetic field, and governors adjust mechanical input. Efficiency improves with design, operation at rated load, and good maintenance. Safety risks include electric shock, arc flash, burns, and moving parts.

In other disciplines, the term generator has different meanings. In mathematics, a generator is an element or set from which all elements of a group or other algebraic structure can be derived via the defining operation. In computing and programming, a generator is a function, object, or process that yields values one at a time, or a random-number generator that outputs a sequence of numbers used for simulations. Generators also appear as generator sets in combinatorics and graph theory.

See also: generator set, alternator, dynamo, generating function, random number generator, yield.