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see generatorgenerator,
in electricity, machine used to change mechanical energy into electrical energy. It operates on the principle of electromagnetic induction, discovered (1831) by Michael Faraday.
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; motor, electricmotor, electric,
machine that converts electrical energy into mechanical energy. When an electric current is passed through a wire loop that is in a magnetic field, the loop will rotate and the rotating motion is transmitted to a shaft, providing useful mechanical work.
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The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



in engineering. (1) The rotating part of motors and machines, in which are located the members that receive energy from the working medium (for instance, the rotor in a Wankel engine) or that transmit energy to a working medium (for instance, the rotor in a rotary pump). In motors, the rotor is connected to a driving shaft; in machines, it is connected to a driven shaft. Rotors are made in the shape of drums, disks, or wheels.

(2) The rotating part of, as a rule, an alternating-current machine. It is usually a cylindrical body with grooves that contain the winding.



the rotating part of an electric machine. As a rule, the concept of a rotor refers to alternating-current machines; in direct-current machines, the rotor is called an armature.

The rotor of an induction machine is usually fabricated from electrical sheet steel and has the shape of a cylinder with grooves that contain the winding. Depending on the type of winding used, induction machines are classified as either phase-wound or squirrel-cage machines. A phase-wound rotor has a three-phase winding with the same number of sections as are in the stator. The sections are usually Y-connected, and their terminals are connected to a starting rheostat through collector rings and brushes. The winding of a squirrel-cage rotor consists of metal bars that are short-circuited at each end.

Rotors in synchronous machines are classified as salient-pole and nonsalient-pole rotors. A salient-pole rotor consists of a yoke and of poles attached to the yoke and equipped with field windings. A nonsalient pole rotor is usually fabricated as a unit from a single steel forging. Grooves for field winding are milled into the forging.


Kostenko, M. P., and L. M. Piotrovskii. Elektricheskie mashiny, 3rd ed., parts 1–2. Leningrad, 1972–73.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


(aerospace engineering)
An assembly of blades designed as airfoils that are attached to a helicopter or similar aircraft and rapidly rotated to provide both lift and thrust.
Disk with a set of input contacts and a set of output contacts, connected by any prearranged scheme designed to rotate within an electrical cipher machine.
Disk whose rotation produces a variation of some cryptographic element in a cipher machine usually by means of lugs (or pins) in or on its periphery.
The rotating member of an electrical machine or device, such as the rotating armature of a motor or generator, or the rotating plates of a variable capacitor.
(mechanical engineering)
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


i. A system of rotating airfoils whose primary function is to produce lift (e.g., propellers and helicopter rotors).
ii. The portion of a turbine or compressor that spins.
iii. A rotating disc or drum to which a series of blades are attached (e.g., compressor, turbine, turbopump, alternator).
iv. A local air mass rotating about a substantially horizontal axis.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved


1. the rotating member of a machine or device, esp the armature of a motor or generator or the rotating assembly of a turbine
2. a device having blades radiating from a central hub that is rotated to produce thrust to lift and propel a helicopter
3. the revolving arm of the distributor of an internal-combustion engine
4. a violent rolling wave of air occurring in the lee of a mountain or hill, in which the air rotates about a horizontal axis
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
Nevertheless, it must also be noted that both terms in expression (10) include the slight effects of rotor arms and friction, which are not considered in the above equation.
The cast rotor of one Avery engine had flown apart, and a piece of it had gone "up through two or three floors with a force equal to that of a cannon shot." The sides and edges of the rotor arms tended to become furrowed and .lagged after long use.
It's a horizontal, cylindrical chamber with a central rotor armed with paddles turning at high speed inside a polygonal screen basket.