Generator - Hatsudenki (English spelling) generator

Japanese: 発電機 - はつでんき（英語表記）generator

A general term for energy conversion devices that convert kinetic energy (rotational motion) into electrical energy. Rotating electrical devices can operate as either electric motors or generators, but those designed specifically for the purpose of generating electricity are called generators. There are various types of generators, including DC generators, synchronous generators, and induction generators.

[Masayuki Morimoto]

Early generators

Following M. Faraday's discovery of electromagnetic induction, generators were developed at the same time as electric motors. Early generators used the rotation of a permanent magnet. In 1832, Hippolyte Pixii (1808-1835) succeeded in generating "wave electricity" by passing a rotating permanent magnet close to a coil. This was the prototype of modern AC generators. Later, in 1869, Z. T. Gramm invented a DC generator using electric brushes and coils. Later, in 1881, E. W. Siemens produced a practical AC generator. At this time, there was also debate over whether electricity should be transmitted as DC or AC, and various DC generators such as the Edison dynamo were developed.

[Masayuki Morimoto]

principle

When a straight conductor is placed in a magnetic field and moved perpendicular to the magnetic field, an electromotive force E = Blv (units: volts) is generated in the conductor, where B is the magnetic flux density of the magnetic field (tesla), l is the length of the conductor in the magnetic field (meters), and v is the speed of the conductor (meters per second). The direction of the electromotive force is given by Fleming's right-hand rule.

The movement of the conductor with respect to the magnetic field only needs to be relative, and even if the conductor remains stationary and the magnetic field moves upward at a speed v , the magnitude and direction of the electromotive force generated in the conductor will be the same as when the conductor is moved downward at a speed v . In an actual generator, either the magnetic poles or the conductor are rotated to create relative motion.

[Naoyoshi Isobe and Masayuki Morimoto]

Generator types

In principle, generators have the same structure as electric motors. Therefore, like electric motors, generators are classified according to the type of terminal voltage (whether they generate DC power or AC power) and whether the rotation speed and the frequency of the generated power are proportional (synchronous). Therefore, generators are classified as follows, combining electric motors and generators, such as DC motors and induction motors.

[1] DC Machine
(1) Self-excited series-wound DC motor, shunt-wound DC motor, and compound-wound DC motor.

(2) Separately excited separately excited DC machine, permanent magnet DC machine.

[2] AC Machine
(1) Synchronous machines: wound rotor synchronous machine, permanent magnet synchronous machine, reluctance machine (reluctance motor).

(2) Induction machines (asynchronous machines) Squirrel-cage induction machine, wound-rotor induction machine, single-phase induction machine.

(3) AC commutator (universal motor).

On the other hand, in addition to being classified according to their principles, generators are also classified according to the prime mover that drives them.

(1) Turbine generator: A high-speed generator driven by a gas turbine or steam turbine.

(2) Water turbine generator A low-speed generator driven by a water turbine.

(3) Engine generator: A synchronous generator that uses a diesel engine or other type of engine as its prime mover.

(4) Wind turbine generator: A very slow generator driven by a wind turbine.

(5) Other generators: Magneto generators, alternators, Edison dynamos, electric generators.

[Masayuki Morimoto]

"Handbook of Electrical Engineering, 7th Edition (2013)" edited and published by the Institute of Electrical Engineers of Japan

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

運動エネルギー（回転運動）を電気エネルギーに変換するエネルギー変換機器の総称。回転電気機器は電動機動作と発電機動作が可能であるが、とくに発電を目的として設計されたものを発電機とよんでいる。直流発電機、同期発電機、誘導発電機などの形式がある。

［森本雅之］

初期の発電機

発電機はM・ファラデーの電磁誘導の発見に続き、電動機と同時期につくられている。初期のものは永久磁石の回転を利用していた。1832年にピクシーHippolyte Pixii（1808―1835）が回転する永久磁石をコイルの近くを通過させて、「波打った電気」を製造することに成功した。これが現在の交流発電機の原型である。その後、1869年のZ・T・グラムは電気ブラシとコイルを使った直流発電機を発明した。その後、1881年にはE・W・ジーメンスが実用的な交流発電機を製造した。またこのころは送電を直流にすべきか、交流にすべきかの議論もあり、エジソンダイナモなどの直流発電機も種々開発された。

［森本雅之］