Exciter

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An excitation machine is an electrical machine that provides the electrical power necessary to supply the excitation winding of a generator with electricity. The power control for the generator is implemented either in the exciter or between it and the generator. Three-phase generators are excited with a direct current field. The exciter machine used to be a DC machine ; today it is a three-phase machine with downstream semiconductor rectification.

In order to save the carbon brushes and slip rings , which are necessary with static excitation devices to transfer the excitation energy to the rotor winding (excitation winding), the rotor and the excitation machine are accommodated on the same shaft . This is the principle of brushless excitation . The great advantage here is that there are no longer any moving parts subject to wear and tear. The excitation machine is a rotor machine ( external pole generator ) which has its excitation windings in the stator and generates the induction voltage in the rotor. A rotating diode rectifier built into the rotor rectifies the voltage and transfers it to the field winding in the generator rotor. The power of the generator can be taken from the terminals of the stator windings. With this version, the control already takes place in the field of the exciter. For this purpose, the auxiliary excitation power, with which the outer poles of the excitation machine are fed, is regulated via an actuator. The disadvantage here is that the achievable changes over time dI E / dt are reduced by the time constant of the exciter. The settling times in the event of faults are therefore longer than with static excitation systems.

See also

literature

  • A. Senner: Electrical engineering. 4th edition. Verlag Europa-Lehrmittel, 1965
  • Rolf Fischer: Electrical machines. 14th, updated and expanded edition. Carl Hanser Verlag, Munich 2007, ISBN 978-3-446-41754-0 .
  • Helmut Lindner, Harry Brauer, Constans Lehmann: Taschenbuch der Elektrotechnik und Elektronik 7th, completely revised edition. Fachbuchverlag Leipzig in Carl Hanser Verlag, Munich 1999, ISBN 978-3-446-21056-1 .

Web links

Wiktionary: Exciter machine  - explanations of meanings, word origins, synonyms, translations