An exciter, in the context of electrical engineering, is a device used to generate an electromagnetic field that induces voltage in the rotor windings of a synchronous generator. It is an essential component of synchronous generators, also known as alternators, used to produce alternating current (AC) electricity.
Here's how an exciter works:
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Generation of Magnetic Field: The exciter consists of a stationary field winding and a rotating armature winding. When direct current (DC) is supplied to the field winding, it generates a stationary magnetic field around the rotor of the synchronous generator.
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Induction of Voltage in Rotor Windings: As the rotor of the synchronous generator rotates within the magnetic field produced by the exciter, voltage is induced in the rotor windings due to electromagnetic induction. This induced voltage creates an electric field in the rotor windings.
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Conversion to Alternating Current: The induced voltage in the rotor windings is then rectified by a set of brushes and slip rings or by solid-state rectifiers to produce DC voltage. This DC voltage is used to power the field winding of the main generator, maintaining the magnetic field necessary for generation of AC electricity.
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Output of Alternating Current: With the magnetic field established by the exciter, the rotor of the synchronous generator continues to rotate, producing alternating current (AC) in the stator windings. This AC output is then transferred to the load or connected to the electrical grid for distribution.
In summary, the exciter serves the crucial function of providing the initial magnetic field required for the operation of a synchronous generator. By inducing voltage in the rotor windings through electromagnetic induction, the exciter enables the generation of alternating current (AC) electricity in the stator windings of the generator. This process allows synchronous generators to produce electrical power efficiently and reliably for various applications, including power generation plants, industrial facilities, and utility grids.
