Eksitaattorijärjestelmän

Eksitaattorijärjestelmä, often translated as exciter system, is a crucial component in many electrical machines, particularly synchronous generators and motors. Its primary function is to control and regulate the magnetic field produced by the rotor. This is achieved by supplying a direct current (DC) to the rotor's field winding. The magnitude of this DC current directly influences the strength of the magnetic field, which in turn affects the output voltage and reactive power of the synchronous machine.

The exciter system typically consists of a DC power source, a voltage regulator, and a means of transferring the DC current to the rotating field winding. Historically, separate DC generators, known as exciters, were used for this purpose. Modern systems often employ static exciters, which utilize semiconductor devices like diodes and thyristors to generate and control the DC field current. Brushless excitation systems are also common, eliminating the need for brushes and slip rings by using a small AC generator mounted on the same shaft as the main machine, whose output is rectified and fed to the rotor field winding.

The voltage regulator is a key part of the exciter system. It continuously monitors the output voltage of the synchronous machine and adjusts the field current to maintain the desired voltage level, even under changing load conditions. This regulation is essential for stable operation of the power grid, ensuring consistent voltage supply to consumers and preventing voltage fluctuations. In addition to voltage control, exciter systems can also be configured to control the reactive power output of the generator, which is important for maintaining system stability and power factor.