Voltage regulation, with special reference to voltage speed regulation

The. severe loading conditions existing in modern power systems, involving very great and rapid fluctuation of load, have fostered the growth of the automatic voltage regulator. As the characteristic of an alternator resembles that of an ordinary direct-current shunt wound generator, in that the terminal voltage falls with increase of load, it is essential that some device be fitted which will automatically increase the excitation of the alternator as the load increases, so that the terminal voltage may remain constant, or even rise with increase of current.