Abstract :
An automatic voltage regulator for an alternator consists essentially of a voltage sensitive element which controls, through suitable apparatus, the excitation of an alternator. In the voltage regulator described herein, the voltage sensitive element is a nonlinear bridge circuit. Its output controls, through a phase shifting circuit, a grid-controlled mercury-vapor tube, the output of which is fed into the field circuit of the alternator. The phase shifting circuit employs a fixed condenser and a variable resistance, the latter being obtained from 2 3-electrode vacuum tubes whose grids are controlled by the nonlinear bridge circuit. The regulator is rugged in construction and at constant frequency provides close regulation without apparent hunting or voltage distortion.
