SELF-EXCITED SHUNT DEVICE FOR AC EXCITER

PURPOSE:To reduce a capacity of an excited shunt device, to reduce in size the device and to improve stability by self-exciting to supply a predetermined field current to an AC exciter by a thyristor rectifier and a constant-excited controller. CONSTITUTION:When an output voltage of an AC exciter (AM) 1 is raised due to any cause, a voltage applied to a thyristor rectifier (ST) 15 is raised. Thus, the ST 15 is so controlled from a constant-excited controller 13 as to lower a DC voltage. As a result, a current to be supplied to a field winding 1b is lowered, an output voltage of the AM 1 is also lowered, and the output voltage is regulated. Thus, the output of the AM 1 is supplied to a main rectifier 11, a rectified DC current is supplied to a field winding 1b of a synchronous machine 12, and output from the machine 12 to a bus side. In this manner, since the constant exciting current is supplied to the winding 1b of the AM 1, a stable point can be obtained by holding at a predetermined position of a field resistance curve.