Semiconductor self-excited excitation circuit

In the figure, Ul - three-phase
rectifier device; U2 - three-phase thyristor rectifier device;
T - excitation transformer; TAl - excitation converter;
TA2 - current transformer; TV - voltage transformer;
ZLT - automatic excitation regulator.
    When the generator is running with load, most of the excitation current
is supplied by the compound excitation current; when the generator is externally short-circuited,
the compound excitation part outputs forced excitation .