Figure 1-29.-Power circuit.
and voltage spikes. Controlling the point during any
positive with respect to cathode, and a trigger pulse is
applied to terminals A and B. SCR1 will conduct current,
applied half cycle of ac voltage that the trigger pulse is
and SCR2 will block current like a normal rectifier bridge,
applied to the gate of the SCRs makes it possible to
for the remainder of the applied half cycle, as shown in
control the output power of the dc power supply.
The signal developed in the power section of the
figure 1-29. Diode D1 and thyrector SP1 (a General
voltage regulator (fig. 1-27) is used as dc control current
Electric silicon controlled diode used for ac surge
to the static exciter.
protection) are used to protect the circuit from transients