Voltage regulator utilizing thyristor switch means

Claim 1

A voltage regulator for use between a power source and a load comprising: a series transformer having an iron core and primary and secondary windings wound about said core; said secondary winding being coupled between said source and said load; an excitation transformer having input means coupled across said load and output means including an output winding having a plurality of taps; a plurality of thyristors each having first and second control terminals, said first terminals being coupled to an associated one of said taps; means for connecting the remaining terminals of said thyristors to said primary winding; means for sensing the voltage across said load; a control pulse generator coupled to said sensing means for generating control pulses only upon the occurrence of changes in the voltage across said load from a desired voltage level; gating means coupled to said control pulse generator for applying control pulse signals to the control terminals of selected ones of said thyristors to maintain a constant voltage output across said load; said iron core being adapted to saturate in the presence of high current; and inductance means coupled between the primary winding of said series transformer and the second terminals of said thyristors, said iron core and said inductance means protecting said thyristors against damage from current surges which may occur due to short-circuit conditions such as the short circuiting of said load.