A.c. power system having alternate sources of supply

Claim 1

AN ALTERNATING CURRENT POWER DISTRIBUTION CIRCUIT WHICH COMPRISES A REGULATOR CIRCUIT FOR FURNISHING ALTERNATING CURRENT POWER TO A LOAD; SAID REGULATOR CIRCUIT INCLUDING A PAIR OF INPUT TERMINALS, A PAIR OF OUTPUT TERMINALS, A LINEAR INDUCTOR, A SATURABLE REACTOR, A CAPACITIVE REACTANCE ACROSS SAID SATURABLE REACTOR FORMING A FERRORESONANT CIRCUIT THEREWITH, AN INPUT CIRCUIT BETWEEN SAID PAIR OF INPUT TERMINALS AND INCLUDING SAID LINEAR INDUCTOR AND A FIRST PORTION OF SAID SATURABLE REACTOR FOR LIMITING THE AMPLITUDE OF THE ALTERNATING CURRENT VOLTAGE PROVIDED AT SAID INPUT TERMINALS, A CHOKE COIL IN SERIES WITH SAID CAPACITIVE REACTANCE FOR FILTERING FROM SAID FERRO-RESONANT CIRCUIT FREQUECIES ABOVE THE ALTERNATING CURRENT FREQUENCY, WHEREBY THE WAVE FORM IN SAID SATURABLE REACTOR IS SHAPED TO BE SUBSTANTIALLY A SINE WAVE FORM, AND AN OUTPUT CIRCUIT BETWEEN SAID OUTPUT TERMINAL INCLUDING AT LEAST SAID FIRST PORTION OF SAID SATURABLE REACTOR FOR PROVIDING A REGULATED SINE WAVE FORM VOLTAGE; A LINE SWITCH FOR SELECTIVELY CONNECTING A PAIR OF CONDUCTORS CARRYING ALTERNATING CURRENT POWER FROM A SOURCE TO THE INPUT TERMINALS OF SAID REGULATOR, SAID LINE SWITCH INCLUDING A PARALLEL PAIR OF OPPOSITELY POLED CONTROLLED RECTIFIERS DISPOSED IN A LOOP CIRCUIT BETWEEN SAID POWER CONDUCTORS, EACH OF SAID CONTROLLED RECTIFIERS INCLUDING AN ANODE AND A CATHODE AND A CONTROL ELECTRODE WHEREIN THE ANODE TO CATHODE POTENTIALS AT SAID PAIR OF RECTIFIERS ARE ALTERNATELY POSITIVE AND NEGATIVE IN ACCORDANCE TO THE ALTERNATING CURRENT POWER POLARITIES; MEANS FOR APPLYING POSITIVE GATING PULSES ALTERNATELY TO THE CONTROL ELECTRODES OF SAID PAIR OF CONTROLLED RECTIFIERS IN SYNCHRONISM WITH POSITIVE ANODE TO CATHODE POTENTIALS THEREON WHEREBY THE ALTERNATING CURRENT POWER SOURCE IS ISOLATED FROM THE REGULATING CIRCUIT UPON FAILURE OF THE POWER SOURCE AND ALSO UPON FAILURE OF THE MEANS FOR APPLYING POSITIVE GATING PULSES TO THE CONTROLLED RECTIFIERS; A LINE VOLTAGE SENSOR RENDERED OPERATIVE RESPONSIVE TO A PREDETERMINED VOLTAGE FROM SAID SOURCE OF ALTERNATING CURRENT FOR RENDERING SAID GATING PULSE APPLYING MEANS EFFECTIVE, AN INVERTER CIRCUIT FOR CONVERTING DIRECT CURRENT POWER TO ALTERNATING CURRENT POWER AND FURNISHING SAID POWER TO THE INPUT TERMINALS OF SAID REGULATOR CIRCUIT, AND A SYNCHRONIZING CIRCUIT ASSOCIATED WITH SAID INVERTER CIRCUIT FOR FURNISHING SAID ALTERNATING CURRENT POWER TO SAID VOLTAGE REGULATOR IN LAGGING PHASE RELATIONSHIP TO SAID ALTERNATING CURRENT LINE POWER; SAID SYNCHRONIZING CIRCUIT INCLUDING A FREE RUNNING OSCILLATOR HAVING A BREAKDOWN TYPE ELECTRON FLOW DEVICE PROVIDED WITH A BIASING CIRCUIT NORMALLY PRODUCING SIGNALS CORRESPONDING IN FREQUENCY TO THE FREQUENCY OF THE SIGNAL SUPPLIED FROM SAID SOURCE, A DETECTOR FOR MATCHING THE PHASE OF THE SIGNALS PRODUCED BY SAID OSCILLATOR TO THE PHASE OF THE SIGNAL SUPPLIED FROM SAID SOURCE AND FOR PRODUCING AN ERROR SIGNAL CORRESPONDING TO THE PHASE DIFFERENCE, AND MEANS FOR APPLYING SAID ERROR SIGNAL TO THE BIASING CIRCUIT OF SAID FREE RUNNING OSCILLATOR TO CORRECT SAID PHASE DIFFERENCE.