Electronic frequency error detector

Claim 1

AN ELECTRONIC FREQUENCY ERROR DETECTOR FOR CONTROLLING THE OUTPUT CIRCUIT OF A.C. POWER SUPPLY IN RESPONSE TO THE FREQUENCY OF SAID POWER SUPPLY, SAID ERROR DETECTOR COMPRISING A FIST FREQUENCY SENSITIVE, ADJUSTAABLE CIRCUIT MEANS OPERABLY CONNECTED TO SAID POWER SUPPLY FOR PROVIDING AN OUTPUT SIGNAL WHEN THE FREQUENCY OF SAID POWER SUPPLY IS BELOW A PREDETERMINED LOWER LIMIT, A SECOND FREQUENCY SENSITIVE, ADJUSTABLE CIRCUIT MEANS OPERABLY CONNECTED TO SAID POWER SUPPLY FOR PROVIDING AN OUTPUT SIGNAL WHEN THE FREQUENCY OF SAID POWER SUPPLY IS ABOVE A PREDETERMINED UPPER LIMIT, A FIRST CONTROL CIRCUIT MEANS IN SAID A.C. POWER SUPPLY CIRCUIT OPERABLE IN RESPONSIVE TO THE OUTPUT OF SAID FIRST FREQUENCY SENSITIVE MEANS TO OPEN SAID POWER SUPPLY CIRCUIT WHEN THE FREQUENCY OF SAID POWER SUPPLY DECREASES BELOW SAID PREDETERMINED LOWER LIMIT, A SECOND CONTROL CIRCUIT MEANS IN SAID A.C. POWER SUPPLY CIRCUIT OPERABLE IN RESPONSE TO THE OUTPUT OF SAID SECOND FREQUENCY SENSITIVE MEANS TO OPEN SAID POWER SUPPLY CIRCUIT WHEN THE FREQUENCY OF SAID POWER SUPPLY INCREASES ABOVE A PREDETERMINED UPPER LIMIT, AND A HOLDING CIRCUIT COMPLETED THROUGH SAID SECOND CONTROL CIRCUIT MEANS TO ENABLE SAID FIRST AND SECOND CONTROL CIRCUIT MEANS DURING PERIODS WHEN THE FREQUENCY OF SAID POWER SUPPLY IS BELOW SAID PREDETERMINED UPPER LIMIT AND TO DISABLE SAID CONTROL CIRCUIT MEANS AND SAID HOLDING CIRCUIT WHEN THE FREQUENCY OF SAID POWER SUPPLY INCREASES ABOVE SAID PREDETERMINED UPPER LIMIT THEREBY PREVENTING AN OUTPUT FROM SAID A.C. POWER SUPPLY AFTER THE FREQUENCY OF SAID POWER SUPPLY INCREASES ABOUT SAID PREDETERMINED UPPER LIMIT UNTIL SUCH HOLDING CIRCUIT IS MANUALLY RESTORED.