Voltage deviation alarm system

Claim 1

APPARATUS FOR MONITORING THE PERFORMANCE OF AND FOR WARNING OF FAILURE OF AT LEAST ONE OF AT LEAST TWO SERVO AMPLIFIERS, EACH OF WHICH NORMALLY DRIVE TO A COMMON NULL OUTPUT INCLUDING; MEANS INDIVIDUAL TO EACH SERVO AMPLIFIER FOR ADJUSTING THE OUTPUT OF THE RESPECTIVE SERVO AMPLIFIER TO A PREDETERMINED VALUE WHEN THE OUTPUT IS AT SAID COMMON NULL VALUE, AN OR GATE HAVING AT LEAST TWO INPUTS AND AN OUTPUT SAID OR GATE INCLUDING, AT LEAST TWO RECTIFIER CIRCUITS, EACH RESPECTIVE RECTIFIER CIRCUIT COUPLED TO A RESPECTIVE INPUT OF SAID AT LEAST TWO INPUTS AND EACH RECTIFIER CIRCUIT COUPLED TO SAID OUTPUT, MEANS FOR COUPLING THE OUTPUT OF EACH RESPECTIVE SAID ADJUSTING MEANS TO A RESPECTIVE INPUT OF SAID AT LEAST TWO INPUTS FOR HOLDING THE RESPECTIVE RECTIFIER CIRCUIT NONCONDUCTIVE WHEN THE OUTPUT OF THE RESPECTIVE ADJUSTING MEANS IS AT SAID PREDETERMINED VALUE AND FOR DRIVING SAID RECTIFIER CIRCUIT WHEN THE OUTPUT OF THE RESPECTIVE ADJUSTING MEANS IS AT A VALUE OTHER THAN SAID PREDETERMINED VALUE, A POTENTIAL DIVIDER CIRCUIT INCLUDING FIRST AND SECOND RESISTORS CONNECTED IN SERIES BETWEEN A CIRCUIT SUPPLY AND A RETURN, SAID OUTPUT OF SAID OR GATE CONNECTED TO A JUNCTION BETWEEN SAID FIRST AND SECOND RESISTORS SO THAT WHEN ANY ONE OF SAID RECTIFIER CIRCUITS ARE CONDUCTING THE POTENTIAL AT SAID JUNCTION IS THE VALUE OF SAID RETURN AND WHEN ALL OF SAID AT LEAST TWO RECTIFIER CIRCUITS ARE NONCONDUCTING THE POTENTIAL AT SAID JUNCION IS SUBSTANTIALLY ABOVE THE VALUE OF SAID RETURN, MEANS COUPLED TO SAID POTENTIAL DIVIDER BETWEEN SAID JUNCTION AND SAID RETURN FOR DEVELOPING A DRIVING POTENTIAL WHEN THE POTENTIAL AT SAID JUNCTION IS ABOVE SAID RETURN, AND MEANS RESPONSIVE TO SAID DRIVING POTENTIAL FOR INDICATING THE OUTPUT OF EACH OF SAID AT LEAST TWO SERVO AMPLIFIERS IS AT SAID COMMON NULL.