High voltage alternating current capacitive measuring apparatus using magnetic cores

Claim 1

CAPACITIVE MEASURING APPARATUS COMPRISING (A) TWO CAPACITORS, (B) A CURRENT COMPARATOR DEVICE COMPRISING (I) A MAGNETIC CORE CLOSED ON ITSELF TO FORM A MAGNETIC CIRCUIT, (II) A DETECTION WINDING AROUND SAID CORE, (III) AND PRIMARY AND SECONDARY WINDINGS AROUND SAID CORE, (C) MEANS CONNECTING ONE OF SAID CAPACITORS IN SERIES WITH ONE OF SAID PRIMARY AND SECONDARY WINDINGS TO FORM A FIRST SERIES CIRCUIT, (D) MEANS CONNECTING THE OTHER OF SAID CAPACITORS IN SERIES WITH THE OTHER OF SAID PRIMARY AND SECONDARY WINDINGS TO FORM A SECOND SERIES CIRCUIT, (E) MEANS CONNECTED TO THE DETECTION WINDING FOR DETECTING ZERO OUTPUT THEREFROM, (F) MEANS CONNECTING A FIRST END OF THE FIRST SERIES CIRCUIT TO A FIRST ALTERNATING POTENTIAL PREDETERMINED IN RELATION TO A REFERENCE POTENTIAL, (G) MEANS CONNECTING A FIRST END OF THE SECOND SERIES CIRCUIT TO A SECOND ALTERNATING POTENTIAL OF THE SAME FREQUENCY AS SAID FIRST ALTERNATING POTENTIAL AND ALSO PREDETERMINED IN RELATION TO SAID REFERENCE POTENTIAL, (H) MEANS CONNECTING THE SECOND END OF THE FIRST SERIES CIRCUIT TO SAID REFERENCE POTENTIAL TO CAUSE A CURRENT TO FLOW IN THE WINDING OF THE COMPARATOR DEVICE IN SAID FIRST SERIES CIRCUIT, (I) AN IMPEDANCE ELEMENT HAVING AN IMPEDANCE SMALL COMPARED TO THE IMPEDANCE OF THE CAPACITOR IN THE SECOND SERIES CIRCUIT, (J) A SOURCE OF VOLTAGE, (K) MEANS CONNECTING A FIRST END OF THE IMPEDANCE ELEMENT TO THE SECOND END OF THE SECOND SERIES CIRCUIT, (L) MEANS CONNECTING THE SECOND END OF THE IMPEDANCE ELEMENT TO A FIRST SIDE OF THE VOLTAGE SOURCE, (M) MEANS CONNECTING THE SECOND SIDE OF THE VOLTAGE SOURCE TO SAID REFERENCE POTENTIAL TO CAUSE A CURRENT TO FLOW IN THE WINDING OF THE COMPARATOR DEVICE IN SAID SECOND SERIES CIRCUIT, (N) THE CONNECTIONS BEING SUCH THAT SAID CURRENTS FLOW IN OPPOSITION TO EACH OTHER TO GENERATE ONLY A DIFFERENCE FLUX IN THE CORE, (O) MEANS FOR MODIFYING THE OUTPUT OF THE VOLTAGE SOURCE IN MAGNITUDE AND PHASE TO BRING THE JUNCTION BETWEEN THE SECOND SERIES CIRCUIT AND THE IMPEDANCE ELEMENT TO SAID REFERENCE POTENTIAL, (P) MEANS SENSITIVE TO THE VOLTAGE ACROSS THE IMPEDANCE ELEMENT FOR GENERATING FROM SUCH VOLTAGE A CONTROL POTENTIAL RELATIVE TO THE REFERENCE POTENTIAL, THE MAGNITUDE AND PHASE OF WHICH CONTROL POTENTIAL IS RELATED TO THE CURRENT IN THE SECOND SERIES CIRCUIT, (Q) AND MEANS FOR GENERATING A CORRECTION CURRENT FROM SAID CONTROL POTENTIAL AND FOR APPLYING SAID CORRECTION CURRENT TO SAID COMPARATOR DEVICE TO GENERATE A FLUX IN THE CORE EQUAL AND OPPOSITE TO THE DIFFERENCE FLUX WHEREBY TO BRING THE OUTPUT OF THE DETECTION WINDING TO ZERO.