Apparatus including mechanical vibration detector means for detecting and locating incipient internal faults in electric induction apparatus

Claim 1

AN INSTRUMENTALITY FOR LOCATING AN INCIPIENT FAULT CHARACTERIZED BY LOW ENERGY SPARKING OR CORONA DISCHARGE INSIDE AN ENCASED LIQUID FILLED STATION ELECTRIC INDUCTION APPARATUS FROM OUTSIDE THE CASING OF SAID APPARATUS WHILE SAID APPARATUS IS CARRYING CURRENT CONDUCTED THROUGH SAID CASING BY AN ENTRANCE LEAD COMPRISING, IN COMBINATION, A CATHODE RAY OSCILLOSCOPE HAVING A HORIZONTAL SEEEP TRIGGER CIRCUIT INPUT TERMINAL AND A VERTICAL DEFLECTION CIRCUIT INPUT TERMINAL, COUPLING MEANS ASSOCITED WITH SAID ENTRANCE LEAD, MEANS INCLUDING A HIGH PASS FILTER AND A WIDE BAND ELECTRONIC AMPLIFIER FOR CONNECTING SAID COUPLING MEANS TO SAID HORIZONTAL SWEEP TRIGGER CIRCUIT INPUT TERMINAL WHEREBY SAID HORIZONTAL SWEEP WILL BE TRIGGERED SUBSTANTIALLY INSTANTANEOUSLY IN RESPONSE TO HIGH FREQUENCY ELECTRIC DISTURBANCES REFLECTED IN SAID ENTRANCE LEAD FROM SPARKING OR CORONA DISCHARGES IN SAID APPARATUS, A CONTACT TYPE TRANSDUCER IN CONTACT WITH A WALL OF THE CASING OF SAID APPARATUS FOR PICKING UP HIGH FREQUENCY MECHANICAL VIBRATIONS TRANSMITTED THROUGH SAID LIQUID TO SAID WALL BY CORONA OR SPARK DISCHARGE IN SAID APPARATUS AND CONVERTING THEM INTO CORRESPONDING FREQUENCY ELECTRICAL OSCILLATIONS, MEANS INCLUDING A SECOND HIGH PASS FILTER AND A SECOND WIDE BAND AMPLIFIER FOR CONNECTING SAID TRANSDUCER TO SAID VERTICAL DEFLECTION INPUT CIRCUIT TERMINAL WHEREBY THE DISPLACEMENT OF THE VERTICAL TRACT OF SAID OSCILLOSCOPE FROM THE ZERO TIME POINT ON THE HORIZONTAL SWEEP AXIS WILL BE A MEASURE OF THE DISTANCE OF SAID FAULT FROM SAID TRANSDUCER.