Patent ID: 9728065
Date: 2017-08-08
CPC Classifications: G08B

Claim:
1. A method of detecting disturbance in a metallic conductor of a monitored infrastructure, the method comprising the steps of providing an inductance sensing circuit including a transformer having a first primary coil and a second primary coil on a metallic conductor side, and a secondary coil on an alarm circuit side, the first primary coil being supplied on a first circuit with an internally generated circuit oscillation by an oscillating power source or oscillator, the second primary coil being physically and electrically connected to the said metallic conductor having a monitorable inductance on a second circuit which is independent of the first circuit such that the oscillating power source or oscillator is not directly connected to the metallic conductor, tuning the inductance sensing circuit based on an electromagnetic field impressed upon the metallic conductor and the internally generated circuit oscillation into the first primary coil, wherein the inductance sensing circuit is tuned as a function of the monitorable inductance on the second circuit, and outputting an alert signal when a tuned output signal from the tuned inductance sensing circuit becomes detuned due to a change in inductance of the metallic conductor by alteration to or removal of at least a portion of the metallic conductor.