Abstract: A cathodic protection system for protecting buried conducting structures, subject to corrosion such as well casings, pipe lines and the like, utilizes a plurality of pulsed D.C. current sources with the negative output terminal of each source connected to a separate structure and the positive output terminal of the sources connected to a common anode located near the structures. A control circuit synchronizes the operation of the several D.C. sources and sets the frequency and width of the output pulses. The amplitude of the output pulses from each D.C. source may be separately adjusted.

Abstract: A circuit and method of cathodically protecting ferrous metal structures such as pipelines or well casings is described disposed in a conductive medium such as the ground. A pair of terminals are connected to an anode spaced from the structure and to the structure. A source of d.c. voltage is periodically connected across the terminal to cause current to flow to the anode and provide electrons at the surface of the structure to inhibit ferrous molecules from going into solution and damaging the integrity of the structure. The current flow due to the induced emf caused by the reactive inductions of the anode/cathode system is limited to inhibit damage to neighboring ferrous structures by providing a high impedance, e.g. an open circuit, between the input terminals during all or part of the time that the d.c. source is not supplying current to the anode/cathode load.

Abstract: A cathodic protection system for protecting buried conducting structures, subject to corrosion such as well casings, pipe lines and the like, utilizes a plurality of pulsed D.C. current sources with the negative output terminal of each source connected to a separate structure and the positive output terminal of the sources connected to a common anode located near the structures. A control circuit synchronizes the operation of the several D.C. sources and sets the frequency and width of the output pulses. The amplitude of the output pulses from each D.C. source may be separately adjusted.