Importance

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Abstract

A method for diagnosing an operating state, i.e., wear, of a contactor which includes a processing unit directing voltage control means; an, actuating coil; means for measuring an electric characteristic of the actuating coil; and a diode in parallel with the coil and the measuring means; the method including creating, for a specific contactor design, a plurality of variation curves of an electric characteristic of the coils of such contactors, over a drop-out period, by testing said contactors by sending a drop-out order fixing a drop-out voltage across the coil; after the drop-out order, repeatedly measuring the electric characteristic of the coil during a drop-out period; later sending a diagnostic drop-out order fixing the same drop-out voltage across the terminals of an actuating coil of a subject contactor being diagnosed; then measuring the same electric characteristic of the subject coil during a drop-out period; identifying a measured value of that characteristic of the subject coil, then comparing that measured value with the variation curves of the plurality of contactors of the same design, thereby diagnosing a state of wear of the subject contactor.

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First Claim