Patent ID: 9733292
Date: 2017-08-15
CPC Classifications: G01R,G06F,H01H

Claim:
1. A method for diagnosing an operating state of a contactor, which contactor comprises: a processing unit for directing a voltage control means; at least one actuating coil; means for measuring at least one electric characteristic of said at least one actuating coil; and at least one free wheel diode connected in parallel with said at least one actuating coil and the means for measuring; the method comprising: creating, for a specific design of contactor, a plurality of variation curves of a plurality of values of an electric characteristic of the actuating coils of a plurality of contactors of said design, over a drop-out period, by testing each of said plurality of contactors of said design by: sending a drop-out order thereby fixing a set drop-out voltage across the terminals of the actuating coil; after sending said drop-out order, repeatedly measuring the value of said electric characteristic of said actuating coil during a drop-out time period; said variation curves for each contactor comprising the plurality of measured values of said electric characteristic from said contactor; then at a later time, sending a diagnostic drop-out order thereby fixing the same set drop-out voltage across the terminals of the subject actuating coil of a contactor whose wear is being diagnosed; after sending said diagnostic drop-out order, measuring the same said electric characteristic of said subject actuating coil during a drop-out time period; identifying at least one measured specific value of the same measured electric characteristic of said subject actuating coil, and comparing said at least one measured specific value with said plurality of variation curves of said same electric characteristic of said plurality of contactors of said same specific design, thereby diagnosing a state of wear of said contactor.