Method and apparatus for monitoring wellness of contactors and starters
AssigneeEaton Corporation
InventorsXin Zhou, Jan Walker
Life of this patent
Estimating the term…
Abstract
A system and method for monitoring the remaining useable life, or “wellness,” of a contactor or motor starter, and for predicting impending faults of such a device, is disclosed. By monitoring actuating coil current, actuating coil voltage, line current, and/or line voltage, the present invention can calculate wellness metrics which, when compared to threshold values, may be used as indicators of remaining life and/or imminent failures. The invention also provides non-mechanical positive indications of proper closures and openings of contacts for safety interlocking.
Claims39
A contactor comprising:
- at least one pair of moveable contacts;
- at least one pair of stationary contacts;
- an electromagnet arranged to cause the at least one pair of moveable contacts to travel to a contacts open position and a contacts closed position with respect to the at least one pair of stationary contacts;
- a coil current sensor connected to output signals indicative of current through the electromagnet during operation cycles of the electromagnet;
- and
- a controller connected to receive the signals from the coil current sensor and programmed to determine a fault indicator therefrom.
A method for predicting contactor fault comprising:
- measuring current through a coil of an electromagnetic contactor;
- determining a contactor performance indicator from at least the coil current;
- and
- electronically predicting contactor fault in a controller from a comparison of the performance indicator and a threshold value.
A switching apparatus comprising:
- a contactor having a DC actuating coil;
- a relay connected to control the contactor and receive inputs therefrom;
- and
- wherein the relay contains a circuit which, upon receipt of the inputs from the contactor, is constructed to:
- cause an evaluation to be performed of at least one of armature pull-in time, over-travel time, and coil current differential from the inputs;
- and
- cause an indication of contactor fault likelihood to be generated based on an outcome of the evaluation.
A method for manufacturing a contactor wellness monitor comprising:
- providing a contactor having an electromagnetic actuating coil;
- arranging electrical components for acquisition of signals indicating at least coil current;
- establishing a number of electrical connections to conduct the signals toward a processing unit;
- and
- programming the processing unit to:
- monitor coil current during operations of the contactor;
- determine at least one of armature pull-in time and coil current differential;
- and
- generate an indicator of contactor wellness therefrom.
Dependencies are inferred from the claim text.