RFID tag based state monitoring of contactors

Patent metadata

Field	Value
Publication number	US-9418808-B2
Application number	US-201514722937-A
Country	US
Kind code	B2
Filing date	May 27, 2015
Priority date	Dec 29, 2014
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

A motor starter or contactor having a radio frequency identification (RFID) tag incorporated therein for accurate determination of the position of contacts in the motor starter/contactor is disclosed. The motor starter/contactor includes separable contacts comprising a fixed contact structure and a movable contact structure having a closed position and an open position. An electromagnet is also included in the motor starter/contactor that is arranged to translate the movable contact structure between the closed position and the open position. An RFID tag is positioned on or adjacent the separable contacts to indicate the position of the movable contact structure in the motor starter/contactor.

First claim

What is claimed is:

1. A contactor comprising:
separable contacts comprising a fixed contact structure and a movable contact structure having a closed position and an open position;
an electromagnet arranged to translate the movable contact structure between the closed position and the open position;
a radio frequency identification (RFID) tag positioned on or adjacent the separable contacts to indicate the position of the movable contact structure; and
an antenna selectively in operable communication with the RFID tag based on the position of the movable contact structure;
wherein the movable contact structure forms a communications path between the RFID tag and the antenna when in the closed position, with the antenna transmitting a switch message when the communications path is formed between the RFID tag and the antenna.

2. The contactor of claim 1 wherein the RFID tag is located on the fixed contact structure and the antenna is located on the movable contact structure.

3. The contactor of claim further comprising an RFID reader configured to receive the switch messages from the RFID tag that indicate the position of the movable contact structure.

4. The contactor of claim 3 wherein the RFID reader is incorporated into a handheld interface device.

5. The contactor of claim 3 wherein the RFID reader transmits interrogator signals to the RFID tag, with the RFID tag generating the switch messages responsive to the interrogator signals.

6. The contactor of claim 1 wherein the contactor further comprises a contactor housing positioned about the separable contacts and the electromagnet, and wherein the RFID tag and the antenna are also positioned within the contactor housing.

7. The contactor of claim 1 wherein the RFID tag is configured to indicate the position of the movable contact structure with the contactor in a de-energized state.

8. The contactor of claim 1 wherein the RFID tag provides for an indication of the position of the movable contact structure without the use of any auxiliary contactors.

9. A method of determining a state of a contactor, the method comprising:
providing a radio frequency identification (RFID) tag on a fixed contact structure of the contactor;
providing an antenna on a movable contact structure of the contactor; and
determining a position of the movable contact structure in one of a contacts open position and a contacts closed position;
wherein determining the position of the movable contact structure comprises:
forming a communications path between the RFID tag and the antenna when the movable contact structure is in the contacts closed position; and
transmitting a switch signal from the antenna to an RFID reader remote from the contactor, the switch signal indicating that the movable contact structure is in the contacts closed position.

10. The method of claim 9 wherein the antenna moves with the movable contact structure, such that the communications path between the RFID tag and the antenna is formed when the movable contact structure is in the contacts closed position.

11. The method of claim 9 wherein determining the position of the movable contact structure comprises transmitting interrogator signals from the RFID reader to the RFID tag, with the RFID tag generating the switch signal responsive to the interrogator signals.

12. The method of claim 9 wherein the position of the movable contact structure is determined while the contactor is in a de-energized state.

13. The method of claim 9 wherein the position of the movable contact structure is determined without the use of any auxiliary contactors.

14. 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;
an RFID tag located on the at least one pair of stationary contacts; and
an antenna located on the at least one pair of moveable contacts;
wherein a communications path between the RFID tag and the antenna is formed by the at least one pair of moveable contacts when the at least one pair of moveable contacts is in the contacts closed position.

15. The contactor of claim 14 wherein, when the at least one pair of moveable contacts is in the contacts closed position, the communications path between the RFID tag and the antenna provides for the antenna to transmit a switch signal to an RFID reader remote from the contactor.

16. The contactor of claim 15 wherein the RFID reader transmits interrogator signals to the RFID tag, with the RFID tag generating the switch signal responsive to the interrogator signals.

17. The contactor of claim 14 further comprising a contactor housing positioned about the at least one pair of moveable contacts, the at least one pair of stationary contacts and the electromagnet, wherein the RFID tag and the antenna are also positioned within the contactor housing.

18. The contactor of claim 14 wherein the RFID tag is configured to indicate the position of the at least one pair of moveable contacts with the contactor in a de-energized state.

Assignees

• Eaton Corp

Inventors

• Blackwood Andrew James
• Pflieger John F

Classifications

• H01H9/168 Primary

  making use of an electromagnetic wave communication · CPC title

• H01H50/08

  Indicators; Distinguishing marks · CPC title

• H01H50/54

  Contact arrangements · CPC title

• G06K19/07773

  Antenna details (antennas for wireless devices, e.g. RFID tags, in general H01Q1/22) · CPC title

• H01H47/002 Primary

  Monitoring or fail-safe circuits · CPC title