Systems and methods for detecting welded contacts in an electromagnetic switch system

Patent metadata

Field	Value
Publication number	US-11901145-B2
Application number	US-202117485734-A
Country	US
Kind code	B2
Filing date	Sep 27, 2021
Priority date	Sep 27, 2021
Publication date	Feb 13, 2024
Grant date	Feb 13, 2024

Abstract

A non-transitory, computer-readable medium may include instructions executable by at least one processor in a computing device to cause the processor to perform operations that include transmitting, to a first power source, a command to provide power to a coil of a switching device with a fixed current profile. The operations also include receiving one or more voltage measurements associated with the coil during a period of time, determining whether the voltage measurements associated with the coil indicate that one or more movable contacts of the switching device are at least partially welded to one or more contacts of an electric circuit, and transmitting an additional command to a second power source to disconnect a current to the coil in response to determining that the voltage measurements indicate that the movable contacts of the switching device are at least partially welded to the contacts of the electric circuit.

First claim

The invention claimed is:

1. A system, comprising:
a first power source; and
a switching device, comprising:
an armature configured to electrically couple one or more movable contacts to one or more contacts of an electric circuit;
a relay coil configured to receive a current from a second power source, thereby causing the armature to electrically couple the one or more movable contacts to the one or more contacts of the electric circuit or electrically disconnect the one or more movable contacts from the one or more contacts after a period of time; and
a control system configured to perform operations comprising:
transmitting a command to the second power source to provide power to the relay coil with a fixed current profile;
receiving one or more voltage measurements associated with the relay coil during the period of time;
determining that the one or more voltage measurements indicate that the one or more movable contacts are at least partially welded to the one or more contacts of the electric circuit; and
in response to determining that the one or more voltage measurements indicate that the one or more movable contacts are at least partially welded to the one or more contacts of the electric circuit, transmitting an additional command to the second power source to disconnect the current to the relay coil.

2. The system of claim 1 , wherein the command to the second power source to provide power to the relay coil is transmitted during a turn-on sequence of the switching device.

3. The system of claim 1 , wherein determining that the one or more voltage measurements indicate that the one or more movable contacts is at least partially welded to the one or more contacts of the electric circuit comprises:
receiving one or more baseline voltage responses associated with the relay coil; and
determining that the one or more voltage measurements differ from respective values of the one or more baseline voltage responses.

4. The system of claim 3 , wherein the one or more baseline voltage responses are associated with a non-welded state of the switching device.

5. The system of claim 4 , wherein determining that the one or more voltage measurements differ from respective values of the one or more baseline voltage responses comprises determining that the one or more voltage measurements are greater than the respective values of the one or more baseline voltage responses.

6. The system of claim 3 , wherein the one or more baseline voltage responses are associated with a welded state of the switching device.

7. The system of claim 6 , wherein determining that the one or more voltage measurements differ from respective values of the one or more baseline voltage responses comprises determining that the one or more voltage measurements are within a threshold of the one or more baseline voltage responses.

8. The system of claim 1 , wherein the additional command to disconnect the current to the relay coil is transmitted to the second power source before the armature electrically couples the one or more movable contacts to the one or more contacts of the electric circuit or electrically disconnects the one or more movable contacts from the one or more contacts.

9. A method, comprising:
transmitting, by a control system to a first power source associated with a switching device, a command to provide power to a relay coil of the switching device with a fixed current profile;
receiving, by the control system, one or more voltage measurements associated with the relay coil during a period of time;
determining, by the control system, that one or more voltage measurements indicate that one or more movable contacts of the switching device are at least partially welded to one or more contacts of an electric circuit; and
in response to determining that the one or more voltage measurements indicate that the one or more movable contacts of the switching device are at least partially welded to the one or more moveable contacts of the electric circuit, transmitting, by the control system, an additional command to a second power source to disconnect a current to the relay coil.

10. The method of claim 9 , wherein determining that the one or more voltage measurements indicate that the one or more movable contacts are at least partially welded to the one or more contacts of the electric circuit comprises:
receiving one or more baseline voltage responses associated with the relay coil; and
determining that the one or more voltage measurements differ from respective values of the one or more baseline voltage responses.

11. The method of claim 10 , wherein the one or more baseline voltage responses are associated with a welded state of the switching device.

12. The method of claim 11 , wherein determining that the one or more voltage measurements differ from respective values of the one or more baseline voltage responses comprises determining that the one or more voltage measurements are within a threshold of the one or more baseline voltage responses.

13. The method of claim 12 , comprising adjusting, by the control system, the threshold of the one or more baseline voltage responses based on an ambient temperature associated with the relay coil.

14. The method of claim 13 , comprising receiving, by the control system, a measurement of the ambient temperature associated with the relay coil before transmitting the command to the first power source to provide power to the relay coil of the switching device with the fixed current profile.

15. The method of claim 10 , comprising:
determining, by the control system, a coil resistance of the relay coil based on one or more additional voltage measurements associated with the relay coil and one or more current measurements associated with the relay coil; and
adjusting, by the control system, a threshold of the one or more baseline voltage responses based on the coil resistance.

16. The method of claim 9 , comprising transmitting a notification indicative of a welded state of the switching device to one or more computing devices.

17. A non-transitory, computer-readable medium storing instructions executable by at least one processor in a computing device, wherein the instructions comprise instructions to cause the at least one processor to perform operations comprising:
transmitting, to a first power source associated with a switching device, a command to provide power to a relay coil of the switching device with a fixed current profile;
receiving one or more voltage measurements associated with the relay coil during a period of time;
determining whether the one or more voltage measurements associated with the relay coil indicate that one or more movable contacts of the switching device are at least partially welded to one or more contacts of an electric circuit; and
in response to determining that the one or more voltage measurements associated with the relay coil indicate that the one or more movable contacts of the switching device are at least partially welded to the one or more contacts of the electric circuit, transmitting an additional command to a second power source to disconnect a current to the relay coil.

18. The non-transitory, computer-readable medium of claim 17 , wherein the command to provide the power to the relay coil is transmitted during a turn-on sequence of the switching device.

19. The non-transitory, computer-readable medium of claim 17 , wherein the additional command to disconnect the current to the relay coil is transmitted to the second power source before an armature of the

Assignees

• Rockwell Automation Tech Inc

Inventors

• Adkins Kyle B
• Carlson Andrew E
• Messersmith David M
• Elmiger David

Classifications

• H01H47/002 Primary

  Monitoring or fail-safe circuits · CPC title

• H01H50/18

  Movable parts of magnetic circuits, e.g. armature · CPC title

• H01H50/44

  Magnetic coils or windings · CPC title

• H01H2047/003

  Detecting welded contacts and applying weld break pulses to coil · CPC title

• H01H9/167

  Circuits for remote indication · CPC title