Device for measuring electrical current and method of manufacturing the same

• US 8,928,337 B2
• Filed: 05/23/2012
• Issued: 01/06/2015
• Est. Priority Date: 01/27/2012
• Status: Active Grant

• Current Assignee: Schweitzer Engineering Laboratories, Incorporated
• Original Assignee: Schweitzer Engineering Laboratories, Incorporated
• Inventors: Kesler, James R., Skendzic, Veselin
• Primary Examiner(s): Baldridge, Benjamin M
• Application Number:
  US13/479,139
• Publication Number:
  US 20130193987A1
• Time in Patent Office: 958 Days
• Field of Search: 324/654, 336/184, 336/173, 336/160
• US Class Current: 324/654
• CPC Class Codes: G01R 15/181 using coils without a magnetic core, e.g. Rogowski coils
• CPC Class Codes: G01R 3/00 Apparatus or processes specially adapted for the manufacture or maintenance of measuring instruments , e.g. of probe tips
• CPC Class Codes: H01F 38/30 Constructions
• CPC Class Codes: H01F 5/02 wound on non-magnetic supports, e.g. formers
• CPC Class Codes: Y10T 29/49071 by winding or coiling

Abstract

Disclosed herein are embodiments of devices for measuring electrical current and related systems and methods for forming and using such devices. According to certain embodiments, devices according to the present disclosure may comprise Rogowski coils. Also disclosed are systems and methods for forming a current measuring device using a bobbin that may allow for the use of a continuous length of wire for all windings associated with the current measuring device. Automated manufacturing techniques may be utilized to facilitate the manufacture of devices for measuring electrical current and/or may reduce the cost of such devices. Various embodiments disclosed herein include the use of a bobbin that may be selectively configured between a linear configuration and a closed configuration. One or more current sensors disclosed herein may be utilized in connection with a motor management relay or other type of intelligent electronic device.

Claims

1. A current sensor, comprising:

a continuous length of wire; and

a one-piece folding bobbin, comprising;

a first end;

a second end;

a plurality of winding sections formed in the one-piece folding bobbin, configured to be wound with the continuous length of wire;

a plurality of living hinges formed in the one-piece folding bobbin and flexibly linking each winding section to its adjacent winding section of the plurality of winding sections and configured to allow the one-piece folding bobbin to transition between a linear configuration and a closed configuration;

wherein the first end and the second end of the one-piece folding bobbin are selectively arranged in proximity to reconfigure the one-piece folding bobbin from the linear configuration to the closed configuration.

2. The current sensor of claim 1, wherein the bobbin further comprises a channel configured to receive a removable winding spindle, the channel configured to allow the winding spindle to pass through the first end, the second end, the plurality of winding sections, and the plurality of hinges in the linear configuration.

3. The current sensor of claim 1, wherein the bobbin further comprises:

a plurality of stepped sections disposed between at least two winding sections and configured to maintain the at least two winding sections in the same relative alignment in the linear configuration and the closed configuration.

4. The current sensor of claim 1, wherein the current sensor comprises a zero-sequence coil.

5. The current sensor of claim 1, wherein the bobbin further comprises a latch disposed on the first end and a keeper disposed on the second end, the latch and keeper configured to secure the first and the second end in the closed configuration.

6. The current sensor of claim 1, wherein the bobbin comprises a self-supporting structure in the closed configuration.

7. The current sensor of claim 1, wherein the current sensor comprises one of a hexagon, an octagon, and a decagon in the closed configuration.

8. The current sensor of claim 1, wherein the current sensor comprises one of an elongated hexagon, an elongated octagon, and an elongated decagon in the closed configuration.

9. The current sensor of claim 8, wherein each of the plurality of hinges comprises a living hinge, and wherein the bobbin comprises a unitary structure.

10. The current sensor of claim 8, wherein the distance between a first winding section disposed on a first side of the living hinge and a second winding section disposed on a second side of the living hinge is reduced in the closed configuration.

11. The current sensor of claim 10, wherein the second layer is disposed on top of the first layer.

12. The current sensor of claim 10, further comprising a first winding pin and a second winding pin, the first winding pin configured to receive a first end of the continuous length of wire and to secure the first end of the continuous length of wire to the bobbin prior to being wound in the first traverse direction, the second winding pin configured to receive a second end of the continuous length of wire and to secure the second end of the continuous length of wire to the bobbin after being wound in the second traverse direction.

13. The current sensor of claim 11, wherein the first winding pin and the second winding pin are each disposed in proximity to the first end of the bobbin.

14. The current sensor of claim 1, wherein the plurality of hinges comprises at least one living hinge.

15. The current sensor of claim 1, wherein the continuous length of wire is wound in a first traverse direction along a length of the bobbin to form a first layer, and the continuous length of wire is wound in a second traverse direction along the length of the bobbin to form a second layer.

16. The current sensor of claim 1, further comprising a plurality of printed circuit board connection pins configured to mount the current sensor directly to a printed circuit board.

17. The current sensor of claim 1, further comprising a flexible ferromagnetic material configured to be inserted into the channel such that the flexible ferromagnetic material forms a closed magnetic structure in the closed configuration.

18. The current sensor of claim 1, wherein the current sensor comprises a Rogowski coil.

19. The current sensor of claim 1, wherein the current sensor is configured to monitor nominal electrical currents between about 0.4 Amperes and 128 Amperes.

20. The current sensor of claim 1, wherein the current sensor is configured to measure transient electrical currents between about 128 Amperes and 2,000 Amperes.

21. The current sensor of claim 1, further comprising a conformal coating disposed along at least a portion of the bobbin and configured to bind the continuous length of wire to the bobbin.

22. The current sensor of claim 21, wherein the intelligent electronic device comprises a motor management relay.

23. The current sensor of claim 1, wherein the current sensor is configured to be disposed within an intelligent electronic device.

24. The current sensor of claim 23, wherein the motor management relay analyzes input from the current sensor to provide protection to a motor.

25. The current sensor of claim 1, wherein:

each winding section of the plurality of winding sections includes a hinge opening opposite to the living hinges; and

the closed configuration of the one-piece folding bobbin comprises the hinge openings each in a closed position.

26. The current sensor of claim 25, further comprising protruding members and receiving members formed in the hinge openings wherein in the closed configuration the protruding member is received in the receiving member.

27. A one-piece folding bobbin for use in connection with a current sensor, the one-piece folding bobbin comprising:

a first end;

a second end;

a first plurality of winding sections formed in the one-piece folding bobbin configured to be wound with a first continuous length of wire;

a second plurality of winding sections formed in the one-piece folding bobbin configured to be wound with a second continuous length of wire;

a plurality of living hinges formed in the one-piece folding bobbin and flexibly linking the first and second plurality of winding sections and configured to allow the one-piece folding bobbin to transition between a linear configuration and a closed configuration;

wherein the first end and the second end are selectively arranged in proximity to reconfigure the one-piece folding bobbin from the linear configuration to the closed configuration.

28. The one-piece folding bobbin of claim 27, wherein the bobbin is configured as a zero-sequence coil comprising:

a first elongated section;

a second elongated section;

wherein the first elongated section is wound with the first continuous length of wire and the second elongated section is wound with the second continuous length of wire.

29. The one-piece folding bobbin of claim 27, wherein the first continuous length of wire is continuous with the second continuous length of wire.

30. The one-piece folding bobbin of claim 27, further comprising a plurality of hinge openings opposite the plurality of living hinges, wherein the closed configuration of the one-piece folding bobbin comprises the hinge openings each in a closed position.

31. The one-piece folding bobbin of claim 30, further comprising protruding members and receiving members formed in the hinge openings, wherein in the closed configuration the protruding member is received in the receiving member.

32. A current sensor, comprising:

a continuous length of wire; and

a one-piece bobbin, comprising;

a first end;

a second end;

a plurality of winding sections formed in the one-piece bobbin, configured to be wound with the continuous length of wire;

a plurality of living hinges formed in the one-piece bobbin and flexibly linking each winding section to its adjacent winding section of the plurality of winding sections and configured to allow the one-piece bobbin to transition between a linear configuration and a closed configuration with the living hinges on an outside circumference of the one-piece bobbin in closed configuration;

wherein the first end and the second end of the one-piece bobbin are selectively arranged in proximity to reconfigure the one-piece bobbin from the linear configuration to the closed configuration.