MAGNETIC SHIELD FOR CURRENT TRANSFORMER IN ELECTRONIC WATT-HOUR METER

• US 20120126787A1
• Filed: 11/24/2010
• Published: 05/24/2012
• Est. Priority Date: 11/24/2010
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Shaw, Bradley Douglas, Ingram, Dwight Wayne
• Granted Patent: US 8,664,935 B2
• Time in Patent Office: Days
• US Class Current: 324/110
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10
• CPC Class Codes: H01F 27/366 made of ferromagnetic material
• CPC Class Codes: H01F 38/30 Constructions

Abstract

An electronic watt-hour meter; a current transformer operatively coupled to the electronic watt-hour meter; a first shield on a first side of the current transformer; and a second shield on a second side of the current transformer, wherein the second side is substantially parallel to the first side, wherein the first shield and the second shield each include a substantially magnetically permeable and conductive metal.

Claims

1. An electronic watt-hour meter, comprising:

a current transformer operatively coupled to the electronic watt-hour meter;

a first shield on a first side of the current transformer; and

a second shield on a second side of the current transformer, wherein the second side is substantially parallel to the first side,

wherein the first shield and the second shield each include a substantially magnetically permeable and conductive metal.

2. The electronic watt-hour meter of claim 1, further comprising:

a third shield on a portion of a third side of the current transformer, wherein the third shield is substantially perpendicular to the first and second shields; and

wherein the third shield includes a substantially magnetically permeable and conductive metal.

3. The electronic watt-hour meter of claim 2, wherein the third shield has a substantially curvilinear planar shape.

4. The electronic watt-hour meter of claim 1, wherein the first and second shields are substantially disc shaped.

5. The electronic watt-hour meter of claim 1, wherein the substantially magnetically permeable and conductive metal includes a low carbon steel.

6. The electronic watt-hour meter of claim 5, wherein the low carbon steel includes less than approximately 0.26 percent carbon content.

7. The electronic watt-hour meter of claim 1, wherein the current transformer is substantially torodial in shape.

8. The electronic watt-hour meter of claim 1, wherein one of the first shield and the second shield is thicker than the other of the first shield and the second shield.

9. The electronic watt-hour meter of claim 1, wherein at least one of the first shield and the second shield substantially shields up to approximately 5000 gauss from an external magnet.

10. An electronic watt-hour meter, comprising:

a current transformer operatively coupled to the electronic watt-hour meter;

a first shield on a first side of the current transformer;

a second shield on a second side of the current transformer, wherein the second side is substantially parallel to the first side;

wherein at least one of the first shield and the second shield substantially shields up to approximately 5000 gauss from an external magnet.

11. The electronic watt-hour meter of claim 10, further comprising:

a third shield on a portion of a third side of the current transformer, wherein the third shield is substantially perpendicular to the first and second shields and

wherein the third shield substantially shields up to approximately 5000 gauss from an external magnet.

12. The electronic watt-hour meter of claim 11, wherein the third shield includes a substantially magnetically permeable and conductive metal.

13. The electronic watt-hour meter of claim 11, wherein the third shield has a substantially curvilinear planar shape.

14. The electronic watt-hour meter of claim 10, wherein the third shield includes a substantially magnetically permeable and conductive metal.

15. The electronic watt-hour meter of claim 14, wherein the substantially magnetically permeable and conductive metal includes a low carbon steel.

16. The electronic watt-hour meter of claim 15, wherein the low carbon steel includes less than approximately 0.26 percent carbon content.

17. A first magnetic shield for a current transformer, comprising;

a substantially disc shape body;

an aperture through approximately a center of the body; and

a gap in the body, the gap extending from an edge of the body to the aperture,

wherein the body includes a substantially magnetically permeable and conductive metal.

18. The magnetic shield of claim 17, wherein the substantially magnetically permeable and conductive metal includes a low carbon steel.

19. The magnetic shield of claim 18, wherein the low carbon steel includes less than approximately 0.26 percent carbon content.

20. The magnetic shield of claim 17, wherein the first magnetic shield is on a first side of the current transformer;

and further comprising;

a second magnetic shield on a second side of the current transformer;

a third magnetic shield on an outer periphery of the current transformer, wherein the third shield is connected with the first shield and the second shield.