Split core status indicator

• US 20090115403A1
• Filed: 08/13/2008
• Published: 05/07/2009
• Est. Priority Date: 09/10/2007
• Status: Active Grant

• Current Assignee: Veris Industries LLC (Schneider Electric SE)
• Original Assignee: Veris Industries LLC (Schneider Electric SE)
• Inventors: Bernklau, James
• Granted Patent: US 8,692,540 B2
• Time in Patent Office: Days
• US Class Current: 324/127
• CPC Class Codes: G01R 15/186 using current transformers with a core consisting of two or more parts, e.g. clamp-on type G01R15/142 - G01R15/16 take precedence; tong testers G01R1/22
• CPC Class Codes: H01F 38/30 Constructions

Abstract

The size of a status indicator for monitoring a current in a power cable is reduced by integrating a bobbin for the secondary winding with a current transformer core and integrating a circuit board including output terminals with a current transformer assembly.

Claims

1. A current transformer comprising:

(a) a first magnetically permeable core portion comprising an elongate base having a cross-section, a first leg projecting substantially normal to said base at a first end of said base and a second leg projecting substantially normal to said base at a second end of said base;

(b) a bobbin affixed to said base of said first core portion and including a portion substantially encircling said cross-section of said base;

(c) a winding conductor including a portion wound on said bobbin and encircling said cross-section of said base; and

(d) a second magnetically permeable core portion hinged to said first core portion to enable conjoining of said first leg and said second leg and said second core portion, said first and said second core portions defining an aperture when said first leg and said second leg are proximate said second core portion, and, alternatively, enabling separation of said second leg and said second core portion.

2. The current transformer of claim 1 wherein said bobbin comprises:

(a) a tube having a first tube end and a second tube end, said tube substantially encircling said cross-section of said base of said first core portion;

(b) a first flange extending outward from said tube proximate said first tube end; and

(c) a second flange extending outward from said tube and spaced apart from said first flange, said winding conductor encircling said tube within a space between said first and said second flanges.

3. The current transformer of claim 1 further comprising a spring member elastically urging contact between said second core portion and at least one of said first leg and said second leg of said first core portion.

4. A device for monitoring current in a power cable, said device comprising:

(a) a first magnetically permeable transformer core portion comprising an elongate base having a cross-section, a first leg projecting substantially normal to said base at a first end of said base and a second leg projecting substantially normal to said base at a second end of said base;

(b) a bobbin affixed to said base of said first transformer core portion and including a portion substantially encircling said cross-section of said base;

(c) a winding conductor including a portion wound on said bobbin and encircling said cross-section of said base;

(d) a second magnetically permeable transformer core portion hingedly connected to said first transformer core portion to enable conjoining of said first leg and said second leg with said second transformer core portion, said first and said second transformer core portions defining an aperture to substantially encircle said power cable when said first leg and said second leg are proximate said second transformer core portion, and, alternatively, enabling separation of said second leg and said second transformer core portion to permit said power cable to be situated between the first and second legs of said first transformer core portion; and

(e) a current switch conductively connected to said winding conductor and responsive to a voltage induced in said winding conductor by a current in said power cable to change a state of conductivity between a first signal terminal and a second signal terminal.

5. The device for monitoring current in a power cable of claim 4 wherein said bobbin comprises:

(a) a tube having a first tube end and a second tube end, said tube substantially encircling said cross-section of said base of said first core portion;

(b) a first flange extending outward from said tube proximate said first tube end; and

(c) a second flange extending outward from said tube and spaced apart from said first flange, said winding conductor encircling said tube within said space between said first and said second flanges.

6. The device for monitoring current in a power cable of claim 4 further comprising a spring member elastically urging contact between said second transformer core portion and at least one of said first leg and said second leg of said first transformer core portion.

7. The device for monitoring current in a power cable of claim 4 further comprising a frame to which said first transformer core portion, said current switch, said first signal terminal and said second signal terminal are affixed.

8. A device for monitoring current in a power cable, said device comprising:

(a) a first magnetically permeable transformer core portion comprising an elongate base having a cross-section, a first leg projecting substantially normal to said base at a first end of said base and including a first leg end portion and a second leg projecting substantially normal to said base at a second end of said base and including a second leg end portion;

(b) a bobbin affixed to said base of said first transformer core portion and including a portion substantially encircling said cross-section of said base;

(c) a winding conductor including a portion wound on said bobbin and encircling said cross-section of said base;

(d) a current switch conductively connected to said winding conductor and responsive to a voltage induced in said winding conductor by a current in said power cable to change a state of conductivity between a first signal terminal and a second signal terminal;

(e) a first housing portion to restrain said first transformer core portion and said current switch;

(f) a second magnetically permeable transformer core portion;

(g) a second housing portion to slidably restrain said second transformer core portion and hingedly attached to said first housing portion to enable conjoining of said first leg end portion and said second leg end portion with said second transformer core portion, said first and said second transformer core portions defining an aperture to encircle said power cable when said second leg end portion and said second transformer core portion are proximate, and, alternatively, enabling separation of said second leg end portion and said second transformer core portion to enable said power cable to be situated between said first and said second legs of said first transformer core portion; and

(h) a spring member elastically urging said second transformer core portion into contact with said first and said second leg end portions of said first transformer core portion.

9. The device for monitoring current in a power cable of claim 8 wherein said bobbin comprises:

(a) a tube having a first tube end and a second tube end, said tube substantially encircling said cross-section of said base of said first core portion;

(b) a first flange extending outward from said tube proximate said first tube end; and

(c) a second flange extending outward from said tube and spaced apart from said first flange, said winding conductor encircling said tube within a space between said first and said second flanges.

10. The device for monitoring current in a power cable of claim 8 wherein said first signal terminal and said second signal terminal are restrained relative to said first transformer core section and said current switch by said first housing portion.

11. The device for monitoring current in a power cable of claim 8 further comprising a mounting base including a plurality of projecting arms slidable on a surface of said second housing portion, at least one of said projecting arm including a latching surface engageable with an engagement surface of said second housing to restrain relative movement of said mounting base and said second housing.