Split core sensing transformer

• US 20060006976A1
• Filed: 10/18/2004
• Published: 01/12/2006
• Est. Priority Date: 07/07/2004
• Status: Active Grant

• Current Assignee: Veris Industries LLC (Schneider Electric SE)
• Original Assignee: Veris Industries LLC (Schneider Electric SE)
• Inventors: Bruno, David
• Granted Patent: US 7,312,686 B2
• Time in Patent Office: Days
• US Class Current: 336/229
• CPC Class Codes: G01R 1/22 Tong testers acting as secondary windings of current transformers
• CPC Class Codes: H01F 27/263 Fastening parts of the core together
• CPC Class Codes: H01F 3/10 Composite arrangements of magnetic circuits
• CPC Class Codes: H01F 30/16 Toroidal transformers
• CPC Class Codes: H01F 38/30 Constructions

Abstract

Separable toroidal segments reduce the size of a sensing transformer that can be installed on an electrical conductor while connected to a device.

Claims

1. A sensing transformer comprising:

(a) a first transformer segment including;

(i) a first magnetically permeable core comprising a sector of a torus having a planar cross-section bounded by a closed curve, said planar cross-section rotated about an axis in said plane of said cross-section but not intersecting said plane of said cross-section; and

(ii) a winding including at least one turn substantially encircling said cross-section of said core; and

(b) a second transformer segment separable from said first transformer segment, said second transformer segment including a second magnetically permeable core comprising another sector of said torus, said second transformer segment being joinable to said first transformer segment to restrain said first and said second cores in substantially toroidal arrangement.

2. The sensing transformer of claim 1 further comprising:

(a) a first segment housing retentively sheathing a portion of said first core; and

(b) a second segment housing retentively sheathing a portion of said second core, said first segment housing and said second segment housing joinable to restrain said first and said second cores.

3. The sensing transformer of claim 1 further comprising:

(a) a first segment housing retentively sheathing a portion of said first core and including a protrusion; and

(b) a second segment housing retentively sheathing a portion of said second core, said second segment housing including a portion arranged to slidably receive said first segment housing and a surface arranged to engage said protrusion so as to resist separation of said first segment housing and said second segment housing.

4. The sensing transformer of claim 1 further comprising:

(a) a first segment housing retentively sheathing a portion of said first core; and

(b) a second segment housing retentively sheathing a portion of said second core, said second segment housing including a portion arranged to slidably receive said first segment housing between said second core and said second segment housing.

5. The sensing transformer of claim 1 further comprising:

(a) a first segment housing retentively sheathing a portion of said first core, said first segment housing including a first surface; and

(b) a second segment housing retentively sheathing a portion of said second core, said second segment housing including a portion arranged to slidably receive said first segment housing, said second segment housing including a second surface arranged to contact said first surface when said first segment housing is received in said second segment housing, one of said first surface and said second surface having a friction enhancing coating.

6. A sensing transformer comprising:

(a) a first transformer segment including;

(i) a first magnetically permeable core comprising a sector of a torus having a planar cross-section bounded by a closed curve, said planar cross-section rotated about an axis in said plane of said cross-section but not intersecting said plane of said cross-section;

(ii) a winding including at least one turn substantially encircling said cross-section of said core; and

(iii) a first segment housing retentively sheathing said first core; and

(b) a second transformer segment separable from said first transformer segment, said second transformer segment including;

(i) a second magnetically permeable core comprising another sector of said torus; and

(ii) a second segment housing retentively sheathing a portion of said second core, one of first segment housing and said second segment housing including a portion arranged to slidably receive the other of said first segment housing and said second segment housing in mating engagement so as to restrain said first core and said second core in substantially toroidal arrangement.

7. The sensing transformer of claim 6 wherein one of said first segment housing and said second segment includes a protruding portion and the other of said first segment housing and said second segment housing includes portions defining an aperture including a surface arranged to engage said protruding portion and resist separation of said first and said second segment housings when slidably engaged.

8. A method of encircling a conductor with a core of a sensing transformer, said method comprising the steps of:

(a) positioning a first transformer segment proximate said conductor, said first transformer segment comprising a substantially toroidal segment having an inner surface, said conductor being positioned proximate said inner surface;

(b) positioning a separate second transformer segment proximate said conductor, said second transformer segment comprising a substantially toroidal segment having an inner surface and a portion arranged to receive in sliding engagement said first transformer segment, said conductor being positioned proximate said inner surface of said second transformer segment; and

(c) pressing said first and said second transformer segments into mating engagement.