Current measuring transformer

• US 4,258,348 A
• Filed: 11/13/1979
• Issued: 03/24/1981
• Est. Priority Date: 11/13/1979
• Status: Expired due to Term

• Current Assignee: STB Transformer Company
• Original Assignee: STB Transformer Company
• Inventors: Tavare, Russell, Belfer, Kenneth H., Stewart, Arnold
• Primary Examiner(s): Kozma, Thomas J.
• Application Number:
  US06/093,866
• Time in Patent Office: 497 Days
• Field of Search: 336/175, 336/176, 336/212, 336/217, 336/105, 336/107, 336/73, 336/184, 336/69, 336/70, 324/127, 324/129, 324/117 R, 324/117 H
• US Class Current: 336/73
• 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

A transformer for measuring current flowing through a conductor includes a U-shaped housing which is adapted to be received about the conductor. A closure member is secured by a sliding hinge assembly to one distal end of the housing, and is adapted to be latched between the distal ends. Within the housing a plurality a U-shaped core laminations are disposed in adjacent laminated groups. The closure member includes a plurality of laminated groups which are disposed to interleave with the distal ends of the U-shaped laminations to form a continuous magnetic circuit about the conductor. Equal secondary windings about the legs of the U-shaped laminations are connected in series to counteract any proximity effect of the conductor within the transformer.

Claims

1. A transformer for measuring current flowing in a conductor, comprising a generally U-shaped housing, a generally U-shaped first core portion disposed in said housing, said first core portion defining a gap adapted to receive the conductor therethrough, a closure member extending across the distal ends of said housing, a second core portion disposed in said closure member and adapted to span the distal ends of said first core portion, said core portions comprising pluralities of magnetic flux-conducting panels disposed in adjacent, laminated groups, every other one of said laminated groups extending outwardly from the respective ends of said core portions and disposed so that the ends of said second core portion cooperatively engage and interleave with said distal ends of said first core portion, sliding hinge means for joining said closure member to said housing with a compound rotating-translating motion, said sliding hinge means including a pair of hinge plates extending outwardly from a distal end of said housing, a pair of slots disposed in aligned fashion in said hinge plates, and a hinge pin affixed to one end of said closure member and having end portions received in said slots in freely rotating and translating fashion, hinge block means secured to said closure member adjacent to said laminated groups extending from one of said distal ends of said first core portion, said hinge block means providing rotational clearance with said one of said ends only when said hinge pin is disposed in the distal-most portions of said slots, latch means for translating both ends of said closure member toward said housing to effect complete engagement and interleaving of said core portions, and coil means secured about one of said core portions to generate a voltage analog of the current induced in said core portions by the conductor.

2. The transformer of claim 1, further including output terminals connected to said coil means, and shorting link means slidably disposed adjacent to said output terminals and adapted to selectively impinge on and electrically short said terminals.

3. The transformer of claim 1, wherein said hinge block means includes a hinge block fixedly secured about said hinge pin.

4. The transformer of claim 3, wherein said hinge block is trapezoidal in cross-sectional configuration transverse to said hinge pin.

5. The transformer of claim 1, wherein said latch means includes a pair of latch assemblies secured to opposed legs of said housing.

6. The transformer of claim 5, further including a pair of detent members secured to opposite ends of said closure member and adapted to be engaged by said latch assemblies.

7. The transformer of claim 1, wherein said coil means includes a pair of coils secured about opposed legs of said core portions and electrically connected in series.