Wire wound core

• US 5,235,488 A
• Filed: 02/05/1992
• Issued: 08/10/1993
• Est. Priority Date: 02/05/1992
• Status: Expired due to Fees

• Current Assignee: Brett Products Incorporated
• Original Assignee: Brett Products Incorporated
• Inventors: Koch, Stuart
• Primary Examiner(s): DEBOER, TODD
• Application Number:
  US07/831,427
• Time in Patent Office: 552 Days
• Field of Search: 361/45, 336/175, 336/177, 336/234, 336/233, 335/281, 335/282
• US Class Current: 361/45
• CPC Class Codes: H01F 2038/305 with toroidal magnetic core
• CPC Class Codes: H01F 3/06 made from wires
• CPC Class Codes: H01F 38/30 Constructions
• CPC Class Codes: H01H 83/144 with differential transformer
• CPC Class Codes: Y10S 174/17 in an electric power conversion, regulation, or protection system
• CPC Class Codes: Y10S 174/25 Transformer

Abstract

Disclosed is a helically wound core of ferrous material used as a differential current sensor core in the ground fault sensor of a ground fault interrupter circuit. The ferrous material comprises a single strand of wire which is wound in helical fashion to create a tubular shaped core comprising a series of wire loops (all part of the single strand) parallel to each other and running the length of the tubular shape. The core is placed around a pair of current carrying lines to be monitored for ground faults (one line leading to and one line leading away from the power source) to interact with the magnetic fields of the lines. Toroidally wound leads wrapped around the wire core act as a secondary and are connected to a ground fault interruption circuit to shut off the power to the conducting lines in the event that the sensor detects a difference in current in the lines. By utilizing wire as the core material, the amount of surface area can be greatly increased over the prior art cores without increasing the cross-sectional area (and, therefore, the overall size) of the core.

Claims

1. A differential current sensing electrical circuit system for detecting ground faults in electric power lines, comprising:

a continuous strand of ferrous material arranged in circular windings of helical fashion so as to form a cylindrical-shaped core composed of said windings in parallel relation to one another and relatively close to one another;

amplifying means in connection with said core for amplifying electrical signals in said core; and

power cut off means for cutting power to said power line in the event an electrical signal is detected in said core, said core being disposed around a portion of said power line so as to interact with the magnetic field of said power line.

2. A wire wound toroidal core adapted for placement around power lines so as to interact with the magnetic field of said power lines upon the occurrence of ground faults in said power lines, said core comprising a single strand of wire helically wound to form a plurality of loops, said loops being situated essentially parallel to one another.

3. A wire wound toroidal core as set forth in claim 2, wherein said strand of wire is wound to form a plurality of layers of said loops, each of said layers comprising a predetermined number of said loops.

4. A wire wound toroidal core comprising a single strand of wire helically wound to form a plurality of loops, said loops being situated essentially parallel to one another, said core enabling inductive interaction between a primary and a secondary placed in the inductive field of said core.