Patent Application
20100012375
1. Field of the Invention
The invention relates generally to electrical conductors and, more particularly, to electrical busways. The invention also relates to coupling assemblies for electrical busways.
2. Background Information
Various electrical components are defined by, and subject to, regulatory requirements. For example and without limitation, the Underwriter's Laboratory (UL) defines an “electrical busway”, at UL 857, as a grounded metal enclosure containing factory mounted conductors that are usually copper or aluminum bars, rods, or tubes. Similarly, the National Electric Code (NEC) defines an electrical busway as a grounded metal enclosure containing factory mounted, bare, or insulated conductors, which are usually copper or aluminum bars, rods, or tubes.
Typically, electrical busways are comprised of a number of straight sections joined by bridge joints. Each of the busway sections includes a plurality of electrical conductors (e.g., wires, cables or other suitable conductive members made from an electrically conductive material such as, for example and without limitation, copper or aluminum) that are insulated by a coating, film or sleeve of a non-conductive material (e.g., electrical insulator) and enclosed in a housing, such as an elongated rail structure. The electrical conductors of the electrical busway receive, for example, different phases of alternating current power and provide power to electrical equipment that is electrically connected to the electrical busway.
Bridge joints are sized to carry current from one electrical busway section to another adjacent electrical busway section. Known bridge joints are sized with only the necessary length to make a straight connection from one electrical busway section to the next. Such joints typically also need to carry the weight of a full section of electrical busway as the busway is often held in the air with only one hanger per section. The bridge joints electrically interconnect the electrical conductors of one electrical busway section with the corresponding electrical conductors of another, different electrical busway section.
Different sections of the electrical busway must be suitably electrically connected to bridge a conductive path between the sections. During installation of a busway run, unplanned obstructions are sometimes installed during construction. In order to accommodate such obstructions, offsets are often needed in the busway. Typically, such offsets have been fabricated by the welding of busbars and enclosure housings in order to form 90 degree angles. Such offsets require special ordering, are labor and cost-intensive, and often cause delays in the construction process.
There is, therefore, room for improvement in electrical busways and in coupling assemblies therefor.
These needs and others are met by embodiments of the invention, which are directed to a coupling assembly for electrically connecting sections of an electrical busway together at an offset from each other.
As one aspect of the invention, a coupling assembly is provided for an electrical busway. The electrical busway includes a first section having a first longitudinal axis and a second section having a second longitudinal axis. The coupling assembly comprises: a plurality of electrical conductors, the plurality of electrical conductors having a first portion and an opposite second portion, the first portion being structured to removably electrically and mechanically couple to the first section of electrical busway, and the second portion structured to removably electrically and mechanically couple to the second section of electrical busway, the electrical conductors having a third longitudinal axis extending between the first portion and the opposite second portion; and a plurality of electrical insulators positioned to electrically insulate the plurality of electrical conductors. The coupling assembly being structured to offset the first longitudinal axis a predetermined non-zero distance from the second longitudinal axis.
The first section of electrical busway may include a plurality of first bus members and the second section of electrical busway may include a plurality of second bus members. Each of the plurality of electrical conductors may be structured to electrically connect a corresponding one of the first bus members of the first section to a corresponding one of the second bus members of the second section.
Each of the plurality of electrical conductors may comprise a first plate having a first surface and an opposite second surface and a second plate having a first surface and an opposite second surface. The opposite second surface of the first plate and the first surface of the second plate may be structured to electrically and mechanically engage a corresponding one of the first bus members of the first section and a corresponding one of the second bus members of the second section.
The plurality of electrical conductors and the plurality of electrical insulators may be arranged in an alternating stack coupled together by a fastening mechanism. The alternating stack may comprise an arrangement of the plurality of electrical conductors and the plurality of electrical insulators wherein each of the plurality of electrical conductors lies between a corresponding pair of the plurality of electrical insulators. The fastening mechanism may comprise a fastening member passing through the alternating stack. The fastening mechanism may comprise a first fastening member passing through the alternating stack proximate the first portion and a second fastening member passing through the alternating stack proximate the second portion.
The third longitudinal axis may be normal to both of the first longitudinal axis and the second longitudinal axis. The electrical conductors may have a generally rectangular cross section.
As another aspect of the invention, an electrical busway is provided. The electrical busway comprises: a first section having a first longitudinal axis; a second section spaced apart from the first section, the second section having a second longitudinal axis; and a coupling assembly comprising: a plurality of electrical conductors, the plurality of electrical conductors having a first portion and an opposite second portion, the first portion removably electrically and mechanically coupled to the first section of electrical busway, and the second portion removably electrically and mechanically coupled to the second section of electrical busway, the electrical conductors having a third longitudinal axis extending between the first portion and the opposite second portion; and a plurality of electrical insulators positioned to electrically insulate the plurality of electrical conductors. The coupling assembly being structured to offset the first longitudinal axis a predetermined non-zero distance from the second longitudinal axis.
As a further aspect of the invention, a coupling assembly for an electrical busway is provided. The electrical busway includes a first section comprising a first housing having a first longitudinal axis and a second section comprising a second housing having a second longitudinal axis. The coupling assembly comprises: a plurality of electrical conductors, the plurality of electrical conductors having a first portion and an opposite second portion, the first portion being structured to removably electrically and mechanically couple to the first section of electrical busway, and the second portion structured to removably electrically and mechanically couple to the second section of electrical busway, the electrical conductors having a third longitudinal axis extending between the first portion and the second portion; a plurality of electrical insulators positioned to electrically insulate the plurality of electrical conductors; and a coupler housing having a first portion structured to be coupled to the first housing and a second portion structured to be coupled to the second housing. The coupling assembly being structured to offset the first longitudinal axis a predetermined non-zero distance from the second longitudinal axis.
A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:
Directional phrases used herein, such as, for example, left, right, front, back, top, bottom and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein.
As employed herein, the term “electrical busway” refers to an assembly of electrical conductors housed within a supporting structure such as, for example and without limitation, a rail structure. The electrical conductors receive electrical power from, for example, a utility or other suitable power source.
As employed herein, the term “electrical conductor” means any known or suitable component expressly intended to conduct electrical current. An electrical conductor may be relatively flexible, and expressly includes, but is not limited to, electrical wires and electrical cables.
As employed herein, the term “bus bar” refers to a substantially rigid (e.g., inflexible) electrical conductor.
As employed herein, the term “electrical terminal” refers to a portion of an electrical busway to which a corresponding electrical conductor is electrically connected.
As employed herein, the statement that two or more parts are “coupled” together shall mean that the parts are joined together either directly or joined through one or more intermediate parts.
As employed herein, the term “number” refers to the quantity one or an integer greater than one (i.e., a plurality).
As shown in
The coupling assembly 50 is provided to facilitate the connection between offset first and second sections 4,6 of electrical busway 2. Referring to
Coupling assembly 50 further includes a plurality of electrical conductors 70 generally separated by a plurality of electrical insulators 90 arranged in an alternating stack between the first and second cover plates 52,54. Preferably each of the electrical conductors 70 and electrical insulators 90 are of generally rectangular planar shape and include a corresponding passage(s) through which the one or more two headed bolts 56 may extend. Referring to
More specifically, as best shown in
While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.
