Improvements in Electrical Conductors or Cables.
Year: 1888

page_text: COMPLETE SPECIFICATION.
Improvements in Electrical Conductors or Cables.
Wo, WILLIAM A. CONNER, Electrician, and JOSEPH W. MARSH, Electrician, both
residents of the City of Pittsburgh, State of Pennsylvania, U.S.A., do hereby declare
the nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
The invention relates to electric conductors and more particularly to large electric
conductors such as are used in electric light systems, for instance, and it has for its
object to produce an electric conductor or cable having a large carrying capacity for
electricity, and at the same time having the electric conductors properly and safely
insulated from each other and the whole arranged in a compact form so as to produce
a cable of the smallest dimensions and one that shall at the same time be flexible to a
greater or less extent; and as a means of attaining these objects our invention consists
in a conductor or cable constructed substantially as hereinafter more particularly
set forth.
Referring to the accompanying drawings:
Fig. 1 is a perspective view illustrating ono form of cable embodying our inven-
tion, and
Fig. 2 is a cross section thereof.
In the use of electric conductors, especially where it is desired to convey powerful
currents of electricity, it is exceedingly desirable that the conductors occupy the
smallest possible space consistent with a construction furnishing enough conducting
medium for the current and sufficient insulation between the conductors and the protect-
ing covering, which is usually placed around the conductors to prevent danger of leaks
or short circuits.
It is also desirable and indeed essential, especially when conductors are to be used
in subterranean passages or conduits, that the conductor or cable should have a certain
degree of flexibility in order that it may be conveniently and speedily handled in

page_text: being introduced into the subterranean passages. Many efforts have been made to
produce a conductor or cable having these characteristics and the present invention
relates more particularly to the construction of a conductor or cable having these
characteristics in a more material degree than heretofore, and at the same time present
a conductor or cable that may be easily and quickly made without involving expensive
machinery and delays in producing the same.
In carrying out our invention a central conductor or core 1 of any material is first
provided, which may be a single large wire or strand, or may be made up as shown in
the drawings, of a number of strands arranged in contact with each other. Over this
central conductor or core 1 is placed an insulating covering 2, which may consist of
any well known materials which are commonly used for this purpose, such for instance,
as cotton fibre and asphaltum. Over this insulating material are arranged a series of
conductors 3, 4, 5, each of which may be either in one piece or strand, or may be made
up of a number of wires, ribbons or strands.
In order to provide the necessary conducting cross section of the conductor and at
the same time to have sufficient insulating material between each conductor of the
series and the central conductor, each conductor is arranged so that it presents a
surface toward the centre of the cable comparatively wide as compared with the
dimensions of the conductor in the direction of the radius of the cable, or in other
words, form each conductor so that its breadth exceeds its thickness and they may bo
said to represent in cross section a segment of a ring or cylinder. By this arrange-
ment of the conductors it will be seen that a larger number of conductors having a
given cross section can be put in a smaller cable and still maintain the necessary and
desirable insulating space or distance between the conductors than in any other form
or arrangement and it will be manifest that while all of the conductors 3, 4, 5, arc
arranged practically equidistant from the central conductor and are separated from
each other sufficiently to prevent leakage or short circuiting, they still form a cable of
small cross section and allow of suflicient flexibility in the cable to answer the requiro-
ments set forth.
These conductors 3, 4 and 5, may be covered and separated by a layer of insulating
material which is of any desired composition, and over this may be placed another
layer of conductors as 6, 7, 8 etc., which have the same characteristics, that is, they
are broader than they are thick and are arranged concentric with the central conductor
or core 1. The conductor 6 is shown as a single ribbon or strip of metal, and the
conductor 7 is shown as made up of a number of thin ribbons superposed one upon,
the other. Over this layer of conductors, and between each conductor in turn is
placed another layer of insulating material 10, which layer separates the conductors
from each other, and over that is preferably placed a protecting covering 11 of lead or
other material as is usually employed in cables of this class. In the practical
manufacture of these cables it is preferable to arrange the conductors around the
central conductors or core in a long spiral, as indicated in the drawings.
It will be evident that in insulating the conductors some plastic insulating material
as suggested may be used, cords or ropes treated with insulating material which will
fill the intervening space between the adjacent conductors may be used and similar
cords or tapes may be placed around each layer of conductors to separate them from
the adjacent layer or from the protective covering when used.
While in the drawings the central conductor is shown as made up of a certain
number of wires, and the next intervening layer as also made up of a number of
wires, it is evident that any desired number may be used or that it may be in the
form of a single strand, or ribbon, or a number of ribbons, as the distinguishing
characteristic of the invention is that the conductors shall be greater in breadth than in
thickness and practically form segments or sections of a ring or circle, and at the same
time be arranged spirally around the central core.
It is not deemed necessary herein to specifically state all the various modifications
of the invention which may be used, as they will be evident to those skilled in the art,
and the invention is not limited to the precise arrangement shown as many other
arrangements may be made embodying the principles of same.

page_text: our said
Having now particularly described and ascertained the nature of
invention, and in what manner the same is to be performed, we declare that what
we claim is :-
--
1. An electric cable or conductor having a number of spirally arranged insulated
conductors, each conductor having a cross section greater in breadth than in thickness,
substantially as described.
2. An electric cable or conductor having one or more central conductors or cores
and a number of insulated conductors arranged spirally in one or more circles around
the central conductor or core and each conductor forming in cross section a segment
of a ring or circle.
a cross
3. An electric cable having a central conductor or core and a number of insulated
conductors arranged spirally around the central conductor, and each having
section greater in breadth than thickness and composed of a number of naked wires or
ribbons, substantially as described.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London,
Applicants Agent.