Improvements in Electrical Cables.
Year: 1889

page_text: Date of Application, 1st Oct., 1889.
Complete Specification Left, 1st Aug., 1890-4ccepted, 6th Sept., 1890
PROVISIONAL
SPECIFICATION.
Improvements in Electrical Cables.
I WALTER TWISS GLOVER of the firm of Walter T. Glover & Co. of London
Electrical Cable Manufacturers do hereby declare the nature of this invention to be
as follows:-
My invention relates to those electrical cables in which provision is made for
obviating the objectionable effects of induction; which cables are usually known as
anti-induction cables. They have been hitherto made by twisting two wires together
but this is objectionable especially where a large number of conductors is contained in
one cable. My invention has for its object to provide an efficient anti-induction cable
which is more compact than are 'those hitherto made. I use either a solid wire or strip
or a strand of fine wires or strips as a conductor and this conductor I insulate and
around this insulation I place an equivalent to the core in the shape of fine wires or
strips and I insulate these if desired. I then lay the requisite number of conductors
so prepared into the cable encasing the cable in insulating and protecting material if
desired.
1000
COMPLETE SPECIFICATION.
Improvements in Electrical Cables.
1 WALTER TWISS GLOVER of the firm of Walter T. Glover & Co. of 10 Hatton
Garden in the City of London, Electrical Cable Manufacturers do hereby declare. the
nature of the said invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
My invention relates to those electrical cables in which provision is made for
obviating the objectionable effects of induction which cables are usually known as
anti-induction cables. They have been hitherto made by twisting two wires together
but this is objectionable especially where a large number of conductors is contained in
one cable.
In telephonic cables in order to avoid or neutralize the effects of induction or as it
is commonly called "cross talk" I have hitherto manufactured cables of single wires,
where the earth forms the return circuit in such a manner that by the use of metallic
foil in and around the wires, and in connection with the earth, the effect of induction
has been very greatly lessened.
In the latest form of these single wire cables I have succeeded in arranging the
several wires surrounded by lead foil in such a systematic manner that it enables the
number of each individual wire to be recognized and traced at either end or throughout
the cable without difficulty.
Under such circumstances as require the use of a metallic circuit for telephone
purposes I have arranged cables in series of pairs but I have preferably selected the
system of arranging the wires in "fours or as I term it in "double pairs" and
making a cable of the required number of "fours."
19
In view of constructing a cable of "fours" in such a manner as to include the
requisite number of metallic circuits in a compact form and at the same time to
arrange them in such a manner that the several members of the "pairs" shall be known
I have devised and arranged a cable of the following form and construction which is
now known as the "magpie" type. In this the wires are arranged alternately in
pairs of black and white that is one set of insulated wires are covered with a black

page_text: "
tape and the other with a white tape. In this arrangement the white pairs represent
"even" numbers and the black pairs "odd" numbers. This plan has in each layer of
fours one set of fours" with a slight deviation which gives it the "
key to the
numbering this deviation consists in changing one of the white wires for a black,
thus giving one pair (No. 0) a, white and black and the second pair (No. 1) two
blacks.
In order to still further counteract the effect of "cross talk" and to produce a
cable which shall practically neutralize the effects of induction, I have constructed
a cable of such form and design which I hereinafter describe for obviating the effects
of induction..
I use
My anti-induction cable is more compact than are those hitherto made.
either a solid wire or strip or a strand of fine wires or strips as a conductor and this
conductor insulate and around this insulation I place an equivalent to the core in
the shape of fine wires or strips and I insulate these. I then lay the requisite number
of conductors so prepared into the cable encasing the cable in insulating and protecting
material as may be necessary.
A cable made according to my invention is very supple as well as compact.
The accompanying drawings illustrate my invention although I do not limit myself
to the details shewn. In Figure 1 a is the conductor which may be either a single
wire or strip or several wires or strips. Around this is the insulation b and outside
this there are arranged the wires or strips o making together an equivalent in cross
sectional area to that of the conductor a. d is the insulation. of the wires or strips e.
Any number of the conductors thus made may be put into a cable for instance
seven as shewn in Figure 2. E is the protecting material surrounding the cable
thus formed.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
An insulated electrical cable or conductor having equivalents of insulated metallic
wire or strips around the main insulated conductor substantially as and for the
purpose herein before described.