IMPROVEMENTS IN INSULATING WIRES. OR ELECTRICAL CONDUCTORS FOR DYNAMO-ELECTRICAL MACHINES OR FOR OTHER PURPOSES ted
Year: 1883

page_text: LETTERS PATENT to John Henry Johnson, of 47 Lincolns Inn Fields, in
the County of Middlesex Gentleman, for an Invention of "IMPROVEMENTS
IN INSULATING WIRES. OR ELECTRICAL CONDUCTORS FOR DYNAMO-ELECTRICAL
MACHINES OR FOR OTHER PURPOSES communicated to him from La Société
A. Chertemps et resident at Paris in the Republic of France
33
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patente on the 18th June 1883.
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN INSULATING WIRES OR ELECTRICAL CONDUCTORS
FOR DYNAMO-ELECTRICAL MACHINES OR FOR OTHER PURPOSES "-a communication
to me from La Société A. Chertemps et C resident at Paris in the Republic of
France
This Invention relates to improvements in the preparation of nonconducting
sompounds for coating and insulating wires or electrical conductora such for
example as are used with dynamo-electrical machines and the like,
In the generation of electric currents by means of dynamo or magneto-electric
machines it has heretofore been difficult to obtain the maximum of effect owing
to the heat resulting from the increased tension of the current which said heat is
liable to destroy the insulation of the coils and render the machines useless
This Invention has for its object providing means for obviating this disadvantage
as hereinafter described.
The coils of wire employed in the aforesaid machines have heretofore been
constructed by winding wires previously covered with an insulating coating of
gutta percha, bitumen or other organic substances which in presence of the elevated
temperature caused by the passage of a current of high tension become carbonized
and thus permanently lose their nonconducting property; hence arise derivations
of the current which render the coils unfit for use.

page_text: According to this Invention inorganic compounds which are bad conductors of
electricity and are not liable to be decomposed by the action of heat are employed
to form a non conducting coating for the wires of electrical generatora. For this
purpose a liquid preparation is employed capable of depositing a salt or other like
product from which the water may be subsequently expelled by evaporation, the
presence of water in the coating being liable to impair the insulation or to dissolve
the materials
In the preparation of this coating oxygenised compounds or salts of silicon or
its analogues, Baron, Aluminium or magnesium are preferably employed; silicate
of potash may also be employed for this purpose, but it is found that the presence
of soda potash or other analogous bases hinders the evaporation of the water in
combination It is therefore preferable to employ the Oxides of the metals herein-
before referred to-videlicet, silica, boric acid, alumina or magnesia, by preference
in a gelatinous condition obtained in a manner well known to Chemists
The product obtained under these conditions being brought to a suitable
consistency is applied to the wire and the water which it contains is afterwards
driven off by evaporation; the wire then remains covered with an absolutely
insoluble insulating coating or varnish not liable to be destroyed by heat
In the case of a wire coiled upon an iron or other core for example, each turn or
layer of wire is coated with this liquid compound which adheres effectually to the
wire and the coil being thus completed the water in combination is evaporated by
any suitable means such as the action of hot or cold air or by causing an electric
current to circulate in the coils and suitably increasing the intensity of the current
BO as to evaporate the water-The coil thus obtained is composed of a wire
surrounded by an insulating varnish through which coil a current of very high
tension may be passed without impairing the insulation
In certain cases organic substances may be combined with the silicious, borio,
aluminous, and magnesian products or compounds herein before referred to provided
that the resulting carbon present in the insulating covering thus prepared is so
surrounded by or enclosed in the nonconducting matter as to be incapable of
effecting the insulation-In certain cases it may be found advantageous to employ
combinations of carbon with the compounds hereinbefore described. The Invention
may be used for insulating conductors of electricity generally.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Johnson in the Great Seal Patent Office on the
13th December 1883.
"
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN INSULATING WIRES OR ELECTRICAL CONDUCTORS
FOR DYNAMO ELECTRICAL MACHINES OR FOR OTHER PURPOSES a communication
to me from La Société A. Chertemps et Cto resident at Paris in the Republic of
France
The said Invention relates to improvements in insulating wires or electrical
conductors such for example as are used with dynamo electrical machines and
the like.
In the generation of electric currents by means of dynamo or magneto electrio
machines it has heretofore been difficult to obtain the maximum of effect owing to
the heat resulting from the increased tension of the induced current which said
heat is liable to destroy the insulation of the coils and injure the machines or
render them useless.
This Invention has for its object obviating this disadvantage. The coils of wire
employed in the aforesaid machines have heretofore been constructed with wires
that have been previously covered with an insulating coating of gutta percha,
bitumen or other organic substances which in presence of the elevated temperature
caused by the passage of a current of high tension become carbonised and thus
permanently lose their non-conducting property; hence arise derivations or short
circuitings of the current or leakages which render the machines unfit for use and
necessitating the insertion of fresh insulated wire in order to restore the machine
to working order.
According to this Invention inorganic compounds which possess the requisite
insulating property and are not liable to be decomposed by the action of heat are
employed to form the insulating or non-conducting coating for the wires. For
this purpose a liquid preparation is employed capable of depositing a salt or other
like product from which the water may be subsequently expelled by evaporation
the presence of water in the coating being liable to impair the insulation or
dissolve the materials. In the preparation of this insulating coating oxygenised
compounds or salts of silicon or its analogues, Boron, Aluminium or Magnesium
are preferably employed; silicate of Potash may also be used for this purpose but
it is found that the presence of soda potash or other analogous bases impedes the
evaporation of the water in combination. It is therefore preferable to employ the
oxides or oxygenised compounds of the metals hereinbefore referred to videlicit
Silica, boric acid, alumina, or magnesia by preference in a gelatinous condition
obtained in a manner well known to chemista.
The product obtained under these conditions being brought to a suitable
consistency is applied to the wire in the form of a coating. The water contained
in this coating is afterwards driven off by evaporation and the wire then remains
covered with an insoluble insulating covering or varnish not liable to be destroyed
by heat.
In the case of a wire coiled upon an iron or other core for example each turn or
layer of wire is coated or varnished with this liquid compound which adheres
effectually to the wire and the water in combination with the insulating material
is evaporated by any suitable means such as the action of hot or cold air or
preferably by causing an electric current to circulate in the coils and suitably
increasing the intensity of the current so as to produce sufficient heat to evaporate

page_text: the water. The coil or bobbin thus obtained is composed of a wire completely
surrounded by or imbedded in an insulating varnish of such a nature that a
current of very high tension may be passed through the coil without impairing
the insulation. Even when the current circulating in the coils is of such a nature
as to heat the wires considerably (but not sufficiently to cause them to glow) the
insulation nevertheless remains so perfect that no leakage or derivation or short
circuiting of the current ensues or practically so.
It is essential to expel the water as hereinbefore described before using the coil
which is incapable of producing an induced current without this operation as the
wires are not effectually insulated when water is present.
In certain cases organic substances may be combined with the silicious boric,
aluminous and magnesian products or compounds hereinbefore referred to provided
that the carbon present in the insulating covering thus prepared is in a noncon-
ducting condition that is to say that the molecules of carbon are so surrounded by
or enclosed in the silica, boron, alumina, or magnesia or non-conducting matter as
to be incapable of affecting the insulation. In certain cases it may be found
advantageous to employ as an insulating coating products consisting of combi-
nations of carbon with the compounds hereinbefore described. It is evident that
these improvements in insulating wires, hereinbefore described more particularly
with reference to coils or bobbins for electrical machines are applicable with equal
advantage to the insulation of electrical conductors generally.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the invention secured to me by the hereinbefore in part
recited Letters Patent is:-
First-The employment in the manufacture of coils or bobbins for electrical
machines of inorganic compounds or substances combined or not with organic
matter and whose non-conducting or insulating property is not liable to be
destroyed by the heat generated in the said coils or bobbins substantially -as
hereinbefore described.
Second As a new article of manufacture electrical wires or conductors
provided with the insulating and heat resisting materials consisting essentially
of the compounds or substances hereinbefore described.
Third: The employment for insulating wires or electrical conductors of the
salts of silicon, boron, aluminium, magnesium or the oxides of these metals
employed either alone or in combination with organic materials or carbon
substantially as hereinbefore described.
Fourth-The manufacture of insulated wires or electrical conductors by
covering or coating them with a salt alone or in combination with carbon as
herein before set forth and then driving off the water contained in the said
materials by means of a drying operation conducted either in a stove or in the
open air or by causing an electric current to circulate in the said wires or
conductors the intensity of the said current being graduated according to the
degree of evaporation required substantially as herein before described.
In witness whereof I the said John Henry Johnson have to this my
Specification set my hand and seal this twelfth day of December One thousand
eight hundred and eighty three.