Improvements in and Relating to Electric Spark-Rupturing Appliances.
Year: 1889

page_text: COMPLETE SPECIFICATION (AMENDED).
Improvements in and Relating to Electric Spark-Rupturing
Appliances.
[Communicated from abroad by PROFESSOR ELIHU THOMSON, of Lynn, Massa-
chusetts, United States of America, Electrical Engineer.]
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex, 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 generally to lightning arresters, safety fuses, electric switches
and devices generally, which have electrodes between which an are might acciden-
tally form and to which are applied a magnet for producing, an are rupturing magnetic
field, an-air-or-gas-blast-or-other-means for displacing, severing or putting out the
are in case it should form.
The object of the invention is to increase the efficiency and certainty of operation
of the arc rupturing devices by permitting them to be brought very close to the
point where the arc may form, to which end I apply a shield or septum of in-
sulating material between the opposed surfaces of the arc rupturing device and
the electrodes or conducting bodies between which the arc to be ruptured is
formed, thereby preventing an are from forming at any other portion of the
electrodes or conductors than those directly subject to the are rupturing force and
permitting the are rupturing device, when of conducting material, to be applied
without danger of defective action very closely to the electrodes.
The protecting shield or septum inay be of any desired material and applied in a
variety of ways either-to-the-electrodes-or- to the arc rupturing devices-or-to-both,
as-may-be-desired:
:
The-said-invention-consists-also-in-the--combination-with-a-safety-fuse;-of-au--are
rupturing device of any suitable-description;-snch-for-instance-as-n-magnet,-applied
te-rupture,-sever-or-disperse-any-electric-are--which-may--tend-to-follow--neross--the
holding-plates-or abutments-of-the-fuse-itself.
In the accompanying drawings
Figure 1 shows in side elevation, and
Figure 2 in section on the line X X Figure 1, the manner of applying an insulating
shield to a lightning arrester in accordance with the present invention.
Figures 3 and 4 illustrate the application of the invention to another form of
safety device, the said figures also showing the manner of applying a magnet to a
safety fuse so as to prevent the formation of an arc.
Figure 5 is a section, and
Figure 6 a side elevation with a part broken away, of another form of the said
invention.
· Figure 7 illustrates the electrodes liable to arcing

page_text: Figures 8, 9, 10, 11 and 12, show mouincations or the invention.
Figures-13-and-14-show-the-munner--of-applying-n-magnet-to-n-safety-fuse-se-as
to-prevent-the-formation-of-an-are:
In most of the figures illustrating this invention, I have shown the poles of an
ordinary single pole lightning arrester. The manner of applying the invention to
other forms of armature or to arresters constructed and connected as hereinbefore
described, or to other are rupturing devices, will however be obvious.
When the invention is applied to an arc rupturing device consisting of a magnet
properly arranged with reference to the electrodes across which the arc to be ruptured
is formed the interposed insulating septum en or shield may be formed by coating or
covering the poles or metallic portions of the magnet with enamel, rubber, or other
insulating material, enamel being preferable on account of its incombustible nature.
By this means discharges or arcs which might otherwise pass from the poles or
electrodes placed in the magnetic field to the magnet pole, thereby escaping the
I find it in fact
action of the magnet in rupturing the same, are prevented.
desirable to apply the insulation shield to all metal portions which are in proximity
to the arc to be ruptured and also to coat or cover the electrodes themselves with
insulating material at parts outside of the magnetic field so that any possibility of a
discharge or arc forming at any other portion of the conductors than those directly
included in the magnetic field may be avoided.
In Figures 1 and 2 M M³, are poles of a magnet, either a permanent or an electro
magnet, between which are mounted the electrodes E, E¹, separated, as in the case
of lightning arrester, by a small interval of space over which a current of sufficiently
high tension may force its way. As shown the electrode E, is connected with a
line L, while the electrode E' is either directly connected to earth or is
carried to earth through the coils C, C', of the magnet of which M M', are the
poles.
The electrodes E, E', are preferably supported by insulating material I I, and
are also preferably coated with enamel or other insulating material, except at their
ends where they approach between the magnet poles. The magnet poles M, M¹, are in
addition coated all over with insulating material or surrounded by caps of insulating
material, lying either close to the pole itself or separated therefrom by a small interval,
it matters not which. Where the coils C, C¹, are exposed to the action of an arc
which might form between the electrodes E, E¹, the coils themselves are coated all
over with a layer of insulating material to a thickness say, of or less, protecting
them from arcing or short circuiting, It will thus be seen that no metallic surfaces
are exposed at or near the magnetic field except the electrodes E, E', of the lightning
arrester. Should a discharge occur to earth from the line L, across the space between
the electrodes E E', due to induction or static charge produced by lightning an
immediate formation of au are may result, especially if the line L, is grounded in like
manner at some other point, and the difference of potential of the grounded parts is
high. Where the line L, is one of heavy current and high potential it is important
to extinguish such an arc almost instantly as it will create such a voluminous gas
The
stream as to do damage to the apparatus and be more difficult of extinction.
powerful magnetic field, however, in which the arc is formed when such magnet is
The
properly magnetized results in a sudden break of such grounded current or arc.
present invention on account of the layer of insulating material covering the poles of
the magnet allows such poles to be approached quite closely to the disrupting
This in fact is
electrodes thereby enhancing very much the intensity of the field.
one of the important results obtained in the present invention.
The invention may with equal effectiveness be applied to the case of electrodes E, E,
normally having a fuse F, extending between them as shown in Figures 3 and 4 and
combined with an arc rupturing magnet the poles of which are indicated at M M¹.
The purpose of using-the-magnet-as-indiented-in-these-figures-and--in-Figures
and-14-is-as-follows-:-
13
The-fuse-Fis-typical-of-an-electric-conductor-aneh-as-an-alloy-adapted-to-face on
the-passage-of-an-abnormal-current-and-thereby-open-the-electric-eirenit-through-it.

page_text: potentmt-a-start-fuse-is-ineffective-to-rupture-the-primary-cirenit
ns-its-melting-is-followed-by-an-are-bridging-the-gap-in-the-eirenit. This--are--will
not-be-formed-if-the fuse-be-made-quite-long-but-such-n-disposition is not economient
on-necount-of-the-added-resistance-of-such-a-long-fuse-wire-us-would-be-needed.
To-overcome-this difficulty-1-combine-with-the-fuse--an-are--rupturing--device--of
any-suitable-charneter-adapted-to-disperse-or-blow-out-the-are--in--ense--one--should
form. A--convenient--means--for--this--purpose-is--n-magnetic-field-prodneed-by a
permanent-or-electromagnet, or-by-n--coil-of-conducting--wire, and--applied--to-the
spnee-between-the-fuse-holding-electrodes, although-I-do-not-by any means--mit
myself-to-sueh-a-means-and-might-use-n-continuous-blast-of-air--or--other-fluid;--or
might-draw-the-electrodes-apart-by-means-of-an-electromagnet--or-spring-when-the
fuse ruptures:
The inagnet poles M, M, applied as shown might be the poles of a permanent
magnet or might be as indicated in Figures +81 and 142, the poles of an electro magnet,
the coils of which are traversed by the current passing through the fuse, or by a
portion of such current, or by current from any other source.
The current might be an alternating current traversing the fuse.
core of the magnet should be laminated, that is made up of separate plates or rods.
In this case the
The electrodes or abutments holding the fuse may be of any desired form and the
magnet may be applied in any way suitable for rupturing the arc.
The magnet poles applied to the fuse are preferably covered with insulating
covering or shield placed close to the fuse F, and the supports themselves which
uphold the fuse are, particularly where they pass outward or outside of the magnetic
Hield between the poles M, M³, also protected or coated or covered with insulating
material, so that an are cannot pass from a point on one of the supports E, outside
of the magnetic field, and whatever arc forms or can form exists in the magnetic
field between the poles M M³, and is disrupted vigorously by the action of the
magnet. In fact the moment the fuse softens the tendency of the magnet is to
rupture it by the magnetization of the current tending to produce motion in the
magnetic field which in turn is enormously intensified the moment the arc is forined
in place of the fuse.
In Figures 5 and 6 of the magnet coil is a single coil C, surrounding the bent portion
of the horseshoe M M¹, and the whole structure coil and magnet are then enclosed
in a complete covering of insulating material, which is shown at J, surrounding the
magnet on all sides and also the coil.
The electrodes, one of which E, is shown in
Figure 5 and both of which E, E¹, are shown in Figure 6 are presented at a small
distance apart between the magnet limbs or poles and are preferably coated as in
Figure 7 by an insulating covering K, K¹, in all positions or portions except where
they are presented to one another. This makes a simple device and is applicable
either to the electrodes as shown or to the electrodes or abutments holding a
fuse.
In Figures 8 and 9, is shown a slight modification, in which the electrodes pass
through openings in magnet poles and therefore have no inside portions or extensions
leading outward from between the poles, each electrode E, E, forming as in the plan
Figure 9, a sort of bent piece inserted through the edge from the outside, and
separated between the poles from its opposite electrode by a sinall space.
case the electrode pieces E, E¹, are of course carefully insulated from the magnet
In this
poles where they pass through the same. This fortn is particularly suitable where
the inaguet is a permanent magnet coated all over with insulating material and
carries the binding posts B, B₁, of connections to the parts of the circuit as in
Figure 1, or otherwise.
In Figures 10 and 11, Figure 10 being an elevation and Figure 11 a plan view of
the electrodes, copper pieces are set in or carried by the magnet poles themselves as
shown, the poles being coated all over with insulating material as before, but the
magnet poles M, M', are not one piece of metal but are two separate pieces kept
part by an insulating layer or septun at I, so as to virtually form an insulating
horse shoe. They may be either permanent magnets or they may be provided with

page_text: magnetizing coils C, wound thereon. In this case one connection is made to M, and
the other from M', is earried to ground, the coil C, being conveniently included in
either circuit or anywhere in the circuit where it is convenient to place it and being
covered up from any possibility of contact with heated gases or ares formed between
the electrodes by a box or covering as indicated in the figure. The insulating layer I,
which may be a slip of mica or slate, or even wood, is sufficient to insulate tbe
magnetic poles M, M', which carry the electrodes E, E¹, and are in connection there-
with, but the magnetism is not so prevented from passing and can readily permeate
the insulation I, and thus the structure becomes in essence a horseshoe magnet as
before whose north and south poles have between them electrodes E, E¹, but in this
case solidly attached to them and carried by the set of poles on their inner opposed
faces. As before the space between the pieces E, E¹, might be replaced by a fuse in
cases where a fuse is required.
Figure 12 shows the manner in which a simple coil C, might be used as a magnet
to produce the magnetic field. In this case the coil is placed so that the plane of
its winding follows the position of the magnet pole and generates a field in which
the electrodes E, E¹, are mounted. To apply the present invention to this structure
the electrodes E, E', would be coated except at their ends with insulating material
and the-coil-C-also-be-coated-all-over-with-a-good-heavy layer--of-insulator--or an
insulating septum or shield of solid insulating material would he interposed between
the coil itself and the discharging electrodes E, E¹. The device Figure 12, while
useful is not by any means as powerful in its actions of breaking an are between the
It is
electrodes E, E¹, as the electro magnet devices which have been described.
in fact an electro inagnet whose core is simply an air core without iron and partakes
therefore of the properties of air maguets in general.
From the foregoing-description-it-will-be-readily-seen-how-the-insulating-shield
er-septum-may-be-applied-to-any-two-electrodes between--which-an-are-may--form;
and-which-have-combined-with-them-an-are-rupturing-device-such-us-n-magnet-or-nu
air-or-fluid-blust;-the-insulation-being-applied-to-all-or-n-part-of-the--apparatus-for
the-purposes-before-stated.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me
claim is
by my foreign correspondent I declare that what
First. In an a magnetic are rupturing device, a shield of insulating material located
between the surfaces of the electrodes and adjacent conducting surfaces of the device
by which the arc is disrupted, as and for the purpose described.
Second. In a magnetic are rupturing device, a divided magnet whose portions
are electrically insulated but free for the passage of magnetism from one to the
other, the poles of which magnet each bear one of a pair of electrodes connected
respectively to the parts of an electric circuit, substantially as described.
Third. The combination with a lightning arrester, of an are rupturing electro
magnet whose poles embrace the space between the arrester plates or electrodes, and
an insulating cap, layer or shield applied to the arrester electrodes and the electro
magnet, either-or-both:
Fourth: The-combination-with-an-electric-safety-strip-or-fuse-of-un-are-rupturing
device;-substantially-as-described:
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.