Improvements in or relating to Lightning Arresters.
Year: 1889

page_text: '
Date of Application, 17th Dec., 1889
Complete Specification Left, 27th Aug., 1890-Accepted, 1st Nov., 1890
PROVISIONAL SPECIFICATION.
Improvements in or relating to Lightning Arresters.
A communication from abroad by THE WESTINGHOUSE ELECTRIC COMPANY, of
Pittsburgh, Pennsylvania, United States of America.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E.. of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool and 6, Bank Street, Manchester, both
in the County of Lancaster and 323, High Holborn in the County of Middlesex,
Civil Engineer, do hereby declare the nature of this invention to be as follows:-
The invention relates to a method of, and the construction of apparatus for protecting
circuits from injury incident to, or resulting from lightning discharges.
When the circut of an electric generator receives a lightning stroke and a discharge
takes place to the earth through a lightning arrester of the usual construction, an are
is established across which the generated current is liable to flow, the generator being
thus short circuited. It becomes desirable, therefore, to provide means for interrupting
the flow of current through such a circuit immediately after the lightning discharge
bas taken place.
The special object of this invention is to cause the circuit, through which the
lightning discharge has taken place, to be interrupted, or so acted upon, as to interrupt
the flow of the current from the generator after the lightning has escaped to the earth.
It is also desirable that the apparatus should be so organised as to allow repeated
lightning discharges to take place to the earth, without its requiring to be re-set or
re-adjusted by hand.
The invention may be described, in general terms, as consisting of one or more pairs
of discharge points or plates placed in such relation to each other and to the circuit to
be protected that the lightning discharge will pass across the intervening space to the
earth and cause such an expansion of the air, or a gas or fluid within an enclosing
chamber, as to either directly or indirectly interrupt the flow of current through the
circuit.
There are many different ways of carrying the invention into practice, but those
shown in the accompanying drawings will serve to illustrate its application:--
Figure 1 is a plan of a portion of one form of the device.
Figure 2 is a vertical section of the same.
Figures 3, 4 and 5 illustrate a modification.
Referring to the figures, A. represents a suitable source of electric currents and L'A
main line conductors leading therefrom or connected therewith. A conductor 2 leads
from the conductor L to the lightning discharge device or arrester B. This device is
constructed as follows:-
-
Two confronting plates or points e¹ c² are separated from each other by the required
intervening space. These points are placed within an enclosing chamber D) of suitable
size. The chamber may be of circular or other convenient form. It is provided with
an opening & which is here shown at the top. This opening consists of a narrow slot
and in it two confronting electrodes are placed.
The circuit connections are as follows:-
The conductor 2 is connected with the point or plate e the plate is connected
with the plate e', and the plate is connected by the conductor 3 with the earth.
When a lightning discharge takes place across the plate cle, it must also form an
are at the plates and . The effect of the formation of an are between
the plates and c² is to produce an expansion of the air or gas within the chamber
The sudden
and create a tendency for it to rush outward from the chamber.

page_text: rush of air through the opening in which the points el and e² are placed will interrupt
the How of current at this point and thus the entire circuit will be interrupted by
the extinguishment of the are at e'. The heat developed at the points ce may aid
in the expansion of the gas..
In this organisation it is desirable that the opening should be of such shape that
the escaping air must pass for the most part between the electrodes or points c¹ e².
The degree of separation of the sets of points is determined by the conditions to be
subserved.
In the modifications shown in Figures 3, 4 and 5, tube e leads from the opening d
and constitutes a continuation thereof. The end of the tube may be closed and openings
made through its wall at the upper end as shown at kk. At some suitable point
within the tube or at the mouth of the opening d, the two electrodes or contact plates
or points ele are placed. These are separated from each other, but are normally
electrically connected by a block or spherical valve d' as shown. This block or ball is
of such size as to more or less completely close the opening d when at rest upon the
points.
The air or gas within the chamber I will be expanded by the heat developed at the
points cas before, and it will escape through the opening . This forces the contact
block or ball away from the plates thus interrupting the circuit connections.
The tube may be so constructed that the ball will return to its former position after the
circuit connections have thus been interrupted and the flow of current from the dynamo
has ceased. In this construction it will be noticed that at the same time that the ball
is raised from the points el e² the rush of air between the points takes place, thus
preventing the formation of an are at these points. The ball thus serves to break the
circuit without forming an are. The separation of the points el may be greater in
this construction than that shown in Figures 1 and 2, if desired.
The connections having once been interrupted and the are destroyed, there will be
little or no danger of its being re-established except by means of another lightning
discharge. The apparatus will thusautomatically re-adjust itself for repeated lightning
discharges.
In practice the discharge plates or points cle² and ele² are preferably of carbon or
some material not easily destroyed by heat. Carbon rods are well adapted to the
purpose. The ball may also be of carbon.
Many other mechanical devices may be used for carrying the invention into effect,
but that which has been described here will serve to illustrate the application of the
invention and its operation.
In some instances it may be desired to employ a liquid having a low degree of con-
ductivity instead of air or gas in the chamber D. The explosion caused by the are
will expand or decompose the fluid and effect the result desired.
It will be understood that a second lightning discharge device of similar construction
may be applied to the line L' upon the other side of the generator, and, in general,
that they may be located at such points as desired.
In some instances it may be desired to dispense with the inner points (Figure 2)
and cause the discharge across the points ele to develop the heat required to force the
air from the chamber D. In this case it will be well to place the points ele near the
inner portion of the opening d. The chamber may be of spherical form. The con-
ductor 3 in this modification would be connected with the plate ².
Dated this 16th day of December 1889.
WM. P. THOMPSON & Co.,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in or relating to Lightning Arresters.
A communication from abroad by THE WESTINGHOUSE ELECTRIC COMPANY, of
Pittsburgh, Pennsylvania, United States of America.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool and 6, Bank Street, Manchester, both in
the County of Lancaster and 323, High Holborn, in the County of Middlesex.
Civil Engineer, 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 a method of and the construction of apparatus for pro-
tecting circuits from injury incident to or resulting from lightning discharges.
When the circuit of an electric generator receives a lightning stroke and a discharge
takes place to the earth through a lightning arrester of the usual construction, an are
is established across which the generated current is liable to flow, the generator may
thus be short circuited. It becomes desirable, therefore, to provide means for
interrupting the flow of current immediately after the lightning discharge has taken
place.
The special object of this invention is to cause the circuit, through which the
lightning discharge has taken place, to be interrupted, or so acted upon, as to
interrupt the flow of the current through it from the generator after the lightning
has escaped to the earth. It is also desirable that the apparatus should be so
organised as to allow repeated lightning discharges to take place to the earth, without
its requiring to be re-set or re-adjusted by hand.
The invention may be described, in general terms, as consisting of one or more
pairs of discharge points or plates placed in such relation to each other and to the
circuit to be protected that the lightning discharge will pass across the intervening
space to the earth and cause such an expansion of the air, or a gas or fluid within an
enclosing chamber, as to either directly or indirectly interrupt the flow of current
through the circuit.
There are many different ways of carrying the invention into practice, but those
shown in the drawings accompanying the Provisional Specification will serve to
illustrate its application:-
TA

page_text: at this point and thus the entire circuit will be interrupted by the extinguishment
of the are at e¹ c. The heat developed at the points etc may aid in the expansion
of the gas.
In this organisation it is desirable that the opening should be of such shape that
the escaping air must pass for the most part between the electrodes or points e¹ c².
The degree of separation of the sets of points is determined by the conditions to be
subserved.
In the modifications shown in Figures 3, 4 and 5, a tube e leads from the opening d
and constitutes a continuation thereof. The end of the tube may be closed and
openings made through its wall at the upper end as shown at kk.
At some suitable
point within the tube or at the mouth of the opening d, the two electrodes or contact
plates or points are placed. These are separated from each other, but are
normally electrically connected by a block or spherical valve d as shown. This
block or ball is of such size as to more or less completely close the opening d when at
rest upon the points.
The air or gas within the chamber D will be expanded by the heat developed at the
points as before, and it will escape through the opening d. This forces the
contact block or ball away from the plates ee, thus interrupting the circuit con-
nections. The tube may be so constructed that the ball will return to its former
position after the circuit connections have thus been interrupted and the flow of
current from the dynamo has ceased. In this construction it will be noticed that
at the same time that the ball is raised from the points e¹e the rush of air between
the points takes place, thus preventing the formation of an are at these points. The
ball thus serves to break the circuit without forming an are. The separation of the
points may be greater in this construction than that shown in Figures 1 and 2,
if desired.
The connections having once been interrupted and the are destroyed, there will be
little or no danger of its being re-established except by means of another lightning
discharge. The apparatus will thus automatically readjust itself for repeated lightning
discharges.
and are preferably of carbon or
Carbon rods are well adapted to the
In practice the discharge plates or points
some material not easily destroyed by heat.
purpose. The ball may also be of carbon.
Many other mechanical devices may be used for carrying the invention into effect.
but that which has been described here will serve to illustrate the application of the
invention and its operation.
In some instances it may be desired to employ a liquid having a low degree of
conductivity instead of air or gas in the chamber 1). The explosion caused by the
are will expand or décompose the fluid and effect the result desired.
It will be understood that a second lightning discharge device of similar con-
struction may be applied to the line L' upon the other side of the generator, and, in
general, that they may be located at such points as desired.
In some instances it may be desired to dispense with the inner points ele²(Figure 2)
and cause the discharge across the points ele to develop the heat required to force
the air from the chamber D. In this case it will be well to place the points ele
near the inner portion of the opening d. The chamber may be of spherical form.
The conductor in this modification would be connected with the plate ².
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 by
my foreign correspondents, I declare that what I claim is:-
1. A lightning discharge device, consisting of a pair of discharge points, plates or
surfaces, an enclosing chamber, a passage or opening from that chamber and means
whereby the expansion of the gaseous or other fluid contents of that chamber,
caused by an electric are between those points, plates or surfaces, shall break the
circuit at another point.
2. The herein before described method of automatically establishing and inter-

page_text: rupting the flow of current for the purposes described, which consists in establishing
an are in a normally interrupted circuit, producing thereby an expansion of the
surrounding air or gas, causing said gaseous matter to rush in a given direction, and
thus interrupt the flow of current through the circuit maintaining the are.
3. In a lightning arrester an interrupted path to earth for the lightning and means
whereby the flow of current from a dynamo or other source of electricity along said
path is stopped by the expansion of a Huid caused by the electricity arcing across said
interruption.
1800
WM. P. THOMPSON & Co.,
Agents for the Applicant.