Improvements in Electrical Cut-outs.
Year: 1889

page_text: Date of Application, 27th Nov., 1889
Complete Specification Left, 25th Aug., 1890-Accepted, 22rd Nov., 1890
PROVISIONAL SPECIFICATION.
Improvements in Electrical Cut-outs.
FRANK BRYAN 11 Brackley Terrace Brackley Road Chiswick, London W. Electrician,
do hereby declare the nature of this invention to be as follows:-
My invention is intended to be used in connection with electrical instruments &
circuits.
It is well known that if a circuit conveying a current of electricity from any
source of high potential be broken, a spark is produced which under certain con-
ditions may be very destructive in its effect.
:
In order to prevent this destructive spark or are from occurring, I use a conducting
wire strip or foil arranged as a shunt or bridge across or between the points where
the circuit is to be broken.
This can be arranged of such a size & material as to fuse with any current less
in strength than that in the main circuit, so that upon breaking the main circuit at
the points mentioned, the current is diverted through the shunt causing it to fuse.
Before this occurs the points between which the circuit is broken have had time
to recede from each other to such a distance as to prevent a destructive spark or arc
from forming.
The shunt or bridge may be introduced in any suitable manner, so as to allow of
easy & quick replacement & may be enclosed in glass or other material.
Dated this 27th day of November 1889.
FRANK BRYAN.
COMPLETE SPECIFICATION.
Improvements in Electrical Cut-outs.
FRANK BRYAN, 11 Brackley Terrace, Brackley Road, Chiswick, London, W
Electrician, 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 :-
My invention is intended to be used in connection with electrical instruments and
circuits.
It is well known that if a circuit conveying a current of electricity from any
source of high potential be broken, a spark is produced which under certain conditions
may be very destructive in its effects.
In order to prevent this destructive spark or arc from occurring I use a conducting
wire, strip or foil arranged as a shunt or bridge across or between the points where
the circuit is to be broken.
This can be arranged of such a size and material as to fuse with any current less
in strength than that in the main circuit, so that upon breaking the main circuit at
the points mentioned, the current is diverted through the shunt causing it to fuse.
Before this occurs the points between which the circuit is broken have had time
to recede from each other to such a distance as to prevent a destructive spark or are
from forming.
The shunt or bridge may be introduced in any suitable manner so as to allow of
easy and quick replacement and may be enclosed in glass or other material.
In the diagrams, Fig. 1 represents a switch and Fig. 2 a magnetic cut out to which
the invention is applied.
In Fig. 1 the fuse is shown as at A B connected to the two points c d at which the
switch arm E makes and breaks contact. In the normal state, with the switch closed,
no appreciable current flows through the wire or strip A B but upon opening the

page_text: switch, the whole current from the battery or dynamo, as the case may be, flows
through the strip and causes it to fuse. This however does not take place until the
switch arm E has already broken contact with the points C D at which points
consequently no spark or arc is formed, provided always that the wire or strip is
not of too small a carrying capacity so as to fuse too instantaneously.
In Fig. 2 the wire or strip A' B' is shown connected to the two mercury
cups FG of the cut out, so that as long as the two cups are joined electrically by
the arm H, no current flows through A¹ B¹ but upon H leaving the mercury in
the cups F G the current flows through A' B' and causes it to fuse, and as before,
this taking place after contact has been broken at the cups F G no arc or spark
takes place there.
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:
The combination with an electrical instrument for automatically breaking circuits
of a conductor of comparatively small cross section placed as a shunt between the
points where the circuit is to be broken substantially as described and for the purposes
set forth.
DL:
1 1
P
L 3000