Improvements in Systems of Electrical Distribution.
Year: 1894

page_text: Date of Application, 4th Sept., 1894-Accepted, 6th Oct., 1894'
COMPLETE SPECIFICATION.
Improvements in Systems of Electrical Distribution.
I, THOMAS CORNELL COYKENDALL, Engineer, of Rondout, Ulster County,
State of New York, United States of America, do hereby declare the nature of
this invention, and in what manner the same is to be performed, to be particularly
described and ascertained by the following statement:-
My invention relates to systems of electrical distribution, and has for its object
to provide systems of distribution with a safety device which will indicate when it
has become safe to throw in the break-switch after the same has become operated
to break the main circuit.
My invention is specially applicable to electric railway systems wherein there is
included in the main line an electro-magnetic break-switch which will be operated
to break the circuit upon a sudden rise in the current due to a ground on line or
analogous cause.
My invention consists in providing a relatively high resistance path to line,
preferably in the form of a shunt around the terminals of the break-switch of such
systems in order to maintain a constant path to line and providing the same with a
suitable indicator for the current.
In the drawing, forming part hereof, A represents the dynamo electric machine
or other source of electric energy of an electric railway or other analogous system
of distribution. ab are the brushes of the same, one of which is connected by
wire 1 with one of the mains or leads B and the other connected through wire 2
and other apparatus, hereinafter described with the other main or lead C. D is
the break-switch or circuit-breaker of the system, with its magnet d and contact
points e e¹ included in the main line. E is the station ammeter. The circuit con-
nections are as follows: The current passes from the positive brush of the
machine a by wire 2, through the station ammeter E, by wire 3, through magnet d,
wire 4, arm, link g, contact pieces e e¹, wire 5, to the lead C. The current from
the negative brush passes by wire 1 to the other lead B. The translating
devices of the system are included in circuit across the leads B C, and in the case
of an electric railway system, one of these leads B will be permanently grounded.
When a ground comes on the line C or from any other cause, such as short
circuiting, the current flowing is suddenly augmented, as will be readily understood,
and the increased volume of the current passing through the magnet d will cause
the said magnet to pull down its armature d', which will release the break-switch,
and cause the contact points e e¹ to be separated by the action of the spring / in
the usual inanner. When this has happened, the line is broken and current no
longer flows, and the machine is net subjected to the danger of being burnt out by
a current of great volume. This is the usual or normal arrangement of the break-
switch in electrical railway systems of distribution, which, as will be seen, does not
provide any means to indicate when the break-switch may be thrown back to close
the main line.
If the break-switch be thrown back while the line is still grounded, the circuit
will be immediately broken at the break-switch in the same manner as before.
The heavy current, however, flowing for a short space of time will have the
effect of pitting the commutator at the point upon which the positive brush rested
at the moment the break-switch was thrown back to close the main line.
These defects I avoid by my invention in a manner to be described. According
to my invention a resistance is connected in shunt around the terminals of the
break-switch by wires 5 and 7 connected to wires C and 3 respectively.
The current which flows in this shunt is caused to actuate any suitable indicator,

page_text: shown in this instance as the station ammeter included in circuit therewith,
although any indicator may be used either in circuit or within the range of
electrical influence of the circuit.
In my improved construction as shown, during the normal operation of the
system, when current is flowing, the greater part will pass to line through the
break-switch and wire 5, only a small portion being shunted by way of wire 7,
resistance F, and wire 6.
When, now, the line becomes grounded, the break-switch will be automatically
operated to open the main circuit. When this has been done, the only path for
the current to line is by way of the shunt, but this path is of such high resistance
that only a small amount of current can pass to line, which small volume will not
be sufficient to in any manner damage the machine. A reading of this small
current will be given on the station ammeter included in circuit, which will
remain deflected as long as a current flows, which will be until the ground on line
has been broken. Or an indicator may be included directly in the shunt, as shown
in dotted lines.
As soon as the ground has been broken or the trouble removed, current ceases to
flow and the pointer of the ammeter will swing back to zero. As soon as the
ammeter shows no reading, the break-switch may be thrown in to complete the
circuit without danger to the machine. By watching the ammeter or indicator
the attendant can at all times tell when the break-switch may be safely thrown in.
It will thus be seen that I have produced an extremely simple, cheap and
efficient safety device and one which is not liable to get out of order, and which
will at all times indicate whether or not the break-switch may be thrown in without
danger to the machine.
I do not herein limit myself to the precise construction and arrangement shown,
as it is obvious that the devices, their construction and arrangement may be
greatly varied without departing from the spirit of my invention.
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 :-
1. In an electrical system of distribution, the combination of a dynamo-electric
machine, mains leading therefrom, a break-switch in series with one of the mains,
a relatively high resistance shunt around the break-switch, and means for indi-
cating the flow of current in the shunt, when the break-switch is open, substantially
as described.
2. In a system of electrical distribution, the combination of a dynamo-electric
machine, mains leading therefrom, an electro-magnetic break-switch in series with
one of the mains, a relatively high resistance shunt around the terminals of the
break-switch and a current indicator in circuit with the shunt when the break-switch
is open, substantially as described.
3. In a system of distribution, the combination of a dynamo-electric machine,
mains leading therefrom, an electro-magnetic break-switch in series with one of the
mains, a relatively high resistance shunt around the break-switch, and an ammeter
in circuit with the shunt, substantially as described.
4. In a system of distribution, the combination of a source of electric energy
mains leading therefrom, a break-switch in series with one of the mains, a high
resistance path to line, forming the sole path to line when the break-switch is open
and means for indicating the flow of current in said high resistance path when the
break-switch is open, substantially as described.
5. In a system of electrical distribution, the combination of a source of electric
energy, mains leading therefrom, a break-switch in circuit with the mains, a
separate normally completed high resistance path to line forming the sole path
to line when the break-switch is open, and means for indicating the flow of curren
in the said high resistance path when the break-switch is open, substantially a
described.

page_text: 6. In a system of electrical distribution, the combination of a source of electric
energy, mains leading therefrom, a break-switch in circuit with the mains, a shunt
around the terminals of the break-switch, a resistance included in the shunt, and a
current indicator in circuit with the shunt when the break-switch is open,
substantially as described.
Dated September 4th 1891
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.