IMPROVEMENTS RELATING TO THE DISTRIBUTION OF ELECTRICITY EMPLOYED IN DISTRICT LIGHTING
Year: 1885

page_text: I JAMES EDWARD HENRY GORDON of 28 Collingham Place Kensington in the
County of Middlesex Electrical Engineer do hereby declare the nature of my
invention for "IMPROVEMENTS RELATING TO THE DISTRIBUTION OF ELECTRICITY
EMPLOYED IN DISTRICT LIGHTING" and in what manner the same is to be performed
to be particularly described and ascertained in and by the following statement :-
In district lighting it is convenient to carry the current from the dynamo room
by means of feeding mains to several distributing centres whence it radiates to the
premises to be lighted. The feeding mains may be each composed of several
smaller cables and be used with apparatus for maintaining a constant electro motive,
force at the distributing centre as described in the Specification of a patent granted
to me No 5624 in the year 1884 or may be of the ordinary type used either alone
or in conjunction with resistances which can be put in or out of circuit as required
to maintain a constant electro motive force at the distributing centre as described
in a Specification lodged by me with an application for a Patent dated the 25th day
of February 1885 N° 2587 or they may be of the ordinary type.
The present invention relates to the construction of the apparatus employed in
the distributing centres.
The improved apparatus consists of a cupboard of a form regulated by the space
available. It must have easily accessible doors in front and should also have doors
at the back which can be opened when required.
A wooden frame reaches across this cupboard dividing it into two portions so
that the front of the frame is seen from the front door and the back from the back
door.
On this frame are fixed "plug boards." The drawings show one typical form
but not the only useful form of one of these plug boards.
Figure 1 is a plan Figure 2 a section Figure 3 an end view and Figure 4 a side
view.
Each plug board consists of a mahogany or other insulating base (a) with an
oblong block (b) of brass or other metal to which a feeding main is connected.
Near this block are fixed a number of smaller metal blocks (c) corresponding to the
number of distributing mains leading from that centre and fed from that feeding

page_text: main. These are connected to the central block (b) by means of plugs (d) which
can be removed at will. Outside each block (c) is another metal block (e) to which
the distributing main is attached. The blocks c. e, c. e. &c are respectively connected
by fusible safety wires f of the usual construction.
In addition to the plug holes between the block b and the small blocks c c &c
there are plug holes in the central block b and in the small blocks o or e.
Separate plug boards are used for the positive and negative feeding main and
for any separate circuits which may be supplied to the centre.
For instance if two circuits come to the centre two positive and two negative
plug boards will be required-four in all.
These plug boards are used for localising faults and for measuring the current in
each distributing main.
137
In case of a fault such as an earth connection appearing on a circuit the plugs dd
must be removed and replaced one by one until on removing one plug the earth
connection censes. We then know that the fault is in the distributing main
governed by that plug or in one of its branches.
To measure current two plugs such as shown at g are connected respectively by
wires to the terminals of any suitable galvanometer ammeter or dynamometer. The
plugs g are inserted respectively into the holes in the central block (b) and into the
small block (e) or c-on the connecting plug (d) being removed the whole current
passes through the galvanometer without. being in any way interrupted.
In case of a fault which melts one of the fusible cut-offs the fact is automatically
telegraphed to the engine room or elsewhere by the following method. A fine
cord his threaded in and out over each fusible wire and sometimes also under rings
or hooks i on the board in the manner shown in section in Figure 2. As long as
the thread is tight it keeps a contact key k open but on its being either burnt
through or let slack by the melting of a fusible wire, contact is made and a signal
telegraphed.
"
A convenient form of signal is the lighting up of a red lamp. There would
be in the engine room as many of these lamps as there are feeding centres in the
district. The lighting up for instance of red lamp N° 3 would mean Accident
in district fed from N° 3 centre." A man would then go to that centre and look
to see which fusible wire had melted and this would show him in which set of
rooms &c i.e. on which distributing main the accident had occurred. The wires
are all attached to the backs of the plug boards and can be got at by opening the
back doors of the cupboard.
'
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
1 claim is
In feeding centres in an electrically lighted district the system of plug boards
for localizing faults for measuring current and for telegraphing the occurrence of
accidents back 'to the engine room substantially as herein described.
CARPMAEL & Co.,
"Agents for the Applicant. 45
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