IMPROVED MEANS FOR REGULATING ELECTRO MOTIVE FORCE IN THE VARIOUS PARTS OF A SYSTEM OF MAINS USED FOR ELECTRIC DISTRIBUTION
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 IMPROVED MEANS FOR REGULATING ELECTRO MOTIVE FORCE IN THE
VARIOUS PARTS OF A SYSTEM OF MAINS USED FOR ELECTRIC DISTRIBUTION and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
In the specification of a former Patent granted to me No 5624 in the year 1884
I described a new form of electric main for supplying an electric current to two or
more "distant points" or "distributing centres" at a distance from a dynamo or
system of connected dynamos-such electric mains consisting not of one large
cable but of several smaller ones and of apparatus for disconnecting these cables as
required for the purpose of keeping the electro motive force at each centre
unchanged in spite of changes in the number of lamps supplied from it.
My present invention consists in another method of carrying out the require-
ments described in the specification above mentioned.
Instead of the main consisting of a number of separate components as in that
specification it is made to consist of a single main or a group of wires connected as
a single main and the regulation is done by the insertion of resistances either at
the dynamo end or the far end or any intermediate point. The insertion of a
resistance produces the same electrical effect as the cutting off of component cables.
The taking in and out of resistances may either be done by contact apparatus
worked by hand or by an automatic apparatus such as is shown in the drawing
hereunto annexed and which is in many respects similar to that described in a
specification lodged by me with an application for a Patent dated the 25th day of
February 1885 N° 2575.
Figure 1 is a side elevation and Figure 2 an end
Figure 3 shews separately a portion of the rim of the
of one of the copper segments carried by it.
elevation of the apparatus.
wheel of the apparatus and
In these figures A is an iron wheel faced with wood into which are let copper
segments b, b. B, B, are metallic brushes capable of moving end wise in slots in
two fixed circular wooden segments a, a, and which at their ends rest against the
side of the wheel. The space between each brush and the brush next to it is rather

page_text: more than the width of a brush and the two copper segments b b are so placed that
when the wheel is turned they come into contact with the brushes-first one would
come into contact with one brush and then the other would come into contact with
another brush and so on.
The resistance coils which are not shewn in the drawing are connected from
brush to brush entering at the first brush and leaving at the last so that as by the
turning of the wheel one or other of the copper segments comes into contact with
the end of one or other of the brushes one or other of the resistances will be short
circuited.
The apparatus also consists of an electrical governor for moving the wheel in
accordance with changes in electro motive force at the distant centre and so as to
correct these changes. The governor shewn in the drawing is a Willans governor
which consists of a solenoid and core e actuating the valves of a hydraulic
cylinder f. The piston rod of this hydraulic cylinder I couple by a connecting rod
to a crank pin d carried by the wheel.
As the Willans governor is an article of commerce and has been fully described
in the specification of a Patent granted to him No 1184 in the year 1883 it need
not he further described. The connections are so made that if the electro motive
force rises too high the Willans governor turns the wheel so that a less number of
the resistances shall be short circuited and vice versa.
Any suitable means may be adopted for keeping the brushes pressed against the
side of the wheel. In the Drawing it is shewn to be effected by a board q which
can slide towards or away from the wheel on pins which project from the fixed
segments a and which is pressed against the back ends of the brushes by springs
mounted on these pins. The board may be faced with india rubber so that it may
press equally against the backs of all the brushes.
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
I claim is
1. In an electrically lighted district in which the lamps are supplied from two
or more centres each in its turn supplied by a feeding main coming from the same
dynamo (or system of connected dynamos) inserting in each feeding main a series
of resistance coils and providing apparatus for short circuiting the resistance coils
one by one as required to keep the electro-motive force at each centre unchanged
in spite of changes in the number of lamps supplied from it.
2. In an electrically lighted district in which the lamps are supplied from two
or more centres each in its turn supplied by a feeding main coming from the same
dynamo (or system of connected dynamos) the means substantially as herein before
described and illustrated in the drawing annexed for keeping the electro-motive
force at each centre unchanged in spite of changes in the number of lamps supplied
from it.