AN IMPROVED MODE OF REGU- LATING ELECTRIC CURRENTS
Year: 1879

page_text: LETTERS PATENT to John Scudamore Sellon, Metallurgist, of Hatton Garden,
in the County of Middlesex, and Henry Edmunds, of Hatton Garden, in the
same County, Engineer, for the Invention of "AN IMPROVED MODE OF REGU-
LATING ELECTRIC CURRENTS."
Sealed the 28th October 1879, and dated the 30th April 1879.
PROVISIONAL SPECIFICATION left by the said John Scudamore Sellon and
Henry Edmunds at the Office of the Commissioners of Patents on the 30th April
1879.
JOHN SCUDAMORE SELLON, Metallurgist, of Hatton Garden, in the County of
Middlesex, and HENRY EDMUNDS, of Hatton Garden, in the same County, Engineer.
"AN IMPROVED MODE OF REGULATING ELECTRIC CURRENTS."
Hitherto in electric lighting by the incandescence of a rod or wire great diffi-
culties have been experienced in controlling the energy of the electric current, there
being a great liability of the metal fusing under a too powerful current. Moreover,
the motive force required to work the dynamo electric machine has been to a great
extent wasted when the electric current has proved too powerful for the work it
was required to perform, the practice of shunting off the excess of electricity having
been adopted instead of the action of the motor being reduced.
We now propose to introduce into the circuit an automatic switch, which as a
retaining or other wire forming part of the switch becomes heated by the passage
of the current, will be brought into action and caused to connect the two collecting
brushes of the dynamo electric machino with each other, and thereby cause the
induced current to cease and free the motive power engine of its work. The auto-
matic switch apparatus may be constructed in various ways, but that which we
have found to work satisfactorily is a spring blade held out of contact with a
metallio stop by means of a fine tension wire. Through this wire the current will
pass to the electric lamp, but when an excess of energy in the current is produced
the wire will become heated, and in heating its tension will be so far relaxed as to
allow the spring blade to make contact with the metal stop before mentioned. This
stop we connect electrically with one of the collecting brushes, the other brush being
connected with the tension wire.

page_text: When contact between the spring blade and the metal stop is made, a short
circuit will be established, and the electro-magnets and electric lamps will be thrown
out of the circuit, thus leaving the motive power engine no other work than that of
overcoming the friction of the machine.
It will be understood that by thus changing the course of the current no electric
flash or secondary spark will be created, and consequently no damage can arise to
the machine, and no overheating of the machine can result.
In addition to this automatic switch we propose to employ an arrangement of
resistance coils which will so control the generation of the electric current as to limit
the quantity produced to the requirements of the work in hand; thus, supposing
that ten lamps are to be brought within the circuit, we provide ten resistances, and
so arrange them with respect to the lamps that as one resistance is thrown out of
circuit one lamp will be brought into circuit, and so on until all the lamps are
brought into action.
As the lamps are thrown out of use the corresponding resistances will be brought
into the circuit, and the quantity of the current will be correspondingly reduced,
the work of the motive power engine being at the same time correspondingly dimi-
nished. The lamps, it should be remarked, will be in the circuit of the exciting
current, which latter may be derived either from the machine which produces the
induced current or from a separate machine.
It will be understood that the automatic switch may be introduced into this
regulating apparatus, its use being to control the generation of the induced current
in the event of the motive power engine overrunning.
Instead of stopping the generation of the electric current when an excess occurs
we propose in some cases to use a modification of the automatic switch, and by its
means to increase the resistance in the circuit as the quantity of the current
increases. For this purpose we fit on the underside of the elastic blade, studs (say
3, 4, or more) arranged in line longitudinally of the blade, and on the bar or frame
which carries the blade we fit corresponding studs, which are all included in the
circuit by means of five conducting wires. While the current is at its normal state,
the tension wire before mentioned will hold down the elastic blade in metallic con-
tact with the fixed studs, and each fine conducting wire will lead off its proportion
of the current, which passes through or along the elastic block. Should however the
tension wire relax by reason of the generation of heat therein, the elastic blade will
rise proportionately, and move out of contact with one or more of the fixed studs,
the fine wire or wires of which will be thrown out of the circuit. The result of this
will be to offer an increased resistance to the passage of the current, and thereby
to limit its effect. In c se however the current should unduly increase beyond the
capacity of control of this modified form of switch, the first described switch will
come into action and stop the generation of the current, as before explained.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Scudamore Sellon and Henry Edmunds in the Great Seal Patent
Office on the 30th October 1879.
JOHN SCUDAMORE SELLON, Metallurgist, of Hatton Garden, in the County of
Middlesex, and HENRY EDMUNDS, of Hatton Garden, in the same County, Engineer.
"AN IMPROVED MODE OF REGULATING ELECTRIC CURRENTS."
Great difficulties have hitherto been experienced in controlling the energy of the
electric current, as, for example, in electric lighting by the incandescence of a rod or
wire, there being in such case great liability of the metal fusing under a too powerful
current. Moreover, the motive force required to work the dynamo-electric machino
has been to a great extent wasted when the electric current has proved too
powerful for the work it was required to perform, the practice of shunting off the
excess of electricity having been adopted instead of the action of the motor being
reduced.
We now propose to introduce into the circuit an automatic switch, which as a
retaining or other wire forming part of the switch becomes heated by the passage
of the current, will be brought into action and caused to connect the two collecting
brushes of the dynamo-electric machine with each other, and thereby cause the
induced current to cease and free the motive power engine of its work.
In the accompanying Drawing Fig. 1 shews in side elevation an automatic switch
apparatus constructed according to our Invention, and applied to a Wallace Farmer
machine, the same being connected with three lights for the purpose of illustrating
the action of the Invention. In this Figure A is the dynamo-electric machine, and
B the switch apparatus. In this apparatus a, a, is n rectangular frame, on the top
of which is fixed a spring blade b. The free end of this blade underlies an adjustable
screw c, carried by the frame a. The spring blade b is held out of contact with the
screw c by means of a fine tension wire d, through which the current will pass to
the electric lamp. For this purpose a wire 1 from the brush e leads to the fixed end
of the spring b, and a wire 2 connects the field magnets of the dynamo-electric
machine through the lamps with the fixed metal block f, to which the lower end of
the tension wire d is attached. To complete the circuit a wire 3 connects the field
magnets with the other collecting brush e of the machine; 4 is a short circuit wire
connecting the brush e' with the contact screw c. The course of the current is as
follows: Leaving the dynamo-electric machine, say at e, it passes through the wire
1 to the blade b, thence by the tension wire d to the metal block f, and by the
wire 2 to and through the lamps, from which it passes to the field magnets of the
dynamo machine, emerging by the wire 3 to the other collecting brush c¹. As the
current passes through the tension wire d to the electric lamps, the development of
an excess of energy in the current will heat the wire, and in heating its tension will
be so far relaxed as to allow the spring blade to make contact with the adjustable
screw C.
When contact between the spring blade and the metal stop is thus made, a short
circuit will be established through the wire 4 and the field magnets of the dynamo
machine, and the electric lamps will be thrown out of the circuit, thus leaving the
motive power engine no other work than that of overcoming the friction of the
machine.
It will be understood that by thus changing the course of the current no electric
flash or secondary spark will be created, and consequently no damage can arise to
the machine, and no overheating of the machine can result.
It will be understood that as the tension wire cools and contracts it will draw the
spring b out of contact with the screw c, and thereby break the short circuit; thus
the action of the machine and the illumination of the lamps will be instantly
restored.

page_text: Fig. 2 shews the adaptation of the switch or regulator B to two dynamo electric
machines connected with a group of electric lamps, the machines A. being used as
an exciter, and the machine A¹ as a distributor.
In this case the wire 1 leads from the brush e of the machine A to the field
magnets of the machine A', round which it passes, emerging at 2; thence it
passes back to the field magnets of the machine À, emerging at 3, and joining the
brush e'.
The current generated in the distributor A' is conducted to and from the lamps
in the following mauner:-Starting from the brush e the current will pass by the
wire 4 to the lamps, thence by the wire 5 to the inetal block f of the regulator.
The tension wire d which connects the block f with the spring b is in this
instance insulated by a small block of vulcanite or equivalent material from its
spring b, and leading from this tension wire d is a wire 6, which joins with the
brush of the machine A¹; 7 is a short circuit wire connecting the contact screw c
with the brush e¹ of the inachine A, and 8 is a short circuit wire connecting the
fixed end of the spring b with the wire 1. When the regulator is in the position
shewn in the Drawing both machines A and A¹ will be in efficient action. Should
however the intensity of the current unduly increase, the spring b will, as before
explained, rise into contact with the screw c, thus short circuiting the brushes o
and e' of the machine A, or in other words stopping the generation of electricity.
In addition to the automatic switch or regulator B we propose to employ an
arrangement of resistance coils, which by the aid of a suitable commutator will so
control the generation of the electric current as to limit the quantity produced to
the requirements of the work in hand; thus, supposing that ten lamps are
to be brought within the circuit, we provide ten resistances, and so arrange them
with respect to the lamps that as one resistance is thrown out of circuit one lamp
will be brought into circuit, and so on until all the lamps are brought into action.
As the lamps are thrown out of use the corresponding resistances will be brought
into the circuit, and the quantity of the current will be correspondingly reduced,
the work of the motive power engine being at the same time correspondingly dimi-
nished. The lamps, it should be remarked, will be in the circuit of the induced
current, but the resistances will be in the circuit of the exciting current, which
latter may be derived either from the machine which produces the induced current
or from a separate machine.
This part of our Invention will be more clearly understood by reference to
Figures 3 and 4, Fig. 3 showing in diagram plan the complete apparatus for con-
trolling the current supplied to a group of lamps, and Fig. 4 shewing the commutator
in vertical cross section.
This commutator may be described as fitted with two sets of studs 1, 2, 3, 4, 5,
and 1*, 2*, 3*, 4*, 5*, arranged concentrically on a disc C, through the centre of
which stands up an arbour g carrying two blades g¹ and h'. The blade g¹ is in
metallic contact with this arbour, and the blade h' is insulated therefrom but is in
metallic contact with a cock h which is fixed to the disc c. These blades are of
such length that they will respectively reach and overlie any one of the two series
of studs for the purpose of making metallic contact therewith. The studs 1 to 5
which are in the range of the blade g' are in direct connection with the resistance
coils i, one coil being interposed between every two adjacent studs. In like manner
the studs 1 to 5 which are in the range of the blade h¹ are similarly connected
with the electric lamp. The stud 1 is connected with one pole of the exciter A.
The other pole of the exciter A is connected with the field magnets of the distri-
butor A', and a wire connects these field magnets with the arbour g; the circuit of
the exciter is completed through the blade gl when in contact with one or other of
its series. The stud 1* is in contact with one pole of the distributor A¹. The other
pole being connected with the cock h, the circuit through the lamps is completed by
the contact of the blade h¹ with one or other of the studs of its series. k is a handle
for actuating the blades g', h¹, simultaneously, and shifting them from one pair of
corresponding studs to another pair, the corresponding studs being 1 and 5*, 2 and

page_text: 4*, and so on. By this arrangement it will be seen that what whatever position
the blades g, h, take, so long as they are in line with each other they will, while
altering the course of the current, adjust the amount of electricity generated to suit
the quality of work required to be performed. It will be obvious that this mode of
regulating the generation and supply of electricity is applicable to electroplating
and other uses.
It will be understood that the automatic switch B may be introduced into this
regulating apparatus, its use being to control the generation of the induced current
in the event of the motive power engine overrunning.
Instead of stopping the generation of the electric current when an excess occurs
we propose in some cases to use a modification of the automatic switch, and by its
means to increase the resistance in the circuit as the quantity of the current
increases. For this purpose we provide the arrangement shewn at Fig. 5; thus we
fit on the under side of the elastic blade b studs, say, three, four, or more arranged
in line longitudinally of the blade, and on the bar or frame a which carries the
blade we fit corresponding studs, which are all included in the circuit by means of
fine conducting wires b¹, bs, 6s, 64, 65. While the current is at its normal state
the tension wire before mentioned will hold down the elastic blade in metallic
contact with the fixed studs, and each fine conducting wire will lead off its propor-
tion of the current from the exciter A to the distributor A', passing through or
along the elastic blade.
Should however the tension wire relax by reason of the generation of heat therein
the elastic blade will rise proportionately and move out of contact with one or more
of the fixed studs, the fine wire or wires of which will be thrown out of the circuit.
The result of this will be to offer an increased resistance to the passage of the
current, and thereby to limit its effect. In case however the current should unduly
increase beyond the capacity of control of this modified form of switch, the first
described switch will come into action and stop the generation of the current as
before explained.
Having now set forth the nature of our Invention of "An Improved Mode of
Regulating Electric Currents," and explained the manner of carrying the same into
effect, we wish it to be understood that under the above in part recited Letters
Patent we claim,―
First. The mode of regulating electric currents by producing a short circuit (and
thereby cutting out the field magnet), as described with reference to Figures 1 and 2
of the Drawings.
Secondly. Regulating the production of electric currents in the manner described
with reference to Figures 3 and 4, and that whether alone or in combination with
the mode of regulating currents described with reference to Figures 1 and 2.
Thirdly. The mode of obtaining the automatic regulation of electric currents as
described with reference to Figure 5.
In witness whereof, I, the said John Scudamore Sellon, have hereunto set my
hand and seal, the Thirtieth day of October, in the year of our Lord Ono
thousand eight hundred and seventy nine.
JOHN S. SELLON. (LS.)