An Improved Automatic Electrical Switch or Cut-out for use in connection with Dynamos and Accumulators to be Charged thereby.
Year: 1890

page_text: Date of Application, 13th June, 1890
Complete Specification Left, 10th Mar., 1891-Accepted, 25th Apr., 1591
PROVISIONAL SPECIFICATION.
An Improved Automatic Electrical Switch or Cut-out for use in
connection with Dynamos and Accumulators to be Charged thereby.
We, FRANCIS MURRAY NEWTON, of The Newton Electrical Engineering
Works, Taunton, in the County of Somerset, Electrical Engineer, and Toм
HAWKINS, of 10, Sydney Terrace, Taunton, aforesaid, Electrician, do hereby
declare the nature of this invention to be as follows:-
This invention relates to an improved automatic electrical switch adapted for
making circuit automatically between a dynamo or other generator of electricity
and an accumulator to be charged by such dynamo or generator when the E.M.F.
of the former exceeds that of the latter, and also to break circuit automatically
when from any cause the E.M.F. of the dynamo or generator falls below that of the
accumulator.
This switch comprises a shunt coil of high resistance arranged between the poles
of the dynamo, and a series coil adapted to have its circuit closed only when the
The coils are each wound on an
E.M.F. of the dynamo reaches a certain limit.
iron core attached to or formed in one with an outer case (hereinafter called an iron
ense) enclosing the coils the whole forming an electro magnet.
When the E.M.F. of the dynamo exceeds that of the accumulator the magnetic
attraction between the iron case containing the shunt coils and the iron case
containing the series coils overcomes the action of gravity or the force of a spring
and causes the shunt electro-magnet, which is made movable on a spindle, to move
towards the iron case containing the series coils, which is fixed, thereby closing the
main circuit by a suitable mechanical device. The main current then passes through
the series coils which acting in the same sense as the shunt coils causes the two iron
As long as the main
cases to be more firmly attracted and ensuring a firm contact.
circuit is closed and the E.M.F. of the dynamo exceeds that of the accumulator the
main and shunt coils act in the same sense but should the E.M.F. of the dynamo
fall below that of the accumulator, the current in the main series coils is reversed
and the two coils now acting in an opposite sense, the attraction between the iron
cases ceases and the force of gravity or in some cases a spring causes the movable
iron case to fall or recede from the fixed one and break the main circuit. Should
this force however be insufficient to overcome the friction of the switch or other
parts of the apparatus, a slight increase in the current flowing back from the
accumulator through the series coils causes sufficient magnetic repulsion between
its iron case and that of the shunt coil magnet to ensure the opening of the switch..
The iron case containing the series main coils may be made movable on a spindle;
in that case the shunt case or magnet would be fixed.
The series coil is of thick wire and forms part of the main circuit, being connected
with the accumulator and with a main insulated contact piece mounted on the base
of the switch. The arrangement of the connections may be modified in several
ways to produce the same result.
The high resistance coil forming a shunt from the dynamo is of fine wire wound
on a core attached to or formed in one with an outer casing enclosing the coil, and is
mounted together with its core and outer casing on a central spindle in such a
manner as to be capable of moving in the direction of its axis towards or away
from the pole face of the series coil, which is stationary and is arranged at a
suitable distance from the pole face of the high resistance coil. The main conductor
from the dynamo terminates in a main contact piece mounted on the base of the
switch, and to which is pivoted, in such a manner as to be in constant electrical
connection with the said contact piece, an arm of conducting material formed with

page_text: a slot in which engages a pin fixed to the outer casing and core of the movable
shunt coil. The construction and operation of the arm may however be modified.
The arrangement is such, that assuming the switch to be open, an increase in the
E.M.F. of the dynamo over that of the accumulator will result in an increase of
power of the electro-magnet constituted by the shunt coil and its core and outer
casing thus causing the same to be attracted and consequently moved along its
central supporting spindle towards the oppositely situated and dissimilar pole face
of the fixed electro magnet constituted by the series coil with its core and outer
casing thus the before mentioned pivoted movable conducting arm will, by the
action of the pin engaged in its slot, be moved into contact with the first mentioned
main contact piece, thereby closing the main circuit through the series coil. The
force of contact of the said conducting arm will be still further increased by the
additional attraction of the fixed electro magnet.
A decrease of E.M.E. of the dynamo as compared with that of the accumulator,
will cause a reversal of the current through the series coil, and thus the pivoted
conducting arm will be moved out of contact with the first mentioned contact piece
thereby breaking the main circuit.
Set screws or other suitable devices may be provided to enable the distance
between the dissimilar pole faces of the electro magnets to be accurately adjusted
for the proper working of the apparatus.
A spring may be provided of a strength calculated to aid in keeping the pivoted
conducting arm out of contact with its opposed contact piece as long as the E.M.F.
Or the arm
of the dynamo does not exceed a predetermined and adjustable limit.
itself may be a spring ȧrm.
10 L1000
W. Lloyd Wise,
1.
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.
COMPLETE SPECIFICATION.
An Improved Automatic Electrical Switch or Cut-out for use in
connection with Dynamos and Accumulators to be Charged thereby.
We, FRANCIS MURRAY NEWTON, of The Newton Electrical Engineering
Works, Taunton, in the County of Somerset, Electrical Engineer, and TOM
HAWKINS, of 10, Sydney Terrace, Taunton, aforesaid, 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: -
This invention relates to an improved automatic electrical switch adapted for
making circuit automatically between a dynamo or other generator of electricity,
and an accumulator to be charged by such dynamo or generator when the E.M.F.
of the former exceeds that of the latter, and also to break the circuit automatically
when from any cause the E.M.F. of the dynamo or generator falls below that of
the accumulator.
This switch comprises a shunt coil of high resistance adapted to be arranged
between the poles of the dynamo, and a series coil adapted to have its circuit closed
only when the E.M.F. of the dynamo reaches a certain limit. The coils are each
wound on an iron core attached to or formed in one with an outer case (hereinafter
called an iron case) enclosing the coils, the whole forming an electro magnet.
When the E.M.. of the dynamo exceeds that of the accumulator, the magnetic
attraction between the iron case containing the shunt coil, and the iron case
containing the series coil, overcomes the action of gravity, or the force of a
spring, and causes the shunt electro-magnet, which is made movable on a spindle,
to move towards the iron case containing the series coils, which is fixed, thereby

page_text: The main current then
As
closing the main circuit by a suitable mechanical device.
passes through the series coil, which, acting in the same sense as the shunt coil,
causes the two iron cases to be more firmly attracted, ensuring a firm contact.
long as the main circuit is closed and the E.M.F. of the dynamo exceeds that of
the accumulator, the main and shunt coils act in the same sense but should the
E.M.F. of the dynamo fall below that of the accumulator, the current in the main
series coil is reversed and the two coils now acting in an opposite sense, the attrac-
tion between the iron cases ceases, and the force of gravity, or in some cases a
spring, causes the movable iron case to fall or recede from the fixed one, and break
the main circuit. Should this force however be insufficient to overcome the
friction of the switch or other parts of the apparatus, a slight increase in the current
flowing back from the accumulator through the series coils causes sufficient magnetic
repulsion between its iron case and that of the shunt coil.magnet to ensure the
opening of the switch.
The arrangement of the connections may be modified in several ways to
produce the same result.
The iron case containing the series main coil may be made movable on a spindle:
in that case the shunt case or magnet would be fixed.
In the accompanying drawings,
Fig. is a sectional elevation, and
Fig. 2 a side elevation, of an electrical switch or cut-out constructed according
to this invention.
Figs. 3 and 4; Fig. 5; and Fig. 6 are sectional elevations illustrating modified
constructions.
Fig. 7 is a detail view.
Referring to Figs. 1 and 2, 1 is a shunt coil of high resistance wound upon an
iron core 2 attached to or formed in one with an outer iron case 3 that encloses
the coil, the whole forming a pot electro magnet hereinafter referred to as the
shunt magnet. The two ends of the coil are connected to two insulated terminals 5
and 6 respectively, by means of which, and wires 7 and they can be connected to
the opposite poles of a dynamo 9. 10 is the series coil wound upon an iron core 11
attached to or formed in one with an iron case 12, these forming together another
pot electro magnet hereinafter referred to as the series magnet. One end of the
series coil is connected to a terminal 13 by which it can be placed, by means of a
wire 13", in connection with one pole of the accumulator to be charged; its other
end is connected to a forked spring contact piece 14 which, as well as the
terminals 5, 6 and 13, is secured to a non conducting base plate or support 15 by
which the switch or cut out can be held in position for use. The series coil is so
wound in relation to the shunt coil, that when a current passes through it from the
dynamo to the accumulator, the magnets will attract each other, and when a
current passes through it in the reverse direction from the accumulator, the magnets
will repel each other. The shunt magnet is mounted upon a central pin 16 so as to
be capable of vertical movement to and from the series magnet which is fixed at a
suitable distance from it. 17 and 18 are brackets fixed to the plate or support 15,
and serving to carry the pin 16, and the series magnet respectively. 19 is a metal
arm pivoted to a metal support 20, which when the switch is in use, is connected to
the main conductor 7 of the dynamo. This arm is formed with a slot 21 into
which projects a pin 22 fixed to the exterior of the case 3 of the shunt magnet, the
arrangement being such that when the shunt magnet moves towards the series
magnet, the pin 22 will raise the arm 19 and force its outer or free end in between
the ends of the spring contact piece 14. The arrangement is such that assuming
the terminals 5 and 6 are connected to the opposite poles of the dynamo, that an
accumulator 23 to be charged has one of its poles connected to the terminal 13, and
the other to that pole of the dynamo which is opposite to that to which the arm 19
is connected, and that the switch is open, that is to say, that the shunt magnet and
arm 19, are in their lowest positions, then upon the E.M.F. of the dynamo rising
above that of the accumulator, the shunt magnet will be excited sufficiently to

page_text: cause it to move towards the fixed series magnet and move the arm 19 into contact
with the contact piece 14 thus placing the accumulator in circuit with the dynamo
through the series coil. The series magnet being now excited, the attraction
between it and the shunt magnet will be increased. Should the E.M.F. of the
dynamo fall below that of the accumulator, the latter will send a current through
the series coil in the reverse direction to that sent by the dynamo thereby reversing
the polarity of the series magnet and causing the shunt magnet to be repelled, so
that the arm 19 will be moved away from the contact piece 14, thus automatically
breaking the connection between the dynamo and accumulator.
The shunt magnet is made of such a weight that the attraction between it and
the series magnet will not be sufficient to cause it to rise and move the arm 19 into
contact with the contact piece 14 until the E.M.F., of the dynamo rises above a
predetermined amount. Or an adjustable spring may be provided to keep the arm
out of contact with the contact piece so long as the E.M.F. of the dynamo does
not exceed a predetermined limit; or in some cases the spring may support part
of the weight of the movable magnet.
In
In the arrangement shewn in Figs. 3 and 4, the shunt magnet has connected to
it a guide pin 16 that works through a sleeve 24 that supports the magnet when
it is in its lowest position, and which is vertically adjustable in the bracket 17 in
order that the distance between the two magnets can be adjusted to adapt the
switch to varying requirements. For the same reason the arin 19 is pivoted to a
vertically adjustable support 25. The pin 22 for operating the slotted arm 19 is
in this case fixed to the lower end of the guide pin 16, and the arm is so arranged
that when raised, its free end passes between and connects two spring contact
pieces 14 and 14 that are insulated from each other. One of these contact pieces,
riz. 14, is connected to the series coil, the other end of which is connected to the
terminal 5 for direct connection with the dynamo. The other contact piece, iz. 14",
is when the switch is to be used connected with the accumulator by a wire 13.
other respects this switch is similar in construction and operation to that shown in
Figs. 1 and 2. In Figs. 1 and 4, the dynamo, accumulator and wire connections
between them are shown diagrammatically. In the arrangement shown in Fig. 5,
the series magnet is supported by two uprights or standards 15" and the shunt
magnet is suspended by a vertical guide pin 16 that passes centrally through the
series magnet and is carried thereby. The distance between the 2 magnets is made
adjustable by the two nuts 16 The arm 19 is mounted and actuated in a similar
manner to the one shown in Figs. 3 and 4, and works in conjunction with two
insulated spring contacts 14, 14, c only of which can be seen in the figure, but
which are arranged like those shown in Figs. 3 and 4. 26 is a ring of insulating
material for carrying the terminals 5 and 6.
Fig. 6 shews an arrangement of switch similar to that shewn in Fig. 2, excepting
that the arm 19 is insulated, and works in conjunction with two spring contacts 14
and 14", that are insulated from each other as shown at 14" in Fig. 7, like those
shown in Figs. 3, 4 and 5, the coils being connected up as in Figs. 3 and 4.
In every case the shunt & series magnets are prevented from touching by a non
magnetic plate or stop placed between the polar surfaces and carried usually by the
fixed magnet.
°
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. An automatic switch or cut-out comprising two pot electro magnets, namely a
shunt magnet and a series magnet, arranged coaxially with their polar faces in
proximity to each other, and one of which is movable towards and from the other
in the direction of its axis, and a contact making device adapted to be operated
by the movable magnet substantially as hereinbefore described for the purposes set
forth.
2. The improved automatic switches or cut-outs for use in connection with

page_text: dynamos and accumulators to be charged thereby, constructed arranged and
operating substantially as herein before described with reference respectively to
and shown in Figs. 1 and 2; in Figs. 3 and 4; in Fig. 5; and in Figs. 6 and 7, of
the drawings annexed.
Dated this 10th day of February 1891
F. M. NEWTON.
TOM.
HAWKINS.