Improvements in connection with Automatic Electric Circuit Breakers for Automatically Closing the Circuit after Breaking.
Year: 1899

page_text: Date of Application, 28th Sept., 1899
Complete Specification Left, 28th June, 1900-Accepted, 28th Nov.,
1900
Improvements in connection with Automatic Electric Circuit Breakers
for Automatically Closing the Circuit after Breaking.
We, BERTRAM HOPKINSON and ERNEST TALBOT, both of 26, Victoria Street,
Westminster, Electrical Engineers, do hereby declare the nature of this invention
to be as follows:-
This invention relates to improvements in automatic circuit breakers which
are operated so as to break the circuit when the current in that circuit exceeds
a certain amount.
In electric traction and other cases it frequently happens that the cause of the
excess of current lasts but a few seconds and according to present arrangements
the circuit breakers are then closed by hand.
This invention consists in combining with the circuit breaker a device whereby
the circuit breaker is automatically closed after opening either immediately or
at an instant determined by the cessation of the current. In one form the
closing is effected by means of a motor which drives through gearing or other-
wise a disc of soft iron at a speed suitable for the closing of the circuit breaker
preferably without the intervention of any form of reducing gear. Opposed to
the soft iron disc is an electro-magnet also of soft iron connected to the moving
part of the circuit breaker so that when by reason of the excitation of its coils
it is attracted to the soft iron disc the rotation of the latter will close the circuit
breaker while at the same time the circuit breaker can move independently of
the soft iron disc so long as the coils of the electro magnet are not excited.
A switch is fixed to the moving part of the circuit breaker and so arranged
as to close the magnet circuit as soon as the circuit breaker is completely open,
to keep it closed while the circuit breaker is closing, and to open it again as soon
as the circuit breaker is completely closed. Current may be supplied to the motor
through this switch or through another switch which performs for the motor
circuit the same cycle of operations as the first switch does for the magnet
circuit.
When the circuit breaker is completely open the electro magnet will be excited
thus locking the moving part of the circuit breaker to the motor, at the same
time the motor will have its circuit completed and will proceed to close the
circuit breaker. As soon as the circuit breaker is completely closed the switches
operating the motor and the electro magnet will be opened and the moving part
of the circuit breaker will be free. If the current in the circuit has then attained
its normal value the circuit breaker will remain closed. If on the other hand
the current is still excessive the circuit breaker will be free to open and the
operation will be repeated again and again, until the current attains its normal
value.
We may also include in the magnet circuit a switch which is opened by the
rising of the plunger of the circuit breaker or by a movement of the electro
magnet which causes the circuit breaker to open. The effect of this is that

page_text: should the excess current persist the circuit breaker will be free to spring back
immediately on its making contact, and before it is completely closed.
According to another method we arrange two circuit breakers either one on the
line and one in the return circuit, or both in one circuit. These circuit breakers
are closed by gearing driven by an electric motor and so arranged as to operate
the two circuit breakers alternately.
The circuit of the motor is closed by the opening of either of the circuit
breakers and the gearing is so arranged that the closing of one circuit breaker is
completed before the closing of the second is commenced: The motor circuit is
maintained by a rotating contact piece after the second circuit breaker is closed
until the gearing is free from the circuit breaker and thereby allows the same
to be free to be automatically opened when required. By this arrangement of
two circuit breakers it is assured that should the cause of the excess of current
continue when the circuit is closed by the second circuit breaker, the first breaker
automatically opens the circuit; similarly should the second circuit breaker
remain closed it will be opened by the closing of the first.
We may combine with either of the arrangements described a device whereby
the circuit of the motor is not completed until the cause of the excess of current
has disappeared. Such device may consist of a switch included in the motor
circuit and kept open by an electro magnet the exciting coil of which is connected
across the terminals of the circuit breaker. So long as the cause of the excess
of current remains there will be a large difference of potential between the
terminals of the circuit breaker the electro magnet will be excited, the switch
kept open and the circuit of the motor thereby kept open. On the disappearance
of the cause of the excess current the difference of potential between the terminals
of tlie circuit breaker will in certain case likewise disappear, the electro magnet
will cease to be excited, and the switch will be closed by a spring. The motor
circuit will thereby be also closed and the motor will proceed to close the circuit
breaker. The switch may conveniently be fixed to the catch which holds the
circuit breaker closed and in such cases a fine wire coil placed as a shunt across
the terminals of the circuit breaker will be wound on the electro-magnet actuating
it in addition to the series coil.
A fly wheel may be placed on the motor the energy of which will serve to
perform the last part of the operation of closing the circuit breaker.
Dated this 28th day of September 1899.
Improvements in connection with Automatic Electric Circuit Breakers
for Automatically Closing the Circuit after Breaking.
We, BERTRAM HOPKINSON and ERNEST TALBOT, of 26, Victoria Street,
Westminster, Electrical Engineers, 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 automatic electric circuit breakers which are operated
80 as to break a circuit when the current in that circuit exceeds a certain
amount.
In electric traction and other cases it frequently happens that the cause of the
excess of current lasts but a few seconds, and according to hitherto existing
arrangements the circuit breakers must then be closed by hand.

page_text: According to this invention we combine with the circuit breaker a device
whereby the circuit breaker is automatically closed either immediately after open-
ing or at an instant determined by the cessation of the cause of excess current.
In one form this purpose is effected by means of a motor which drives one part
of an electromagnetic clutch, the other part of which is connected to the moving
part of the circuit breaker. Current is supplied to the motor and to the coil
which magnetises the clutch by a switch or switches arranged so as to be opened
and closed at the proper times. The arangement is such that the circuit breaker
in opening moves independently of the parts actuated by the motor because at
that time the clutch is not magnetised.
Current may be supplied to the motor through the same switch as that which
supplies the magnetising current or through another switch which performs for
the motor circuit, the same cycle of operations as the other switch does for the
magnetizing circuit.
Figures 1, 2 and 3 of the accompanying drawings illustrate in views at right
angles to each other an arrangement of apparatus in accordance with this form
of our invention.
Figures 4 and 5 are diagrams of electric connections for the said apparatus
suitable for instance in a storage battery station at a distance from the main
generating station. The type of circuit breaker to which reference is made
particularly through this specification is shewn in greater detail in Figures 6
and 7, but our invention can be applied to any type of circuit breaker by making
suitable modifications in the details.
Referring to Figures 1, 2 and 3, the armature of an electric motor E transmits
motion by the toothed wheels ee and worm e through a worm wheel
formed
on the disc H to a soft iron ring J which is bolted to the said disc H. The said
ring J has a groove in it to receive the coil F of insulated wire. The disc H is
loose on the shaft G.
A disc L is keyed on to the shaft G the said disc L having secured to it a
soft iron ring K which therefore cannot move independently of the shaft.
Cylinders M¹ M³ of insulating material are fixed on to the bosses of the discs L
and H these cylinders supporting the conductive rings N1 N2 N3. The brushes (¹
02 03 which respectively bear on the rings N1 N2 N3 are carried by brush
holders B C to which they are connected by insulating blocks P1 P2 so that the
brushes and their terminals are insulated from one another and from earth.
The two ends of the coil Fare respectively connected to the rings N2_N³. Q
is a spring fitted loosely round the shaft G to keep the faces of the rings J and K
in contact with each other when not magnetized. The said spring can be adjusted
by the nut q.
An arm A is keyed on the shaft G and provided at a with a connection by
which it is fixed to the moving part of the circuit breaker the axes of rotation
of the said moving part and of the shaft G being in the same straight line so
that the rotation of the shaft G in one direction will close the circuit breaker
while the circuit breaker will, in opening, rotate the said shaft in the other
direction. We will presume that the movement of the circuit-breaker in open-
ing is through a quadrant.
On the circumference of the ring K is fixed a quadrant R of insulating material
on the outerside of which is mounted a second quadrant ST one side T of
which is made of non-conductive material the other S of conductive metal. D
is a spring conductive brush fixed to the base of the apparatus in such a position
that it always bears on one or the other side of the quadrant S T, when any part
The two ends of the
of the said quadrant is opposite to the said brush.
quadrant S, T, are tapered off and turned out slightly in opposite directions so
that the brush D bearing on one side of the quadrant S, T, during the partial
revolution of the ring K in one direction will spring over and bear on the other
side of the said quadrant during the revolution of the said ring in the opposite
direction. The said brush D is arranged to bear on the conductive side S during

page_text: the closing of the circuit-breaker and on the non-conductive side T during the
opening of the circuit breaker. Stops are arranged so that the total angular
movement is only one quadrant of a circle in either direction. The end of the
non-conductive quadrant R which is opposite the brush D when the circuit breaker
is fully opened is produced beyond the length of the quadrant proper and has
fixed to it at this part a conductive spring piece V in electrical connection with
the part S so that the brush D having borne on the non-conductive part T during
the breaking of the circuit by the switch will afterwards spring into contact
with the spring piece V. The other end of the quadrant S, T, is so placed rela-
tively to the arm A that the brush D springs out of contact with the conductive
side $ immediately after the moving part of the circuit breaker in closing has
engaged with its catch.
Referring to the diagram Fig. 4 the plunger Z of the circuit breaker is sur-
rounded by the ordinary coil in series with the circuit breaker, whereby on the
occurrence of a short circuit the said plunger is pulled up and by striking the
catch releases the circuit breaker. The said plunger Z is also surounded by
a fine wire coil, connected as a shunt across the terminals of the circuit breaker,
whereby the said plunger is held up so long as the difference of potential between
those terminals exceeds a certain value. The magnetising coil F of the ring J
and the motor E are connected to a portion of the battery and are controlled by
the quadrant contact-maker on the ring R and by the switch W which is in
serics with them. This switch is so placed that it is opened by a projection from
the plunger Z on the said plunger rising and closes again when the plunger
falls.
comes
Assuming the circuit-breaker to be closed, the brush D will be on the non-
conductive side of the quadrant S, T, and no current will pass through the motor,
or the coil F. The ring K and the circuit breaker will therefore be free to move
independently of the ring J. On an excess current occurring the plunger Z will
be jerked up and striking the catch U will free the circuit breaker which will be
driven out by the spring Y. At the same time the line being dead there will
be a considerable difference of potential between the terminals of the circuit
breaker so that a current will flow round the fine wire coil surrounding the
plunger Z which will be held up and therefore the switch W will be kept open.
As the arm A gives partial rotation to the shaft G and disc L and ring K
as soon as the circuit-breaker is completely opened the brush D
into contact with the spring piece V. When the short-circuit ceases the differ-
ence of potential between the terminals of the circuit-breaker drops to a much
smaller value, and the plunger Z falls thus allowing the switch W to close. The
circuit of the motor and of the magnetising coil F is now completed and the
motor proceeds to drive in the circuit-breaker, the moving part of which is now
by magnetic attraction between the rings K and J locked to the parts actuated
by the motor. As soon as the circuit breaker is completely closed the brush D
which has been in contact with the conductive part of the quadrant S, T, springs
over the end of the quadrant S, T, to the non-conductive part thus breaking the
circuit of the motor and magnet and leaving the circuit-breaker free to come out
when next an excess current occurs. Should the short circuit occur again
during the operation of replacing the circuit-breaker the plunger Z will be jerked
up by the excess current as soon as the circuit breaker makes contact and the
switch W will be opened and the circuit breaker being freed, will be driven out
again by the spring Y.
In the arrangement illustrated in Figure 5 the fine wire coil round the
plunger Z is dispensed with and the motor and magnet are connected to the line.
So long as the latter is dead the circuit-breaker cannot be driven in, but as soon
as it becomes alive (which will happen when the cause of excess current has
disappeared and the line has been excited at some other point) the circuit breaker
will be driven in. In other respects the arrangement is the same as that illus-
trated by Figure 4.

page_text: In order to prevent sticking owing to residual magnetism when the current
in the magnetic coils is interrupted, we prefer to slightly separate the faces of
the rings J and K by thin pieces of non magnetic material which may con-
veniently consist of three slips of copper foil soldered on to the face of the
ring K.
According to another form of our invention we arrange two circuit breakers
either one on the line and one in the return circuit, or both in one circuit. These
circuit-breakers are closed by gearing driven by an electric motor, and so arranged
as to operate the two circuit breakers alternately.
The circuit of the motor is closed by the opening of either of the circuit
breakers, and the gearing is so arranged that the closing of one circuit breaker
is completed before the closing of the other circuit breaker is commenced. The
motion of the motor is maintained by a rotating contact piece, or by a fly-wheel,
after the second circuit-breaker is closed, until the gearing is freed from the
circuit-breaker, thereby leaving the latter free to be automatically opened when
required. By this arrangement of two circuit-breakers, should the cause of the
excess of current continue when the circuit is closed by the second circuit-breaker,
it is assured that the first circuit-breaker automatically opens the circuit, similarly
should the second circuit breaker remain closed, it will be opened by the closing
of the first.
Figures 6 and 7 are views at right angles to one another illustrating a method
of carrying into effect this arrangement according to our invention. The two
circuit breakers are mounted so that the axes of rotation of their moving parts XX'
are in the same line and these moving parts are provided with arms XX³. The
shaft G, driven through the worm and worm wheel by the motor E, carries
two cranks A A¹ pointing in opposite directions, and of such length that if either
circuit-breaker be open the corresponding crank will engage with the arm
attached to its moving part as shewn by dot-and-pick lines in Figure 7, and in
the course of the next quarter of a revolution of the shaft, will drive the circuit-
breaker home, and disengage itself when the operation is completed. During
this operation the other circuit-breaker will be free to come out, the crank
opposite to it being out of the way of its arm. Should it come out, however, as
would be the case if the short circuit be still persisting, it will again be driven
in during the next half revolution of the crank and, in this manner, the circuit-
breakers will be put in, and come out, alternately, until the short circuit dis-
appears.
In order to prevent the motor from continually running we prefer to make
use of a switch which shall act to break the motor circuit if both circuit-breakers
be in, but to complete it if either be out. Such switch may be of any convenient
form for example it may conveniently consist of two spring contacts placed in
parallel with one another, and in series with the motor, and so arranged, one on
each circuit-breaker, that the spring is lifted and the contact broken by the
moving part of the circuit-breaker just before its hook U₁ engages with the
catch U. The momentum of the motor will usually be sufficient to push the
circuit-breaker through the short distance remaining after the contact is broken,
but, if insufficient, it can be augmented by the addition of a fly-wheel.
We prefer with this second form of our invention as with the first to make use
of a device whereby the motor circuit is not completed, or current not supplied
to the motor, until the cause of excess current has disappeared. This device will
be essentially the same as that described with reference to Figs. 4 and 5. It
may consist of a switch operated by an electro-magnet whose coils are placed in
parallel with both circuit-breakers, or the same result may be attained by work-
ing the motor from the line so that power is not supplied to it unless the line be
alive.
This device is more particularly applicable to storage battery stations worked
in combination with a central generating station. The arrangement illustrated
in Fig. 4 may however be applied to other cases in which the line is fed only at one

page_text: point. In such a case the resistance of, and number of turns in, the fine wire
coil actuating the switch W, will be so chosen that the plunger will be held up
and the switch kept open, so long as the resistance in the line is less than a
certain amount. As soon as the resistance rises above that amount as will happen
when the short circuit is removed, the plunger will fall and the switch will thus
be closed and the circuit breaker driven in.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:-
1. The combination with an electric circuit breaker of mechanism for replacing
the circuit breaker to complete the circuit, such mechanism being set in opera-
tion when the difference of potential between the terminals of the circuit-breaker
falls below a certain value substantially as herein before described.
2. The combination with an electric circuit breaker of a line supplied with
current both through the circuit breaker and at some other point, and means
actuated by the electrical potential of the line for replacing the circuit-breaker
substantially as herein before described.
3. Means for replacing a circuit breaker the said means consisting of an
electro magnetic clutch one part of which is fixed to the moving part of the circuit
breaker and the other part of which is driven by a motor so as to close the circuit
breaker and a switch fixed to the said moving part of the circuit breaker and
operating to close the circuit of the electro magnet whilst closing the circuit
breaker and to open the said circuit immediately after the circuit breaker has
engaged with its catch and to keep it open during the act of opening the circuit
breaker until the moving part thereof has been fully thrown out substantially
as herein before described.
4. In combination with the arrangement claimed by the preceding third claim-
ing clause of a switch included in the circuit of the electro-magnet and opened
and held open by the action of the plunger of the circuit breaker substantially
as hereinbefore described.
5. The combination of two circuit-breakers in series and of gearing driven by
a motor so arranged as to replace them alternately and during the replacement
of one to leave the other free to come out, substantially as hereinbefore described.
6. The combination with the arrangement claimed by the preceding fifth
claiming clause of a switch or switches included in the motor circuit and so
arranged that the said circuit is broken when both circuit-breakers are in and
made when either is or both are out substantially as herein before described.
7. For use in combination with a circuit-breaker mechanism for replacing the
circuit breaker the said mechanism being constructed or arranged substantially
as herein before described and illustrated with reference to Figures 1, 2 and 3 of
the accompanying drawings.
8. Means for setting in operation the replacing mechanism of a circuit breaker
substantially as hereinbefore described with reference to Figures 4 and 5 of the
accompanying drawings.
9. The combination of two circuit breakers in series and mechanism for re-
placing them substantially as hereinbefore described with reference to Figures 6
and of the accompanying drawings.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.