Improvements in Electric Switches and Cut-outs or Circuit Breakers
Year: 1896

page_text: Reprinted as amended in accordance with the decision of the Supervising Examine
acting for the Comptroller-General dated the 13th day of July 1908.
Date of Application, 27th Oct., 1896
Complete Specification Left, 23rd July, 1897-Accepted, 4th Sept., 1897
Communicated from abroad by Alexander Jay Wurts of Pittsburgh in the County
of Allegheny and State of Pennsylvania United States America Engineer.
"Improvements in Electric Switches and Cut-outs or
Circuit Breakers."
I, REGINALD BELFIELD, of 32, Victoria Street S.W. in the County of London,
Electrician, do hereby declare the nature of this invention to be as follows:-
This invention relates to circuit breakers or switches and has for its object to
improve the constructional details of automatic circuit breakers and of ordinary
switches.
The chief points of novelty in the invention consist firstly in the means
employed for preventing the movement of the switch arm to break the circuit
when the apparatus is jarred or jolted; secondly, means for preventing the too
rapid working of automatic circuit breakers due to a momentary increase of
current; thirdly in an improved construction of circuit breaker for multiphase
systems arranged so that the overloading of any one conductor of the system causes
all the conductors to be interrupted; fourthly in improved means for preventing
damage to the terminals of the switch or contact breaker when the circuit is made
or broken.
The invention furthermore comprises various improvements in detail the nature
of which will be hereafter set forth.
In order that the nature of the invention may be clearly understood it will now
be described with reference to the accompanying drawings in which
Figure 1 is a side elevation of a circuit breaker provided with special means for
preventing interruption of the circuit through jarring or jolting of the apparatus.
Figure 2 is a detail view.
Figure 3 is a diagram of the circuits in a slightly modified construction.
Figure 4 is a side elevation partly sectional of a similar device arranged to open
either when the power circuit is broken or overloaded.
Figure 5 is a front elevation of the same.
Figure 6 is a diagram of the cireuits.
Figure 7 is a modified arrangement of circuits illustrating also a longitudinal
sectional view of a portion of the device.
Figure 8 is a detailed view showing a further modification of circuits.
Figure 9 is a diagram explanatory of a circuit breaker applied to a multiphase
system. The said circuit breaker being adapted to interrupt the circuit in every
wire of the system when an overload occurs in any of them.

page_text: Figure 11 is a side elevation of the same.
Figure 12 is a diagram of the circuits.
Figure 13 a sectional view illustrating a modification of one of the parts
Figure 14 & perspective view of another part.
Figure 15 side elevation of a modified form of the circuit breaker.
Figure 16 a diagram of the circuits through the same.
Figure 17 is a side elevation partly sectional of a quick acting circuit breaker the
circuit being closed.
Figure 18 is a similar view shewing the circuit breaker partially closed parts
being broken away.
Figure 19 is a perspective view of a detail.
Figure 20 is a front elevation of the circuit breaker in open position.
Figure 21 is a section on the line y-y Figure 20.
Figure 22 is a detail view hereinafter explained.
Referring to Figure 1, the numeral 1 indicates the insulating base plate on
which the operative parts of the circuit breaker are mounted, and 2 is the arm
which carries the movable switch contacts at one end and at the other end is
pivoted in a block 3 bolted to the base plate 1. Projecting from the movable
contact member is a catch 5, with which engages a latch 6, the latter being
pivoted to the plate or bracket 7, or other suitable stationary portion of the
device. The plate or bracket 7 is bolted to the base 1, and pivoted thereto,
approximately at its centre of gravity, is an armature 8, provided at its front
end with an opening 9, through which extends a headed pin 10, the body of which
has a diameter somewhat less than that of the perforation 9. This pin 10 is
connected at its lower end to the latch 6 and is of sufficient length so that the
front end of the arinature 8 may be moved up a considerable distance before
coming into contact with the head of the pin to raise the latch out of engage-
ment with the catch 5. The armature is preferably substantially T-shaped, as
shown, and its rear end is provided with two screws 11, or other suitable devices
which may be adjusted to project a greater or less distance beyond the upper
face of the armature, as may be found desirable in practice. The plate or bracket 7
extends forward at its upper end at right angles to the main portion, and this
extension supports a magnetizable core 12. The plate or bracket 7 is preferably
constructed of iron, in order that a good magnetic circuit may be provided for the
coils 13, which is wound about the core 12, and is attached at its two extremities
to the binding posts 14 and 15. The binding post 15 extends through the base
plate 1 and has one of the terminals of the main circuit connected to it, as shown.
The post 14 also extends through the base plate and has connected to it a wire
which leads to one of the stationary switch contacts, as indicated more clearly in
Figure 3. Bolted to the rear of the base 1 is a permanent magnet 16, the poles
of which are located in proximity to the rear end of the armature 8 when it is in its
elevated position and in such a position that the projecting ends of the screws 11
may engage therewith. It being desirable that some portion or portions of the
armature should be maintained substantially at the point of magnetic saturation,
I prefer to make the screws 11 of magnetizable metal.
The operation of the device is as follows. While a normal current only passes
through the circuit, the attractive force exerted upon the front end of the
armature 8 by the magnet 12, 13, will be insufficient to move the armature from the
position shown in the drawing. Further, inasmuch as the armature is pivoted
approximately at the centre of gravity, a force such as gravity or sudden jars, or
any force acting equally on either end of the armature will not tend to displace it,
for the reason that its moments are equal. The armature can only be displaced by
means of the local action of the magnet 12, 13. Accidental movement, therefore,
of the armature is prevented by virtue of the fact that the armature is pivoted at

page_text: the centre of gravity. The function of the permanent magnet 16 is twofold: it is
first only intended to provide a load for the armature, against which the magnet
12, 13 is to act, the load being adjustable through the adjustment of the screws 11.
The function of this load is the same as that of the weights provided in circuit
breakers now in use, the difference being that this load has not the property of inertia.
Second, the permanent magnet holds the armature in a fixed position until time of
critical current, when instant release occurs. In the old form of weighted armature,
where the property of inertia exists, it frequently happens that with a slowly increasing
current through the critical current, the arinature will be raised comparatively
slowly and thereby fail to acquire sufficient momentuin to release the detent. This
is due to the inertia of the armature and the time required to accelerate this
inotion. With the balanced armature and permanent magnet for load, not only is
the inertia greatly reduced, but when the armature is released from the permanent
magnet it passes at that end from a strong magnetic field into a rapidly weakening
one, and at the other end from a weak field into a rapidly increasing field, thereby
securing rapid acceleration, even though the current be slowly increased through
the critical amount.
It is obvious that an electromagnet of proper strength may be employed instead
of the permanent magnet shown.
In Figure 3 I have shown diagrammatically an arrangement of circuits in which
the main wire of the circuit is given one turn around one leg of the permanent
magnet at 17, this arrangement being employed in order to keep the magnetization
of the magnet 16 at an approximately constant value.
Referring now to Figures 4 to 6 the movable contact arm 2 is pivoted at its
lower end to a fixed block 23, which is provided with a recess in which fits a pin 24
provided with a collar between which and the end of the recess is placed a coiled
spring 25. The upper end of the pin 24 impinges against a roller 26 mounted in
an extension 27 of the arm 2 projecting beyond its pivot. The arm 2 is provided
at its upper end with the usual contact devices 28 which engage with the stationary
contacts 29 mounted upon the base. Projecting slightly beyond the end of the
movable contact arm is a catch 30 with which engages a roller 31, mounted upon
the end of a latch 32, which has the form of a bell crank lever, this latch being
pivoted at its middle portion to a suitable projection on the base. Pivoted also to
the base, or a suitable projection thereon, is an armature 33 normally extending
horizontally outward from this pivoted end and supported in that position by the
magnet. The armature is provided at its outer, free end with an adjustable
weight or weights 34, in the present instance shown as a screw provided with nuts
which may be moved inward or outward thereon, and thus made to serve as variable
weights. The armature 33 is also provided at its under side with a lug 35, in which
is mounted a screw 36 in such position as to come into contact with the upper end of
the latch 32 when the armature swings downward under the action of gravity, this
screw 36 being adjustable in order to regulate the position of its point with refer-
ence to the end of the latch 32 with which it engages. Supported by a suitable
bracket or plate 37, adjustably mounted upon the base is an electromagnet 38
having the usual laminated core 39. Mounted upon the base is a receptacle 40,
formed of conducting material, preferably iron, and having a bulb 41 of con-
siderable capacity at its bottom and a vertical chamber 42 of small diameter
extending upward therefrom. This chamber is partially filled with a liquid which
has a high degree of expansion when heated, mercury being preferred for this
purpose. One of the stationary contacts of the circuit breaker is connected to the
lower end of this receptacle by means of a conductor 43, and the magnet coil is
connected to the upper end of the receptacle by the conductor 44. A contact
device 45 projects into the upper end of the receptacle 40 and is insulated
therefrom. This contact device is connected to the main circuit conductor 46 by
a conductor 47 as shown in Figure 5.
When the current through the main circuit the magnet and the device 40
increases to such an extent as to heat and expand the inercury in the latter,

page_text: it will rise in the channel 42 and carry the metal ball 48 into engagement with
the contact 45 and thus complete the circuit around the magnet. The magnet
being thus shortcircuited, the armature 43 will swing into contact with the latch 42
and move it out of engagement with the catch 40.
It is obvious that the armature will also drop as above indicated, if the main
circuit is accidentally interrupted from any cause.
In Figure 7 and 8 I have shown a modification suitable for alternating current
circuits, a secondary coil 49 being provided for the magnet 25 the circuit through
which is closed by means of the liquid, its containing vessel and the supple-
mental contacts. In Figure 8 two supplemental stationary contacts 50 are provided
in lieu of the single contact 45.
It will be understood that a device which will operate to close a short circuit or
a secondary circuit having a different construction from that shown may be
employed, and I do not wish to limit my invention in this particular. The
ball 48 may also be dispensed with if desired, but I regard it as useful in order to
prevent oxidation of the mercury by the arc which may form when the circuit
is broken at this point.
Referring now to Figure 9, 51 and 52 are two-phase generators each provided
with two conductors 53, 54, for the two phases of current, and a conductor 55
common to both phases. In each of the conductors 53 and 54 is included a circuit.
closing device 56, such, for example, as is shown at 40 in Figure 7 and which will
be hereinafter designated as the time element of the system, it being so constructed
and arranged as hereinabove described that after an excessive current has passed
for a predetermined interval of time an auxiliary circuit is closed. Each of the time
elements 56 is connected with one of the stationary contacts 57 of the circuit inter-
rupting device, the other stationary contacts being connected to the terminals of
the line conductors 53 and 54. The movable contacts 58 of the circuit interrupter
are all mechanically connected to operate together, and those for each phase are
electrically connected so as to bridge the corresponding stationary contacts 57. The
movable member of the switch is normally held in its closed position by means of a
catch 59 connected to an armature 60, as is usual in this class of devices. In
order to raise the armature 60 and the latch con nected therewith, I provide a
suitable electro-magnet 61, the coil of which is connected in a local circuit 62, 63
supplied with current from any suitable source, that shown in the present case
being a transformer 64. This local circuit 62, 63 is normally open, as indicated in
the drawing, and is closed through any one of the time elements 56, whenever the
current in the conductor in which such time element is included becomes sufficiently
overloaded to actuate the circuit closing device.
It is obvious from the illustration and foregoing description that whenever the
current in any one of the conductors 53, 54, exceeds a predetermined limit, all of the
circuits from that particular generator will be automatically interrupted. It will
also be understood that any number of generators and circuits may be connected
with the local circuit in the inanner shown. It will also be understood that this use
of a local circuit for energizing the controlling magnet for the circuit breaker may
be employed in connection with a single phase system of distribution, if desired,
and hence I do not limit my invention to use in connection with multiphase-
circuits as shown in the drawing.
It being often desirable in large power houses to open any one of several circuit
breakers from a given point which may be more or less remote from such circuit
breakers, I extend the local circuit conductors indicated at 65, 66 and 67 to the
point from which it is desirable to actuate the circuit breakers and locate at this
point suitable circuit, closing devices 66 one for each circuit breaker. These circuit
closing devices may be push buttons or any other desired form of hand operated
means whereby the local circuit may be closed through any one of the controlling
magnets 61 when is desired to open the circuit breaker with which such magnet
is connected.

page_text: Referring now to Figures 10, 11, 12 and 13, 72 are the stationary contact terminals
suitably supported by the base. Each of these stationary contact terminals con-
sists of a bundle of conductors soldered to a base piece 73 and also fastened thereto by
means of bolts or screws 74, as shown in Figure 11. The outer free ends of these
contact terminals are bevelled as indicatod in the drawing in order to provide the
necessary contact face for engagement with the movable contact devices. These
stationary contacts are arranged in pairs, one for each branch of the circuit. In the
present instance the switch is shown as designed for use in a two phase circuit pro-
vided with three line conductors, one of which is common to both phases, there
being thus provided three pairs of such contact terminals. Bolted to each base 73
is a spring 75, which bears at its tree end a contact block 76, formed mainly
of carbon or some other suitable conducting and substantially infusible material,
and having a contact face plate 77, or copper or other good conducting metal
extending through a portion of its length.
The movable member of the circuit breaker comprises an arm 78 pivoted to a
block or casting 79 upon the base 1, such block or casting being provided with leaf
springs 80 for the reception of the arm 78, and also with the usual spring, not
shown, for throwing the arm backward when released. The arm 78 is provided at
its free end with a bar 81 of sufficient length to bridge all the stationary contacts,
and mounted upon this bar are three contact plates 82, suitably insulated from the
bar 81 by mnica 821 or otherwise, and so located that they will respectively bridge
the several pairs of stationary contacts corresponding to the three conductors of
the circuit. Each of the plates 82 is extended beyond the outer edge of the sup-
porting bar 81, and has fastened to it a contact piece 83 for engagement with the
corresponding stationary contact 76. As shown in the drawing, the plate 82 is bent
around the outer ends of the main portions of the pieces 83 and set into the face of
the same so as to provide a metal face which extends over a portion of the length of
the said piece to engage with the corresponding plate 77 of the contact 76. The
main portion of this contact 83 is formed of carbon or some other substantially
infusible, conducting material and is of substantially the same form as the part 76
except that it has a convex bearing surface, whereas the part 76 has a corresponding
concave bearing surface, the curvature of these parts being substantially that of
the arc of a circle struck from the pivotal axis of the arm 8 as a centre when the
circuit breaker is closed.
It is obvious that the portion of the plate 82 which ruskes contact with the
part 77 of the contact 76 may be a separate piece if desired. It is here shown as an
integral part of the plate 82, in order to provide a better conducting path for the
As the volume of current to be interrupted by this breaker will, however,
ordinarily not be very great, the screws which fasten the auxiliary contact plate
with the main contact will probably under ordinary circumstances afford a
sufficiently good conducting path for the current.
84 is a magnet core preferably laminated and suitably fastened to and supported
by a base piece 84. This core is provided with a few turns of wire 85, forming
part of the middle or common conductor, 86, of the circuit, and the two legs of the
core are each surrounded by a coil 87 of fine wire, these coils 87 being connected in
series and so arranged with reference to the coil 85 that when the circuit through
them is closed, they will be inductively influenced by the current through the
coil 85 and have an opposite magnetizing effect of the current in the coil 85.
88 is an armature pivoted to the base piece 84' and provided with a screw or
other projection 88. 89 is a latch also pivoted to the base piece 84', or some other
suitable support, and provided at its outer free end with a roller 90. This roller
engages with the hooked end or catch of a plate or piece 91 projecting from the
free end of the arm 78. Projecting upwardly from the latch 89 is a piece 92 in
position to be engaged by the screw 881 when the arinature 88 falls in order to
withdraw the latch and release the movable member of the breaker.
As will be readily understood from the foregoing description, when a normal
current is carried by the main circuit, the magnetizing effect of the current in the

page_text: coil 85 will serve to retain the armature 88 in contact with the free ends of the
core 84; but if the current in this circuit fails for any reason, or if the circuit in-
cluding the coils 87 is closed so as to counteract the magnetizing effect of the
coil 85, the armature 88 will be released and will effect the release of the movable
member of the breaker which will be instantly thrown open.
In order to guard against the opening of the circuit when a current in excess of
the normal current is only momentary, I provide a device which will be now
described. 92 is a tube forined of insulating material, preferably glass, and sup-
ported by means of a pair of clips or brackets 94 and 95, the upper clip 95 being
provided with a clamping screw 95 in order that the tube may be adjusted longi
tudinally, if desired, the reason for such adjustinent being more fully set forth
hereinafter. These tubes are partially filled with liquid 96, glycerine being a
desirable liquid for this purpose, its character being such that the movement of a
solid body through it must necessarily be slow. I do not desire to limit my in-
vention, however, as regards the particular liquid employed. The upper end of
each tube is closed, preferably by means of a stopper 97, of some suitable
insulating material such as wood, cork, or vulcanized fibre, and through this stopper
extend two contacts 98. Each tube 93 is surrounded by a coil 99 which forms a
part of the corresponding side of the main circuit, and inside the tube is a core
which is mainly formed of magnetizable material and is provided with means for
closing the circuit between the two contact terminals 98. This core, as shown in
Figure 10 of the drawings, is constructed of a bundle of iron wires 100 through
which extends a rod 101 of any suitable material, screw-threaded at both ends.
Upon its lower end is mounted a cap 102 of insulating material, such, for example,
as wood, and on its upper end is a circuit closing piece 103 formed of good con-
ducting material and screwed upon the upper end of the rod 100. This circuit
closing piece is preferably slotted as indicated at the right in Figure 10 in order to
prevent the setting up of Foucault currents therein by induction from the coil 99.
Between this circuit elesing piece 103 and the bundle of wires, 100, is a cap 104
for engagement with the upper ends of the wires and together with the cap 102
and rod 100 retaining such wires in a compact bundle. "The upper ends of the
contacts 98 are connected in circuit with the coils 87 as is clearly indicated in
Figure 12 of the drawings, so that when an excessive current traverses either of
the coils 99, the core will be caused to move upward, but on account of the body of
liquid in the tube, the core will move slowly until it has nearly reached the limit
of its upward movement so that there will be no danger of its closing the
secondary circuit unless the excessive current continues for a material length of
time, the period necessary for the closing of the circuit being determined by the
position of the tube 93, which may be adjusted longitudinally to the desired
position.
In Figure 13 is shown a modification of the circuit closing device in which the
iron wires 100 are held together by means of a cord 105 wrapped around them and
the contacts 98 are so arranged that the upper end of the rod 101' will press them.
into engagement instead of bringing a circuit closing bridging piece between them,
as is the case in the construction shown in Figure 10. In other respects the form
shown in Figure 13 is substantially the same as that shown in Figure 10.
The device shown in Figure 13 or the modification shown in Figure 10, is admir-
ably adapted for use as a dash pot, if instead of clamping it in position it be left
free to move longitudinally through its coil. When used for this purpose, the cir-
cuit contacts carried by stopper of the tube would obviously be omitted and the
tube might be entirely filled with liquid, if desired. The differential movement
between the core and tube due to the mechanical resistance of the liquid is such as
to render the devico peculiarly desirable in many cases where retardation of the
movement of a mechanical element is necessary."
In the form of the apparatus illustrated in Figures 10 and 11, the circuits of
which are diagrammatically shown in Figure 12, the armature is normally held in
contact with the poles of the magnet and is dropped to release the movable mem-

page_text: ber of the circuit breaker either when the current fails in the main circuit, or when
there is an overload which persists for a sufficient length of time to close the
secondary circuit. It is necessary to employ this form of the apparatus only in
cases where it is desired to automatically open the circuit breaker both for overload
and the failure of current in the main circuit. In view of the fact that it is some-
times difficult to so adjust the apparatus that the arinature will be maintained in
its position in contact with the poles of the magnet through wide variations in the
amount of current in the circuit, and also because of the humming noise which is
caused by the action of the alternating current upon the iron of the core and
armature, it is often preferable to employ a breaker in which the armature is
norinally separated from the poles of the magnet and is raised into engagement
therewith in order to release the movable member of the breaker.
Such a form of apparatus is illustrated in Figures 15 and 16. The several parts
of this form of apparatus with the exception of the featuros which will herein-
after specifically pointed out are the same in construction and mode of operation
as those heretofore described. The armature 881 of this form of breaker is
pivoted to the base piece in substantially the same manner as the armature 88
already described, and is provided with a depending pin 106 which extends through
an opening of somewhat larger size in the latch 80' and is provided at its lower
end with a head 107. It will be understood from this construction that in the
normal condition of the apparatus the armature will be in its lowest position and
will serve to withdraw the latch 89 from the catch 91 only when it is raised into
contact with or proximity to the ends of the magnet core 841. It will be seen by
reference to Figure 16 that two primary coils 107, 108 one for each outer conductor
of the two-phase circuit are employed, and that a single secondary coil 109 is
located in inductive relation to the said primary coils. The coil 109 is in series
with a coil 110 on the core 8411 and the terminals of the circuit, including these
coils 109 and 110 are constructed and arranged in the same manner as the terminals
of the secondary circuit described in connection with the other form of the
apparatus.
It will be understood from the foregoing description that if the current of either
phase increases beyond the critical amount and is maintained for a sufficient length
of time to close the secondary circuit, a secondary current will be set up by induc-
tion in the coils 109 and that such current will energize the coil 110 thus magnet-
ising the core 8411 and raising the armature 8811 the lost notion between the
head 107 of the pin 106 and the latch 89 having the effect of causing the head
107 to give a sharp, quick blow to the latch, and thus withdraw it from the
catch 91.
In some cases where the voltage of the main circuit is not too high, the coils
107, 108 and 109 of Figure 16 may be dispensed with and the coil 110 included in
a shunt to the main circuit which is normally open and which may be closed by
either of the circuit closing devices above described, as will be readily understood.
The arrangements above described are equally well adapted to circuits having a
different number of phases and a different number of conductors to that shown.
It will also be understood that instead of locating the secondary circuit closing
means in the two separate branches, such means may be located in the line which
is common to the two phases, if desired. I prefer the construction shown how-
ever.
Referring now to Figures 17 to 22, 162 is a hollow block or casting secured to
the base and provided with the usual leaf spring jaws 163 for the reception of the
arm 164 of the movable member of the circuit breaker when it is thrown open.
The arın 164 is journalled at its inner end upon a pintle 165, mounted and free to
turn in the casting 162. A stop piece 166, having a lug 166 is mounted upon
the pintle 165 and rigidly fastened to it be a set screw 167. A block 168 is
pivoted to the piece 166 and bears against the upper end of a coiled spring 169.
A rod 170 depends from the block 168 and serves to retain the spring 169 in its
proper position. The arin 164 is provided with the usual handle 171 and also with

page_text: a small roller 172 the latter being in position to be engaged by the hook at the end
of latch 173, when the breaker is closed. The contact portion of the movable
member of the breaker is a bar or plate 174, to which are fastened, preferably at
its upper edge, two curved contact springs 175, the purpose of which will be
hereinafter more fully described.
Suitably fastened to the bar or plate 174 and preferably between the same
and the adjacent portion of the arm 164, is a spring plate 176, preferably formed
of copper and having two curved end proportions projecting beyond the bar 174.
Fastened to each projecting end of this spring plate is an auxiliary contact piece 177,
comprising a block 178 formed of carbon or some other good conducting material,
which is practically infusible, and a plate 179 of copper or other metal having
a high degree of conductivity. I prefer to form the blocks 178 of carbon, but I do
not desire to limit my invention to this material, for the reason that graphite,
or some composition which has the necessary conducting properties and is practically
infusible by electric ares, may be employed in lieu thereof. Each metal plate 179
is set into a recess which is formed in the outer face of the block 178 and extends
through a portion only of its length, so that the outer face of the plate and that of
the free end of the block combine to form a single snooth contact surface. The
contacts 177 being connected by a single copper plate, a good conducting path
between them is ensured irrespective of the character of the contact between
the said plate and the bar 174.
The ends of the supporting spring 176 are preferably clamped between the
blocks 178 and plates 179 so as to inake good electrical contact with the said
parte.
I prefer to give the faces of the contact pieces 177 the form of the arc of a circle
struck from the centre of the pintle 165 when the circuit breaker is closed. These
contacts are also slotted longitudinally, as clearly indicated in Figure 29, such
slots extending a short distance into the supporting spring place, in order that the
contacts may adapt themselves to any irregularities in the surface of the stationary
contact terininals with which they engage. Each of the main stationary contact
terminals 180 consists of a bundle of thin plates, which are clamped together
and to a projection on a supporting base piece 181. Tho inner end of each contact
terminal is also preferably united to the part 181 by solder or amalgam. These
leuinae, or the larger portion of thein, terminate in a plane, which is inclined at
such an angle to the base of the circuit breaker that the contact bar or plate 174
will make a close contact therewith. The angle of the plane of the contact ends of
theso laminae is also such that the bar or plate, 174 will engage them one after
another, beginning with the outermost one, in closing the breaker, thus successively
lifting or deflecting each of the said ends slightly from its normal position.
As will be seen by reference to Figures 17 and 18 of the drawings, this operation
results in a maximum deflection of the free ends of the outer laminae and in little
or no deflection of the innermost ones. A sliding engagement between the parts
174 and 180 is also effected, which helps to ensure a good contact between them
and keeps the contact surfaces bright and clean. While I prefer to form these
contacts of thin copper plates, it will be understood that the individual elements of
which the contact is composed may have any other form in cross-section which
inay be found convenient, provided they are sufficiently resilient to effect the
desired result.
Suitably fastened, preferably by means of bolts, to a projection on each supporting
piece 181, is a spring plate 182, to the outer end of which is fastened a terminal
contact 183, with which the corresponding movable contact 177 engages. Each of
these contacts 183 comprises a block 184 and a plate 185, which are preferably
made of the same materials as are the corresponding blocks 178 and plates 179 of
the contacts hereinbefore described. The curvature of the contact faces of the
contacts 183 is also the same as that of the faces of contacts 177 except that it is
concave instead of conver. This curvature of the engaging faces of the shunt
contacts ensures a good electrical contact between the entire engaging surfaces,

page_text: not only when the breaker is closed but during the opening of the same, until
the metal portions of the contacts are separated.
The construction of the shunt contacts partially of metal and partially of carbon,
or some other substantially infusible conducting material, is an important improve-
ment over the carbon shunt contacts which have heretofore been employed in this
class of devices. In the employment of shunt contacts made entirely of carbon in
circuit breakers employed to open circuits carrying heavy currents, it has been found
that the carbon was not a sufficiently good conductor to shunt all of the current
around the main circuit terminals, and that consequently such main circuit
terminals often became seriously injured by the arcs due to the unshunted current,"
so much so, in fact, that it was necessary to cut away the blistered surfaces before
the switch could be again closed. With the present construction of shunt contacts,
it will be readily seen that a complete metal path is provided for the current until
the main contacts have become separated a considerable distance, and that conse-
quently the entire current will be shunted. The conductibility of the shunt path
for the current is also materially improved in the form of circuit breaker shown by
curving the metal contact faces in the manner above described. When the metal
contact plates of the shunt become separated, the current will obviously be com-
pelled to take the path provided by the infusible material, so that the final inter-
ruption will occur, as in the old form of breaker, where the resulting arc can do
little, if any, dainage.
These stationary shunt contact blocks also have their free ends bevelled or inclined
toward each other, as indicated most clearly in Figure 22, in order that the inter-
ruption of the current shall occur at their outermost points. This feature of con-
struction is desirable, in order that the contacts may be placed near enough
together to make a compact structure without danger of arcing across from one
terininal to the other.
The location of the stationary shunt contacts side by side above the main body
of the breaker is desirable since the arcs formed between the separated terminals
are substantially horizontal and therefore easily interrupted, and, furthermore, all
danger of injury to the main terminals is substantially avoided by reason of such
location. Any tendency to arcing between the stationary contacts is largely
counteracted by the repelling action excited by the arcs against each other.
Instead of employing a solenoid or magnet coil for actuating an armature to
release the movable member of the circuit breaker when the current increases
beyond the predetermined limit, as is usual in this class of devices, I utilize one of
the main contacts of the circuit breaker for this purpose, and in lieu of the usual
solenoid or inagnet core, I provide a body of magnetizable metal, preferably in the
form of a band 186, which partially surrounds the stationary contact and is of
sufficient width and thickness to provide a good magnetic circuit.
As shown in Figure 20 of the drawings, this band 186 is fastened in position by
means of the bolts which fasten the contact 180 to the base piece 181, and is bent
around the edges of the contact in such manner that the end near the central line
of the breaker projects somewhat beyond the face of the contact and at right angles
to the plane of its back, the other end projecting a materially less distance. This
particular form of band is not essential, but it has been found operative and useful
in practice.
Below the stationary contacts and substantially midway between them is located
a block or casting 187 provided at one side with an arm 188, between which and
the base of the casting is pivoted a bar armature 189. This armature 189 is pro-
vided with an opening 190 midway between the stationary contacts through which
extends a bolt 191, the head of which rests upon the upper surface of the armature.
The bolt 191 also extends through a similar opening in the latch 173, and is pro-
vided with a nut, so that when the armature is actuated by the magnet above
described, the first part of its movement will serve to raise the bolt until the nut is
brought into engagement with the latch 173, and a further movement will serve to

page_text: withdraw the latch from the roller 172, thus permitting the movable member of the
breaker to be instantly thrown back by the action of the spring 139. The lost
motion between the armature and latch is employed in order to permit the arma-
ture to enter the strongest part of the magnetic field before acting upon the latch,
thereby ensuring an effective and sudden releasing blow.
In order to ensure the retention of the movable member of the breaker in its
closed position until the volume of current at which it is designed to open is reached,
and to ensure a sudden tilting of the armature and consequent withdrawal of the latch
when the current reaches the maximum allowable limit, I provide the second sta-
tionary member 180 of the breaker with an iron band 186, preferably of the same
shape as the band 186, except that the portions adjacent to the edges of the contact
are materially shorter than the corresponding portions of the band 186, in order thas
the number of lines of force passing through the adjacent end of the armature shall
be less than the number threading the opposite end. The necessity of some expedient
whereby the pull of this magnet shall be made weaker than that of the other is obvious,
since the magnetic pull at this end constitutes a load which must be overcome in order
to effect the withdrawal of the latch, but it will be understood that means different
from that shown, whereby the strength of the magnet or the action of the same
upon the armature is modified, may be employed, if desired. The character of the
load is such that when the pull upon the opposite end of the armature is sufficient
to overcome it, the tripping action will occur with a sharp, sudden jerk, which is
particularly effective and desirable in this class of apparatus.
I also provide the load end of the armature with a small set screw 192 the inner end
of which bears against the outer end of the band 186 and is adjustable in order to
provide for different loads. I prefer to make this screw of magnetizable metal, in
order that it may serve as a saturated element in the magnetic circuit; but it may be
made of other material, if desired. Any other suitable adjustable device may also be
employed in lieu of the screw. 193 is a bar or rod provided with a suitable scale
and supported from the arinature and parallel to it by means of rods 194. A weight 195
is mounted upon the bar 193 in such manner that it may be moved back and forth
thereon in accordance with the critical load for which the breaker is to be set. 36
is a screw for clamping the weight 195 at any desired position on the bar 193.
197 and 198 are bars or strips provided with outwardly projecting upper ends and
with handles at their lower ends. These bars have a slot and pin connection with
the base and serve respectively, when pressed upwardly, to tilt the armature in
the one direction or the other.
It will be understood from the foregoing description that the breaker may be set
by means of the screw 192 and weight 195 to open any desired load, and that when
such load is reached, the latch will be withdrawn with a sudden jerk due to the sudden
release of the armature by the load magnet and the lost notion between the latch
and armature. The spring 169 will then act through the parts 168, 166, and 166*
to separate the contacts, after which the arm 164 will fall away from the lug 166
and between the leaf springs 163, by reason of the impetus imparted by the spring 169
and the action of gravity.
Immediately upon the separation of the main contacts, which will occur without
material frictional resistance, the entire current will be shunted through the copper
plates 179 and 185 and the spring supports 176 and 182. When the plates 179 and
185 become cuiupletely separated, the current will be forced to take the path through
the infusible biocks 178 and 184, and will be finally interrupted at the outermost
corners or tips of these blocks.
It is therefore apparent that under ordinary circumstances, all possibility of injury
to the main contacts of the breaker is obviated. Should it happen, however, that
the current should not be entirely shunted through the auxiliary contacts, any current
which fails to make that path will be interrupted between the springs 175 and the
outer sides of the ends of the stationary contacts, where it will do little, if any, harm.
I desire it to be understood that my invention is not limited to the particular
construction and arrangement of the parts shown and described, since the devices

page_text: may be considerably modified without departing from the spirit and scope of the
invention.
Dated this 27 day of October 1896.
W. P. THOMPSON & Co.,
Patent Agents for the Applicant,
322, High Holborn, W.C.
Improvements in Electric Switches and Cut-outs or
Circuit Breakers.
I REGINALD BELFIELD of 32 Victoria Street, S.W. in the County of London Elec-
trician 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:-
The chief points of novelty in the invention consist firstly-in-the-means-employed
for-preventing-the-movement-of--the--switch--arm-te--break--the--cireuit--when--the
apparatus-is-jarred-or-jolted; secondly,-means-for preventing-the-too-rapid-working
+f-automatie-eircuit-breakers-due-to-a-momentury-increase-of-current--thirdly-in-an
improved-construction-of-circuit-breaker-for-multiphase--systems--arranged-so-that
th.-overloading-of-any-one-conductor-of-the-system--causes-all-the-conductors-to-be
interrupted-fourthly an improved means for preventing damage to the terminals
of the switch or contact breaker when the circuit is made or broken.
The invention-furthermore-comprises various-improvements-in-detail--the--nature
of-which-will-be-hereafter-set-forth.
In order that the invention may be clearly understood I will now describe the
same with reference to certain the drawings filed with the Provisional Specification;
in which
Figure-2-is-a-detail-view:
Figure--is-a-side-elevation-of-a-eireuit-breaker--provided-with--special--means-for
preventing-interruption-of-the-circuit-through-jarring-or-jolting-of-the-apparatus.
Figure-3-is-a-diagram-ef-the-eirenits-in-a-slightly-modified-construction.
Figure-4-is-a-side-elevation-partly-sectional-of-a-similar--device-arranged-to-open
either-when-the-power-eireuit-is-broken-or-overloaded.
Figure-b-is-a-front-elevation-of-the-same:
Figure-6-is a-diagram of-the-eireuits.
Figure 7-is-a-modified-arrangement-of--eirenits--illustrating-also-a-longitudinal
seotional-view-of-a-portion-of-the-device.
Figure-S-is-a-detailed-view-showing-a-farther-modification-of-eireuits.
Figure-0-is-a-diagram-explanatory-of-a-eirenit-breaker--applied--to--a--multiphase
system, the-said-eirenit-breaker-being-adapted-to-interrupt-the-eireuit-in-every-wire
of-the-system-when-an-overload-occurs-in-any-of-them.
Figure 10 is a front elevation partly sectional of a circuit breaker shewing the im-
proved means which-only-opens-the-eireuit-after-an-excessive-current-therein has-con-
tinued-for-a-certain-length-of-time.
Figure 11 is a side elevation of the same.
Figare-12-is-a-diagram-of-the-eirenite.
Figure-13-a-sectional-view-illustrating-a-modification-of-one-of-the-parts.
Figare 14 a perspective view of another one of the parts.
Figure 15 side elevation of a modified form of the circuit breaker.
Figure-10-a-diagram-of-the-circuits-through-the-same.

page_text: Figure 17 is a side elevation partly sectional of a quick acting circuit breaker the
circuit being closed.
Figure-18 is-a-similar-view showing the--eirenit--breaker-partially--elosed--parts
being-broken-away.
Figure 19 is a perspective view of a detail.
Figure 20 is a front elevation of the circuit breaker in open position.
Figure-21-is-a-section-on-the-line-y-y-Figure-13.
Figure 22-is-a-detail-view hereinafter-explained.
Referring-to-Figure-1,-the-numeral-1-indientes-the-insulating-base-plate-on-which
the-operative-parts-of-the-eireuit--breaker-are--mounted, and--is--the-arm-hich
earries the movable-switch contacte-at-ne-end-and-at-the--other-end-is-pivoted-in-a
block-3-bolted-to-the-base-plate-1.-Prejeeting-from--the--movable-contact-member
is-a-eateh-5,-with-which engages-a-lateh-6,-the-latter-being-pivoted--to--the--plate-or
bracket-i-or-other-suitable-stationary-portion-of the-device. The-plate-or-bracket-7
is-belted-to-the-base-1;-and-pivoted-thereto, approximately-at-its-centre-of-gravity,
is an-armature-8,-provided-at-its--front-end with--an--opening--0,-through-whi h-ex-
tende-a-headed-pin-10,-the-body-of-which-has-a-diameter--somewhat-less--than-that
of-the-perforation-0.-This-pin-10-is-connected-at-its-lower-end-to-the-latch
G-and-is
of sufficient-length-so-that-the-front-end-of-the-armature-8-may-be-moved-up-a-eon-
siderable-distanee-before-coming-into--contact-with--the--head-of-the-pin-to-raise the
lateh-out-of-engagement with the catch-5.-The-armature-is-preferably substantially
T-shaped,-as-shown,-and-its-rear-end-is-provided-with-two--serows-11,-or-other-suit-
able-devices-which-may-be-adjusted-to-project-a-greater-or-less-distance-beyend-the
upper-face-of-the-armature;-as-may-be--found--desirable--in-practice. The-plate--or
bracket-7-extends-forward-at-its-upper-e..d-at-right-angles-to-the-main-portion, and
this-oxtension-supports-a-magnetisable-core-12.-The-plute-or-bracket-7-is-preferably
constructed-of-iron;-in-order-that-a-good-magnetic--eireuit--may-be-provided-for-the
ceil-13,-which-is-wound-about-the coil-12,-and-is-attached-at-its--two--extremities-to
the-binding-posts-14-and-16.-The-binding-post-15-extends-through-the-base-plate-1
and-has-one-of-the-terminals-of--the--main--eirenit--conneeted--te-it-as-shown.-The
post-14-also-extends-through-the-base-plate-and-has--connected--te--it--a-wire-which
leads-to-one-of-the-stationary-switch-contacts,-as indiented-more elearly-in-Figure-3.
Bolted-to-the-rear-of-the-base-1-is-a-permanent--magnet--16,-the-poles-of-which-are
located-in-proximity-to-the-rear-end-of-the-armature-S-when--it--is--in--its--elevated
position-and-in-sach-a-position-that-the--projecting-ends--of--the--serews-11-may-en-
gago therewith.-It-being-desirable-that-some-pertion-or-portions--of--the-armatape
should-be-maintained-substantially-at-the-point-of-magnetie--saturation,-I-prefer-te
make-the-serews-11-of-magnetizable metal-
The-operation-of-the-device-is-as-follows--While--a--normal--enrrent-only-passes
through-the-circuit, the-attractive-force-exerted-upon the front-end-of the armature-8
by the-magnet-12,-13, will-be-insufficient-to-move-the--armature--from--the-position
shown in-the-drawing. Further, inasmuch-as-the-armature is pivoted approximately
at-the-centre-of gravity, a foree-sueh-as-gravity--or-sudden-jurs;-or-any-loree-acting
equally-en-either-end-of-the armature-will-not-tend-to-displace-it, for-the-reason-that
its-moments-are-equal. The armature-ean-only-be- displaced--by-means-of-the-local
action-of-the-magnet-12-13-Aeerdental--movement, therefore,-of-the-armature--is
prevented-by-virtue-of-the-fast-that-the-armature-is-pivoted-at-the centre-of-gravity.
provide-a-load-for-the-armature,-against-which-the-magnet-12,-13, is to a t-the-load
The--function--of-the-permanent-magnet-16-is-twofold-:-it-is-first-only-intended-to
being-adjustable-through-the-adjustment--of-the--s-rews--11.-The--function-of-this
load is-the-same-as-that-of-the-weights-provided-in eireuit-breakers--now-.n-use,-the
difference-being-that-this-load-has-not-the-property-of-inertia. Second, the-perma-
nent-magnet-holds-the-armature--in-a-fixed-position--until--time-of--critical-current,
when-instant-release-occurs. In-the--old--form--of--weighted-armature,--where--the
property-of-inertia-exists,-it-frequently-happens-that-with-a--slowly-increasing-eur-
rent-through-the-eritical-current-the-armature-will-b-raised-e munratively-slowly
and-thereby-fail-to-acquire-sufficient momentum-to-release-the-detent,-This-is--due

page_text: to-the-inertia-of-the-armature-and the-time-required-to-accelerate-its-motion-With
the-balanced-armature-and--permanent--magnet--for-lead-not-only--is--the--inertia
greatly-redu ed;-but-when-the-armature-is-released-from-the-permanent--magnet--it
passes-at-that-end--from--u--strong-magnetie--field-into--a--rapidly-weakening--one;
and-at-the-other-end-from-a-weak-field-into-a-rapidly-inereasing-field;-thereby-secur-
ing-rapid-acceleration;-even-though-the-current--be-slowly--inereased--through-the
eritical-amount
It-is-obvious-that-an-electromagnet-of-proper-strength -may-be--employed-instsad
of-the-permanent magnet-shown:
In-Figure-3-I-have-shown-diagrammatically-an-arrangement-of--cireuits-in-which
the-main-wire-of-the-eirenit-is-given-one-turn--around--one--leg--of-the--permanent
magnet-at-17,-this-arrangement-being-employed-in-order-to-keep-the-magnetization
of-the-magnet-16-at-an-approximately-constant-value.
Referring-now-to-Figures 4-to-6-the-movable-contact-arm is pivoted-at-its-lewer
end-to-a-fixed-block-23,-which-is-provided-with-a-recess--in-which-fits-a-pin-24-pro-
vided-with-a-celler-between which-and-the--end--of--the--reeess--is--placed--n--coiled
spring-26: The-upper-end-of-the-pin-24-impinges-against-a-roller-26-me nted-in-an
extension-2-of-the-arm-2-projecting-beyond-its-pivot. The arm-2-is-provided-at-its
stationary-con-
apper-end-with-the-usual-zontuet-devices-23-which--engage-with-the
taets-20-mounted-apon-the-base.-Projecting-slightly-beyond-the--end--of-the-mor
able-contact-arm-is-a-cateh-30-with-which-engages-a-roller--31,--mounted--upon-the
end-of-a-latch-32,-which-has-the-form-of-a--bell-erank-lever-this-latch-being-pivoted
at-its-middle-portion-to-a-suitable-projection-on-the-bas::Pivoted-a'so-to-the-base,
or-a-snitable-projection-thereon,-is--an-armature-33-normally-extending-horizontally
outward-from-this-pivoted-end-and-supported-in-that-position-by-the-magnet. The
armature-is-provided-at-11s-outer,-free-end-with-an--adjustable-weight-or-weights-34,
in-the-present-instance-shown-as-a-s.rew-provided-with-nuts--which--may-be-moved
inward-or-outward--thereon,--and--thus--made--to-serve--as--variable--weights.-Th
armature-33-is-also provided-at-its-under-side-with-a-lug-35,-in-which-is--mounted--a
serew-36-in-sueh-position-as-to-come-into-contact-with-the-upper-end-of-the-lateh-33
when the-armature--swings -downward--under--the--aeti n-of-gravity,-this-serew-36
being-adjustable-in-order-te-regulate-the-position-of-its-point-with -reference-to--the
end-of-the-lateh-33--with--which--it-engages-Supported--by--a-suitable-bracket-or
plate-37, adjustably-mounted--upon--the--base-is-an--electromagnet-38--having-the
nual-lam.nated-core-39.-Mounted upon-the-base-is-a-receptacle-40,-formed-of-con-
dueting-material-preferably-iron,-and-having-a-balb-41-of-considerable-capacity-at
its-bottom-and-a-vertical-chamber-42 of-small diameter-extending-upward-therefrom.
This-chamber-is-partially-filled-with-a liquid which has-a-high--degree-of-expansion
when-heated-merenry-being preferred-for-this-purpese: One-of-the-stationary-con-
taets-of-the-eireuit-breaker-is-connected-to-the-lower end-of-this-receptuele-by-means
of-a-conductor-43,-and-the-magnet-eoil-is-connected-to-the--upper-end-of-the-reeep-
taele-by-the-condnetor-44.-A-contact-device-45-projects-into-the--upper--end-of-the
receptaele-40-and-is-insulated-therefrom. This-contact- device-is--connected-to-the
main-eirenit-conductor-46-by-a-conductor-47-as-shown-in-Figure-5.
When-the-eurrent-through-the-main--eireuit--the--magnet--and-the-device--19-in-
Greases-to-such-an-extent-as-to heat-and-expand--the-mereury--n--the--latter;-it-w.ll
rise-in-the-channel-42-and-earry-the metal--ball--48-inte--engagement-with-the-een-
taet-45-and-thus-complete-the-eirenit-around-the-magnet.-The-m gnet--being-thus
it-out-of-engagement-with-the eateh-40.
short-eirenited,-the-armature-43-will-swing-into-contact-with-the-lateh-42-and-move
It is obvious-that-the-armature-will-also-drop-as-above-indicated;-if-the-main-air-
enit-is aeeidently-interrupted-from-any-cause.
In-Figures-7-and-8-I-have-shown-a-modification-suitable--for--alternating-earrent
eireuits,-a-secondary-coil-40-being-provided-for--the-magnet-25--the-cirenit-through
which is closed-by-means-of-the-liquid, its containing-vessel-and-supplemental-con-
tacts In Figure-8-two-supplemental-stationary-contacts-60-are-provided--in-lien-of
the-single contut-45.

page_text: It-will-be-understood-that-a-device-which-will-operate-to-close-a-short-cir uit-ora
secondary-eireuit-having-a-different-construction-from-that-shown may be employed,
and
I-do-not-wish-to-limit-my-invention-in--this--particular.-The--ball-48-may-also
be dispensed-with-if-desired, but I-regard-it-us-useful-in-order-to--prevent-oxidation
point.
of-the-mereury-by--the-are--which--may--form--when--the-eirenit--is--broken-at-this
Referring-now-to-Figure-0,-51-and-52-are-two-phase--generators--each--provided
with-two-conductors-533-64,-for-the-two-phases-of-euerent,-and-a-conductor-5-com-
men-to-beth-phases.-In-each--of-the-conductors--53--and--64--is--included-a cireuit
elesing-device-50,-such,-for example,-as-is-shewn-at 40-in Figure-7-and which will be
hereinafter-designated-as-the-time--element-of-the-system,--it--being-so-constructed
a-predetermined-interval-of-time-an-auxiliary--eireuit--is--elosed.-Each-of-the-time
elements-56-is-connected-with-one-of-the--stationary-contacts-67-of-the-eirenit-inter-
and-arranged-as-bereinabove-described that-after-an-excessive-current-has-passed-for
rupting device,-the-other-stationary-contacts-being connected-to-the-terminale of the
line-conductors-53 and 54.-The-movable-contacts-08-of-the-eireuit-interrupter-are
all-mechanically-connected-t.-operate-together-and-these--for-each-phase-are-elee-
trically-connected-so-as to-bridge--the--corresponding-stationary contacts-57.-The
eateh-0-connected-to an-armature-60,-as-is-usual-in-this-e'ass-of-devices.
In-order
movable-member-of-the-switch-is-no mally-held-in-its-elosed-position-by-means-of-a
to-aise-the-armatar-GO-and-the-lateh-connected therewith,--I-provide--a- suitable
electro-magnet-61,-th coil-of-which-is-connected-in-a--local- eirenit--62-63-supplied
with-enrrent-from-any-suitable-souree;-that-shown-in-the-present-case-being-a-trans-
former-64-This-local-eireuit-02,-63-is-nermally-open;-as--indi ated-in-the-drawing,
and-is-closed-threagh-any-one-of-the-time-elements-50,-whenever-the-current-in-the
eendnetor-in-which-sueh-time-element is-ineluded-becomes-sufficiently-overloaded-to
netuate-the circuit-elosing-device:
It-is-obvious-from-the-illustration--and--foregoing--deseription--that-whenever-the
enrrent-in-any-one-of-the-conductors-53,- 54,-exeeeds--a--pred.termined-limit,-all-of
the-eirenits-from-that-particular-generator--will--be--automatically interrupted. It
will-also-be-understood-that-any-number-of-generators-and-eirenits-may-be-connee-
use-of-a-leeal-eirenit-for-energising-the-controlling--magnet--for-the--eireuit-breaker
may-be-employed-in-connection-with-a-single-phase-system-of-distribution, if desired;
and-henee-1-do-not-limit-my-invention-to-use-in-eenneetien-with-multiphase-circuits
ted-with-the-loeal-eireuit-in-the-manner-shown: It-will-also-be-understood-that-this
as-ehe vn-in-the-drawing.
l-being often-desirable-a-large-power-houses-to-open--any--one-of-several-eireuit
breakers-rom a-given-point-which-may-be-more-or-less--remote--from-sueh-eireuit
breakers, I-extend-the-local-eirenit--conductors-indicated-at--65,-60;-and-67-to-the
tent-fr m-which-it-is-desirable-to-netuate--the--sir uit-breakers--and--leeate-at-this
peint-suitable-eirenit-elosing-devices 63-one-for-each-eireuit-breaker. These-eireuit
elesing-devices-may-be-push-buttons--or--any--other--desired-form--of-hand-operated
magnets-61-when-it-is-desired-to-open-the-eireait-breaker--with-which-sneh-magneɓ
means-whereby-the-local-eirenit-may-be-elosed-through-any--on--f- the-controlling
is-connected.
Referring now to Figures 10, 11, 12 and 13, 72 are the stationary contact ter-
minals of a circuit breaker suitably supported by the base. Each of these stationary
contact terminals may consists of a bundle of conductors soldered to a base piece 73
and also fastened thereto by means of bolts or screws 74, as shewn in Figure 11.
The outer free ends of these contact terminals are bevelled as indicated in the draw-
ing in order to provide the necessary contact faces for engagement with the mov-
able contact devices. These stationary contacts are arranged in pairs, one for each
branch of the circuit. In the present instance the switch is shown as designed for
use in a two phase circuit provided with three line conductors, one of which is com-
mon to both phases, there being thus provided three pairs of such contact terminals.
Bolted to each base 73 is a spring 75, which bears at its free end a contact block 76,
formed mainly of carbon or some other suitable conducting and substantially. in-

page_text: fusible material, and having a contact face plate 77, of copper or other good conduct-
ing metal, extending through a portion of its length.
The movable number of the circuit breaker comprises an arm 78 pivoted to a
block or casting 79 upon the base 1, such block or casting being provided with leaf
springs 80 for the reception of the arm 78, and also with the usual spring, not shown,
for throwing the arm backward when released. The arm 78 is provided at its free
end with a bar 81 of sufficient length to bridge all the stationary contacts, and
mounted upon this bar are three contact plates 82, suitably insulated from the bar 81
by mica 821 or otherwise, and so located that they will respectively bridge the
several pairs of stationary contacts corresponding to the three conductors of the cir-
cuit. Each of the plates 82 is extended beyond the outer edge of the supporting
bar 81, and has fastened to it a contact piece 83 for engagement with the corres-
ponding stationary contact 76. As shown in the drawing Figure 14, the plate 82
is bent around the outer ends of the main portions of the pieces 83 and set into the
face of the same so as to provide a metal face which extends over a portion of the
length of the said piece to engage with the corresponding plate 77 of the contact 76.
The main portion of this contact 83 is formed of carbon or some other substantially
infusible, conducting material and is of substantially the same form as the part 76
except that it has a convex bearing surface, whereas the part 76 bas a corresponding
concave bearing surface, the curvature of these parts being substantially that of the
arc of a circle struck from the pivotal axis of the arm 78 as a centre when the cir-
cuit breaker is closed.
It is obvious that the portion of the plate 82 which makes contact with the part 77
of the contact 76 may be a separate piece if desired. It is here shown as an integral
part of the plate 82, in order to provide a better conducting path for the current.
As the volume of current to be interrupted by this breaker will, however, ordinarily
not be very great, the screws which fasten the auxiliary contact plate with the main
contact will probably under ordinary circumstances afford a sufficiently good con-
ducting path for the current.
84-is-a-magnet-eore preferably laminated-and-suitably-fastened-to-and-supported
by-a-base-piece-84'-This-core-is-provided-with-a--few-tures--of--wire--85,-forming
part-of-the-middle-or-common-conductor, 86,-of-the-cireuit,- and--the-two-legs-of-the
cere-are-each-surrounded-by-a-coil-8i-of-fine-wire,-these--coils 87-being-connected-in
series-and-so-arranged-with-reference to-the-coil-85-that--when--the-cireuit-through
them-is-closed, they-will-be-inductively influenced-by the current-through the-coil-$5
and-have-an-apposite magnetising-effect-of-the-eurrent-in-the-eoil-Sǎ.
88-is-an-armature-pivoted-to-the-base-piece 81'-and-provided with-a-serew-cr-other
able-sapport;-and-provided-at-its euter-free-end--with-a-roller--00:-This-roller-en-
end-of-the-arm-78. Projecting-upwardly from-the-lateh-So-is-a-piece-02-in-position
to-be-engaged-by-the-serew-88'-when-the-armature 88-falls-in-order-to-withdraw-the
lateh-and release-the-movable-member-of-the-breaker.
projection-881-80-is-a-lateh-also-pivoted--to-the-base-piece-84,-er-some-other-suit-
gages-with-the-hooked-end-or-catch-of-a-plate-or-piece--01--projecting-from-the-free
As-will-be-readily understood-from-the-foregoing--description,-when-a-normal-eur-
rent is-earried-by-the-main--eirenit,--the--magnetizing--feet-of-the--current-in-the
coil-Să-will-serve-to retain-the-armature--88--in--contact--with--the-free-ends-of--the
eore-84-+-bat-if-the current-in-this-circuit-fails-for-any--reason--or if-the-eirenit-in-
elading-the-coils-87-is-closed-se as to counteract the magnetizing effect-of-the-coil S5,
the-armature-SS-will-be-released-and-will-effeet-the-release-of-the-mevable-member
ef-the-breaker-which-will-be-instantly-thrown-open.
In-order-to-guard-against-the opening-of-the-eirenit-when--a--current-in-excess-of
the-no: mul-eurrent--is-only--momentary, I provide-a-device-which--will--now--be
deseriked:-02-is-a-tube-formed-of-insulating material, preferably-glass, and-supper-
ted-by-means-of-a-pair-of-elips-or-brackets-04-and-05, the--apper -clip-05-being-pro-
vided-with-a-clamping-serew-00-in-order-that-the-tabe may be adjusted--longitu-
dir ally, if desired, the-reason-for such adjustment-being-more fully set forth herein-
aiter These-tabes-are-partially filled-with--liquid 06,--glycerine--being--a-desirable
.

page_text: liqnid-for-this-purpose, its character-being-such-that-the-movement-of-a-solid-body
through-it-must-necessarily be-slow. I--do-not-desire-to-limit-my-invention, how-
ever,-as-regards-the-particular-liquid-employed. The--upper--end--of-euch -tube-is
closed, preferably-by-means-of-a-stopper--07--of-some--suitable-insulating-material
such-as-wood, cork,-or-vuleanized-fibre,-and-through--this--stopper-extend-two-con-
taets-08 Each tube-03-is-surrounded-by-a-coil-00-which-forms-a part-of-the-corres-
pending-side-of-the-main-eirenit,-and-inside--the-tube--is-a-core--which--is--mainly
formed-of-magnetizable-material-and-is-provided-with-means-for--elosing-the-eirenis
between-the-two-contact-terminals--08.-This-core;-as--shown--in--Figure-10-of-the
drawings,-is-constructed-of-a-bundle-of--iron-wires--100--through--which--extends-a
rod-101-of-any-suitable-material-serew-threaded-at-both-ends.-Upon-its-lewer-end
is-mounted-a-cap-102-of-insulating-material;-sueh, for example, as wood;-and-on-its
apper-end-is-a-eireuit-elosing-piece-103-formed-of-good--conducting--material--ant
serewed-upen-the-apper-end-of-the-red-101-This--eirenit-elesing-piece-is-preferably
slotted-as-indicated-at-the-right-in-Figure 10-in-order--to--prevent-the-setting-up-of
Foucault-enrrents-therein-by-induction--from--the--coil--00-Between--this--eireuit
elesing-pieee-103-and-the-bundle-of-wires, 100,-is-a-cap-101-for-engagement with the
upper-ends-of-the-wires and together-with-the-cap-102-and-red--101-retaining-sueh
wires-in-a-compact-bundle.-The-upper-ends-of-the-contacts-08-are-connected-in-eir
euit-with-the-coils-87-as-is-elearly indicated-in Figure-12--of--the--drawings,-so-that
when-an-excessive-current-traverses either-of-the-coils-00,-the-eore-will-be-eansed-to
move-upward,-but-on-aeeeant-of-the-body-of-liquid--in-the-tube; the-core-will-move
slowly-until-it-hos-nearly-reached-the-limit-of--its-upward--movement-so-that-there
will-be-ne-danger-of-its-closing-the-seeendary-eirenit-unless--the--excessive--eurrent
continues-for-a-material-length-of-time;-the-period-necessary-tor--the--elosing-of-the
eirenit-being-determined-by-the-pesition-of-the-tube-03;-which-may-be-adjusted-lon-
gitudinally-to-the-desired position.
In-Figure-13-is-shewn-a-modification-of-the-circuit-closing-device--in-which-the
iron-wires-100-are-held-together-by-means-of--a-cord-105-wrapped-around-them-and
the-eentsets-08-are-so-arranged-that-the--apper-end-of-the-red-101'-will-press-them
into-engagement-instead-of-bringing-a-eirenit--elesing-bridging-pieee-between-them;
as-is-the-ease-in-the-eonstruction-shown-in-Figure-10.-In--other--respects-the-form
shown-in-Figure-13-is-substantially-the-same-as-that-shown-in-Figure-10.
The-device-shown-in-Figure-13-or-the-modification--shown--in-Figure 10,-is-admir-
ably-adapted-for-use-as-a-dash-pot,-if-instead-of-elamping-it-in-position-it-be-left-free
to-move-longitudinally-through-its-eoil. When-used--for--this--purpose,-the-circuit
eontaets-earried-by-the-stopper-of-the-tube-would-obviously be-omitted-and-the-tube
might-be-entirely-filled-with-liquid,-if-desired. The-differential-movement between
the-core-and-tube-due-to-the-mechanical-resistanee-of-the liquid-is-such-as-to-render
the-device-peeuliarly desirable-in-many-eases-where-retardation-of-the-movement-of
a-mechanical-element-is-necessary.
In-the-form-of-the-apparatus--illustrated--in--Figures--10--and--11,-the-eireuits-of
which-are-diagrammatically-shown-in-Figure-12,-the-armature--is-normally-held-in
of-the-eirenit-breaker-either-when-the--enrrent-fails-in-the--main--eirenit,-or--when
there is-an-overload-which-persists-for-a-sufficient-length-of-time-to-elose-the-secon-
dary circuit-It-is-necessary-to-employ-this-form-of-the--apparatus-only-in--eases
where-it-is-desired-to-automatically-open-the-eirenit-breaker--both-fer-overload-and
the-tailare-of-enrrent-in-the-main-eirenit.-In-view-of-the-fact-that--it-is-sometimes
difficult-to-so-adjust-he-apparatus-that-the-armature-will-be-maintained-in-its-posi-
contact-with-the-peles-of-the-magnet and-is-dropped-to-release-the-movable-member
tion-in-contact-with-the-poles-of-the-magnet through--wide-variations-in-the-amount
of-current-in-the-eirenit,-and-also-because-of-the-humming-noise-which-is-eansed-by
the-action-of-the-alternating-current-upon-the-iron-of-the--core-and-armature, it--in
often-preferable-te-employ-a-breaker-in-which-the-armature--is--normally-separated
from-the-poles-st the-magnet-and-is-raised-into-engagement--therewith--in-order--te
release-the-movable-member-of-the-breaker
Such-a-form-of-apparatus-is-illustrated-in-Figures-15-and- 16.-The-several-parts

page_text: of-this-form-of-apparatus-with-the-exception-of-the--features-which--will-be-herein-
after-specifically-pointed-out-are-the-same-in-construction-and-mode-of-operation-as
these-heretofore-deser.bed-The-armature-SS"-of-this-form-of-breaker-is-pivoted-to
the base-piece-in-substantially the-same manner-as-the-armature SS-already-described;
and is-provided with-a-depending-pin--106--which--extends--through--an--opening-of
somewhat-larger-size-in-the-lateh--80-and-is--provided--at--its--lower--end--with--a
head-10-It-will-be-understood-from-this-construction--that-in--the-nermal-condi-
tion-of-the-apparatus-the-armature-will-be-in-its--lowest-position-and-will-serve-to
withdraw-the-latch 80'-from-the-catch-01-only-when-it-is-raised-into-contact-with-or
proximity-to-the-ends-of-the-magnet--core-S01.-It--will--be--seen--by--reference-te
Figure-16-that-two-primary-coils-107-108-one-for-each-outer-conductor--of-the-two-
phase-eireuit-are-employed,-and-that-a-single-secondary-coil-100-is-located-in-induc-
tive-relation-to-the-said-primary-coils.-The-coil-100--is-in-series--with-a-eoil-110-on
the-core-84" and-the terminals-of-the-eireuit,-inelnding-these-eoils-100-and-110-are
constructed-and-arranged-in-the-same-manner--as--the--terminals-of--the--secondary
eireuit-described-in-connection-with-the-other-form-of-the-apparatas.
It-will-be-understood-from-the-foregoing-deseription-that-if-the-current--of--either
phase-increases-beyond-the-critical-amount-and-is-maintained-for-a-sufficient-iongth
of-time-to-close-the-secondary-cirenit,-a-secondary current will-be-set-up-by induction
in-the eeils-100-and-that-such-current-will-energize--the--coil-110-thus-magnetising
the-core-84"-and-raising-the-armature-8811-the-lost--motion--between--the--head-107
of-the-pin-108-and-the-lateh-80'-having-the-effect-of-causing-the-head-107-to-give-a
sharp, quick-blow-to the-lateh; and-thus-withdraw-it-from-the-catch-01:
In-some-cases-where-the-voltage-of-the-main-eirenit-is-not-tee-high-the-coils-107;
108-and-100-of-Figure-16-may-be-dispensed-with--and--the--coil--110--included-in-a
shunt-to-the-main-eirenit-which-is normally-open-and-which-may-be-closed-by-either
et-the-eirenit-elosing-devices-above-described;-as-will-be-readily-understood.
The-arrangements above-described-are-equally-well-adapted--to-circuits--having-a
different-number-of-phases-and-a-different-number-of-conductors-to-that-shown:-It
will-also-be-understood-that-instead-of-loeating-the-secondary-eirenit-elesing-means
in-the-two-separate-branches, such-means-may-be-located--in-the-line-which-is-com-
men-to-the--two-phases-if-desired,-I-prefer-the-construction-shown-however.
Referring now to Figures 17 19 and 20, which
represent the application of my im-
proved means to another form of circuit breaker the to-22,-162-is-a--hollow-block-or
easting-secured-to-the-base-and-provided-with-the-usual leaf-spring-jaws-163-for-the
reception-of-the-arm-164-of-the-movable-member-of--the--circuit--breaker-when-it-is
ted-and-free-to-turn-in-the-casting-162.-A-stop--piece--166,-having-a--lag--166-is
mounted-apon-the-pintle-165-and-rigidly-fastened-to-it--by--a--set--serew--167.-A
bleek-168 is-pivoted-to-the-piece-166-and-bears--against--the--upper--end-of-a-eoiled
spring-160 A-red-170--depends--from-the-block-168--and--serves--to--retain--the
spring--160--in--its--proper--position:-The--arm--164--is-provided--with--the--asual
handle-171-and-also-with-a-small-roller-172-the--latter-being--in--position-te--be-en-
gaged--by--the--hook--at-the--end-of--lateh-173,--when-the-breaker-is-closed.
thrown-epen. The arm-164-is-journalled-at-its--inner-end-upon-a-pintle-165,-moun-
The
contact portion of the movable member of the breaker is a bar or plate 174, to which
are fastened, preferably at its upper edge, two curved contact springs 175, the pur-
pose of which will be hereinafter more fully described.
Suitably fastened to the bar or plate 174 and preferably between the same and the
adjacent portion of the arm 164, is a spring plate 176, preferably formed of copper
and having two curved end portions projecting beyond the bar 174. Fastened to
each projecting end of this spring plate is an auxiliary contact piece 177, com-
prising a block 178 formed of carbon or some other good conducting material, which
is practically infusible, and a plate 179 of copper or other metal having a high degree
of conductivity. I prefer to form the blocks 178 of carbon, but I do not desire to
limit my invention to this material, for the reason that graphite, or some composi-
tion which has the necessary conducting properties and is practically infusible by elec-
tric arcs, may be employed in lieu thereof. Each metal plate 179 is set into a recess

page_text: which is formed in the outer face of the block 178 and extends through a portion
only of its length, so that the outer face of the plate and that of the free end of the
block combine to form a single smooth contact surface. The contacts 177 being
connected by a single copper plate, a good conducting path between them is
ensured irrespective of the character of the contact between the said plate and the
bar 174.
The ends of the supporting spring 176 are preferably clamped between the
blocks 178 and plates 179 so as to make good electrical contact with the said
parts.
I prefer to give the faces of the contact pieces 177 the form of the arc of a circle
struck from the centre of the pintle 165 when the circuit breaker is closed. These
contacts are also slotted longitudinally, as clearly indicated in Figure 20, such slots
extending a short distance into the supporting spring plate, in order that the con-
tacts may adapt themselves to any irregularities in the surface of the stationary con-
tact terminals with which they engage. Each-of-the-man-stationary-contact-terminals
180 consists of-a-bundle-of-thin-plates, which are elamped-together-and-to-a-projection
en-a-supporting-base-piece-181. The-inner-end-of-each-contact-terminal-is-also-pre-
ferably-united-to-the-part-181-by-solder-or--amalgam.-These--lamine or-the-larger
portion-of-them;-terminate-in-a-plane,-which-is-inelined-at-sneh-an-angle-te-the-base
of-the-eircuit-breaker-that-the-centaet-bar-or-plate--174--will--make--a-close-contact
therewith: The-angle-of-the-plane-of-the-contuet-ends of-these-lamine-is-also-such
that-the-bar-or-plate-174-will- engage-them-one--after--another;--beginning-with-the
outermost-one;-in elesing-the-breaker,-thus-suecessively-lifting-or-defleeting-each-of
the-said-ends-slightly-from-ite-normal-position.
As-will-be-seen-by-reference-to-Figures-17-and-18-of-the-drawings-this-operation
er-no-deflection-of-the-innermost-ones.-A-sliding-engagement-between-the-parts-174
and-180-is-also-effected,-which-helps-to-ensure-a-good--contact--between-them-and
keeps-the-contact-surfaces-bright-and-elean.-Contacts--of-this-description -may be
used-in-ordinary-switches-as-well-as-in-eut-outs-such-as--shown. While-I-prefer-to
form-these-eontaets-of-thin-copper-plates,-it-will--be-understood-that-the-individual
results-in-a-maximum-deflection-of-the-free-ends-et-the--outre-- lamine-and-in-little
elements-of-which-the-contact-is-composed-may have any-other-form-in-cross-section
which-may-be-found-convenient, provided-they-are-sufficiently-resilient-to-effect-the
desired-result.
Suitably fastened, preferably by means of bolts, to a projection on each support-
ing piece 181, is a spring plate 182, to the outer end of which is fastened a ter-
minal contact 183, with which the corresponding movable contact 177 engages.
Each of these contacts 183 comprises a block 184 and a plate 185, which are prefer-
ably made of the same materials as are the corresponding blocks 178 and plates 179
of the contacts herein before described. The curvature of the contact faces of the
contacts 183 is also the same as that of the faces of contacts 177 except that it is
concave instead of convex. This curvature of the engaging faces of the shunt con-
tacts insures a good electrical contact between the entire engaging surfaces, not
only when the breaker is closed but during the opening of the same, until the metal
portions of the contacts are separated.
The construction of the shunt contacts partially of metal and partially of carbon,
or some other substantially infusible conducting material, is an important improve-
ment over the carbon shunt contacts which have heretofore been employed in this
class of devices. In the employment of shunt contacts made entirely of carbon in
circuit breakers employed to open circuits carrying heavy currents, it has been found
that the carbon was not a sufficiently good conductor to shunt all of the current
around the main circuit terminals, and that consequently such main circuit terminals
often become seriously injured by the arcs due to the unshunted current, so much so,
in fact, that it was necessary to cut away the blistered surfaces before the switch
could be again closed. With the present construction of shunt contacts, it will be
readily seen that a complete metal path is provided for the current until the main
contacts have become separated a considerable distance, and that consequently the

page_text: entire current will be shunted. The conductibility of the shunt path for the current
is also materially improved in the form of circuit breaker shown by curving the
metal contact faces in the manner above described. When the metal contact plates
of the shunt becomes separated, the current will obviously be compelled to take the
path provided by the infusible material, so that the final interruption will occur,
as in the old form of breaker, where the resulting are can do little, if any, damage.
These stationary shunt contact blocks also have their free ends bevelled or in-
clined toward each other, as indicated most clearly in Figure 15, in order that the
interruption of the current shall occur at their outermost points. This feature of
construction is desirable, in order that the contacts may be placed near enough to-
gether to make a compact structure without danger of arcing across from one ter-
minal to the other.
The location of the stationary shunt contacts side by side above the main body of
the breaker is desirable since the arcs formed between the separated terminals are
substantially horizontal and therefore easily interrupted, and, furthermore, all dan-
ger of injury to the main terminals is substantially avoided by reason of such loca-
tion. Any tendency to arcing between the stationary contacts is largely counter-
acted by the repelling action excited by the arcs against each other.
Instead-of-employing-a-solenoid-or--magnet--eoil-for--actuating--an--armature--to
release-the-movable-member-of-the-circuit-breaker--when--the--current-inereases-be-
yond-the-predetermined-limit,-as-is-usual-in-this-elass-of-devices,-I-utilize-one-of-the
main-eontacts-of-the-circuit-breaker--for--this--purpose,--and--in--lieu--of--the--usual
solenoid-or-magnet-eore, I-provide-a-body-of-magnetizable--metal,
preferably-in-the
form-of-a-band-180,-which-partially-surrounds-the-stationary-eonta 6-and-is-of-suffi-
eient-width-and-thickness-to-provide-a-good-magnetic-eireuit.
As shown-in-Figure-20-of-the-drawing,-this--band--186-is--fastened--in position-by
means of-the-belts-which-fasten-the-contact-180-in-the-base--piece--181,-and-is-bent
around-the-edges-of-the-contact-in-sueh-manner-that-the--end--near-the-eentral-line
to-the-plane-of-its-back,-the-other-end-projecting-a-materially--less--distance.-T.is
partienlar-form-of-band-is-not-essential,-but-it-has--been-found-operative-and-useful
of-the-breaker-projects-somewhat-beyond-the-face-of-the-contnet-and at-right-angles
in-practice.
Below-the-stationary-costaets-and-substantially--midway between-them-is-located
a-bleek-or-easting-187 provided-at-one-side-with--an-arm -188,--between--which-and
the-base-of-the-casting-is-pivoted-a-bar--armature--180.-This-armature-is-provided
with-an-opening 100-midway-between the stationary-contacts-through-which-extends
a-belt-101,-the-head of-which-rests-upon-the-upper-surface--of-the-armature.-The
belt-101-also-extends-through a-similar-opening--in-the--lateh-178,
-and-is-provided
with-a-nut;-so-that-when-the-armature-is-actuated-by-the-magnet--above--deseribed,
the first-part-of-its-movement-will-serve-to-raise-the-belt--until--the-nut -is-brought
inte-engagement-with-the-latch-178,-and-a-further-movement-will-serve-to-withdraw
to-be-instantly-thrown-bael-by-the-nction-of-the-spring--160-The-lost-motion-be-
tween-the-armature-and-latch-is-employed-in-order-to-permit-the-armature-to-enter
the-lateh-from-the-roller-12, thus-permitting-the-movable-member--of--the-breaker
the-strongest-part-of-the-magnetic-field-before-acting-upen-the-latch, thereby ensur-
ing-an-effective-and-sudden-releasing-blow.
In-order-to-ensure-the-retention--of-the-movable--member-of-the-breaker-in-its
elosed-position-until-the-volume of earrent-at-which-it-is-designed-to open-is-reached,
and-to-ensure-a-sudden-tilting-of-the--armature--and--consequent--withdrawal-of-the
lateh-when-the-current-reaches-the-maximum-allowable-limit;-I--provide-the-second
stationary-member-180-of-the-breaker-with-an-iron--band--186,--preferably--of-the
same-shape-as-the-band-186,-except that-the--portions--adjacent--to-the-edges-of-the
contact-are materially shorter-than-the-corresponding portions-of-the-band-186,-in
order-that-the-number-of-lines-of-force--passing--through--the--adjacent--end-of-the
armature-shali-be-less-than-the-number-threading-the-opposite-end. The necessity
of-seme-expedient whereby-the-pull-of this magnet-shall-be-made-weaker-than-that
of-the-other is-obvious,-since-the-magnetie-pall-at-this-end-constitutes-a-load-which

page_text: must-be overcome-in-order-to-effect-the-withdrawal-of-the--lateh,-but-it-will-be-an-
derstood-that-means different-from-that-shown, whereby-the-strength-of-the-magnet
or-the-action-of-the--same--apon--the--armature--is--modified,--may-be--employed, it
desired. The-character-of-the-load-is-such--that--when--the--pull upon-the-opposite
action-will--oeear-with
end-of-the-armature-is-sufficient-to-overcome-it,-the-tripping
a-sharp,-sudden-jerk,-which-is-particularly--effective-and-desirable--in--this-class-of
apparatus.
Ialso provide-the-lead-end-of-the-armature-with-a-small-set-serow--102-the-inner
end-of-which-bears-against-the-outer-end-of-the-band-186-and-is-adjustable-in-order
to-provide-for-different-leads. I-prefer-to-make-this-serow-of-magnetizable--metal,
in-order-that-it-may-serve-as-a-saturated--element-in-the--magnetie-eireuit-+-but-it
may-be-made-of-other-material, if--desired. Any-other--suitable--adjustable--device
may-also-be-employed-in-lieu-of-the-serew.-193-is--a--bar--or-rod--provided-with--a
snitable-scale-and-supported -from--the--armature--and--parallel--to-it-by-means-of
reds-194. A weight-105-is-mounted-upon-the-bar-103-in-sueh-manner-that--it-may
be-moved-back-and-forth-thereon-in-accordance-with-the-critical-load-for-which-the
breaker is-to-be-set-36-is-a-serew-for-clamping-the-weight-105-at-any-desired-posi-
tion-on-the-bar-193.-107-and-198-are-bars-or-strips--provided--with-outwardly-pro-
jeeting-upper-ends-and-with-handles-at-their--lower-ends-Thess-bars-have-a-slet
and-pin connection-with-the-base-I-and--serve-respectively,-when-pressed-upwardly,
to-tilt-the-armature-in-the-one-direction-or-the-other.
It-will-be-understeed-from-the-foregoing-deseriptien-that-the-breaker-may-be-set
when-sueh-load-is-reached;-the-lateh-will-be-withdrawn-with-a--sudden--jerk-due--te
the-sudden-release-of-the-armature-by-the-load-magnet-and-the-lost-motien-between
the-lateh-and-armature:-The-spring-160-will-then-net-through--the-parts-168,-166;
lug-166-and-between-the-leaf-springs-1633-by--reason--of--the--impetus-imparted-by
by-means of the serew-102-and-weighs 105-to-open-at--any-desired--load,--and--that
and-166-to-separate-the-contacts, after-which-the-arm-164--will-fall-away-from-the
the-spring-160-and-the-action-of-gravity.
Immediately upon the-separation of-the-main-contacts,--which--will-eeeur-without
material-frie:ional-resistance,-the-entire-current-will-be-shanted-through-the-copper
plates-170 and-185-and-the-spring-supports-176-and-182-When the plates-170 and
185-become- eompletely-separated;-the--current-will-be--forced-to-take--the--path
through-the-infusible-bleeks-178-and-184,-and--will--be--finally--interrupted--at-the
outermost-corners-or-tips-of-these bleeks.
It-is-therefore-apparent-that-under ordinary-eirenmstances,--all--possibility-of-in-
jury-to-the-main-contacts-of-the-breaker-is-obviated. Should-it-happen, however,
that-the-eurrent-should-not be entirely-shunted--through-the-auxiliary-contacts,-any
eurrent which-fails-to-take-that-path-will-be-interrupted--between--the--springs-175
and-the-outer-sides-of the-ends-of-the-stationary-contacts;-where--it--will-do-little, if
any, harm.
I desire it to be understood that my invention is not limited to the particular con-
struction and arrangement of the parts shewn and described, since the devices may
be considerably modified without departing from the spirit and scope of the in-
vention.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, as communicated
to me by my foreign correspondent, I declare that what I claim is :-
1. In-an-automatie-electromagnetie-eireuit-breaker-the-provision-of-a-perm?nent
magnet-or-an-electromagnetic-eoil-which-tends to-maintain-the-eirenit-elosed.
2. An-automatie-electromagnetie-eireuit-breaker-by-means of which-the-eirenit-is
broken-when-but-not-until-a-current-exceeding-a--predetermined--strength-has-been
passing-for-a-definite-period-of-time;-either-with-or--without-means-whereby-the-eir-
euit-is-broken-when-the-earrent-falls-below-a-predetermined-limit:
3. A-eireuit-breaker-fer-multiphase-systems-arranged--so-that-the-overloading-of
any-one-conductor-of-the-system-causes-all-the-conductors-to-be--interrupted-either
at-once-or-after-such-overload-has-existed-for-a-definite-length-of-time.

page_text: 4.- In-a-switch-or-eireuit-brealter--a--contuet--consisting--of--n--number-of-plates
which-are-successively-deformed-when-the-switch-is-closed:
5. In a switch or circuit breaker having more than one set of contacts, the pro-
vision of metallic contacts through which the current flows after the main contacts
have been opened and before the circuit is finally broken through infusible contacts
provided for that purpose.
6. Cireuit-breaking-devices-constructed-in-the--manner--doseribed-with-reference
to-any-of-the-forms-shewn-in-the-neeompanying-drawings-and-operated-as-specified.
Dated this 23rd day of July 1897
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C.,
Agents for the Applicant.

page_text: I, REGINALD BELFIELD, of 32, Victoria Street, City of Westminster, County of
London, Electrician, do hereby declare the nature of this invention to be as
follows:-
This invention relates to electric switches and comprises the improvements
hereinafter described.
It has been found with switches of the ordinary construction that the contacts
rapidly deteriorate owing to the spark which occurs on breaking a heavy current
through the switch. Switches have therefore been constructed with auxiliary
carbon contacts so located relatively to the ordinary contacts of the switch that
on manipulating the switch so as to break the circuit the current is first shunted
through the carbon contacts and finally broken there so that the spark on break-
ing passes between carbon blocks and not through the metallic contacts of the
switch. It will be obvious that, with a switch constructed in this manner having
copper contact pieces and carbon contact pieces arranged so that the current is finally
ruptured between the carbon contact pieces, on making the circuit through the switch
the current will first pass through the carbon contacts and then through the copper
or main contacts of the switch. According to the present invention switches of
this description are so constructed that although upon breaking the circuit. the
final break occurs between carbon contact blocks, on making the circuit on the
contrary the first contact will be made by the copper contacts.
In order that the nature of the invention may be clearly understood I will
now proceed to describe with reference to the accompanying drawings various
methods of carrying out the same in practice.
Figure 1 is a side elevation partly sectional of a switch provided with two sets
of contacts in parallel, arranged so that the circuit shall be broken through one
set of contacts but made through the other set of contacts.
Figure 1.
Figure 2 is a sectional view on the line a
Figures 3 to 5 are detail views of the contacts.
Figure 6 a front elevation of a modification.
Figure 7 is a detailed sectional view and
Figures 8 and 9 are respectively a perspective view and a front elevation of

page_text: Referring now to Figures 1 to 4 of the drawings 111 represents a switchboard
panel of the usual material and construction, and 112 the stationary main
contacts which, as shown, are preferably laminated and provided with
beveled contact faces. These contacts are respectively fastened to con-
ducting blocks 113 preferably by means of screws, as shown. They
or otherwise united
may also be soldered to the blocks if desired,
Each of the
in such a manner as to make a good low resistance joint.
blocks 113 is provided with sockets 113" for the reception of the ends of the
conductors 114, and with binding screws 115 for retaining the ends of the con-
ductors in the sockets. The terminal blocks 113 are mounted upon a plate 116
of suitable non-combustible insulating material. Each terminal block 113 is
provided on its inner face with a plate 117 of carbon or other substantially infu-
sible conducting material. This plate may extend circumferentially over the
entire face of the terminal block, or over a portion only as may be desired. 118
is the actuating handle of the switch which is mounted upon the shaft 119 the
latter being mounted in suitable bearings 120 and 121. Between the bearings 120
and 121 the shaft is preferably square in cross-section, as indicated in the draw-
ings. The movable main contact 122 is mounted upon the squared portion of
the shaft 119 and is extended through the plate 116 in the form of a sleeve 123.
A protecting disc 124 of suitable insulating material abuts against the end of the
sleeve 123, which is opposite the arms of the contact 122, which engage with
the faces of the stationary contacts 112. The sleeve 123 is preferably surrounded
on one side of the plate 116 with a collar 125, the sleeve and collar being held
together by a screw-thread engagement. Fastened to the collar 125 by means
of screws or otherwise is a plate 126 provided with two stops 127. A ring 128
is mounted upon the collar 125, so as to be free to turn thereon and is provided
with two arms 129 and 130. In the end of each of these arms is journalled a
roller 131 which is composed of carbon or some other substantially infusible con-
ducting material, and as shown in Figures 1 and 2, these rolls are mounted in
yielding bearings in order that the rollers may move freely over the contact faces of
the terminal blocks 113, and at the same time may make good contact therewith.
The arm 130 is provided with projections 132 which are in position to engage the
stops 127. 133 are stops with which the arms of contact 122 engage to limit
the movement of said contact in either direction.
In cases where it is desired to open and close two or more switches simul-
taneously, as in multiphase work, for example, the shaft 119 may be made of such
length as to permit of mounting thereon the movable members of the desired
number of switches, so that all may be operated by means of a single handle 118.
The operation of the switch above described is as follows. Assuming the parts
to be in the position shown in Figures 1 and 2, and the operator facing the front
of the switchboard, if the handle 118 be turned from left to right, the projec-
tion 132 on the arm 130 will engage the stop 127, as indicated in Figure 2, and
in this position of the parts the rollers 131 will remain in contact with the carbon
plates 117, after the main contacts 112 and 122 have become separated, thus
shunting the current through the auxiliary contacts and interrupting it when
the rollers leave the contact plates 117. So far as this particular operation is
concerned, it does not differ materially from that of the devices heretofore
employed for preventing arcing between the main current carrying contacts. In
the operation of closing The switch, however, the movement of the handle 118
from right to left will serve to bring the left hand stop 127 into engagement with
the corresponding projection 132, since there is sufficient friction between the
ring 128 and the adjacent stationary part of the device with which it is in contact
to prevent its movement until the said stop engages with the projection 132.
This lost motion between the movable main contact 122 and the rollers 131 is
sufficient to ensure the engagement of the said main contact with the contacts 112
before the rollers 131 engage with the carbon plates 117.
In the modification shown in Figure 5, the carbon plate 117 is shown as

page_text: mounted upon supporting springs 134. This construction may be utilised in
lieu of the spring supports for the bearings of the contact rollers 131, or in con-
nection therewith, as may be desired. Furthermore, it will be understood that
moveable contacts which make frictional sliding engagement with the plate 117
may be employed in lieu of the rollers 131, if desired, the invention being in
no wise limited as regards the particular form of the various features of the
switch.
Referring now to Figures 6 to 9, 136 is a supporting ring, which is preferably,
but not necessarily, of insulating material. Mounted upon the lower side of
this ring are metal contact pieces 137, these being the stationary main contacts.
Bolted to the ring 136 and also to the contact pieces 137, and thus in electrical
connection with the latter is a corresponding number of shunt contacts 138.
These contacts preferably consist of a main body or backing piece 139 of metal,
and a contact block or plate 140 of carbon or other substantially infusible con-
ducting material. Each contact block 140 is provided with a core, 141 of brass
or other metal and screws 141", 141b extend through the backing piece 139 and
the said core.
142 is a notched disc which is loosely mounted upon a shaft 143, or on a sleeve
carried by said shaft, the latter being provided with a suitable actuating handle
(not shown).
A pawl 144, having a roller 145, mounted in its free end, is suitably attached
to the ring 136, and spring-pressed against the edge of the disc 142. Rigidly
mounted upon the shaft 143 is an arın 146, on the outer end of which is pivoted
a frame 147. This frame 147 carries two rollers 148, constructed of carbon or
some other substantially infusible material, and has an arm 149 projecting
inwardly toward the shaft 143 from between the two rollers. The arm 149 is
bifurcated at its inner end, and this bifurcated end engages a pin 150 on the
notched disc f42. The arm 146 is provided near its outer end with two inwardly
projecting stop lugs 151, and the arm 149 is provided with a single lug 152,
which projects outwardly between the lugs 151. Another arm 153 is rigidly
mounted upon the shaft 143, and is provided at its outer end with a laminated
The
spring 154, to the free end of which is fastened a metal contact piece 155
arms 146 and 149 project in front of the ring 136 in such position that the
rollers 148 may engage with the faces of the carbon blocks 140 of the auxiliary
contacts and the arm 153 projects behind the ring 136, so as to bring the contact
piece 155 in position to engage with the stationary contact pieces 137. Since
this contact piece 155 is located midway between the two rollers 148, one or the
other of the rollers must drag behind the contact piece whichever may be the
direction in which the shaft 143 is turned. By means of the construction
described, if the shaft 143 be turned from left to right when the roller is in one
of the notches in the disc 142, the binding action between the roller and the
adjacent tooth will be sufficient to hold the disc temporarily in that position, and
hence the pin 150 will rock the arm 149 to the right and throw the right hand
roller down into position to engage the face of the stationary contact 138 after
the contact 155 has left the corresponding stationary contact 137, thus providing
for the interruption of the circuit through the auxiliary carbon contacts. This
action will take place at every position during the movement from left to right.
If the movement be reversed, the pin 150, as will be readily seen, will act upon
the arm 149, and rock it in the other direction until the stop 152 comes into
engagement with the corresponding stop 151, and thus bring the other roller 148
in position to drag behind the contact 155, and thus interrupt the circuit at the
carbon contacts. The relative construction and arrangement of parts is such,
however, that the frame carrying the rollers will rock back into such position in
passing from one notch to another that the circuit will always be closed through
5 the main metal contacts.
This construction of switch is particularly well adapted for use in connection
with controllers for railway motors, but it is obviously also suitable for use in

page_text: other relations where it is necessary to make and break a circuit in succession
through a series of contacts.
Dated this 27th day of November 1896.
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant
I, REGINALD BELFIELD, of 32 Victoria Street, City of Westminster, County of
London, 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 electric switches and comprises the improvements
hereinafter described.
It has been found with switches of the ordinary construction that the contacts
rapidly deteriorate owing to the spark which occurs on breaking a heavy current
through the switch. Switches have therefore been constructed with auxiliary
carbon contacts so located relatively to the ordinary contacts of the switch that
on manipulating the switch so as to break the circuit the current is first shunted
through the carbon contacts and finally broken there so that the spark on break-
ing passes between carbon blocks and not through the metallic contacts of the
switch. It will be obvious that with a switch constructed in this manner having
copper contact pieces and carbon contact pieces arranged so that the current is finally
ruptured between the carbon contact pieces, on making the circuit through the switch
the current will first pass through the carbon contacts and then through the copper
or main contacts of the switch. According to the present invention switches of
this description are so constructed that although upon breaking the circuit the
final break occurs between carbon contact blocks, on making the circuit on the
contrary the first contact will be made by the copper contacts.
In order that the invention may be clearly understood I will now proceed to
describe the same with reference to the drawings filed with the Provisional
Specification:-
Figure 1 is a side elevation partly sectional of a switch provided with two sets
of contacts in parallel arranged so that the circuit shall be broken through one
set of contacts but made through the other set of contacts.
Figure 2 is a sectional view on the line rx Figure 1.
Figures 3 to 5 are detail views of the contacts.
Figure 6 is a front elevation of a modification.
Figure 7 is a detailed sectional view and
Figures 8 and 9 are respectively a perspective view and a front elevation of
details.
Referring now to Figures 1 to 4 of the drawings 111 represents a switchboard
panel of the usual material and construction, and 112 the stationary main con-
tacts which as shown, are preferably laminated and provided with bevelled
contact faces. Contacts of this nature are fully described in my Specification
No. 23942 of even date herewith. These contacts are respectively fastened to
conducting blocks 113 preferably by means of screws, as shown. They may also
be soldered to the blocks if desired, or otherwise united in such a manner as to
make a good low resistance joint. Each of the blocks 113 is provided with
sockets 113 for the reception of the ends of the conductors 114, and with binding
screws 115 for retaining the ends of the conductors in the sockets. The terminal
blocks 113 are mounted upon a plate 116 of suitable non-combustible insulating

page_text: material. Each terminal block 113 is provided on its inner face with a plate 117
of carbon or other substantially infusible conducting material. This plate may
extend circumferentially over the entire face of the terminal block, or over a
portion only as may be desired. 118 is the actuating handle of the switch which
is mounted upon the shaft 119 the latter heing mounted in suitable bearings 120
and 121. Between the bearings 120 and 121 the shaft is preferably square in
cross-section, as indicated in the drawings. The movable inain contact 122 is
mounted upon the squared portion of the shaft 119 and is extended through the
plate 116 in the form of a sleeve 123. A protecting disc 124 of suitable insulat-
ing material abuts against the end of the sleeve 123, which is opposite the arms
of the contact 122, which engage with the faces of the stationary contacts 112.
The sleeve 123 is preferably surrounded on one side of the plate 116 with a
collar 125, the sleeve and collar being held together by a screw-thread engage-
ment. Fastened to the collar 125 by means of screws or otherwise is a plate 126
provided with two stops 127. A ring 128 is mounted upon the collar 125, so
as to be free to turn thereon and is provided with two arms 129 and 130. In
the end of each of these arms is journalled a roller 131 which is composed of carbon
or some other substantially infusible conducting material, and as shown in
Figures 1 and 2, these rolls are mounted in yielding bearings in order that the
rollers may move freely over the contact faces of the terminal blocks 113, and
at the same time may make good contact therewith. The arm 130 is provided
with projections 132 which are in position to engage the stops 127.
stops with which the arms of contact 122 engage to limit the movement of said
contact in either direction.
133 are
In cases where it is desired to open and close two or more switches simul-
taneously, as in multiphase work, for example, the shaft 119 may be made of
such length as to permit of mounting thereon the movable members of the desired
number of switches, so that all may be operated by means of a single handle 118.
The operation of the switch above described is as follows. Assuming the parts
to be in the position shown in Figures 1 and 2, and the operator facing the front
of the switchboard, if the handle 118 be turned from left to right, the projec-
tion 132 on the arm 130 will engage the stop 127, as indicated in Figure 2, and
in this position of the parts the rollers 131 will remain in contact with the carbon
plates 117, after the main contacts 112 and 122 have become separated, thus
shunting the current through the auxiliary contacts and interrupting it when the
rollers leave the contact plates 117. So far as this particular operation is con-
cerned, it does not differ materially from that of the devices heretofore employed
for preventing arcing between the main current carrying contacts. In the
operation of closing the switch, however, the movement of the handle 118 from
right to left will serve to bring the left hand stop 127 into engagement with the
corresponding projection 132, since there is sufficient friction between the
ring 128 and the adjacent stationary part of the device with which it is in contact
to prevent its movement until the said stop engages with the projection 132.
This lost motion between the movable main contact 122 and the rollers 131 is
sufficient to ensure the engagement of the said main contact with the contacts 112
before the rollers 131 engage with the carbon plates 117.
In the modification shown in Figure 5, the carbon plate 117 is shown as
mounted upon supporting springs 134. This construction may be utilised in lieu
of the spring supports for the bearings of the contact rollers 131, or in connection
therewith, as may be desired. Furthermore, it will be understood that movable
contacts which make frictional sliding engagement with the plate 117 may be
employed in lieu of the rollers 131, if desired, the invention being in no wise
imited as regards the particular form of the various features of the switch.
Referring now to Figures 6 to 9, 136 is a supporting ring, which is preferably,
ut not necessarily, of insulating material. Mounted upon the lower side of
his ring are metal contact pieces 137, these being the stationary main contacts.
Bolted to the ring 136 and also to the contact pieces 137, and thus in electrical

page_text: connection with the latter is a corresponding number of shunt contacts 138. These
contacts preferably consist of a main body or backing piece 139 of metal, and a
contact block or plate 140 of carbon or other substantially infusible conducting
material. Each contact block 140 is provided with a core, 141 of brass or other
metal and screws 141, 141, extend through the backing piece, 139, and the said 5
core.
142 is a notched dise which is loosely mounted upon a shaft 143, or on a
sleeve carried by said shaft, the latter being provided with a suitable actuating
handle (not shown).
A pawl 144, having a roller 145, mounted in its free end, is suitably attached 1
to the ring 136, and spring-pressed against the edge of the disc 142. Rigidly
mounted upon the shaft 143 is an arm 146, on the outer end of which is pivoted
a frame 147. This frame 147 carries two rollers 148, constructed of carbon or
some other substantially infusible material, and has an arm 149 projecting
inwardly toward the shaft 143 from between the two rollers. The arm 149 is 1
bifurcated at its inner end, and this bifurcated end engages a pin 150 on the
notched dise 142. The arm 146 is provided near its outer end with two inwardly
projecting stop lugs 151, and the arm 149 is provided with a single lug 152,
which projects outwardly between the lugs 151. Another arm 153 is rigidly
mounted upon the shaft 143, and is provided at its outer end with a laminated 2
spring 154, to the free end of which is fastened a metal contact piece 155. The
arms 146 and 149 project in front of the ring 136 in such position that the
rollers 148 may engage with the faces of the carbon blocks 140 of the auxiliary
contacts and the arm 153 projects behind the ring 136, so as to bring the contact
piece 155 in position to engage with the stationary contact pieces 137. Since
this contact piece 155 is located midway between the two rollers 148, one or the
other of the rollers must drag behind the contact piece whichever may be the
direction in which the shaft 143 is turned. By means of the construction
described, if the shaft 143 be turned from left to right when the roller is in one
of the notches in the disc 142, the binding action between the roller and the
adjacent tooth will be sufficient to hold the disc temporarily in that position,
and hence the pin 150 will rock the arm 149 to the right and throw the right
hand roller down into position to engage the face of the stationary contact 138
after the contact 155 has left the corresponding stationary contact 137, thus
providing for the interruption of the circuit through the auxiliary carbon con-
tacts. This action will take place at every position during the movement from
left to right. If the movement be reversed, the pin 150, as will be readily seen,
will act upon the arm 149 and rock it in the other direction until the stop 152
comes into engagement with the corresponding stop 151, and thus bring the
other roller 148 in position to drag behind the contact 155, and thus interrupt
the circuit at the carbon contacts. The relative construction and arrangement of
parts is such, however, that the frame carrying the rollers will rock back into
such position in passing from one notch to another that the circuit will always
be closed through the main metal contacts.
This construction of switch is particularly well adapted for use in connection
with controllers for railway motors, but it is obviously also suitable for use in
other relations where it is necessary to make and break a circuit in succession
through a series of contacts.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed as communicated to me
by my foreign correspondent I declare that what I claim is :-
1. A switch or circuit breaker having a set of metallic contacts and a set of
infusible conductive contacts so arranged that the circuit will be made through
the metallic contacts and broken through the infusible contacts, one operating
handle being employed for both purposes.
2. A switch having in addition to the ordinary switch arm an auxiliary arm

page_text: carrying infusible conductive contacts and so arranged that lost motion occurs
between the switch arm and the auxiliary arm when the former is operated,
whereby the infusible contacts are caused to both make and break after the
ordinary contacts.
3. A switch of the kind described having two sets of infusible moving contacts
mounted at the extremities of a rocking arm pivoted eccentrically to the switch
arm, and means whereby the arm is rocked so as to make the rearmost contact
operative when the switch is manipulated.
4. Switches constructed and operating substantially as described with reference
to either of the forms shewn in the accompanying drawing.
Dotad this 22nd day of Tule 1807
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.