Remote controlled circuit breaker

A low voltage circuit breaker in a moulded case comprises a breaker unit (10) and a remote control unit coupled to it that controls the swing of a bistable movable contact (22) housed in the breaker unit. A trip mechanism (50) cooperates with movable contact (22) in the case of a fault to swing movable contact (22) into open circuit position independently of the remote control mechanism (48). A resetting handle (88) must be actuated in order to render the circuit breaker reoperative.

The invention concerns a low voltage circuit breaker having a movable 
contact carried by a tilting contact arm and cooperating in the closed 
circuit or make position with a stationary contact, the said contact arm 
being actuated by a spring that moves the contact arm selectively into 
either of two stable positions, one to close the circuit breaker contacts, 
the other to open them, exclusive of any other intermediate position, and 
a heavy duty remote control mechanism having a pivoting rocker arm 
cooperating with said spring to swing the said movable contact arm sharply 
from the closed position into the open position and vice-versa following a 
remote control signal. 
Electrical installations, especially consumer distribution systems, 
frequently comprise remote controlled apparatus of the kind mentioned, in 
particular remote operated snap switches or contactors enabling a load 
supply circuit to be switched ON or OFF by manual or automatic remote 
control. The circuit is protected by a separate apparatus, specifically a 
circuit breaker that opens automatically on the occurrence of an overload 
or fault. This invention stems from the fact that these two apparatuses 
are generally mounted on the same panelboard, so that an association of 
both remote control and protective functions in one and the same apparatus 
would lead to considerable savings in manufacturing and installation 
costs. 
One of the features of the apparatus according to the invention is that it 
comprises in addition an automatic overload and/or fault trip mechanism 
cooperating with the said movable contact arm to shift this arm into the 
open circuit or break position when suppressing a fault current and to 
hold the movable contact arm in break position independently of the 
position of the remote control mechanism as long as the trip mechanism 
remains in the tripped position, and a trip mechanism resetting component 
to authorize remote operated closing of the circuit breaker when the trip 
mechanism is in the reset position. 
The remote control mechanism and the trip mechanism are independent one of 
the other but both act on the same movable contact, the linkage between 
the remote control mechanism and the movable contact being designed so as 
to avoid any obstruction of the action of the trip mechanism. The heavy 
duty remote control mechanism is capable of carrying out several tens of 
thousands of operations whereas the trip mechanism has the features of a 
circuit breaker with respect to the energy and speed required to cut out a 
short-circuit current. 
There are known circuit breakers equipped with an electrical control 
permitting make and/or break operations controlled from a distance. The 
electrical control acts directly on the handle or on the mechanism of the 
circuit breaker which is designed for a limited number of operations, say 
a few thousand. These remote controlled circuit breakers are usable in 
some special cases, e.g., centrally grouped controls, but are not suitable 
for heavy duty remote controlled operations. On the other hand, it is both 
difficult and expensive to manufacture circuit breakers that are capable 
of ensuring a great number of operations. The combination, according to 
the invention, of two independent mechanisms in the same apparatus, 
retains the advantages of the low energy remote control mechanism and 
those of the high energy trip mechanism which has to ensure only a limited 
number of operations. 
The movable contact arm and the remote control rocker arm form a 
snap-action bistable system, the movement of one of the elements entailing 
that of the other, so that they always occupy the same position. Whatever 
the contact opening mode, the rocker arm is in the correct position for 
the next closing control action. 
After tripping on a fault, the trip mechanism must be reset by actuating a 
resetting handle, to authorize a remote controlled closing operation. The 
handle automatically takes up open circuit position when the contacts are 
separated on tripping, but it cannot take up this position unless the 
contacts are effectively separated. The position of the handle in open 
circuit position is a visible and reliable indication that the contacts 
are open. 
In one embodiment of the invention the apparatus comprises an 
electromagnetic trip mechanism with an extractor that acts on the movable 
contact to shift it rapidly into the break position when tripping on a 
fault. Tripping on overload is ensured by a bimetal in the usual way, with 
the arc blown into a quench chamber associated with the contacts. 
All the component parts are housed in a moulded case, for instance, 
belonging to the modular system known by the trade name MULTI 9, the pole 
pitch being 18 mm. Naturally the apparatus may comprise several poles side 
by side. The remote control actuator proper is housed in an independent 
moulded case of the same model, fastened firmly to the circuit breaker 
unit to form a rigid one piece assembly. This remote control mechanism is 
conveniently of the type familiar in remote operated snap switches, that 
causes a change in position on each control pulse. It may be of a 
different type, for instance with two electro-magnets, one for closing, 
the other for opening, or with a single electro-magnet in conjunction with 
a drawback spring. The remote control unit is equipped with an emergency 
operating lever which replaces the remote control mechanism for manual 
opening or closing of the apparatus. When work is required on the load 
circuit it is an advantage to override the remote control to avoid any 
undesired closing, and for this purpose the resetting handle is designed 
to permit a manual opening operation of the contacts similar to a tripping 
operation on a fault that renders the remote control mechanism 
inoperative. This handle ensures dependable disconnection and to prevent 
unwarranted handling it is shaped so that a tool is needed to actuate it. 
It will be obvious that the applications of this novel switchgear are 
numerous, from the simple remote operation of a lighting circuit to the 
automatic control of electric machines through programmable controllers. 
Its model and pole pitch comply with the requirements of a modular system 
into which it can be conveniently incorporated.

On the figures, a circuit breaker, having the general reference 10, 
comprises a moulded case 12 with a profile corresponding to the modular 
system known by the trade name MULTI 9. Several single pole units 10 can 
be asemmbled or placed side by side to constitute a multipole apparatus 
with either each unit in its own case 12 or all the units grouped in a 
single multipole case. Only one of the poles of the circuit breaker is 
described in detail hereafter, all the others being identical in all 
respects. Case 12 contains a stationary contact 14 connected by a 
conductor 16 to a current input terminal 18, as well as a movable contact 
20 carried by a contact arm 22, swivel mounted on a stationary pivot 24 
fixed in Case 12. Movable contact 20 is electrically linked by braid 26 to 
the to the input of a tripping coil 28 that has its output linked by braid 
30 to bimetal 32 that is connected to the opposite terminal 34. When 
contacts 14, 20, are in closed circuit position, as shown on FIG. 1, the 
current input at a given time via terminal 18 flows through closed 
contacts 14, 20, coil 28 and bimetal 32 before it is output via the 
opposite terminal 34. When contacts 20, 14, are open, as shown on FIG. 2, 
the circuit is broken. The movable contact arm 22 extends beyond pivot 24 
and at its far end 36 from contact 20, a tension spring 38 is fastened 
that has its opposite end 40 fastened to a lever or rocker arm 42 mounted 
to rotate on a stationary pin 44 fixed in case 12. When contacts 14, 20, 
are in the closed position, shown on FIG. 1, spring 38 exerts a force on 
contact arm 22 that tends to make arm 22 pivot in an anticlockwise 
direction, pressing movable contact 20 against stationary contact 14. When 
lever 42 is pivoted in an anticlockwise direction, shown by arrow 0 on 
FIG. 1, by a drive mechanism that will be described hereafter, the line of 
action of spring 38 is shifted beyond a neutral point corresponding to the 
alignment of points 36, 40, 24, to reverse the direction of the moment 
acting upon contact arm 22 which moves sharply into the circuit open 
position illustrated on FIG. 2. The opening movement of movable contact 
arm 20 is limited by a fixed stop 46. When lever 42 is pivoted in the 
opposite direction indicated by arrow I, beyond neutral point, contact arm 
22 is tilted to bring contacts 14, 20, into the circuit closed position. 
The combination of contact arm 22, spring 38 and swivel lever 42 forms a 
bistable mechanism by which the opening and closing of contacts 14, 20, 
can be remote operated, called hereinafter remote control mechanism 43. 
Case 12 houses a trip mechanism 50 comprising an electromagnetic trip 
control with coil 28 and a thermal bimetal trip control 32. A plunger 52 
slides inside coil 28 and cooperates in the attracted position with hammer 
54 that pivots trip-rod 56. Plunger 52 carries an extractor 58 the head 60 
of which strikes contact arm 22 and pulls it into open circuit position 
when plunger 52 is attracted. Bimetal 32 cooperates with trip-rod 56 in 
the case of overload (see FIG. 3) by pivoting it in the clockwise 
direction so that a catch 62 is released from a hook 64 that rotates on 
stationary pivot 66 fixed in case 12. Hook lever 64 is elbow-shaped and at 
its far end carries a slide 68 into which a finger 70 fixed to lever 72 of 
a toggle 74 is engaged. Finger 70 also is engaged in a slide 76 carried by 
one of the arms of a lever or swivel part 78 mounted to rotate freely on 
pivot 24 coaxially to contact arm 22. Part 78 has two other arms, one of 
which carries on its end a thrust 80 driving contact arm 22, while the 
other arm cooperates at its end 82 with a coiled trip spring 84. The 
second lever 86 of toggle 74 is part of a resetting handle 88 mounted to 
rotate on stationary pivot 90. A drawback spring 92 exerts an 
anticlockwise force on handle 88, the travel of handle 88 being limited by 
stops represented by the extreme ends of the opening into case 12 made for 
handle 88. When handle 88 is in the reset position, as illustrated on 
FIGS. 1 and 2, spring 84 tends to pivot part 78 in clockwise rotation, but 
this rotation is prevented by toggle 74 which is in a position beyond 
neutral, precluding any upward movement (on the figure) of finger 70, 
driven by slide 76. In this position thrust 80 is separated from contact 
arm 22 by a clearance "j", preventing any action on contact arm 22 while 
contacts 14, 20, are in closed circuit position. When trip-rod 56 is 
pivoted due to the action of a deflection of bimetal 32 in the case of an 
overload, or to the action of plunger 52 in the case of a short-circuit, 
hook 64 is released and the kinematic link constituted by slides 68, 76 
and finger 70 is broken. This break frees slide 76 and swivel part 78 is 
driven in clockwise rotation by spring 84, which via thrust 80 drives 
contact arm 22 towards the open circuit position. The break in link 68, 
70, 76 also allows finger 70 to move and toggle 74 to fold in due to the 
action of drawback spring 92, which moves handle 88 into the open circuit 
position. 
FIGS. 3 and 4 illustrate this tripping phase and the final open circuit 
position after tripping, where hook 64 has returned to the latched 
position due to the action of drawback spring 94. The swivel of contact 
arm 22 driven by spring 84, which exerts a much greater force than spring 
38, entails a shift in fastening point 36, and, beyond the neutral point 
corresponding to an alignment of points 44, 36, 40, moves swivel lever 42 
into the open circuit position illustrated on FIGS. 2 and 4. When contacts 
14, 20, are in open position after tripping, as shown in FIG. 4, spring 
84, by means of swivel part 78, holds contact arm 22 in the open position 
independently of remote control mechanism 48. A remote control signal to 
close causing swivel lever 42 to pivot clockwise has no effect on contact 
arm 22 that is locked by the much greater force exerted by spring 84. As 
soon as the closing control signal terminates, swivel lever 42 is drawn 
back to its initial open circuit position by spring 38. 
Resetting of trip mechanism 50 is carried out by pivoting handle 88 
clockwise, causing toggle 74 to extend beyond neutral point, forcing 
finger 70 to slide in slide 68 and push slide 76 downwards. This movement 
of slide 76 entails an anticlockwise rotation of swivel part 78, opposing 
the force of spring 84, towards the initial position of thrust 80. 
Contacts 14, 20, are arranged alongside the entrance of a quench chamber 
with deionizing plates 96. An arc guide 98 connected to stationary contact 
14, leads the arc drawn between separated contacts 14, 20, to quench 
chamber 96 according to normal practice in circuit breakers. 
Next to circuit breaker unit 10 is mounted a remote control unit 100 that 
has a moulded case 102 with the same profile (FIG. 6). Case 102 houses an 
electro-magnet 104 with a plunger 106 that actuates a swivel lever 108 
hinged at its end on a fixed point 109 in case 102. Lever 108 carries a 
push-rod 110 the end of which cooperates selectively with shoulders 112, 
114 of a rocker 116, mounted to rotate on a stationary pin 118. During 
this movement, pusher-rod 110 pivots slightly opposing a drawback force 
exerted by spring 120. When electro-magnet 104 is deenergized, lever 108 
and push-rod 110 are brought back to their original position, ready for 
the next operation when electro-magnet 104 is again energized. During this 
next operation, push-rod 110 cooperates with shoulder 114, to pivot rocker 
116 in the opposite direction. This mode of operation is current practice 
in remote operated snap switches and will not be further described here. 
The movement of rocker 116 is transmitted by linkage 122 to a swivel 
handle 124 mounted to rotate on a stationary pin 126. Swivel handle 124 
carries an arm 128 which at one end has a finger 130 leading through the 
adjoining walls of cases 12, 102, to pin into the swivel lever of rocker 
arm 42 in circuit breaker unit 10, so as to join mechanically rocker arm 
42 and rocker 116. When cases 12, 102 are assembled side by side, pins 44, 
126 are practically in line. Moulded case 102 has connection terminals 132 
for the wires operating electromagnet 104 by remote control. 
The circuit breaker according to the invention operates in the following 
manner: 
In the position circuit breaker reset, shown on FIGS. 1 and 2, contacts 14, 
20, can be opened and closed by remote control by energizing 
electro-magnet 104 in remote control unit 100. On the first control 
signal, rocker 116 is tilted anticlockwise as shown on FIG. 6, entailing a 
corresponding movement of swivel lever or rocker arm 42 towards the closed 
circuit position shown on FIG. 1. As soon as the neutral point, where 
points 36, 40, 24 are aligned, is crossed, movable contact arm 22 pivots 
towards the circuit closed position. When electro-magnet 104 is 
de-energized, lever 108 and push-rod 110 return to their original 
position, while rocker 116 and rocker arm 42 remain in the stable circuit 
closed position. The next control signal energizing electro-magnet 104 
causes rocker 116, and rocker arm 42 to pivot in the opposite direction, 
bringing movable contact arm 22 into the open circuit position once the 
neutral point, corresponding to alignment of points 36, 40, 24, is 
crossed. Trip mechanism 50 is not involved by these remote controlled 
operations and movable contact arm 22 swings freely under the effect of 
spring 38. Such a mechanism requiring low driving energy can easily carry 
out a large number of operations. Handle 124 constitutes an emergency 
operating means for manual opening and closing of contacts 14, 20. 
When an overload occurs, with the circuit breaker in the closed circuit 
position, bimetal 32 is deflected to the right on FIG. 3 and causes 
trip-rod 56 to pivot in the direction that releases hook 64. Hook 64 is 
also released when a short-circuit is detected by coil 28 which attracts 
plunger 52 and causes push-rod 54 to push trip-rod 56 in the direction 
that releases hook 64. Once the hook is released, the link between toggle 
74 and slide 76 is broken and swivel part 78 is rotated clockwise by 
spring 84, while thrust 80 pushes movable contact arm 22 into the open 
circuit position. The considerable driving force of spring 84 allows a 
high-speed displacement of movable contact arm 22, assisted in the case of 
a short-circuit by the action of extractor 58 fixed to plunger 52. Spring 
84 holds movable contact arm 22 in the open circuit position independently 
of any remote control signal, since spring 38 cannot overcome the force of 
spring 84. In the tripped open position, shown on FIG. 4, handle 88 has 
taken up the open circuit position, whereas hook 64 is once again latched. 
The circuit breaker will not be reoperative until handle 88 is swung into 
the reset position by a manual resetting action. This swinging movement 
extends toggle 74, and finger 70 guided by slide 68 pushes slide 76 
against the force of spring 84 to give the initial separation position of 
movable contact arm 22. Handle 88 and toggle 74 are held in the reset 
position by the force exerted on finger 70 by slide 76, so that toggle 74 
remains in a position beyond neutral point. After resetting, the circuit 
breaker is ready for further operations remote controlled by mechanism 48 
as described above. 
The arc drawn between contacts 14, 20, on tripping due to overload or 
short-circuit, is blown towards the deionizing plate chamber 96 where it 
is rapidly quenched. It should be noted that once contacts 14, 20, are 
opened on tripping, swivel lever 42 automatically takes up the 
corresponding open position, authorizing a remote control signal to close 
the contacts by energizing electro-magnet 104. 
To work on the circuit, it can be disconnected by moving handle 88, by 
means of a tool for instance, from the reset position into the open 
circuit position. This swinging movement causes toggle 74 to fold in and 
thrust 80 to pivot due to the action of spring 84. If contacts 14, 20, are 
closed, they are automatically brought into the open circuit position due 
to the action of thrust 80. If contacts 14, 20, are already in open 
circuit position, thrust 80 holds contact arm 22 in open circuit position, 
thereby preventing contacts 14, 20, from closing, in particular through 
remote control mechanism 48. The fact that handle 88 is in the open 
circuit position is a reliable indication that contacts 14, 20, are open. 
Indeed, should contacts 14, 20, stick due to a shortcircuit current 
causing mechanism 50 to trip, slide 76 will be held in position by thrust 
80, pressing against contact arm 22, and will prevent handle 88 from 
moving into the open circuit position. 
The complete system is particularly simple and the fact that remote control 
mechanism 48 and trip mechanism 50 operate independently of each other 
means that each can be adapted specifically to its respective function of 
remote control and protection. The whole system can be housed in a 
standard model case for circuit breaker or miniature switchgear so that it 
can readily be incorporated in a distribution cubicle or distribution 
switchboard. 
The control unit can obviously be constucted in a different way, for 
instance with two electro-magnets, one to open, the other to close, the 
circuit, or with any other operating mechanism of swivel lever 42. 
The invention naturally covers any alternative embodiment, in particular 
one in which the control unit is built into the circuit breaker unit, or 
again, one excluding any manual operation.