Generator circuit breaker

The generator circuit breaker includes synchronization means for separating its main contacts before its arcing contacts are separated. It has a lever which is hinged at one of its ends to a fixed contact piece and which is constrained to move firstly with the moving main contact and secondly with the moving arcing contact by means of a spring, and with a ramp having two horizontal levels interconnected by a sloping intermediate portion, the ramp serving as a sliding support for a trigger member which prevents or authorizes movement of the moving arcing contact. This organization makes it possible for the moving contacts to be synchronized mechanically in simple and single manner.

FIELD OF THE INVENTION 
The invention relates to a generator circuit breaker comprising a fixed 
tubular main contact and a moving tubular main contact that moves relative 
to the fixed tubular main contact in a "longitudinal" direction, the main 
contacts defining a volume within which there is disposed a vacuum or gas 
"bottle" having a fixed arcing contact and a moving arcing contact which 
moves relative to the fixed arcing contact in said longitudinal direction, 
synchronization means serving to separate the main contacts before the 
arcing contacts separate. 
BACKGROUND OF THE INVENTION 
Such a circuit breaker is usually placed between a generator in an 
electricity power station and a transformer connected to a power transport 
line. 
In known manner, the main contacts are sufficiently massive to be capable 
of withstanding high nominal currents without heating up excessively. They 
define a relatively large volume which is more difficult to put under gas 
pressure or into a vacuum than is a "bottle" of small size placed inside 
said volume. The bottle has a fixed arcing contact and a moving arcing 
contact which are less massive since they do not have to withstand the 
breaking current of the circuit breaker. 
In French patent application FR 89/13279, the moving main contact and 
moving arcing contact extend in a common longitudinal direction, and are 
moved in translation parallel to said direction by pneumatic means having 
pistons and cylinders. 
Those means are not without their drawbacks. 
Firstly, it is necessary to provide electrically controlled valves to 
synchronize the displacements of the pneumatic actuators for the moving 
main contact and for the moving arcing contact. In particular, the moving 
main contact must accomplish sufficient displacement to withstand a 
transient electrical voltage prior to the moving arcing contact opening. 
Secondly, at the end of the stroke of the moving arcing contact, it is not 
possible to obtain acceleration that is satisfactory, enabling the circuit 
breaker to open with great efficiency, unless relatively sophisticated 
apparatus is used for feeding gas to the pneumatic actuators. 
OBJECTS AND SUMMARY OF THE INVENTION 
The object of the invention is to provide a generator circuit breaker in 
which the moving contacts are actuated by a small number of mechanical 
means that are synchronized in simple manner. 
To this end, the invention provides a generator circuit breaker comprising 
a fixed tubular main contact and a moving tubular main contact that moves 
relative to the fixed tubular main contact in a "longitudinal" direction, 
the main contacts defining a volume within which there is disposed a 
vacuum or gas "bottle" having a fixed arcing contact and a moving arcing 
contact which moves relative to the fixed arcing contact in said 
longitudinal direction, synchronization means serving to separate the main 
contacts before the arcing contacts separate, wherein the synchronization 
means comprise a lever which is hinged at one of its ends to a fixed 
contact piece and which is constrained firstly to move with the moving 
main contact and secondly to move with the moving arcing contact by means 
of a spring, and a ramp having two horizontal levels interconnected by a 
sloping intermediate portion, the ramp serving as a sliding support for a 
trigger member, which trigger member prevents the moving arcing contact 
from moving while said trigger member is sliding on one of the horizontal 
levels of the ramp, and releases the moving arcing contact to move by 
engaging the sloping intermediate portion and while sliding over the other 
horizontal level of the ramp. 
The invention also provides a generator circuit breaker comprising a fixed 
tubular main contact and a moving tubular main contact that moves relative 
to the fixed tubular main contact in a "longitudinal" direction, the main 
contacts defining a volume within which there is disposed a vacuum or gas 
"bottle" having a fixed arcing contact and a moving arcing contact which 
moves relative to the fixed arcing contact in said longitudinal direction, 
synchronization means serving to separate the main contacts before the 
arcing contacts separate, wherein the synchronization means comprises a 
lever which is hinged at one of its ends to a fixed contact piece and 
which is constrained firstly to move with the moving arcing contact and 
secondly to move with the moving main contact by means of a wheel guided 
in a groove formed in the moving main contact and having two horizontal 
levels interconnected by a sloping intermediate portion, movement of the 
moving main contact, when the wheel is guided by the inclined intermediate 
portion of the groove, entraining movement of the moving arcing contact by 
pivoting the lever. 
The lever common to the two moving contacts of the circuit breaker of the 
invention makes it possible to move them in translation using a single 
mechanical control, thereby reducing the number of means that need to be 
implemented to move them. 
Movement of the moving main contact is synchronized relative to movement of 
the moving arcing contact in simple manner using a ramp or a groove having 
two horizontal levels that are interconnected by a sloping intermediate 
portion. The arcing contacts open only under drive from the sloping 
intermediate portion. They make it possible to establish a distance 
between the main contacts that is sufficient to withstand a transient 
electric voltage prior to the arcing contacts opening.

MORE DETAILED DESCRIPTION 
In FIG. 1, the circuit breaker of the invention is inserted between 
portions 1 and 2 of a phase conductor of an electricity line. Portions 1 
and 2 of the conductor are connected mechanically and electrically to a 
fixed main contact 5 and to a fixed contact piece 4 of the circuit 
breaker. These contacts co-operate with a main contact 6 that is movable 
relative thereto in a longitudinal direction D. Co-operation between the 
fixed main contact 5 and the moving main contact 6 is provided by a ring 
of contact fingers 5A. A sliding contact 4A provides co-operation between 
the fixed contact piece 4 and the moving main contact 6. 
The fixed main contact 5, the fixed contact piece 4, and the moving main 
contact 6 are all tubular in shape, defining an inside volume in which 
there is located a "bottle" 15 that is evacuated or that contains a gas 
such as sulfur hexafluoride SF.sub.6. This bottle has a cylindrical 30 
insulating envelope 15A provided with a metal end wall 15B having a 
central hole 15C through which a moving arcing contact 15D slides. The 
bottle is held in a fixed position in the volume by arms that are not 
shown but that are fixed to its end wall 15B. The central hole of the 
bottle is sealed by means of a bellows 15E. 
Since the vacuum or the gas is restricted to inside the bottle, the 
pressure that surrounds between the main contacts is preferably equal to 
atmospheric pressure. 
The bottle is closed at its end opposite to the end wall 15B by a metal end 
wall 15F carrying a fixed arcing contact 15G mounted inside the bottle, 
and a ring of metal contact fingers 15H mounted outside the bottle. 
The moving main contact 6 is secured to a lever 171 via a rigid rod 22. One 
end of the lever 171 is hinged about a pivot 18 secured to the fixed 
contact piece 4. The moving arcing contact 15D is connected to the same 
lever 171 via a spring 19. 
A ramp 21 having two horizontal levels 21A and 21C interconnected by a 
sloping intermediate portion 21B has one of its ends secured to the lever 
171. 
A trigger member 23, comprising a frame 23A housing a retractable catch 23B 
mounted on a spring 23C and movable in translation perpendicularly to the 
longitudinal direction D through a hole 25A formed in a fixed plane 25 
inside the volume of the circuit breaker slides on the ramp 21 and is held 
in contact with the ramp under drive from a spring 23D compressed between 
the ramp 21 and the fixed plane 25. 
A single control (not shown) serves to move the main contact 6 in 
translation along direction D. It is also possible to rotate the lever 171 
using the control. 
The circuit breaker described above operates as follows: 
On opening, the translation movement of the moving main contact 6 in 
direction D along arrow O acts via the rod 22 and the lever 171 to move 
the ramp 21 in translation, which is accompanied by the frame 23A sliding 
along the horizontal level 21A of the ramp. The projecting position of the 
catch 23B which results from the combined action of the spring 23C and of 
the spring 23D prevents the moving arcing contact 15D from moving in 
translation on direction D, and causes the spring 19 to be extended. 
The moving main contact 6 travels along a fraction of its opening stroke 
that corresponds to being at a distance from the fixed main contact 5 that 
is sufficient, in air, to withstand a transient electrical voltage applied 
to the circuit breaker. Once this distance has been travelled, the frame 
23A engages the sloping intermediate portion 21B of the ramp, and then 
travels along horizontal level 21C of the ramp, under drive from the 
spring 23D. The offset between the two horizontal levels of the ramp 21 
enables the catch 23B to be withdrawn from the moving arcing contact 15D, 
which is then released and moves quickly in translation under drive from 
the spring 19. 
On closing, movement of the moving main contact 6 in translation on 
direction D along arrow F acts via the rod 22 and the lever 171 to move 
the ramp 21 and the moving arcing contact 15D in translation. The frame 
23A slides over the horizontal level 21C of the ramp, engages the sloping 
intermediate portion 21B, and moves to horizontal level 21A. Once the 
moving arcing contact 15D and the fixed arcing contact 15G have come into 
contact, the catch 23B projects from the fixed plane 25 under the combined 
action of springs 23C and 23D. Thereafter, the moving main contact 6 
completes its closure stroke. The additional stroke of the moving main 
contact 6 compared with the moving arcing contact 15D causes the spring 19 
to be compressed. 
In this particular embodiment, the circuit breaker has several advantages. 
Firstly, the speed in translation of the moving main contact 6 is 
relatively slow, which given the massive nature of its parts, makes it 
possible to reduce the mechanical power required to control movement 
thereof. In addition, the translation movement of the moving arcing 
contact 15D is relatively fast, thus making it possible to minimize the 
exposure of the arcing contacts to the interruption current. 
Furthermore, the distance required in air for withstanding the transient 
voltage between the main contacts is determined, as a function of the 
nominal voltage of the electricity line, by the lengths of the horizontal 
levels of the ramp. 
FIG. 2 shows a second particular embodiment of the invention in which 
elements that are common with those of FIG. 1 are given the same 
references. A lever 172 is hinged at one of its ends to pivot about a 
pivot 18 connected to the fixed contact piece 4. A recess 27 is formed 
through the moving main contact 6 to allow the lever 172 to pass through 
without hindering movement of the moving main contact 6 in translation. 
The moving arcing contact 15D is secured to the lever 172 via a rigid rod 
24. 
One or two identical grooves 29 are formed in the thickness of the side 
surface of the moving main contact 6 and are disposed symmetrically about 
a midplane of the circuit breaker, as represented by the plane of FIG. 2. 
Each groove has two horizontal levels 29A and 29C, interconnected by 
respective sloping intermediate portions 29B. 
A rigid rod 26 is disposed perpendicularly to the midplane of the circuit 
breaker and is rigidly connected to the lever 172. 
Identical wheels 31 are carried at the two ends of the rigid rod 26 and are 
guided along the two grooves 29. 
The above-described circuit operates as follows: 
On opening, movement of the moving main contact 6 in translation in 
direction D along arrow O causes the wheels 51 to run along the grooves at 
horizontal level 29C. The lever 172 is not subjected to force from the 
moving main contact 6. It remains stationary, as does the moving arcing 
contact 15D. 
The moving main contact 6 travels along a portion of its stroke 
corresponding to taking up a distance from the fixed main contact 5 that 
is sufficient, in air, to withstand a transient electrical voltage of the 
circuit breaker. Once this distance has been travelled, the wheels 31 
reach the sloping intermediate portions 29D of the grooves 29. In this 
zone, they continue to travel along the grooves, but are caused to follow 
an angular path which, in turn, rotates the lever 172. Via the rigid rod 
24, the lever 172 moves the moving arcing contact 15D quickly in 
translation, thereby separating it from the fixed arcing contact 15G. 
When the moving main contact finishes off its opening stroke, the wheels 31 
run along the grooves on the horizontal level 29A. The lever 172 remains 
stationary, as does the moving arcing contact 15D. 
On closure, the moving main contact 6 moves in translation on direction D 
along arrow F, thereby causing the wheel 31 to run along the grooves on 
horizontal level 29A. The lever is not subjected to any force from the 
moving main contact 6 and remains stationary, as does the moving arcing 
contact 15D. 
The wheels then engage the sloping intermediate portions 29B of the grooves 
29. In this zone, they continue to run along the grooves, but they are 
subjected to angular displacement, thus rotating the lever 172 and causing 
the moving arcing contact 15D to move in rapid translation to close 
electrical contact with the fixing arcing contact 15G. 
While the moving main contact 6 completes its closure stroke, the wheels 31 
run along the grooves on horizontal level 29C, thereby enabling the moving 
main contact 6 to have a stroke that is longer than that of the moving 
arcing contact 15D. The lever 172 remains stationary, as does the moving 
arcing contact 15D. 
In this particular embodiment, the circuit breaker has the advantage of 
determining the speed and the acceleration of the moving arcing contact 
15D by means of the slope of the sloping intermediate portion 29B. 
FIG. 3 shows a variant of the preceding embodiment in which the lever, now 
referenced 173, is folded and bent in an approximately central portion to 
define the groove 29. It should be understood that the fold in the lever 
defines the inside of the groove 29. 
The connection in displacement between the moving main contact 6 and the 
lever 173 is provided by a wheel 31 mounted to rotate freely on the rigid 
rod 26 whose two ends are fixed to the moving main contact 6. 
The operation of this circuit breaker in opening and in closing is 
analogous to that described with reference to the embodiment shown in FIG. 
2. 
In particular, the movement of the moving main contact 6 causes the moving 
arcing contact 15D to move by pivoting the lever 173 under drive from the 
wheel 31 running along a first portion 29A of the groove 29. 
While the main contact 6 is finishing off its opening stroke, the wheel 31 
runs along a second portion 29B of the groove 29 which occupies a level 
that is horizontal because of a change in the slope of the second portion 
29B relative to the first portion 29A. In this way, the lever 173 and the 
moving arcing contact 15D remains stationary. 
In this variant, the tube constituting the moving main contact 6 is of 
smaller weight, thereby making it possible to reduce control energy 
requirements.