Device for switching in a resistance when a circuit breaker closes a circuit

The invention relates to a resistance switch-in device for switching in only when a circuit breaker closes, said switch-in device including a moving arcing contact in an interrupter chamber. The device is characterized in that the switch-in contacts (2 and 3, 32 and 33) are disposed in the interrupter chamber (1) of the circuit breaker and that since at least one (2,32,33) of said switch-in contacts is a moving contact, it moves on a path parallel to that of the moving arcing contact (5). The invention applies in particular to connecting a load to long-distance high-tension circuits that are unloaded.

FIELD OF THE INVENTION 
The invention relates to a circuit-breaker, including a closing resistance 
switch-in device for limiting over-voltages during simple closing or 
during rapid reconnection cycle of unloaded long lines. 
BACKGROUND OF THE INVENTION 
Now, for a fairly large number of devices of this type which easily allow 
the arc to be quenched without switching in a resistor, it is generally 
preferable for the closing resistance to be switched in only before the 
main contacts close and to avoid switching in the resistance during arc 
interruption. 
The above disposition avoids the need to install an arc interrupter unit on 
the resistance switch-in contacts and makes it possible to reduce the 
dimensions of the resistance. The dispositions of the prior art consist in 
connecting an auxiliary closing chamber in parallel with the main chamber 
of the circuit-breaker, e.g. as described in French patent application No. 
77 25 777. However, such dispositions are always bulky and therefore 
expensive. 
The invention aims to provide a less bulky resistance switch-in device 
which operates when a circuit breaker closes with a more economical cost 
price. 
SUMMARY OF THE INVENTION 
The invention provides a resistance switch-in device for switching in a 
resistance during closing but not during opening of a circuit breaker, 
said switch-in device including firstly main contacts and arcing contacts 
in a interrupter chamber; the switch-in devices for said resistance being 
disposed in the interrupter chamber which is of insulating material, with 
said resistance being disposed coaxially in said interrupter chamber and 
to one end of said contacts. 
According to another characteristic, one of the contacts which causes the 
closing resistance to be switched in is fixed to one of the arc 
interrupter contacts and it is disposed slidably with respect to one of 
the arcing contacts. 
The relative positions of the contact, which, with respect to the arcing 
contact, slides between the opening position of the circuit breaker and 
its closing position, are determined by two stops, an opening stop and a 
closing stop. The opening stop controls the closing of the switch-in 
contacts before the closing of the arcing contacts and the closing stop 
controls the opening of the switch-in contacts before the opening of the 
arcing contacts. 
One of the stops can be fixed to the stationary support of the moving 
arcing contact of the arc interrupter unit while the other stop can be 
either also fixed to the stationary support of the moving arcing contact 
or fixed to the stationary support of the stationary contact. 
The closing resistance is switched in, either by means of two contact parts 
which co-operate together, the first being disposed on the moving arcing 
contact and the support, the second being fixed fast with the support of 
the stationary arcing contact so as to allow a relative movement of the 
first part with respect to the stationary contact or by means of two 
contact parts, one of which is disposed slidably on the stationary arcing 
contact and is provided with a delay device. 
The delay device includes a piston which moves in opposition to a spring in 
a cylinder equipped with a one-way valve. 
With the closing resistance connected between the stationary arcing contact 
and the contact ensuring that said resistance is switched in during the 
closing operation, said resistance can be disposed inside an insulating 
torus which has any given generating surface and whose directing circle 
center is in the vicinity of the axis of the interrupter chamber. 
The characteristics and advantages of the invention become apparent from 
the description given hereinafter of the embodiments given by way of 
examples and illustrated in the accompanying drawings.

DESCRIPTION OF PREFERRED EMBODIMENTS 
FIG. 1 illustrates a high-voltage circuit-breaker which includes an arc 
interrupter chamber inside an insulating casing 1, said chamber being 
filled with a dielectric gas such as sulphur hexafluoride. 
The insulating casing 1 of the cut-out chamber contains a tubular main 
moving contact 8 and a main stationary contact formed by a set of contact 
fingers 9 disposed at the ends of supports 23, a tubular moving contact 2, 
a tubular stationary contact 3 which switches in a closing resistance 4 
and cut-out arc contacts namely a moving arcing contact 5 and a stationary 
arcing contact 6; the moving arcing contact 5 is provided with a blast 
nozzle 7. The main contacts 8 and 9 pass the current when the 
circuit-breaker is in the closed position. To the left, on the moving part 
side, the current enters through a stationary tube 10 integral with a 
stationary piston 11, with a fixed stop 12 for the tubular moving contact 
2, and with stationary fingers 13 which pass current between the tube 10 
and a moving shaft 14 which is driven by a drive rod 15 and guided by a 
shoulder 16 free to slide in the tube 10 which thus acts as a support for 
the moving components. The shaft 14 supports a moving cylinder 17 whose 
end is provided with recesses 18 each of which contains a ball 19 urged 
outwardly by a spring. The balls co-operate with two grooves 20 and 21 
formed inside the tubular contact 2 which is disposed concentrically 
around a moving cylinder 17 along which it can slide from one groove to 
the other. The moving cylinder 17 is provided with a sliding contact 53 
which electrically connects the tubular contact 2 thereto. The moving 
cylinder 17 which surrounds the stationary piston 11 ensures that the gas 
is compressed. On the stationary contacts side, the current which comes 
from an end plate 22 passes through the supports 23 whose opposite ends 
are constituted by arms 23' with two wide openings between them, to the 
fingers 9 and to a stop 24. 
The fingers at the end of the tubular contact 3 are insulated from the 
support 23 by insulating parts 25. A spring 26 is used to install the 
resistance 4 resiliently between a metal end 27 of the casing 1, which end 
is electrically connected to the end plate 22 and connections 28 which 
pass through the openings between the arms 23' of the support 23, thereby 
insulating them from these supports. 
The device operates as follows. 
FIGS. 2 and 7 schematically illustrate a sequence of positions which are 
characteristic of a closing operation followed by an opening operation of 
the device illustrated in FIG. 1. These figures correspond to fragmentary 
illustrations of the device in FIG. 1 and even when subsequently referred 
to not all the components shown in FIG. 1 are always illustrated in these 
figures. In the fully open position illustrated in FIG. 2, the voltage 
appears between the moving contacts, namely, the switch-in contact 2, the 
arcing contact 5 and the main contact 8 on one side and the stationary 
contacts, namely, the switch-in contact 3 and the arcing contact 6. The 
stop 24 and the main contact 9 are set further back than the other 
stationary contacts. 
The movement of the components 5,7,8,14,16, 17 of the moving portion drives 
the switch-in contact 2 by means of the ball 19 in the groove 21. The 
tubular contacts 2 and 3 come into contact with each other to switch-in 
the resistance 4, the circuit being constituted by the conductive 
components 10, 13,14,17,53,2,3,28,4,27,22, as illustrated in FIG. 3. In 
FIG. 4, the fact that the moving portion continues to move causes the 
arcing contacts 5 and 6 to touch each other and to short-circuit the 
resistance 4, the circuit then being constituted by the conductive 
components 10,13,14,5,6, 23 and 22. Simultaneously, the switch-in contact 
2 touches the stop 24. The continuation of the movement of the moving part 
leads to the position in FIG. 5. This position corresponds to the closed 
position; the main contacts 8 and 9 touch each other and short-circuit the 
arcing contacts. The circuit is constituted by the conductive components 
10,13,14,8,9,23 and 22. Simultaneously, the stop 24 prevents the contact 2 
from moving with the moving portion and with the balls 19 which form a 
part thereof and the balls move from the groove 21 to the groove 20. 
To effect an opening operation starting from the closed position 
illustrated in FIG. 5, components 5,7,8,14,15, 16 and 17 of the moving 
portion move towards the left. When the equipment is in the position shown 
in FIG. 6, the main contacts 8 and 9 are already separated and the 
resistance switch-in moving contact 2, driven by the balls 19 which are in 
the groove 20, is about to part from the stationary switch-in contact 3, 
but the arcing contacts 5 and 6 are still in contact with each other and 
short-circuit the circuit of the resistance and thereby prevent it from 
being switched in when the contact opens. The moving portion continues its 
movement towards the open position until the moving parts are in the 
position shown in FIG. 7, where the distance between the tubular switch-in 
contacts 2 and 3 is greater than the distance between the arcing contacts 
5 and 6 and where the moving switch-in contact 2 meets the fixed stop 12. 
During the subsequent movement, the stop 12 prevents the tubular switch-in 
contact 2 from moving with the moving part and the balls 19 which form 
part thereof move out of the groove 20 into the groove 21, this 
corresponding to the fully open position illustrated in FIG. 2. 
In FIG. 8, the stops 12 and 24 are replaced respectively by stops 29 and 30 
and the end piece 31 of the tubular moving contact 2 abuts against these 
stops to switch-in the closing resistance, said closing resistance causing 
the balls 19 to move from the groove 20 to the groove 21 at the end of the 
contact 2 and vice-versa when the rod 15 and the moving cylinder 17 which 
is integral therewith move. Like the stops 12 and 24, the stops 29 and 30 
are fixed, but they are both located on the moving contact side. 
FIG. 8, which corresponds to the opening position of FIG. 2, shows how, 
during a closing operation, the equipment passes through a position 
identical to that illustrated in FIG. 3. When the equipment passes from 
the position which corresponds to FIG. 4 to that which corresponds to FIG. 
5, the end piece 31 abuts on the fixed stop 30 instead of the contact 2 
abutting on the fixed stop 24. This prevents the contact 2 from moving 
with the moving portion and moves the balls 19 from the groove 21 to the 
groove 20 (as in FIG. 5). During the opening operation, the equipment 
passes through a position identical to that illustrated in FIG. 6. When 
the equipment passes from the position which corresponds to that 
illustrated in FIG. 7 to the open position which corresponds to that 
illustrated in FIG. 2, the end piece 31 abuts against the fixed stop 29 
(instead of the contact 2 abutting against the fixed stop 12). This 
prevents the contact 2 from moving with the moving portion and moves the 
balls 19 from the groove 20 to the groove 21 (as in FIG. 2). 
In FIGS. 9 and 10, the stationary parts (tube 10, piston 11 and the contact 
fingers 13) which are identical to the same stationary parts in FIGS. 1 
and 8 are not illustrated. One of the contacts for switching in a closing 
resistance 32 is fixed firmly to the moving portion as are the contacts 5 
and 8 at the end of the cylinder 17. A second switch-in contact 33 is 
fixed on a piston 34 which moves in a stationary cylinder 35. 
Said cylinder is fast with the stationary components 6 and 9 and with the 
support 23 and is insulated therefrom by an insulating part 25. When, 
during the closing operation, the contact 32 pushes the contact 33 away, 
the piston pushes back a compression spring 36 and the gas compressed in a 
cylinder 35 escapes through a one-way valve 37. The contact 33 is 
electrically connected to the cylinder 35 by a sliding contact 38. The 
guide means of the piston 34 in the cylinder 35 include a calibrated 
leakage duct schematically illustrated at 39. In combination with the 
valve 37, said duct determines the valve opening delay. 
In the fully open position illustrated in FIG. 9, the stroke of the piston 
34 is limited by a stop 40 fixed in the cylinder 35. 
The device in FIGS. 9 and 10 operates as follows: during the closing 
operation, the position of the equipment passes from that illustrated in 
FIG. 9 to that illustrated in FIG. 10 and successively, part 32 comes into 
contact with part 33, thus switching the closing resistance 4 into the 
circuit as in FIG. 3, then the arcing contact 5 comes into contact with 
the arcing contact 6, thus short-circuiting the resistance (as in FIG. 4), 
then the permanent contact 8 comes into contact with the permanent contact 
9, this corresponding to the closed position (FIG. 10). Meanwhile, the 
contact 32 pushes the contact 33 and the piston 34 away, pressing back the 
compression spring 36. The compressed gas in the cylinder 35 escapes 
through the valve 37. This prevents the movement of the moving portion 
from being slowed down. During the opening operation which corresponds to 
passing from the position illustrated in FIG. 10 to that illustrated in 
FIG. 9 the contact 33 follows the action of the contact 32 with some 
delay, since the one-way valve 37 is closed by the partial vacuum in the 
cylinder 35. Due to the calibrated leakage duct 39 in the guide means of 
the piston 34, the pressure in the cylinder 35 tends to be balanced 
progressively with respect to the pressure in the chamber; the spring 36 
must overcome the difference in pressure between the two surfaces of the 
piston and slowly moves the contact 33. In these conditions, the contacts 
32 and 33 are separated from each other before the arcing contacts 5 and 
6. This prevents the resistance from being switched in during the opening 
operation. The equipment therefore comes to the fully open position 
illustrated in FIG. 9. 
The total length of the cut-out chamber may be reduced while the same 
insulating casing 1 is used, replacing the longitudinal closing resistance 
4 of FIG. 1 by a resistance 42 with an angular shape illustrated in FIGS. 
11 and 12. The preceding modification enables the length of the metal end 
41 of the casing 1 to be greatly reduced. The resistance 42 formed by a 
set of components 43 stacked in a toroidal chamber, for example, is 
contained in an annular insulating casing 44 and is insulated from the 
metal end 22 by insulating spacers 45. The resistance components 43 are 
held by clamping plates 46 and 47. The plate 46 is linked to the 
connections 28 of FIGS. 1 to 11 and 33 of FIGS. 9 and 10 by a connection 
48 while the plate 47 is linked to the metal end 41 by the connection 49. 
The annular resistance 42 may also be a spiral instead of a circle. 
The advantages of the devices in accordance with the invention are the 
following: 
with the devices of FIGS. 1 to 10, the same casing 1 may contain the main 
contacts and the arcing contacts as well as the switch-in contacts which 
allow the resistance to be switched in only during the closing operation 
and not during the opening operation. Further, these devices allow the 
closing resistor to be housed in the same casing; and 
these devices allow the use of the usual circuit-breaker mechanisms 
provided for closing and cutting out without switching in resistances and 
the switch-in device which is added is well adapted to moving portions 
with long strokes which are usual at high voltages, where closing 
resistances are used. 
The device does not greatly increase the diameter of the casing. The 
advantage of the devices of FIGS. 1 to 8 is that they are not very bulky 
and do not use any springs other than those of the balls. 
The advantage of the device of FIG. 8 is that it cancels all shocks on the 
end of the switch-in contact 2. This avoids having to modify the curve of 
the corresponding surface. Further, the stops 29 and 30 can be provided 
with shock-absorber devices since the available space is larger than with 
the devices of FIGS. 1 to 7. 
The device of FIGS. 9 and 10 sometimes damps shocks and sometimes avoids 
them when coming into contact with the stops. During the closing 
operation, when the contacts 32 and 33 come into contact with each other, 
the spring 36 is pushed back and compresses a gas at 35. This corresponds 
to a resilient shock. During the opening operation, the gas-operated delay 
device takes the place of the stop to avoid a shock--a disposition which 
can be used advantageously in short-stroke devices such as high-tension 
compressed air equipment. 
The annular resistances of FIGS. 11 and 12 have the following advantages: 
the metal end 41 of the casing 1 is shorter. The shape of the end 41 
(shorter with a larger diameter) reduces glow discharges. It is more 
simple to assemble and fix the resistor 42. 
It is evident that the invention is in no way limited to the embodiments 
which have just been described and illustrated and which have been given 
only by way of examples; in particular, without going beyond the scope of 
the invention, some dispositions can be modified or some means can be 
replaced by equivalent means, or even, some components can be replaced by 
others which could perform the same technical function or and equivalent 
technical function.