Electricity: circuit makers and breakers – Liquid contact – Time delay
Patent
1986-02-04
1987-09-29
Macon, Robert S.
Electricity: circuit makers and breakers
Liquid contact
Time delay
200148R, 200148C, H01H 3364
Patent
active
046970550
DESCRIPTION:
BRIEF SUMMARY
The invention relates to an arc extinction device for a self-expansion and gas insulation electrical switch or circuit breaker comprising: notably sulphur hexafluoride, contacts being hollow, expansion of the gas initially compressed in the arc chute takes place, under the action of the arc drawn between the contacts separated when the circuit breaker opens,
A prior art circuit breaker of this kind is described in French Pat. Nos. 2,515,418 and 2,418,963 filed by the applicant. The divisional arc chute containing the contacts is formed by a cylindrical-shaped housing. Breaking tests have shown a certain off-centering of the arc drawn between the separated annular electrodes of the contacts. This arc off-centering problem leads to an increase in the breaking time which limits the performance of the switchgear.
The object of the invention is to improve the arc centering in a gas insulation circuit breaker or switch, notably of the self-expansion and/or rotating arc type, and to increase the breaking performances of the circuit breaker.
The arc extinction device according to the invention is characterized by the fact that the divisional arc chute comprises opposite the contact separation area a curved side revolution surface of a non linear curve, notably convex or concave, in such a way as to form an acoustic resonator reflecting the pressure waves inward, causing the gases to converge towards said separation area, and that the separable contacts are located in the vicinity of the middle area of said arc chute.
According to an embodiment of the invention, the wall of the arc chute has a spherical shape or spherical cross-section such that the acoustic resonator has a vibration antinode in the center of the sphere.
According to an alternative embodiment of the invention, the arc chute has an ellipsoidal shape arranged in such a way that the contacts are located apreciably at the level of the two focal spots in the circuit breaker open position. This results in better centering of the arc, in particular in the vicinity of the electrodes.
At least one of the contacts can be fitted with a permanent magnet or an electromagnetic coil to cause the arc to rotate inside the arc chute.
The wall of the arc chute is made of an insulating material, notably epoxy resin based, or of any other material having a high reflection coefficient .
Other advantages and characteristics will become more clearly apparent from the following description of various embodiments of the invention, given as examples only and represented in the accompanying drawings, in which:
FIG. 1 is an axial cross-sectional view of a circuit breaker according to the invention, represented in the open position,
FIGS. 2 to 7 show a schematic partial sectional view of several embodiments of the invention.
FIG. 1 shows a rotating arc self-expansion electrical circuit breaker 10, comprising a cylindrical-shaped insulating housing 12, sealed at opposite ends by base plates 14, 16. The housing 12 is tight and filled with high dielectric strength electronegative insulating gas, such as sulphur hexafluoride. Inside the housing 12 a divisional arc chute 18 is located which houses a system of separable coaxial contacts 20, 22. The stationary contact 20 formed by a conductor tube 24 supported by the base plate 14, is fitted at its opposite end with an electrode 26 facing an annular contact surface 28 of the moving contact 22. The latter comprises a support tube 29 mounted sliding axially in the housing 12 and securedly attached to a control rod 30 which passes through a central opening 32 in the base plate 16 fitted with a seal 34. A conducting strip 36 or any other flexible or sliding conductor provides the electrical connection between the tube 29 of the moving contact 22 and the base 16. Connection terminals 36, 38 of the pole of the circuit breaker 10 are associated with the base plates 14, 16, made of conducting material.
The two tubes 24, 29 of the stationary 20 and moving contacts 22 each comprise an internal axial outflow duct 40, 42 and radial orifices 44, 4
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Amalric Jean
Bernard Georges
Marzocca Joseph
Petit Daniel
Walter Jean-Jacques
Gerin Merlin
Macon Robert S.
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