Patent EA-001575-B1 (EA)
Title: An extinguishing chamber for a high-voltage circuit breaker
Inventor: RAPHARD DENIS
IPC: H01H33/985
Filed: 1999-01-26
Abstract: 1. An extinguishing chamber extinguishing chamber for a high voltage circuit breaker isolated by a high dielectric strength gas, and equipped with an arc extinguishing device by self-expansion of the gas, said chamber comprising : - an enclosure (12) made of insulating material containing a stationary contact device (16) operating in conjunction with a movable contact (14) arranged at the end of a conducting tube (20), which passes with sliding through one of the panels (22) of the enclosure (12) moving between a closed position and an open position of the contacts, - an electromagnetic coil (18) for rotation of the arc on the contact track (32) situated on the front face of the coil (18), said coil being securedly affixed to the stationary contact device (16) to form an overhanging module on the opposite panel (26) of the enclosure (12), - means for the chamber (10) to communicate with the external volume of the enclosure (12) when self-expansion of the gas takes place after the contacts have separated, - the stationary contact device (16) being coaxially surrounded by the cylindrical coil (18), and comprising a plurality of contact fingers (42) arranged circumferentially to confine a hollow space receiving the movable contact (14). characterized in that each contact finger (42) of the stationary contact device (16) comprises a composite metallic structure having : - a copper main body (52) shaped as a cylindrical sector for flow of the permanent current in the closed position of the movable contact (14), - an electrode (54) made of refractory conducting material, brazed onto the front end of the body (52) to constitute a stationary arcing contact arranged near to the arc rotation track (32), - and a segment (58) made of ferromagnetic material brazed onto the periphery of the electrode (54) and of a part of the body (52), said segment being located inside the coil (18) to obtain optimum guiding of the arc on the track (32). 2. The extinguishing chamber according to claim 1, characterized in that the electrode (54) is made of a cupro-tungsten alloy base. 3. The extinguishing chamber according to claim 1 or 2, characterized in that the segment (58) is made of steel. 4. The extinguishing chamber according to claim 1, characterized in that the electrode (54) and the segment (58) of each contact finger (42) are separated from the contact track (32) by an axial gap of small thickness, enabling switching of the arc for excitation of the coil (18) when the movable contact (14) separates from the electrode (54). 5. The extinguishing chamber according to claim 1, characterized in that each contact finger (42) is provided with a rear edge (46) mounted with latching on a centring part (48) of a current conducting stud (24). 6. The extinguishing chamber according to claim 5, characterized in that the coil (18) is connected to the stud (24) by copper support arms (34) forming spacers separated from the contact fingers (42) by insulating pads (36). 7. The extinguishing chamber according to claim 6, characterized in that a spring (44) in the form of a curved blade is inserted between each insulating pad (36) and the corresponding contact finger (42). 8. The extinguishing chamber according to claim 6, characterized in that the coil (18) is formed by axial stacking of conducting turns (18A) insulated from one another by insulating intercalated parts (18B), and that the rear face of the coil (18) opposite the track (32) is equipped with steel washers (38, 40), the assembly being secured by fixing screws (30). 9. The extinguishing chamber according to claim 1, characterized in that the communication means are formed by the hollow tube (20) of the movable contact (14).