Gas-blast circuit breaker having a floating puffer piston driven by electromagnetic force

Claim 2

An electromagnetic puffer type gas blast circuit breaker comprising a casing member confining an arc extinguishing gas, a pair of terminals through whic current flows during the closed condition of said breaker, a pair of contactors capable of such disengaging as to induce an arc, a primary coil fixed to a rod member through which current flows into said coil member upon disengagement of said contactors for generating a magnetic field therein, a movable short-circuit body, said short-circuit body being magnetically directly connected with said coil upon disengagement of said contactors, said coil and short-circuit body being positioned at the rear side of the direction of gas blasting, and being movable in the direction of gas compression, connected magnetically to said primary coil, for producing a magnetic repulsive force between said primary coil and said short circuit body, a commutating device for inserting said primary coil into a circuit to be cut off in accordance with a breaking command, a device for compressing a part of said arcextinguishing gas driven by said magnetic repulsive force, and a gas-guiding device blasting a high pressure gas obtained by said compressing device against said arc, wherein said compressing device is designed to be operated independently from an opening motion of said contactors after operation of said commutating device.

Claim 3

An electromagnetic puffer type gas-blast circuit breaker apparatus comprising: a first stationary electrical contactor; a second electrical contactor disengageably coupled with said first contactor, so that current flows between said first and second contactors during the closed condition of said breaker; a first conductive element connected to said second contactor and being mechanically displaced during the breaking of said breaker; a primary coil electrically engageable with said first conductive element upon separation of said first and second contactors, while being normally de-energized during the engagement of said contactors; a conductive body magnetically directly coupled with said primary coil and displaceable with respect thereto for generating a repulsive magnetic force with respect to said primary coil, said coil and said conductive body being positioned at the rear side of the direction of gas blasting; first means for supplying current through said first contactor, said second contactor, said first conductive element and said primary coil to induce a magnetic field within said coil, whereby said magnetic field will be inductively coupled with said conductive body; second means for supporting an arc extinguishing gas; third means, coupled with and displaceable with respect to said second means and coupled with said conductive body, for compressing said arc extinguishing gas, the compression displacement of said third means being independent of the displacement of said first conductive element, so that substantially the entire magnetic repulsive force acting upon said third means is consumed for compressing said gas supported by said second means; fourth means, coupled with said first means, for separating said first and second contactors, and for generating an electriC arc therebetween, and fifth means, responsive to the separation of said first and second contactors, and being coupled to said second means, for directing compressed arc extinguishing gas onto said arc, so as to extinguish said arc.

Claim 4

An electromagnetic puffer type gas-blast circuit breaker apparatus comprising: a first stationary electrical contactor; a second electrical contactor disengageably coupled with said first contactor, so that current flows between said first and second contactors during the closed condition of said breaker; a first conductive element connected to said second contactor and being mechanically displaced during the breaking of said breaker; a primary coil electrically engageable with said first conductive element upon separation of said first and second contactors, while being normally de-energized during the engagement of said contactors; a conductive body magnetically directly coupled with said primary coil and displaceable with respect thereto for generating a repulsive magnetic force with respect to said primary coil, said coil and said conductive body being positioned at the rear side of the direction of gas blasting; first means for supplying current through said first contactor, said second contactor, said first conductive element and said primary coil to induce a magnetic field within said coil, whereby said magnetic field will be inductively coupled with said conductive body; second means for supporting an arc extinguishing gas; third means, coupled with and displaceable with respect to said second means and coupled with said conductive body, for compressing said arc extinguishing gas, the compression displacement of said third means being independent of the displacement of said first conductive element, so that substantially the entire magnetic repulsive force acting upon said third means is consumed for compressing said gas supported by said second means; fourth means, coupled with said first means, for separating said first and second contactors, and for generating an electriC arc therebetween, and fifth means, responsive to the separation of said first and second contactors, and being coupled to said second means, for directing compressed arc extinguishing gas onto said arc, so as to extinguish said arc.

Claim 5

A gas blast circuit breaker comprising: a. a casing member confining an arc extinguishing gas; b. a pair of terminals through which current flows during the closed condition of said breaker; c. a stationary contact member electrically connected to one of said terminals; d. a movable contact member disengageably contacting with said stationary contact member, whereby current flows directly between said contact members during normally closed operation of said breaker and an arc forms between said contact members upon disengagement thereof during breaking; e. means for compressing a part of said arc extinguishing gas comprising a cylinder member, a piston member disposed within said cylinder member and means for operating said compressing means, said operating means including an operating rod member, connected to an operating mechanism responsive to a breaking command, for initiating disengagement of said contact members and for engaging said contact members, and electromagnetic operating means for generating a magnetic repulsive force acting upon said cylinder member and said piston member, said electromagnetic operating means comprising a movable coil member fixed to said rod member, normally short circuited when current flows between said terminals, for generating a magnetic field upon disengagement of said contact members, and a movable short circuit member, fixed to said piston member and directly magnetically coupled with said coil member, for producing said magnetic repulsive force between said coil member and said short circuit member to thereby actuate said piston member towards the direction of gas compression, said piston member and said cylinder member being so designed that a compression movement of said piston member within said cylinder member is effected independently of said rod member to thereby minimize a gas compression reaction force acting upon said operating mechanism; f. nozzle means for blasting said compressed arc extinguishing gas from said cylinder member onto said arc upon disengagement of said contact members, whereby said arc is extinguished, wherein said coil member is positioned at the rear side of said cylinder member with respect to the direction of gas blasting from said nozzle member; and g. means for switching off said movable contact member from one of said terminals upon displacement thereof, whereby current flows between said coil member and one of said terminals to thereby produce said magnetic field.

Claim 6

A gas blast circuit breaker comprising: a. a casing member confining an arc extinguishing gas; b. a pair of terminals through which current flows during the closed condition of said breaker; c. a stationary contact member electrically connected to one of said terminals; d. a movable contact member disengageably contacting with said stationary contact member, whereby current flows directly between said contact members during normally closed operation of said breaker and an arc forms between said contact members upon disengagement thereof during breaking; e. means for compressing a part of said arc extinguishing gas comprising a cylinder member, a piston member disposed within said cylinder member and means for operating said compressing means, said operating means including an operating rod member, connected to an operating mechanism responsive to a breaking command, for initiating disengagement of said contact members and for engaging said contact members, and electromagnetic operating means for generating a magnetic repulsive force acting upon said cylinder member and said piston member, said electromagnetic operating means comprising a movable coil member fixed to said rod member, normally short circuited when current flows between said terminals, for generating a magnetic field upon disengagement of said contact members, and a movable short circuit member, fixed to said piston member and directly magnetically coupled with said coil member, for producing said magnetic repulsive force between said coil member and said short circuit member to thereby actuate said piston member towards the direction of gas compression, said piston member and said cylinder member being so designed that a compression movement of said piston member within said cylinder member is effected independently of said rod member to thereby minimize a gas compression reaction force acting upon said operating mechanism; f. nozzle means for blasting said compressed arc extinguishing gas from said cylinder member onto said arc upon disengagement of said contact members, whereby said arc is extinguished, wherein said coil member is positioned at the rear side of said cylinder member with respect to the direction of gas blasting from said nozzle member; and g. means for switching off said movable contact member from one of said terminals upon displacement thereof, whereby current flows between said coil member and one of said terminals to thereby produce said magnetic field.

Claim 7

A gas blast circuit breaker according to claim 3, wherein said short circuit member has a cylindrical shape and is fixed, adjacent to said coil member, to said piston member.

Claim 8

A gas blast circuit member according to claim 3, wherein said piston member is mechanically biased in the direction opposite to that of gas compression.

Claim 9

A gas blast circuit breaker according to claim 4, wherein at least one of said coil member and short circuit member have such an axial length so that the electromagnetic force has a flat characteristic.

Claim 10

A gas blast circuit breaker comprising: a. a casing member confining an arc extinguishing gas; b. first and second terminals through which current flows during the closed condition of said breaker; c. a stationary contact member electrically connected to said first terminal; d. a movable contact member disengageably contacting said stationary contact member and connected to said second terminal through a switching arrangement for switching a current path from the normally closed condition to the breaking condition, whereby current flows directly between said contact members during the normally closed condition of said breaker and an arc forms between said contact members upon disengagement Thereof during breaking; e. an operating rod member electrically connected to said movable contact member during the closed condition of said breaker and mechanically connected to an operating mechanism responsive to a breaking command; f. a cylinder member, fixingly mounted on said rod member and having a bottom wall; g. a piston member slidably mounted on said rod member and disposed within said cylinder member, whereby a part of said arc extinguishing gas is compressed in said cylinder member; h. a nozzle member, mounted on said bottom wall of said cylinder member and surrounding said contact members, for blasting compressed gas onto said arc; i. a movable coil member, movable in the direction of gas compression, short circuited only during the normally closed condition of said breaker but having its short circuited condition removed upon displacement of said switching arrangement, for generating a magnetic field; j. a movable short circuit member, directly magnetically connected with said coil member by said magnetic field and carrying said piston member, for producing a magnetic repulsive force between said movable short circuit member and said coil member, said coil member and short circuit member being positioned at the rear side of the direction of gas blasting, so that a compression movement of said piston member is effected independently of said rod member to thereby minimize a compression reaction force acting upon said operating mechanism; k. first means for fixingly supporting said coil member on said rod member; and l. second means for movably supporting said rod member.

Claim 11

A gas blast circuit breaker comprising: a. a casing member confining an arc extinguishing gas; b. first and second terminals through which current flows during the closed condition of said breaker; c. a stationary contact member electrically connected to said first terminal; d. a movable contact member disengageably contacting said stationary contact member and connected to said second terminal through a switching arrangement for switching a current path from the normally closed condition to the breaking condition, whereby current flows directly between said contact members during the normally closed condition of said breaker and an arc forms between said contact members upon disengagement Thereof during breaking; e. an operating rod member electrically connected to said movable contact member during the closed condition of said breaker and mechanically connected to an operating mechanism responsive to a breaking command; f. a cylinder member, fixingly mounted on said rod member and having a bottom wall; g. a piston member slidably mounted on said rod member and disposed within said cylinder member, whereby a part of said arc extinguishing gas is compressed in said cylinder member; h. a nozzle member, mounted on said bottom wall of said cylinder member and surrounding said contact members, for blasting compressed gas onto said arc; i. a movable coil member, movable in the direction of gas compression, short circuited only during the normally closed condition of said breaker but having its short circuited condition removed upon displacement of said switching arrangement, for generating a magnetic field; j. a movable short circuit member, directly magnetically connected with said coil member by said magnetic field and carrying said piston member, for producing a magnetic repulsive force between said movable short circuit member and said coil member, said coil member and short circuit member being positioned at the rear side of the direction of gas blasting, so that a compression movement of said piston member is effected independently of said rod member to thereby minimize a compression reaction force acting upon said operating mechanism; k. first means for fixingly supporting said coil member on said rod member; and l. second means for movably supporting said rod member.

Claim 12

A gas blast circuit breaker according to claim 7, wherein said short circuit member has a cylindrical shape of such an axial length that the electromagnetic force has a flat characteristic.

Claim 13

A gas blast circuit breaker according to claim 7, wherein said coil member has more than one turn in the axial direction.

Claim 14

A gas blast circuit breaker comprising: a. a casing member confining an arc extinguishing gas; b. first and second terminals through which current flows during the closed condition of said breaker; c. a stationary contact member electrically connected said first terminal; d. a movable contact member disengageably contacting said stationary contact member and connected to said second terminal through a switching arrangement, whereby current flows directly between said contact members during the normally closed condition of said breaker and an arc forms between said contact members upon disengagement thereof during breaking; said movable contact member being electrically connected with an operating rod member mechanically connected to an operating mechanism responsive to a breaking command; e. a cylinder member, electrically insulated from said rod member and slidably mounted on said rod member and having a bottom wall; f. a piston member, disposed within said cylinder member, electrically insulated from and fixedly mounted on said rod member, whereby a part of said arc extinguishing gas is compressed in said cylinder; g. a nozzle member, mounted on said piston member and surrounding said contact members, for blasting compressed gas onto said arc, said nozzle member communicating with said cylinder through an aperture formed in said piston member; h. a coil member, short circuited only during the normally closed condition of said breaker and fixed to said rod member through which current flows into said coil member upon disengagement of said contact members but having its short circuited condition removed upon displacement of said switching arrangement, for generating a magnetic field; i. a cylindrical movable short circuit member, concentrically adjacent said coil member and directly magnetically coupled with said coil member during said breaking and fixed to said cylinder member, for generating a magnetic repulsive force due to induction current occurring therein, saId coil member and short circuit member being positioned at the rear side of the direction of gas blasting, so that a compression movement of said cylinder member is effected independently of said rod member to thereby minimize a compression reaction force acting upon said operating mechanism; j. means for commutating current flowing between said terminals to said coil member; k. first means for fixedly supporting said coil member on said rod member; and l. second means for supporting movably said rod member.

Claim 15

A gas blast circuit breaker comprising: a. a casing member confining an arc extinguishing gas; b. first and second terminals through which current flows during the closed condition of said breaker; c. a stationary contact member electrically connected said first terminal; d. a movable contact member disengageably contacting said stationary contact member and connected to said second terminal through a switching arrangement, whereby current flows directly between said contact members during the normally closed condition of said breaker and an arc forms between said contact members upon disengagement thereof during breaking; said movable contact member being electrically connected with an operating rod member mechanically connected to an operating mechanism responsive to a breaking command; e. a cylinder member, electrically insulated from said rod member and slidably mounted on said rod member and having a bottom wall; f. a piston member, disposed within said cylinder member, electrically insulated from and fixedly mounted on said rod member, whereby a part of said arc extinguishing gas is compressed in said cylinder; g. a nozzle member, mounted on said piston member and surrounding said contact members, for blasting compressed gas onto said arc, said nozzle member communicating with said cylinder through an aperture formed in said piston member; h. a coil member, short circuited only during the normally closed condition of said breaker and fixed to said rod member through which current flows into said coil member upon disengagement of said contact members but having its short circuited condition removed upon displacement of said switching arrangement, for generating a magnetic field; i. a cylindrical movable short circuit member, concentrically adjacent said coil member and directly magnetically coupled with said coil member during said breaking and fixed to said cylinder member, for generating a magnetic repulsive force due to induction current occurring therein, saId coil member and short circuit member being positioned at the rear side of the direction of gas blasting, so that a compression movement of said cylinder member is effected independently of said rod member to thereby minimize a compression reaction force acting upon said operating mechanism; j. means for commutating current flowing between said terminals to said coil member; k. first means for fixedly supporting said coil member on said rod member; and l. second means for supporting movably said rod member.

Claim 16

A gas blast circuit breaker according to claim 10, wherein said short circuit member has a cylindrical shape of such an axial length that the electromagnetic force has a flat characteristic.

Claim 17

A gas blast circuit breaker according to claim 10, wherein said coil member has more than one turn in the axial direction.

Claim 18

A gas blast circuit breaker comprising: a. a casing member confining an arc extinguishing as; b. first and second terminals through which current flows during the closed condition of said breaker; c. a stationary contact member electrically connected with said first terminal; d. a movable contact member disengageably contacting with said stationary contact member and connected to said second terminal through a switching arrangement, whereby current flows directly between said contact members during the normally closed condition of said breaker and an arc forms between said contact members upon disengagement thereof during breaking, said movable contact member being electrically connected with an operating rod member mechanically connected to an operating mechanism which is responsive to a breaking command; e. a cylinder member, electrically insulated from said rod member and slidably mounted on said rod member and having a bottom wall; f. a piston member, disposed within said cylinder member, electrically insulated from said rod member and fixedly mounted on said rod member, whereby a part of said arc extinguishing gas is compressed in said cylinder member; g. a nozzle member, mounted on said piston member and surrounding said contact members, for blasting compressed arc extinguishing gas onto said arc, said nozzle member communicating with said cylinder member through an aperture formed in said bottom wall; h. a coil member, short circuited during the normally closed condition of said breaker and fixed to said rod member through which current flows into said coil member upon displacement of said switching arrangement but having its short circuited condition removed upon displacement of said switching arrangement, for generating a magnetic field; i. a cylindrical movable short circuit member, concentrically adjacent said coil member and directly magnetically coupled with said coil member during said breaking and fixed to said cylinder member, for generating a magnetic repulsive force due to induction current occurring therein. said coil member and short circuit member being positioned at the rear side opposite to that of the direction of gas blasting, so that a compression movement of said cylinder member is effected independently of said rod member, to thereby minimize a compression reaction force acting upon said operating mechanism; j. means for commutating current flowing between said terminals to said coil member; k. first means for fixedly supporting said coil member on said rod member; l. second means for movably supporting said rod member; and m. means for biasing said piston member towards the direction of gas compression, whereby said piston member follows said rod member until said magnetic repulsive force is exerted on said piston member.

Claim 19

A gas blast circuit breaker comprising: a. a casing member confining an arc extinguishing as; b. first and second terminals through which current flows during the closed condition of said breaker; c. a stationary contact member electrically connected with said first terminal; d. a movable contact member disengageably contacting with said stationary contact member and connected to said second terminal through a switching arrangement, whereby current flows directly between said contact members during the normally closed condition of said breaker and an arc forms between said contact members upon disengagement thereof during breaking, said movable contact member being electrically connected with an operating rod member mechanically connected to an operating mechanism which is responsive to a breaking command; e. a cylinder member, electrically insulated from said rod member and slidably mounted on said rod member and having a bottom wall; f. a piston member, disposed within said cylinder member, electrically insulated from said rod member and fixedly mounted on said rod member, whereby a part of said arc extinguishing gas is compressed in said cylinder member; g. a nozzle member, mounted on said piston member and surrounding said contact members, for blasting compressed arc extinguishing gas onto said arc, said nozzle member communicating with said cylinder member through an aperture formed in said bottom wall; h. a coil member, short circuited during the normally closed condition of said breaker and fixed to said rod member through which current flows into said coil member upon displacement of said switching arrangement but having its short circuited condition removed upon displacement of said switching arrangement, for generating a magnetic field; i. a cylindrical movable short circuit member, concentrically adjacent said coil member and directly magnetically coupled with said coil member during said breaking and fixed to said cylinder member, for generating a magnetic repulsive force due to induction current occurring therein. said coil member and short circuit member being positioned at the rear side opposite to that of the direction of gas blasting, so that a compression movement of said cylinder member is effected independently of said rod member, to thereby minimize a compression reaction force acting upon said operating mechanism; j. means for commutating current flowing between said terminals to said coil member; k. first means for fixedly supporting said coil member on said rod member; l. second means for movably supporting said rod member; and m. means for biasing said piston member towards the direction of gas compression, whereby said piston member follows said rod member until said magnetic repulsive force is exerted on said piston member.

Claim 20

A gas blast circuit breaker according to claim 13, wherein said short circuit member has a cylindrical shape of such an axial length that the magnetic force has a flat characteristic.

Claim 21

A gas blast circuit breaker according to claim 13, wherein said coil member has more than one turn in the axial direction.

Claim 22

A gas blast circuit breaker comprising: a. a casing member confining an arc extinguishing gas; b. first and second terminals through which current flows during the closed condition of said breaker; c. a stationary contact member electrically connected with said first terminal; d. a movable contact member disengageably contacted with said stationary contact member and connected to said second terminal through a switching arrangement, whereby current flows directly between said contact members during the normally closed condition of said breaker and an arc forms upon disengagement thereof during breaking, said movable contact member being electrically connected to an operating electroconductive rod member mechanically connected to an operating mechanism responsive to a breaking command, said rod member being so designed that said movable contact member is disengaged from said stationary contact member; e. a cylinder member, electrically insulated from said rod member and having a bottom wall provided with a cylindrical extending portion; f. a nozzle member surrounding said contact members, slidably disposed within said extending portion and having a flange portion, whereby movement of said nozzle member is restricted, for blasting compressed gas onto said arc; g. a piston member slidably mounted on said rod member, whereby a part of said arc extinguishing gas is compressed in said cylinder member; h. first means for mechanically biasing said piston member against the direction opposite to that of gas compression; i. second means for preventing blasting of said compressed arc extinguishing gas from said nozzle member until a gas pressure in said cylinder member reaches a predetermined value, said second means including said flange portion and said cylindrical extending portion; j. a coil member, short circuited during the normally closed condition of said breaker and fixed to said rod member through which current flows into said coil member upon displacement of said switching arrangement but having its short circuited condition removed upon disengagement of said contact members, for generating a magnetic field; k. a movable short circuit member, concentrically adjacent said coil member, directly magnetically connected with said coil member during said breaking and fixed to said piston member, for producing induction current therein due to said magnetic field, whereby a magnetic repulsive force is produced between said coil member and said short circuit member, said coil member and short circuit member being positioned at the rear side of the direction of gas blasting, whereby a compression movement of said piston member is effected independently of said rod member, to thereby minimize a compression reaction force acting upon said operating mechanism; l. third means for fixingly supporting said coil member on said rod member; and m. fourth means for supporting movably said rod member.

Claim 23

A gas blast circuit breaker comprising: a. a casing member confining an arc extinguishing gas; b. first and second terminals through which current flows during the closed condition of said breaker; c. a stationary contact member electrically connected with said first terminal; d. a movable contact member disengageably contacted with said stationary contact member and connected to said second terminal through a switching arrangement, whereby current flows directly between said contact members during the normally closed condition of said breaker and an arc forms upon disengagement thereof during breaking, said movable contact member being electrically connected to an operating electroconductive rod member mechanically connected to an operating mechanism responsive to a breaking command, said rod member being so designed that said movable contact member is disengaged from said stationary contact member; e. a cylinder member, electrically insulated from said rod member and having a bottom wall provided with a cylindrical extending portion; f. a nozzle member surrounding said contact members, slidably disposed within said extending portion and having a flange portion, whereby movement of said nozzle member is restricted, for blasting compressed gas onto said arc; g. a piston member slidably mounted on said rod member, whereby a part of said arc extinguishing gas is compressed in said cylinder member; h. first means for mechanically biasing said piston member against the direction opposite to that of gas compression; i. second means for preventing blasting of said compressed arc extinguishing gas from said nozzle member until a gas pressure in said cylinder member reaches a predetermined value, said second means including said flange portion and said cylindrical extending portion; j. a coil member, short circuited during the normally closed condition of said breaker and fixed to said rod member through which current flows into said coil member upon displacement of said switching arrangement but having its short circuited condition removed upon disengagement of said contact members, for generating a magnetic field; k. a movable short circuit member, concentrically adjacent said coil member, directly magnetically connected with said coil member during said breaking and fixed to said piston member, for producing induction current therein due to said magnetic field, whereby a magnetic repulsive force is produced between said coil member and said short circuit member, said coil member and short circuit member being positioned at the rear side of the direction of gas blasting, whereby a compression movement of said piston member is effected independently of said rod member, to thereby minimize a compression reaction force acting upon said operating mechanism; l. third means for fixingly supporting said coil member on said rod member; and m. fourth means for supporting movably said rod member.

Claim 24

A gas blast circuit breaker according to claim 16, wherein said coil member has more than one turn in the axial direction.

Claim 25

A gas blast circuit breaker according to claim 16, wherein said short circuit member has a cylindrical shape.

Claim 26

A gas blast circuit breaker comprising: a. a casing member confining an arc extinguishing gas; b. first and second terminals through which current flows during the closed condition of said breaker; c. a stationary contact member electrically connected to said first terminal; d. a movable contact member disengageably contacting said stationary contact member through a switching arrangement, whereby current flows directly between said contact members during the normally closed condition of said breaker and an arc forms upon disengagement thereof during breaking, said movable contact member being electrically connected with an operating electroconductive rod member mechanically connected to an operating mechanism responsivE to a breaking command, said rod member being so designed that said movable contact member is disengaged from said stationary contact member in accordance with said breaking command; e. a stationary cylinder member electrically insulated from said rod member; f. a first piston member slidably disposed within said cylinder member, having a sufficiently smaller axial length than said cylinder member and having a hook portion; g. a nozzle member, surrounding said contact members, engaged with said hook portion, for blasting said arc extinguishing gas onto said arc upon disengagement of said contact members; h. a second piston member, disposed within a chamber having a larger volume than said cylinder member and communicating with said cylinder through valve means; i. a stationary coil member disposed at the rear side of the direction of gas blasting, de-energized during the normally closed condition of said breaker but being energized upon disengagement of said contact members, for generating a magnetic field therein; j. a movable short circuit member disposed within said chamber, and magnetically directly connected with said stationary coil member upon disengagement of said contact members, whereby induction current is incuded in said short circuit member by the action of said magnetic field; k. means for switchably displacing said rod member, to thereby cause current to flow into said coil member upon disengagement of said contact members; and l. means for mechanically biasing said short circuit member against the direction opposite to that of gas compression.

Claim 27

A gas blast circuit breaker comprising: a. a casing member confining an arc extinguishing gas; b. first and second terminals through which current flows during the closed condition of said breaker; c. a stationary contact member electrically connected to said first terminal; d. a movable contact member disengageably contacting said stationary contact member through a switching arrangement, whereby current flows directly between said contact members during the normally closed condition of said breaker and an arc forms upon disengagement thereof during breaking, said movable contact member being electrically connected with an operating electroconductive rod member mechanically connected to an operating mechanism responsivE to a breaking command, said rod member being so designed that said movable contact member is disengaged from said stationary contact member in accordance with said breaking command; e. a stationary cylinder member electrically insulated from said rod member; f. a first piston member slidably disposed within said cylinder member, having a sufficiently smaller axial length than said cylinder member and having a hook portion; g. a nozzle member, surrounding said contact members, engaged with said hook portion, for blasting said arc extinguishing gas onto said arc upon disengagement of said contact members; h. a second piston member, disposed within a chamber having a larger volume than said cylinder member and communicating with said cylinder through valve means; i. a stationary coil member disposed at the rear side of the direction of gas blasting, de-energized during the normally closed condition of said breaker but being energized upon disengagement of said contact members, for generating a magnetic field therein; j. a movable short circuit member disposed within said chamber, and magnetically directly connected with said stationary coil member upon disengagement of said contact members, whereby induction current is incuded in said short circuit member by the action of said magnetic field; k. means for switchably displacing said rod member, to thereby cause current to flow into said coil member upon disengagement of said contact members; and l. means for mechanically biasing said short circuit member against the direction opposite to that of gas compression.

Claim 28

A gas blast circuit breaker according to claim 19, wherein said coil member has more than one turn in the axial direction.

Claim 29

A gas blast circuit breaker according to claim 19, wherein said short circuit member has a cylindrical shape.

Claim 30

A gas blast circuit breaker according to claim 19, wherein said valve means is a check valve for preventing the supplying of said arc extinguishing gas in said chamber until said piston member is actuated to compress said gas.