US3251970A

US3251970A - Resetting control apparatus for switchgear

Info

Publication number: US3251970A
Application number: US179567A
Authority: US
Inventors: Gonek Stanislaw Mieczyslaw; Rowlinson Henry
Original assignee: English Electric Co Ltd
Current assignee: English Electric Co Ltd
Priority date: 1961-03-17
Filing date: 1962-03-14
Publication date: 1966-05-17
Anticipated expiration: 1983-05-17
Also published as: CH394344A; FR1439845A; DE1275186B; BE649003A; GB1023151A; SE301829B; NL6406509A

Description

y 7, 1966 s. M. GONEK ETAL 3,251,970

RESETTING CONTROL APPARATUS FOR SWITCHGEAR Filed March 14, 1962 United States Patent This invention relates to control apparatus for switchgear.

According to this invention, control apparatus for switchgear comprises exhaust valve means which is opened in response to movement of an operating mechanism to cause an operation of a circuit breaker and resetting means actuated by the operation of said circuit-breaker to reset said ope-rating mechanism and thereby to allow said exhaust valve to reclose.

One embodiment of control apparatus in accordance with the invention will now be described with reference to the "accompanying drawing, which shows diagrammatically the operative part of a circuit-breaker and the associated control apparatus. 7

The invention will be described as applied to a single circuit-breaker though it will be appreciated that two circuit-breakers are commonly employed in series, in which case the structure will be symmetrical about the line XX and the control apparatus will operate in the same fashion with respect to the second circuit-breaker as with respect to that described.

The circuit interrupter shown generally at 12 is mounted on a common central casing 23 by means of which it is connected to the other circuit-breaker in series. The operation of the circuit-breakers is controlled by a common exhaust valve 18 which may be operated to place the common outlet passage 20 of the circuit-breakers in communication with the atmosphere through passages 22. The circuit-breakers are also connected through a common passage 21 to a source of gas pressure. In the following description the gas will be referred to as air though it will be understood that any other suitable gas may be em ployed.

The line connection 10 is connected to an endplate 24 on which is mounted a contact 25, the endplate being supported from the central casing 23 by means of a porcelain insulator 26. The contact 25 is mounted for limited movement, but is'usually referred to in the art as the fixed contact. Co-ope-rating with fixed contact 25 is a moving contact 27 which is arranged to slide within the cylinder 28 which forms part of the casing 23.

The moving contact 27 is connected to a piston 29 by means of a rod 30. The rod co-operates with a lever 31 pivoted at 32 which engages a collar 33 to compress a spring 34 which is situated between the collar and the pivotally-mounted collar '35. The arrangement is such 'as to give a toggle action, the spring 34 urging the moving contact 27 to each of its extreme positions. The pass-age 21 forms part of the base of the central casing 23 and communicates with a space 36 surrounding the co-operating contacts 25, 2-7. The space 37 within the cylinder 28 is not in communication with the space 36 when the

contacts

25, 27 are closed but communicates directly with the passage 20 and thus with the exhaust valve 18. The ducts 22 are formed in the casing 38 of the exhaust valve 18.

The valve is of the balanced type and is loaded to the closed position by. a spring 39. The interior of the casing 38 is connected through a conduit 40 with the space 36 so that it is in communication with the pressure source.

The valve is provided with an annular operating piston 41, the space below which can be placed in communication either with the pressure source or with atmosphere.

The operating mechanism comprises a vertical rod 58 which is biased upward by a spring 59 so as to move upward when the operating detent (not shown) is tripped. A lever 60 pivoted near its centre is connected at one end to the rod 58 and at its other end to the cent-re of a bellcrank lever 61, the ends of which are connected respectively to an operating mechanism, in the form of rod 62, and to a rod 63 which is connected in turn to the end of lever 31 remote from the rod 30.

The operating rod 62 has adjacent each end a valve member; the

valve members

64, 65 are loaded respectively by

springs

66, 67 towards the operating rod. One valve member 64 is in communication through conduit 68 with the space 69 on the left of piston 29 as seen in the drawing; in one position (that toward which it is spring-loaded) the valve member 64 places the space 69 in communication through conduit 70 with the passage 21, and in the other position it places the space 69 in communication with atmosphere through port 71. The space 72 on the right of piston 29 is in communication through conduit 73 with the passage 20. The other valve member 65 is in communication through conduit 74 with the space 75 below the annular operating piston 41 of the exhaust valve 18, and in the position toward which it is spring-loaded places the space 75 in communication with atmosphere through port 76; in its other position it places the space in communication with the passage 21 through conduit 77.

When the ciIcuit breaker 12 (and, where two circuitbreakers are employed in series, the other corresponding circuit-breaker on the other side of the line XX) are closed the corresponding electric circuit is made, the exhaust valve 18 is closed, and the

spaces

36, 37 and passage 20 contain air under pressure as a result of the slow leakage of air which occurs between the contact 27 and the cylinder 28.

When the circuit breaker is tripped, the rod 58 moves upwards under the influence of spring 59, rocking the lever 60 about its pivot and thus, through the bell crank lever 61, moving the operating mechanism 62 down. This moves the valve member 65 to place the space 75 beneath the operating piston of the valve member 18 in communication with the passage 21 which contains air under pressure. The exhaust valve 18 thus opens and air flows from the space 72 on the right-hand side of piston 29 through

passages

73, 20 and thence to atmosphere through the exhaust valve 18. Since the left-hand side of piston 29 is still subjected to the high pressure in passage 21 through

conduits

68, 70, the piston 29 and moving contact 27 move to the right, breaking the circuit through the

contactsv

25, 27.

It will be appreciated that a blast of air from the pressure source 21 occurs between the contacts as they separate, extinguishing the arc in well-known fashion.

This movement of the contact 27 compresses the toggle spring 34 as the piston 29 moves through its central position, the spring thereafter assisting movement of the contact 27 to its extreme position. The lower end of lever 31 is moved to the left, as shown, rocking the bellcrank lever 61 through rod 63. The bell-crank lever, being pivoted to the end of lever 60, causes the operating mechanism 62 to be moved upward, thus allowing the valve 65 to be moved to its uppermost position under the influence of spring 6'7. The operating mechanism 62 is thus reset in its central position. This causes the space 75 to be vented to atmosphere through conduit 74 and port 76 and the exhaust valve 18 therefore closes again under the influence of spring 39.

Closing of the exhaust valve 18 causes the pressure in the passage 20 and the space 72 to rise until it is equal to that in chamber 36. The pressures on both sides of piston 29 are then equalized and the moving contact remains where it is under the restraint of the toggle spring 34.

To close the

contacts

25, 27 the rod 58 is moved downward against the spring 59. This rocks lever 60 about its pivot and raises the central pivot of bell-crank lever 61 which in turn raises the operating mechanism 62. This actuates valve 64, overcoming spring 66, to vent the space 69 on the left-hand side of piston 29 to atmosphere through conduit 68 and port 71. As the space 72 is still connected to passage 21 through conduit 73, space 37 and space 36, the piston 29 is caused to move to the left, bringing the contact 27 into abutment With the fixed contact 25.

This movement of piston 29 rocks lever 31, causing its lower end to move to the right, thereby through rod 63 to rock the bell-crank lever 61 which in turn causes the operating mechanism 62 to be moved downward to its central position. Valve 64 then moves downward under the influence of spring 66, which places space 69 in com munication with the pressure source. Since the space 72 is at substantially the pressure of the source, as a result of the exhaust valve 18 being closed, the pressures on each side of piston 29 are substantially equalized; the

' movable contact 27 remains in the closed position under a space to said exhaust valve means, first pressure-responsive means connected to said movable hollow contact to move it between said open and closed positions, means defining a first pressure space on one side of said pressure-responsive means, means defining a second pressure space on the other side of said pressure-responsive means, resilient means urging said movable hollow contact to both open and closed positions, second pressure-respom sive means connected to said exhaust valve means to perate it, means defining a third pressure space on one side of said second pressure-responsive means such that increase of pressure in said third pressure space tends to open said exhaust valve means, resilient means loading said exhaust valve means in the sense of closing, first valve means connected to said pressure source and to said first pressure space, and having a first port opening to low pressure, said first valve means having a first position in which said first pressure space is connected to said pressure source, and a second position in which said first pressure space is connected to said first port, spring bias means to bias said first valve means to its first position, second valve means connected to said pressure source and to said third pressure space and having a second port opening to low pressure, said second valve means having a first position in which said third pressure space is connected to said second port, and a second position in which said third pressure space is connected to said pressure source, spring. bias means to bias said second valve means to its first position, an operating member positioned to operate said first valve means and said second valve means, said operating member having a first neutral position, a second position in which it moves said first valve means from its first position to its second position, and a third position in which it moves said second valve means from its first position to its. sec ond position, and resetting means connected to said movable hollow contact and to said operating member, whereby when said operating member .is moved to its second position said first pressure space, is connectedto said first port and the consequent fall of pressure in said first pressure space causes said movable hollow contact to be urged to its closed position, said resetting means on such movement to the closed position returning said operating member to its first neutral position and allowing said first valve means to return to its first position, and whereby when said operating member is moved to its third position said third pressure space is connected to said pressure source, thereby causing the exhaust valve means to open, whereby a fall of pressure occurs in said second pressure space causing said movable hollow contact to be moved to the open position, said resetting means on such movement to the open position returning said operating member to its first neutral position, and allowing said second valve means to return to its first position, thereby causing the exhaust valve means to close under the influence of said resilient means.

2. Electric switchgear comprising a pair of cooperating contacts, one of which is a movable hollow contact, having a closed position and an open position, means defining a first space in which said contacts are situated, a pressure source, a free communication from said pressure source to said first space, a second space in communication with the interior of said movable hollow contact, exhaust valve means, a connection from said second space to said exhaust valve means, first pressure-responsive means connected to said movable hollow contact to move it between said open and closed positions, means defining a first pressure space on one side of said pressure-responsive means and connected to said pressure source, means defining a second pressure space' on the other side of said pressure-responsive means and in communication with said exhaust valve means, resilient means urging said movable hollow contact to both open and closed positions, second pressure-responsive means connected to said exhaust valve means to operate it, means defining a third pressure space on one side of said second responsive-pressure means to load it in the sense of opening'said exhaust valve means, resilient means to bias said exhaust valve means in the sense of closing, valve means connected to said pressure source and to said third pressure space and having a port opening to low pressure, said valve means having a first position inwhich said third pressure space is connected to said port, and asecond position in which said third pressure space is connected to said pressure source, whereby movement of' said valve means from 'said first position to said second position causes opening of said exhaust valve which in turn causes a fall of pressure in said second pressure space, which in turn causes said movable hollow contact to move from the closed position to the open position, and resetting means interconnecting said movable hollow contact and said valve means to reset said valve means in said first position on movement of said hollow movable contact to its open position, whereby said third pressure space is cut off from said pressure source and is connected to said port, thus causing the exhaust valve means to close under the influence of said resilient means.

3. Electric switchgear comprising a pair of cooperating contacts, one of which is a movable hollow' contact, having a closed position and an open position, means defining a first space in which said contacts are situated, a pressure source, a free communication from said pressure source to said first space, a second space in communication with the interior of said movable hollow contact, exhaust valve means, a connection from said second space to said exhaust valve means, first pressure-responsive means connected to said movable hollow contact to move it between said open and closed positions, means defining a first pressure space on one side of said pressureresponsive means and connected to said pressure source,

and means defining a second pressure space on the other side of said pressure-responsive means and in communication with said exhaust valve means, resilient means urging said movable hollow contact to both open and closed positions, second pressure-responsive means connected to said exhaust valve means to operate it, means defining a third pressure space on one side of said second pressure-responsive means to load it in the sense of opening said exhaust valve means, resilient means to bias said exhaust valve means in the sense of closing, valve means connected to said pressure source and to said first pressure space and having a port opening to low pressure, said valve means having a first position in which said first pressure space is connected to said ressure source, and a second position in which said first pressure space is connected to said port, whereby on movement of said valve means from said first position to said second position said first pressure space is cut oil? from said pressure source and is connected to said port and thus the pressure in said first pressure space falls, causing said hollow movable contact to be urged to move from its open position to its closed position, and resetting means interconnecting said hollow movable contact and said valve means, whereby said valve means is reset in its first position on movement of said hollow movable contact from its open position to its closed position.

4. Electric switch gear comprising a pair of cooperating contacts, one of which is a movable hollow contact, having a closed position and an open position, means defining a first space in which said contacts are situated, a pressure source, a free communication from said pressure source to said first space, a second space in communication with the interior of said movable hollow contact, exhaust valve means, a connection from said second space to said exhaust valve means, pressure-responsive means connected to said movable hollow contact to move it between said open and closed positions, means defining a pressure space on one side of said pressure-responsive means such that a reduction of pressure in said pressure space urges said movable hollow contact in the sense of opening, said pressure space being in communication with said exhaust valve means, an operating member operative to open said exhaust valve means on movement in one sense and to close said exhaust valve means on movement in the other sense, whereby movement of said operating member in said one sense causes said exhaust valve means to open thereby causing a fall of pressure in said pressure space and thereby causing movement of said hollow movable contact to its open position, and resetting means connected between said hollow movable contact and said operating member, whereby on movement of said hollow movable contact to said open position, said operating member is reset, thereby to cause said exhaust valve means to close.

5. Electric switchgear comprising a pair of cooperating contacts, one of which is a movable hollow contact, having a closed position and an open position, means defining a first space in which said contacts are situated, a pressure source, a free communication from said pressure source to said first space, a second space in communication with the interior of said movable hollow contact, exhaust valve means, a connection from said second space to said exhaust valve means, pressure-responsive means connected to said movable hollow contact to move it between said open and closed positions, means defining a pressure space on one side of said pressure-responsive means, operating means comprising a valve to vent said pressure space to a low pressure, whereby on actuation of said operating means the pressure in said pressure space is reduced and said hollow movable contact moves in the direction of closing, and resetting means interconnecting said hollow movable contact and said operating means whereby on movement of said hollow movable contact to said closed position, said operating means is reset.

6. Electric switchgear comprising a fixed contact, a movable contact, and means for opening and closing said contacts, said means comprising a cylinder, 2. piston in the cylinder connected to the movable contact, means supplying air under pressure to both sides of the piston at each end of the stroke, and means for exhausting the air on one side of the piston when at one end of the stroke whereby the pressure on the other sideof the piston moves it to the other end of the stroke.

7. A device as in claim 6 further comprising means supplying air under pressure between the contacts simultaneously with the movement of the movable contact away from the fixed contact.

8. A device as in claim 6 further comprising resilient means urging the piston to each of its extreme positions.

References Cited by the Examiner UNITED STATES PATENTS 1,304,286 5/1919 Emden 200148 2,213,658 9/1940 Thommen 200-148 2,275,885 3/1942 Bartlett 200l48 3,043,940 7/1962 Leeds 200-148 3,163,737 12/1964 Gonek et al. 200-448 KATHLEEN H. CLAFFY, Primary Examiner. BERNARD A. GILHEANY, Examiner.

M. GINSBURG, ROBERT S. MACON, Assistant Examiners.

Claims

6. ELECTRIC SWITCHGEAR COMPRISING A FIXED CONTACT, A MOVABLE CONTACT, AND MEANS FOR OPENING AND CLOSING SAID CONTACTS, SAID MEANS COMPRISING A CYLINDER, A PISTON IN THE CYLINDER CONNECTED TO THE MOVABLE CONTACT, MEANS SUPPLYING AIR UNDER PRESSURE TOI BOTH SIDES OF THE PISTON AT EACH END OF THE STROKE, AND MEANS FOR EXHAUSTING THE AIR ON ONE SIDE OF THE PISTON WHEN AT ONE END OF THE STROKE WHEREBY THE PRESSURE ON THE OTHER SIDE OF THE PISTON MOVES IT TO THE OTHER END OF THE STROKE.