US2597126A

US2597126A - Circuit breaker with blast valve motor assisting the contact motor

Info

Publication number: US2597126A
Authority: US
Inventors: Ira W Paterson
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1949-08-17
Filing date: 1949-08-17
Publication date: 1952-05-20
Anticipated expiration: 1969-05-20

Description

l. W. PATERSON CIRCUIT BREAKER WITH BLAST VALVE MOTOR ASSISTING THE CONTACT MOTOR Filed Aug. l'. 1949 May 20, 1952 Patented May 20, 1952 CIRCUIT BREAKER WITH BLAST VALVE MOTOR ASSISTING THE CONTACT MOTOR Ira W. Paterson, Milton, Mass., assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application August 17, 1949, Serial No. 110,686

(Cl. 2GB- 82) 11 Claims. l

This invention relates to electric circuit breakers, and more particularly to operating mechanisms for electric circuit breakers of the fluid operated type. Speciiically, this invention is an improvement on the circuit breaker operating mechanism disclosed and claimed in C. D. Ainsworths application Serial No. 119,284, filed October 3, 1949.

A pneumatic or fluid operated mechanism for an electric circuit breaker should provide ccntrolled opening forces that produce a high initial acceleration for rapidly separating the arcing contacts. It is desirable, however, to increase the opening speed by some method other than the method which increases the opening speed by virtue of the fluid blast acting on the movable contacts within the arc chutes.

Many types of circuit breaker systems have used a fluid motor for actuating the arcing contacts. This fluid motor was usually controlled by a valve which caused actuation of the contact actuating iiuid motor in a predetermined sequence with other circuit breaker control equipment. Operating mechanism of this type, however, requires a relatively large initial force in order to rapidly separate the relatively movable arcing contacts, which are usually in frictional engagement.

In accordance with the invention claimed, a new and improved operating mechanism involving two fluid motors, is provided to rapidly separate a pair of cooperating arcing contacts in an electric circuit breaker. The nrst motor, which actuates a blast valve to valve open position, is connected with the second motor, which actuates the arcing contacts of the circuit breaker, so as to boost the action of the second motor, thereby effectively utilizing more completely the total energy of the iirst motor upon blast valve actuation. More particularly, the iirst motor actuates a differential type blast valve to control a supp-ly valve to the pneumatic contact actuating motor and boosts the action of the pneumatic contact actuating motor, thereby increasing the speed of contact separation. This improved arrangement provides an operating mechanism which increases the opening speed of the circuit breaker system.

It is therefore one object of the present invention to provide a new and improved 4pneumatic operating mechanism for circuit breakers of the r uid blast type.

Another object of the present invention is to provide a new and improved fluid operating mechanism for electric circuit breakers which provides controlled pneumatic opening forces which pro- 2 duce a high initial acceleration for rapidly separating the arcing contacts.

A further object of the present invention is to provide a new and improved arrangement for two fluid motors in which one motor boosts the action of the other motor.

A still further object of the present invention is to provide a new and improved arrangement for two sequentially operated fluid motors in which one motor boosts the action of the second motor in a predetermined sequence.

A still further object of the present invention is to provide a new and improved pneumatic operating mechanism for actuating a uid blast electric circuit breaker in Which the actuating force of a blast valve boosts the action of a pneumatic contact actuating motor to rapidly separate a pair cf cooperating arcing contacts.

Objects and advantages other than those set forth will be apparent from the following description when read in connection with the accompanying drawing in which the single iigure is a diagrammatic showing oi a circuit breaker and a pneumatic operating mechanism therefor embody/ing the present invention.

Referring more particularly to the drawing by characters of reference, the ligure illustrates a circuit breaker including as a constructive element thereof a reservoir 6 constituting a, source of supp-ly of fluid under pressure, which will be assumed herein to be compressed air, supplied from a suitable compressor (not shown). Although in general, circuit breakers of the type herein considered are provided with a plurality of similar pole structures, one for each phase of a polyphase electric circuit, only one such pole structure or pole unit is shown in the gure and the circuit breaker will be described in detail as if it were of the single pole type.

l'Ehe circuit breaker comprises a iixed arcing Contact 'l and a cooperating movable arcing contact S connected in an electric circuit through terminal studs 9 and lil. The arcing contacts are mounted to engage within an arcing chamber ll which is aligned with an arc chute I2. The arcing chamber I! is axially aligned with a hollow insuiator I3 which provides a connection between reservoir 6 and arcing chamber l I through a suitable blast valve i4 for the purpose of directing a blast of arc extinguishing fluid under pressure between the arcing contacts and through the arcing chamber ll.

The d ierential type blast valve i4 comprises fluid motors l 3 and ll for controlling a blast inlet port iii, Motor Hi comprises a cylinder 20, a piston 2|, a piston rod 22, a spring 23, and an inlet port 24. Motor |1 comprises a cylinder 25, a piston 216, a return spring 21 for pist-cn 26, a vent 28, and an exhaust port 26. Valve 3| for closing an exhaust port 32 is adapted to be operated by motor i1. Cylinder' 33 cooperates with cylinder 25 of motor i1 to provide an exhaust port 34. Piston 26, when actuated by air under pressure actuates valve 3i and opens exhaust port 32 against the action of spring 21. As long as exhaust `port 32 remains closed, air under pressure supplied from reservoir 8 through inlet port 24 cooperates with spring 23 to maintain piston 2| in the position shown.

Inlet port 35 o blast valve |4 supplies fluid motor I1 with operating fluid under pressure for actuating piston Inlet port 35, however, is controlled by a slide valve I5 provided with a piston i which opens and closes port 35 upon predetermined circuit conditions.

A solenoid type control valve 36 controls the opening of blast valve i4 upon the `occurrence of a predetermined electrical condition of the electric circuit controlled. Control valve 36 may be o any suitable known type and is diagrammatically shown as a valve of the magnetic type. Pipes 44 and 45 connect valve 36 to differential type blast valves associated with other phase structures of the circuit breaker. Pipe 45 connects valve 36 to reservoir 6.

The movable arcing contact 8 is actuated by a fluid motor 41 through the medium of a crankshaft 48, a pair of cranks 5|, 52, and a connecting rod 53. Fluid motor 41 comprises a cylinder 54,

a piston 55, a hollow piston rod 56 movable with piston 55 and connected through a link 51 to crank 5|, ports 53, 60, a pair of control valves 58, 6| for ports 52, 03, respectively, springs 64, 65 for biasing control valves 58, 6|, respectively, to

their closed positions, valves 66, 61, and springs J 68, 1| for biasing valves 66, 61, respectively, to their closed positions. Piston rod 56 is provided with a plurality of

exhaust ports

12, 13 for exhausting pressure from the ends of the cylinder. A pipe line 66 connects port 10 of motor 41 to slide valve |5.

The contact actuating huid motor 41 is controlled by a valve 15 which regulates the time at which fluid under pressure is supplied from reservoir 5 through a pipe line 16 to motor 41. Valve 15 comprises a valve element 82 forming a. valve stem 83, a biasing spring 64 and

ports

85, 86, 89 and 88. Spring 64 biases valve element 82 in valve closing direction, thus closing port 85 and prohibiting the passage of air from pipe line 16 through port 86, valve 15 and port 80 to air inlet port 60 of motor 41. As illustrated in the drawing valve 15 may be mounted immediately adjacent motor 41 with port 90 of valve 15 and port 68 of motor 41 interconnected.

Valve 15 is connected by means of port 86 and pipe line 81 to an inlet port 88 of trip predominating valve 11. Trip predominating valve 11 further comprises a cylinder 3|, piston 92, valve element 83, spring 94, an inlet port 86 which is connected to a suitable solenoid type closing control valve 01 and a port 89 which interconnects with a port 18 of cylinder 54. Control valve 91 is connected to reservoir 6 through pipe line 98.

A means such as a mechanical interconnecting rod and lever arrangement is provided for actuating control valve 15 upon actuation of piston 2| and piston rod 22 of motor I6. This interconnecting rod and lever arrangement comprises a lever I0| pivoted at a point |02 with one end 4 thereof connected at a point |03 to piston rod 22 and the other end connected to one end of a connecting rod |04. The other` end of connecting rod |04 is pivotally secured to a crank |05 which oscillates with a shaft |06 through a given arcuate path. A second crank |01 mounted on shaf t |06 and provided to oscillate through a given arcuate path therewith, actuates valve stern 83 of control valve 15 upon clockwise movement thereof. Fluid motor |6 controls fluid motor 41 through the medium of control valve 15 and thus provides for rapid vsequential operation thereof.

A pneumatic brake |08 comprising brake shoes acting on a drum ||2 connected to shaft 43 is provided for arresting the movement of shaft 48 -at a predetermined time to lessen the impact of the 4moving mass of the movable contact assembly. Piston 55 controls the supply of air from cylinder 54 of motor 41 through a pipe ||4 to a cylinder ||6 provided with a piston |5. The cylinder and the piston are connected to brake shoes to produce the retarding action.

-In accordance with the invention claimed a mechanical interlocking or booster means ||1 is provided for boosting the action of the pneumatic contact actuating motor 41. Booster means ||1 comprises a lever arm ||8 secured to shaft |06 and a cooperating lever arm ||8 secured to crankshaft 48. Upon clockwise actuation of shaft |06, lever arm ||8 engages a surface |20 on lever arm ||9 and rotates lever arm ||8 and crankshaft 48 counterclockwise.

The circuit breaker illustrated in the drawing is shown with the cooperating arcing contacts in the closed circuit position and the pneumatic operating mechanism in the corresponding position. An opening operation is initiated by energization of the tripping solenoid control valve 36, thereby causing air under pressure from reservoir 6 to pass through pipe 46 to and through valve 36, valve |5 through port 35 to the fluid motor |1 and through pipes 44 and 45 to any similar motor associated with other phase structure of the circuit breakers. Air under pressure causes piston 26 of motor` |1 to move against the action of spring 21 and to actuate valve 3|, thus opening port 32 which exhausts the air under pressure trapped in cylinder 20 through ports 34. This exhausting action reduces the pressure behind piston 2| of fluid motor |6 and enables the air under pressure in reservoir 6 acting on the portion of the top side of piston 2| surrounding the seat of the blast valve to overcome the action of spring 23. A blast of air under pressure then passes through the hollow insulator I3, through the arcing chamber and into the arc chute |2.

Upon the actuation of piston 2| of fluid motor |6 in blast valve opening direction, piston rod 22 of fluid motor I6 rotates lever |0| counterclockwise which in turn actuates connecting rod |04 to rotate crank |05 and shaft |06 clockwise. Clockwise rotation of shaft |06 causes actuation of shaft 83 of control valve 15 in valve opening direction, thus causing air under pressure from reservoir 6 to flow through pipe line 10, to and through valve 15, through port 60 and into cylinder 54 of contact actuating fluid motor 41 and into pipe 69. Air under pressure in the contact opening end of cylinder 54 passes through ports 62 and overcomes the bias of spring 64 to open control valve 58 and actuate piston 55 in contact opening direction. Upon movement of piston 55 in contact opening direction, piston rod 56 of fluid motor 41 rotates crank 5|, shaft 48, and

crank 52 counterclockwise, thus actuating connecting rod 53 to separate the arcing contacts 1, 8. Movement of piston 55 in contact separating direction opens port 59, and air under pressure ows through pipe II4 to cylinder II6 of brake I 08. Movement of piston II5 under the action of air under pressure applies the shoes of brake I U8 to retard the movement of the moving arcing contact 8.

Blast valve I4 is actuated to valve open position by reducing the pressure behind piston 2| of fluid motor I6, thereby enabling the air under pressure in reservoir 6 acting on the portion of the top side of piston 2I surrounding the seat of the blast valve to exert a rst actuating force to overcome the action of spring 23. Upon cracking of blast valve I4, i. e., the initial movement of piston ZI in valve opening direction, the air under pressure in reservoir 6 acts on the total area of piston 2I and creates a force much greater than that needed to rapidly move piston 2 I to the bottom of cylinder 20. The second actuating force, inherent in the blast valve operation, which results from the air pressure on the portion of piston 2I serving to open port I8, is available for contact actuation, but heretofore has been wasted as excess energy. In order to utilize this excess energy a new and improved booster means is provided to harness the excess energy of the blast valve for aiding the contact actuating motor to more rapidly separate the arcing contacts, thus providing a faster and more eflicient circuit breaker operating mechanism. By utilizing the excess energy of the blast valve I4, the contact actuating motor 41 may be reduced in size and weight, thereby permitting a lighter and faster operating pneumatic mechanism for circuit breaker operation.

Upon actuation of blast valve I4 in valve opening direction to the extent necessary to enable the blast pressure to be exerted on the entire area of piston 2| and the resulting clockwise rotation of shaft |06, lever arm I I8 engages surface I2II of lever arm II9 and boosts the contact actuating motion of fluid motor 41 by also rotating crank shaft 48 under the action of the excess force available at piston 2I. The high initial acceleration of blast valve I4 produces a hammer blow by lever arm II1 on the engaging surface of lever arm II 9 a predetermined time after the blast valve is set in motion, thus boosting the action of motor 41 and quickly separating the arcing contacts. This booster action of blast valve I4, which may be exerted over the entire stroke of piston 55 or over only part of such stroke, decreases the time necessary for contact separation as evidenced from the following data recorded on the operation of a cross air blast circuit breaker before and after this invention Was added to the operating mechanism of the circuit breaker system.

Before At 150 lbs. p. s. i. operating pressure the arcing contacts parted in 4.2 cycles and were fully opened in 10.2 cycles.

At 200 lbs. p. s. i. operating pressure the contacts parted in 3.8 cycles and were fully open in 9.3 cycles.

After At 150 lbs. p. s. i. operating pressure the contacts parted in 3.6 cycles and were fully opened in 8.5 cycles.

At 200 lbs. p. s. i. operating pressure the contacts parted in 3.3 cycles and were fully opened in 7.75 cycles.

Ports

12, 13 are provided in the hollow piston rod 56 of motor 41 for exhausting the air under pressure that might be trapped in the cylinder 54 on the trailing side of piston 55 at the end of its stroke, thus permitting rapid reversal motor action. In addition, valves 66, 61 are so designed to overcome the biasing action of their respective springs 68, 1I to permit rapid exhausting of the air under pressure on the leading side of piston 55.

In order to conserve air under pressure in reservoir 6 and to rapidly close the blast valve at a given predetermined time, air under pressure in pipe line 69 actuates piston I9 thus closing the air inlet port 35 to blast valve I4 and any other blast valves of the circuit breaker. The pressure on piston 26 of motor I1 is relieved by exhaust port 29, and spring 21 biases piston 26 to the position shown. Any air under pressure having leaked past piston 26 is exhausted through vent 28. The movement of piston, 25 under the action of spring 21 lowers valve 3I against its valve seat and permits a back pressure to build up under piston 2I such that in combination with the biasing action of spring 23 returns piston 2I to the position shown, thus closing blast valve I4.

A closing operation is initiated by energization of the closing solenoid control valve 91, thereby causing air under pressure from reservoir 6 to pass through valve 91, port 96 of valve 11, valve 11, port 18 of cylinder 54, and into the closing end of fluid motor 41. The air further flows through ports 63, opens valve '61 against the biasing effect of spring 65 and actuates piston 55 of fluid motor 41 in contact closing direction, thus closing the arcing contacts.

If opening and closing impulses are substantially simultaneously initiated by

valves

36 and 91, respectively, air under pressure from pipe line 16 flows through control valve 15, port 86 of valve 15, pipe 81, inlet port 88 of trip predominating valve 11 and actuates piston 92 thereof upward, thus actuating valve element 93 to close port 99 in cylinder 9|. Closing air from valve 91 is, thus, restrained from reaching cylinder 54.

through port 99 of trip predominating valve 11 and port 18 of Huid motor 41 to close the arcing contacts. Once valve element 93 is actuated to closed position, no contact closing pressure impulse can be passed through valve 11 as long as closing solenoid valve 91 remains open since valve 91 feeds air to the chamber below valve element 93 thereby holding valve element 93 in closed position. As long as the blast valve remains open, air is supplied under piston 92 through valve 15, which action also holds valve element 93 is closed position.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein Without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In combination: a rst device, a first iluid operated motor for actuating said rst device, a second device, a second fluid operated motor for actuating said second device, a valve for admittingr iluid under pressure to said second motor, mechanical means actuated by said iirst motor for actuating said valve, and mechanical means actuated by said first motor for actuating said second device in common with said second motor.

2. In combination: a first device, a flrst fluid operated motor for actuating said flrst device, a second device, a second fluid operated motor for actuating said second device, a valve for admitting fluid under pressure to said second motor, mechanical means actuated by said first motor for actuating said valve, and booster means actuated by said first motor for aiding said second motor to actuate said second device.

3. In combination: a first device, a first fluid operated motor comprising a cylinder and a piston for actuating said ilrst device, a second device provided to operate in sequence with said first device, a second fluid operated motor coinprising a cylinder and a piston for actuating said second device, a source of fluid under pressure, valve means for controlling the time at which fluid under pressure is supplied to said second motor, means interconnecting said ilrst device and said valve means for actuating said Valve means upon actuation of said piston of said first motor, and booster means actuated by said first motor for aiding said second motor to actuate said second device.

4. In an interlocking system for two fluid operated motors intended to operate in sequence, the combination comprising: a first device, a first fluid operated motor for actuating said first device, a second device, a second fluid operated motor for actuating said second device, a source of f uid under pressure, a valve for admitting fluid under pressure to said second motor, mechanical means operated by said first motor for actuating said valve, and booster means actuated by said ilrst motor for aiding said second motor to actuate said second device, said booster means and said second motor acting on said second device in a predetermined sequence.

5. In a fluid blast circuit interrupter, the combination comprising: a source of fluid under pressure, separable arcing contacts for establishing an are, a blast valve arranged to provide a blast of fluid under pressure from said source for extinguishing the arc drawn upon separation of said arcing contacts, a rst fluid operated motor comprising a cylinder and a piston for actuating said blast valve, a second fluid operated motor arranged to operate in sequence with said blast valve comprising a cylinder and a piston for separating said arcing contacts, valve means for controlling the time at which fluid under pressure is supplied to said second motor, mechanical means interconnecting said valve means and said piston of said rst motor for actuating said valve means upon actuation of said first motor, and booster means actuated by said first motor for aiding said second motor to actuate said arcing contacts, said booster means and said second motor acting on said arcing contacts in a predetermined sequence.

6. In a fluid blast circuit interrupter, the combination comprising: a source of fluid under pressure, separable arcing contacts for establishing an arc, a blast valve arranged to provide a blast o fluid under pressure from said source for extinguishing the arc drawn upon separation of said arcing contacts, a first fluid operated motor comprising a cylinder and a piston for actuating said blast valve, a second fluid operated motor arranged to operate in sequence with said blast valve comprising a cylinder and a piston for separating said arcing contacts, means arranged immediately adjacent said second motor for controlling the time at which fluid under pressure is supplied from said source to said second motor and comprising a valve adapted to be actuated by said piston of said first motor, and booster means actuated by said first motor for aiding said second motor to actuate said arcing contacts, said booster means and said second niotor acting on said arcing contacts in a` predetermined sequence.

7. In a fluid blast circuit interrupter, the combination comprising: a source of fluid under pressure, separable arcing contacts foi` establishing an arc, a blast valve arranged to provide a blast of fluid under pressure from said source for extinguishing the arc drawn upon separation of said arcing contacts, a first fluid operated motor comprising a cylinder and a piston for actuating said blast valve, a second fluid operated motor arranged to operate in sequence with said blast valve comprising a cylinder and a piston for separating said arcing contacts, valve means for controlling the time at which fluid under pressure is supplied to said second motor, mechanical means interconnecting said valve means and said piston of said first motor for actuating said valve means upon actuation of said first motor, and booster means actuated by said first motor for actuating said arcing contacts in common with said second motor.

8. In a fluid blast circuit interrupter the combination comprising: a source of fluid under pressure, separable arcing contacts for establishing an arc, a blast valve arranged to provide a blast of fluid under pressure from said source for extinguishing the arc drawn upon separation of said arcing contacts, a first fluid operated motor comprising a cylinder and a piston for actuating said blast valve, a second fluid operated motor l; arranged to operate in sequence with said blast valve comprising a cylinder and a piston for separating said arcing contacts, valve means for controlling the time at which fluid under pressure is supplied to said second motor, mechanical means interconnecting said valve means and said piston of said first motor for actuating said valve means upon actuation of said first motor, and booster means for actuating said arcing contacts by said first motor in common with said second motor upon admission by said valve of fluid under pressure to said second motor.

9. In a fluid blast circuit interrupter, the combination comprising: a source of fluid under pressure, separable arcing contacts for establishing an arc, a blast valve arranged to provide a blast of fluid under pressure from said source for extinguishing the arc drawn upon separation of said arcing contacts, a first fluid operated motor comprising a cylinder and a piston for providing first and second actuating forces, said first force actuating said blast valve to valve open position, a second fluid operated motor arranged to operate in sequence with said blast valve comprising a cylinder and a piston for separating said arcing contacts, valve means for controlling the time at which fluid under pressure is supplied to Said second motor, mechanical means interconnecting said valve means and said piston of said first motor for actuating said valve means upon actuation of said first motor, and booster means actuated by said second force of said first motor for aiding said second motor to actuate said arcing contacts, said booster means and said second motor acting on said arcing contacts in a predetermined sequence.

10. In a uid blast circuit interrupter, the combination comprising: a source of uid under pressure, separable arcing contacts for establishing an arc, a blast valve arranged to provide a blast of uid under pressure from said source for extinguishing the arc drawn upon separation of said arcing contacts, a first iiuid operated motor comprising a cylinder and a piston for providing first and second sequential actuating forces, said first force actuating said blast valve to Valve open position, a second iiuid operated motor arranged to operate in sequence With said blast Valve comprising a cylinder and a piston for separating said arcing contacts, valve means for controlling the time at which iiuid under pressure is supplied to said second motor, mechanical means interconnecting said valve means and said piston of said iirs-t motor for actuating said valve means upon actuation of said rst motor, and booster means actuated by said second force of said rst motor a predetermined time after the initial actuation of said blast Valve for aiding said second motor to actuate said arcing contacts, said booster means and said second motor acting on said arcing contacts in a predetermined sequence.

11. In a iiuid blast circuit interrupter, the combination comprising: a source of fluid under pressure, separable arcing contacts for establishing an arc, a blast Valve arranged to provide a blast of uid under pressure from said source for extinguishing the arc drawn upon separation of said arcing contacts, a first iuid operated motor comprising a cylinder and a piston for providing a irst and a second sequential actuating force, said rst force actuating said blast valve to valve open position, a second iiuid operated motor comprising a cylinder and a piston for separating said arcing contacts, valve means for controlling the time at which fluid under pressure is supplied to said second motor, mechanical means interconnecting said valve means with said piston of said rst motor for actuating said valve means upon actuation of said rst motor, and booster means actuated by said second force of said rst motor a predetermined time after the initial actuation of said rst motor for aiding said second motor to actuate said arcing contacts.

IRA W. PATERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number v Name Date 747,722 Rickman Dec. 22, 1903 763,310 Mundy June 21, 1904 1,865,105 Houplain June 28, 1932