US3164705A

US3164705A - Fluid-blast circuit interrupters with retractable impedance probe

Info

Publication number: US3164705A
Application number: US92677A
Authority: US
Inventors: Charles F Cromer
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1961-03-01
Filing date: 1961-03-01
Publication date: 1965-01-05
Anticipated expiration: 1982-01-05
Also published as: GB948876A; CH400294A; DE1192290B

Description

Jan. 5, 1965 c F CROMER 3,164,705

FLUID-BLAST dIRUIT INTERRUPTERS WITH RETRACTABLE IMPEDANCE PROBE Filed March 1, 1961 2 Sheets-Sheet 1 a a L? INVENTOR Charles F Cromer BY W ATLI'ORNEY Jan. 5, 1965 c. F. CROMER 3,164,705

FLUID-BLAST CIRCUIT INTERRUPTERS WITH RETRACTABLE IMPEDANCE PROBE Filed March 1. 1961 2 Sheets-Sheet 2 United States Patent 3,164,705 FLUID-BLAST CKRCUIT INTERRURTERS WITH RETRACTABLE IMPEDANCE PRDBE Charles F. Cromer, Level Green, Pa, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pin, a

corporation of Pennsylvania Filed. Mar. 1, 1961, Ser. No. 92,677 7 Claims. (Cl. 200-148) This invention relates to fluid-blast circuit interrupters in general, and, more particularly, to improved arc-extinguishing structures therefor.

A general object of the present invention is toprovide an improved and highly effective arc-extinguishing structure for a fluid-blast circuit interrupter.

A more specific object of the present invention is the provision of an improved fluid-blast circuit interrupter utilizing shunting impedance means to modify the recovery-voltage transient.

Still a further object of the present invention is to provide an improved fluid-blast circuit-interrupting structure suitable for interrupting circuits having relatively high rates of rise of recovery-voltage transient.

A more detailed object of the present invention is to provide an improved fluid-blast arc-extinguishing structure utilizing a retractable fluid-actuated probe to insert a shunting impedance means, such as a resistance, into the circuit during the opening operation thereof.

Low ohmic value resistors are readily adapted to circuit interrupters to modify severe recovery voltage transients. To avoid excessive temperature rise of the resistor assemblies, the number of cycles, or the time, the resistor assembly is subjected to circuit voltage must be kept to a minimum. One method of minimizing this time is to avoid insert of the resistor assembly on the breaker closing stroke.

It is a further object of the present invention to pro vide a novel impedance shunting assembly, which will be operative to shunt the main arc during the breaker opening stroke, but which will not be in the circuit during the breaker closing stroke. As a result, the temperature rise of the resistor assembly will be considerably reduced.

Still a further object of the present invention is the provision of an improved compressed-gas arc-extinguishing unit, in which blast-valve means are utilized to control the blast of gas from a reservoir, or chamber. A gasactuated resistor probe is responsive to opening of the blast valve to shunt a resistor assembly into the circuit on the breaker opening stroke. During the breaker closing stroke, when the blast valve is closed, the gas-actuated resistor probe will, of course, be in its retracted position, thereby avoiding the insertion of the resistor assembly into the breaker circuit during such a closing operation of the interrupter.

In U.S. patent application filed January 16, 1961, Serial No. 82,847, by Charles F. Cromer, and assigned to the assignee of the instant application, there is illustrated and described a novel fluid-blast circuit-interrupting structure in which a shunting impedance assembly is utilized to lower the rate of rise of the recovery voltage transient.

It is a further object of the present invention to improve upon the interrupting structure of the aforesaid Cromer patent application, so as to prevent the resistor assembly from being in the circuit during the breaker closing stroke.

Further objects and advantages will readily become ap parent upon reading the following specification, taken in conjunction with the drawings, in which:

FIGURE 1 is an end elevational view of a multi-pole high-power circuit interrupter embodying features of the present invention;

See

FIG. 2 is a longitudinal sectional view taken through one of the tank structures of the circuit interrupter of FIG. 1, illustrating the internally-disposed arc-extinguish ing assemblage, such assemblage being illustrated in the closed-circuit position;

FIG. 3 is a considerably-enlarged substantially vertical sectional view taken through the right-hand circuit-inten rupting unit of the arc-extinguishing assemblage illustrated in FIG. 2, the contact structure being illustrated in the fully closed-circuit position;

FIG. 4 is a View somewhat similar to that of FIG. 3, but illustrating the position of the several parts in the partially open-circuit position; and,

FIG. 5 is a diagrammatic view illustrating the relation of the shunting impedance in the novel circuit-interrupting unit of the present invention.

Referring to the drawings, and more particularly to FIG. 1 therefor, the reference numeral 1 generally designates a three-pole multi-phase double-pressure compressed-gas circuit interrupter. FIG. 1 illustrates an end view of the structure, and consequently only the end tank 2 as shown. A mechanism housing 3 is disposed at the end of the three breaker tanks, and encloses a suitable operating mechanism, not shown, which is effective to simultaneously actuate the arc-extinguishing assemblages 4 (FIG. 2) disposed interiorly of the tank structures 2.,

Extending downwardly interiorly within each one oi the tank structures 2 is a pair of terminal bushings 5, 6, which serve to carry the controlled circuit into the tank 2. The tanks 2 and the mechanism housing 3 are sup ported upon steel beams 7 supported upon a concrete foundation 8. Preferably the ends of each tank 2 con tain hinged covers it), 11 which permit inspection within the tank structures 2.

With reference to FIG. 2 of the drawings, it" will be observed that supported at the lower ends 12, 13 of the terminal bushings 5, 6, respectively, are

support castings

14, 15, Which fixedly support into position the arc-ex tinguishing assemblage 4.

The arc-extinguishing assemblage 4 generally comprises a plurality of serially-related arc-interrupting units 16 of the gas-blast type, the configuration of which is more readily apparent from an inspection of FIG. 3 of the drawings. Disposed adjacent the right-hand end of the arcextinguishing assemblage 4 is a high-pressure storage tank 17. A blast-valve mechanism 18 is operable to control the blasting of gas out of the high-pressure storage tank 17 and toward the three gas-blast interrupting units 16 to effect are extinction thereat.

The movable contact assemblage 20 generally comprises a pair of outer longitudinally-extending insulating operating rods 21, which are bridged by cross-bars 22 (FIG. 3) to the middle portions of which are fixedly secured the movable main contacts 23. The rod-shaped movable main contacts 23 make engagement with relatively stationary contact structures 24. As shown more in detail in FIG. 3 of the drawings, the relatively stationary contact structure 24 includes a plurality of circumferentially disposed contact fingers 25 and a somewhat centrally positioned arcing horn 26.

In the closed circuit position of the interrupter 1, illustrated in FIG. 3, it will be observed that the arcing horn 26 protrudes interiorly within the interior region 27 of the movable main contact 23, and good contacting engagement is provided by the main relatively stationary contact fingers 25 bearing against the movable contact 23.

With further reference to FIG. 2, it will be noted that an opening accelerating spring 31 biases the movable con tact assemblage 20 toward the left in an opening direction. This movement is resisted by the tension exerted by an operating rod 32 formed of insulating material, and

I) d interconnecting the movable contact assemblage as with an external operating mechanism disposed within mechanism compartment 3. Reference may be had to United States patent application, filed January 23, 1959, Serial No. 788,668, now Patent No. 3,057,983, by Russell N. Yeckley, Joseph Sucha and Benjamin P. Baker, and assigned to the assignee of the instant application.

A minute and detailed description of the several parts associated with the circuit interrupter 1 are contained in the aforesaid Yeckley et al. patent application. For the purpose of understanding the present invention, it is only necessary to know that operation of the blast-valve mechanism 18 is operable to force the blast valve 33 (FIG. 3) toward the right and away from its seat to permit the blasting of gas in the direction indicated by the arrows 35. The gas-blast not only blasts into the adjacent interrupting unit 16, but also passes down a plurality of insulating

blast tubes

37, 38 and into the adjacently disposed gas-blast interrupting units 16 to efiect arc extinction therein. The arrangement is such that sufficient gas blast pressure exists simultaneously in all three interrupting units 16 at the time of actual contact parting. As a result, simultaneous extinguishing action is exerted within each of the interrupting units llti.

Reference may be had to United States patent application filed October 17, 1960, Serial No. 63,201, by Russell N. Yeckley, Joseph Sucha and Roswell C. Van Sickle, and assigned to the assignee of the instant application for a description of the blast-valve mechanism 18. The operation of this blast valve mechanism 18 forms no part of the present invention, and consequently a description thereof is deemed unnecessary.

With reference to FIG. 2 of the drawings, it will be observed that a pair of insulating tie-bars 39 mechanically connect the end clamp castings 14, and serve to fixedly secure into proper position the stationary contact structures 24, associated with each of the gas blast interrupting units 16. In addition, it will be observed that the stationary contact structures 24, associated with the middle and left-hand interrupting units 16, contain rightwardly extending relatively stationary contact fingers 49, which serve to guide the adjacently-disposed movable contacts 23, and to carry current therefrom to the adjacent relatively stationary contact structure 24 of the adjacent unit 16.

During the opening operation, the mechanism, not shown, disposed interiorly within the mechanism housing 3 is unlatched to permit thereby the crankshaft 43 to rotate in a clockwise direction. Because of the biasing action exerted by the opening accelerating spring 31, the entire movable contact assemblage 20, comprising the plurality of movable contacts 23, interconnected by the insulating tie-bars 21, will move as a unit, toward the left in a circuit-opening direction.

With reference to FIG. 4, it will be observed that the arc-resisting tip portion 44 will separate from the contact fingers drawing a main current are 45.

The right-hand end of the main current are as will terminate at the arcing horn 26, whereas the left-hand end of the main current are 45 will be affixed at the arc-resisting ti portion 44. It will be observed that there is associated with the interrupting unit 16 a shunting impedance assembly, generally designated by the reference numeral 47. Specifically, the shunting impedance assembly 47 comprises a resistor assembly 48. The resistor assembly 48 could be a helically arranged coil, but, as shown, it comprises a stack of serially-connected spiralb-wound ribbon type resistor elements. Its right-hand end is connected, as at 49, to the relatively stationary main contact structure 24.

A gas-actuated retractable resistor probe assembly 50 is provided, comprising a probe 51 biased outwardly by a retracting spring 52 and having a piston portion 53 associated therewith. An insulating tube 54 and a tube connector 55 interconnect the region 56 with the lower side of the piston 53. As a result, when the blast valve 33 is opened, the gas blast not only blasts through the fluid flow guide 57, but also passes through the

tubing

54, 55 to move the probe 51 inwardly into contacting engagement with the relatively movable main contact 23. This will facilitate the interruption of the main current we 45, and, upon inserting the resistor 48, will serve to rcduce the amperage of the current to be interrupted, as well as to improve the power factor.

Upon continued leftward opening movement of the tubuiar movable main contact 23 away from the resistor probe 51, a residual current are 58 will be established between the tip portion 44 of the movable contact 23 and the probe 51 as shown in FIG. 4. Due to the presence of the gas blast passing through the orifice opening 59 of the flow director 57, this residual current are will be quickly extinguished. This action may occur even before the movable contact 2 3 clears the orifice 59.

Upon closing of the blast valve 33, the pressure within the region 56 will be reduced to that of the region 60 within the general interior of the tank 2, and the retracting spring 52 will be effective to withdraw the probe 50 downwardly to its retracted position, as illustrated in FIG. 3 of the drawings.

It will be observed that during the closing operation of the interrupter 1, when the mechanism disposed interiorly within the mechanism housing 3 is eflective to cause closing of the movable contact assemblage 20, the gas-blast valve 33 will remain closed, and since no pressure is exerted upon the piston portion 53 of the probe 51, the probe 51 will remain in its lower retracted position during the entire closing stroke of the interrupter. This has the important advantage of reducing the heating effect upon the impedance assemblage 47, and to therefore render the same suitable for longer operating life.

FIG. 5 somewhat diagrammatically illustrates the relationship of the resistance 48 to the relatively stationary and

movable contacts

24, 23. It will be apparent that with the novel interrupting structure disclosed, that the resistor assembly 47 is in circuit only during the opening operation, when its presence is required to reduce the rate of rise of the recovery voltage transient. During the closing operation of the interrupter, the resistor assembly 47 is out of the circuit, and consequently is not subjected to heating.

From the foregoing description, it will be apparent that there is provided an improved gas-blast type of circuitinterrupting unit 16 equipped with a shunting resistor assembly 47. The shunting resistor assembly 47 is connected to the movable main contact 23 by means of one or more retractable resistor probes 50. The probe assemblies 50 consist essentially of a cylindrical probe housing 61, the probe 51, the shunting resistance assembly 48 and the retrieving spring 52.

The probe housing 61 is securely fastened to the resistor assembly 47, and

tubing

54, 55 interconnects the

regions

56 and 62 of the resistor probe.

When the circuit interrupter 1 is called upon to make an opening operation, the blast valve 33 is operated providing relatively high pressure gas to the volume 56, and gas flows through the interrupting chamber. Pressure also builds up on the face 53 of the probe piston 51 in the housing 61 forcing the probe 51 against the movable contact 23. As the movable contact 23 is withdrawn, an arc is established between the movable contact and the relatively stationary contact assembly. This main arc is then interrupted, and the shunt resistor 48 is inserted into the circuit. As the moving contact 23 is further withdrawn, a low-current arc is drawn between the movable contact 23 and the probe 51, which is readily interrupted at the first current zero. As soon as the blast valve 33 closes, the

regions

56, 62 quickly fall to near their original low pressure value and the probe 51 is retrieved to the position illustrated in FIG. 3 by the retracting spring 52.

Since the probe 51 is retracted, it will not insert the resistor 48 on the breaker closing stroke, thus reducing the total time the resistor 48 is subjected to voltage.

Although there has been illustrated and described a specific structure, it is to be clearly understood that the same was merely for the purpose of illustration, and that changes and. modifications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the invention.

l claim as my invention! 1. A gas blast circuit interrupter including separable main contacts separable to establish a main current arc, agas blast actuated impedance probe assembly including a retractable probe and a shunting impedance connected therewith, gas blast means for not only effecting extinction of the main current are but also actuation of the probe assembly to insert the impedance in shunt relationship across the main current are, and said retractable probe being out of proximity of the region between the separable main contacts during the closing stroke of the interrupter.

, a gas blast actuated impedance probe assembly including a retractable probe and a shunting impedance connected therewith, retractable spring means for retracting. the probe upon a cessation of the gas blast, gas blast means for not only etfecting extinction of the main current are but also actuation of the probe assembly to insert the impedance in shunt relationship across the main current arc, and said retractable probe being out of proximity of the region between the separable main contacts during the closing stroke of the interrupter.

3. An interrupting. unit for a gas blast circuit interrupter including an insulating flow director having an opening, a movable tubular contact movable out of said opening during the opening operation, a relatively stationary contact structure disposed on the up-strcam side of the opening and cooperable with the relatively movable tubular contact to draw an arc, a gas blast actuated impedance probe assembly including a retractable probe and a shunting impedance connected therewith, gas blast means fornot only effecting extinction of the main current are but also actuation of the probe assembly to insert the impedancein shunt relationship across the main cur-. rent arc, and said retractable probe being out of proximity of the region between the movable contact and the relativeiy stationary contact structure during the closing stroke of the interrupter.

4. A gas blast circuit interrupter including a separable pair of main contacts separable to establish a main current arc, gas blast means including a blast valve opened during the opening operation for sending an arc-extinguishing blast of gas toward said main currentarc to effect the extinction thereof, impedance means, an impedance probe, said impedance means connected between one of said separable contacts and said impedance probe, means utilizing the pressure of the gas upon opening the blast valve for advancing said impedance probe into close proximity with the other of said separable main contacts,

whereby the main current are may more easily be extinguished, and said impedance probe being out of proximity of the region between the separable main contacts during the closing stroke of the interrupter.

5. A gas blast circuit interrupter including a separable pair of main contacts separable to establish a main cur rent arc, gas blast means including a blast valve opened during the opening operation for sending an arc-extinguishing blast of gas toward said main current are to effect the extinction thereof, impedance means, an impedance probe, said impedance means connected between one of said separable contacts and said impedance probe, a relatively stationary operating cylinder for housing said impedance probe, conduit means interconnecting said operating cylinder with the down stream side of said blast valve, whereby opening of the blast valve will send a blast; of gas through the conduit means and into the operating cylinder to advance the probe into near proximity with the other of said separable main contacts, and said impedance probe being out of proximity of the region V between the separable main contacts during the closing stroke of the interrupter. I

6. The combination in a gas blast circuit interrupter of a relatively stationary contact and a cooperable tubular movable contact separable therefrom to establish a main current arc, gas blastmeans including a blast valve opened during the opening operation for sending an arc extinguishing blast of gas toward said main current are to effect the extinction thereof, impedance means, an impedance probe, said impedance means connected between said relatively stationary contact and said impedance probe, said impedance probe having a piston portion, a relatively stationary operating cylinder for guiding said piston portion, conduit means interconnecting said operating cylinder with the down stream side of said blast valve, whereby opening of the blast valve will send a blast of gas through the conduit means and into the operating cylinder to advance the probe into near proximity with the movabletubular main contact, and said impedance probe being out of proximity of the region between the separable main contacts during the closing stroke of the interrupter.

7. The combination in a gas blast circuit interrupter of a relatively stationary main contact and a cooperable tubular movable main contact separable therefrom to establish a main current arc, gas blast means including a blast valve opened during the opening operation for sending an arc extinguishing blast of gas toward said current are to effect the extinction thereof, impedance means, an impedance probe, said impedance means connected between said relatively stationary contact and said impedance probe, said impedance probe having a piston portion, a relatively stationary operating cylinder for guiding said piston portion, conduit means interconnecting said operating cylinder with the down stream side of said blast valve, whereby opening of the blast valve will send a blast of gas through the conduit means and into the operating cylinder to advance the probe into near proximity with the movable tubular main contact, spring means for retracting said advanced impedance probe following cessation of the gas blast upon closing of the blastvalve, and said impedance probe being out of proximity of the region between the separable main contacts during the closing stroke of the interrupter.

References tilted in the tile of this patent FOREIGN PATENTS 546,399 I Great Britain July 10, 1942 105,722 Sweden Oct. 20, 1942 122,533 Australia Oct. 18, 1946 267,793 Switzerland July 1, 1950

Claims

1. A GAS BLAST CIRCUIT INTERRUPTER INCLUDING SEPARABLE MAIN CONTACTS SEPARABLE TO ESTABLISH A MAIN CURRENT ARC, A GAS BLAST ACTUATED IMPEDANCE PROBE ASSEMBLY INCLUDING A RETRACTABLE PROBE AND A SHUTTING IMPEDANCE CONNECTED THEREWITH, GAS BLAST MEANS FOR NOT ONLY EFFECTING EXTINCTION OF THE MAIN CURRENT ARC BUT ALSO ACTUATION OF THE PROBE ASSEMBLY TO INSERT THE IMPEDANCE IN SHUNT RELATIONSHIP ACROSS THE MAIN CURRENT ARC, AND SAID RETRACTABLE PROBE BEING OUT OF PROXIMITY OF THE REGION BETWEEN THE SEPARABLE MAIN CONTACTS DURING THE CLOSING STROKE OF THE INTERRUPTER.