US2688672A - Sectionalizing switch - Google Patents

Description

Sept. 7, 1954 Filed Oct. 10, 1951 WITNESSES: 427

A. W. EDWARDS SECTIONALIZING SWITCH Fig.l. I5

2 Sheets-Sheet l INVENTOR Andrew W.Edw0rds.

p 7, 1954 A. w. EDWARDS 2,688,672

SECTIONALIZING SWITCH Filed Oct. 10, 1951 2 Sheets-Sheet 2 Fig.2.

WITNESSES: INVENTOR Angrew W.EdwordZ J ATTORNE Patented Sept. 7, 1954 SECTIONALIZING SWITCH Andrew W. Edwards, East McKeesport, Pa., as-

signor to Westinghouse Electric Corporation East Pittsburgh, Pa., a corporation of Pennsylvania Application October 10, 1951, Serial No. 250,587

Claims. I

My invention relates generally to circuit interrupters, and it has reference in particular to automatic line sectionalizing switches.

Line sectionalizing switches are used in conjunction with automatic reclosing circuit breakers for isolating faulted sections of the line in order to maintain the maximum amount of service continuity. They comprise, in general, a switch mechanism which is controlled by a fault counter which is arranged to open and lock open the switch mechanism after a predetermined number of operations of an associated reclosing circuit breaker, while such circuit breaker is open. To obtain the best performance, the fault counters must be arranged to reset to their initial position if the number of closely successive fault interruptions by the reclosing breaker is not sufficient to cause opening and locking open of the switch mechanism. The fault counters must also be co-ordinated with the counting means of an associated reclosing circuit breaker, so as to make it impossible to cause lockout of the circuit breaker by repeated manual reclosing of the sectionalizing switch. Thus, it must be impossible for the fault counter of the sectionalizing switch to reset before that of the reclosing breaker. One way of accomplishing this result is to make the reset time of the sectionalizing switch counter greater than that of the longest resetting time of any reclosing breaker with which the sectionalizing switch may be used. This calls for relatively close manufacturing tolerances in counters of the dashpot type, which are difficult to obtain and are at the same time costly.

Accordingly, it is an object of my invention to provide in an automatic sectionalizing switch, novel means for delaying the reset of the fault counter thereof.

Another object of my invention is to provide in an automatic sectionalizing switch having a fault counter, for preventing reset of the counter, only when the switch is open.

It is also an object of my invention to provide in an automatic sectionalizing switch for utilizing releasable restraining means actuated by the switch operating mechanism for preventing reset of the fault counter while the switch contacts are open.

It is an important object of my invention to provide in an automatic sectionalizing switch using a fluid operated fault counter which normally resets during a predetermined time interval after operation, for preventing the reset interval from commencing until the switch is reclosed.

Yet another object of my invention is to provide in an automatic sectionalizing switch for supporting releasable restraining means on the operating mechanism of the switch for preventing reset of the fault counter thereof while the switch is open.

Another important object of my invention is to provide in an automatic sectionalizing switch for utilizing magnetic means actuated by the operating mechanism of the switch for preventing reset of the fault counter thereof until the switch is reclosed.

These and other objects of this invention will become more apparent upon consideration of the following detailed description of preferred embodiments thereof, when considered in connection with the accompanying drawings, in which:

Figure l is a substantially central vertical section of a sectionalizing switch embodying the invention in one of its forms, with the fault counter shown only partly in section;

Fig, 2 is an enlarged side elevational view of a principal part of the contact operating mechanism and the fault counter of a switch similar to that of Fig. l, with the fault counter shown in section, but illustrating a different embodiment of the invention; and

Fig. 3 is a side elevational view of the operating mechanism and counter of Fig. 2 shown in the open position.

Referring to the drawings, it will be seen that an automatic sectionalizing switch or sectionalizer I1 is shown in Fig. l as being enclosed within a metal tank 21, which is provided with an insulating liner 28, and which is surmounted by a top casting 29. The form of sectionalizer described herein may be substantially similar to that described in detail in the copending application Serial No. 189,082 of James M. Wallace, filed October 9, 1950, and entitled Circuit Interrupter and Counter Therefor, which application is assigned to the assignee of the present invention, and while this invention includes certain features of cooperation with this particular form of sectionalizer, it is not limited thereto, because it will be apparent that it may be embodied in sectionalizers which are of a specifically different form. As described in the said Wallace application, an incoming line 15 enters through a bushing 3! which terminates inside of the tank. The circuit then continues, through a conductor 32 to a sectionalizer coil 19. From the sectionalizer coil IS, the circuit continues through a conductor 33 which is insulated from conductor 32 by insulation 35, back underneath the bushing 31 for the incoming lead [5, and thence to the terminal 34 which constitutes one of the stationary contacts of the sectionalizer which are disposed to be engaged by a movable contact 26. Ordinarily, the sectionalizer has two bushings, each with its lead passing through the bushing, and each bushing terminates, at its bottom, in one of the stationary contacts of the sectionalizer, but since Fig. 1 shows an approximate central section through the sectionalizer, the second stationary contact is not visible. The movable contact 28 is shown as a contact bar or bridge which presses up against the underside of the stationary contacts 3A and the other stationary contact (not shown) in the closed position of the sectionalizer, and which is lowered by gravity, to operate the sectionalizer, upon the release of a pull rod 36, which is shown in the form of an upwardly extending insulating tube having guide links 25 pivotally connected thereto and to a bracket 38 on the rod 36 intermediate the ends of the bar 20, by a pivot 39 and to a stationary pivot 4 l.

The sectionalizer I! can operate either in air, or in an insulating oil, or other insulating fluid. It is sometimes desirable for the counter 31 to operate in oil, as it involves dashpot or fluid flow operation, as subsequently described, which is somewhat more difficult to obtain in air, with the necessary time constants. It is sometimes desirable to have the contacts Sic-2B also operating in oil. Consequently, the apparatus is illustrated, by way of example, as having the counter 3'? and the contacts 3d2ll immersed in oil 459 which is contained in the tank 21.

A counter-and-lockout mechanism 23 is segregated, into its component parts, consisting of the counter 31 and an operating-mechanism.

The operating mechanism com-prises a bellcrank trigger 53 disposed to support a roller 50 at one end of a lever A! which is pivotally supported by a fixed pivot 48 on a U-shaped bracket 49 secured to the casting 29, and carries a pivot 44 which comprises one of the terminal points of a lever 43. A toggle mechanism, including a lever 46 pivotally connected to the lever as by a pivot 45, and an operating-handle 60 pivotally supported on the casting 29 by a pivot S I, comprises the other terminal point of support for the lever 43. The pull rod 36 is connected to the lever l3 by a pivot 42. The trigger 53 has a downwardly extending abutment portion 56 which is adapted to be tripped when an upward movement of a trip pin 51 of the counter 3'! raises said abutment point 56 of the trigger, whereupon the linkage of the operating mechanism permits the pull rod 36 and the movable contact member 20 to drop freely in the opening operation of the mechanism.

The counter 37 is suspended from the top of the top casting 29, by means of a plurality of depending insulating supports or tubes ll], which support a bottom plate H of the counter.

The counter proper 31 comprises, as show-n in Figs. 1 and 2, a vertically disposed tube 72, which is preferably made of brass or other non-magnetizable metal. The lower end of the tube is disposed to be closed by a plug 13 of iron or other magnetic material, while the top of the tube 12 is open. The series current coil i9 surrounds a portion of the tube 1-2, intermediate between its upper and lower ends.- Immediately above the coil [9 is a perforated magnetizable plate 74 which is secured to the bottom plate H by bolts 15. The plates are perforated so as to surround the tube 12. The plates Hand H serve as the two pole pieces of an electromagnetic circuit, the excitation of which is provided by the coil I9.

Inside of the tube 12 is a magnetizable core or armature 16, which is sliclably movable, with a close fit of say perhaps 3 mils radial clearance, within said tube. The armature 16 normally extends partly above and partly below the level of the upper plate 14, being located by means of a shoulder 69 in the tube, while the plug 73 is disposed partly above and partly below the lower plate H. Both the armature 16 and the plug 13 thus extend partly within and partly without the space between the two plates is and l I.

In accordance with the description of the copending Wallace application, the armature 16 may comprise two relatively movable elements, namely, a core 11 of iron or other magnetic material having a cylindrical extension 18 at the upper end, and a movable cap or piston of a non-magnetic material such as brass, closely surrounding the extension. Snap rings of iron or other suitable magnetic materia1 may be disposed in spaced grooves on the piston 88 to provide projecting ribs which are vertically spaced from each other by a spacing which is preferably approximately the same distance as the closable distance between the core I! and the plug 13 so that it will magnetically lock the piston in its different stepped positions against unwanted vertical displacement or slippage. A snap ring 88 of magnetic material may be disposed in a groove 81 about the tube '12 in line with the plate 14 to assist in concentrating the magnetic flux between the plate and the rings 85. A compression spring :19 is disposed between the core 11 and the plug 73, so that when the coil I9 is sufficiently energized, such as by a fault current, the core 11 is drawn downwardly towards the plug, storing up energy in the interposed compression spring 19, as will be more fully described hereafter.

Both the core T7 and the plug 13 are provided with central bores 81, and the lower end of each of these bores is provided with an orifice closable by means of a ball check valve 82, so that the fluid which is entrapped within the closed lower end of the tube 12 resists any rapid downward movement of the piston ac, because of the closing of the ball valve 82 in the plug 13, while the valves permit the free upward movement of the piston '80 and core Tl. The entrapped fluid could be any gas or liquid having the required viscosity in comparison with the mechanical clearances which are provided. The idea is to permit the respective core TI and piston 80 to move freely upwardly, in a step-by-step motion, as will be subsequently described, while permitting them to drift back downwardly again, by fluid leakage, at a very slow rate.

At the top of the armature 15 'of the piston 80, is afifixed an upstanding pin 84, which extends upwardly to a point'above the open top end of the tube 12. This pin 84 is surrounded by a tubular tip or trip pin 57, which is capable of serving as an adjustable vertical extension of the pin 84. This vertical adjustment is effiected in any one of a plurality of vertical spaced positions corresponding to the spacing between the core 7'! and the plug 13, by means of a cottervpin 85, .so that adjustment may be made for any desired number of counts, such as 1, 2, 3 or 4, within the range of the counting-mechanism 31 In order to increase the resetting time of the counter 3'! after the sectionalizing switch has locked open, releasable means such as the belltially horizontal arm 9| depending leg 92 crank spring 90 may be provided. The spring 90 may comprise, as shown in Fig. 1, a substan having an angularly related leg 82 disposed to be engaged by the lower edge of the lever 43 when the switch opens. A may be connected to the arm 9| by a loop 93 disposed to be positioned about the roller 63 on the pivot 54 of the bellcrank lever 53. The leg 92 may be provided with a foot 95 disposed to be inserted under the lower edge of the trip pin 51 when the arm 9| is engaged by the lever 43. This edge may be beveled as at 98 to facilitate releasing the trip pin.

In the operation of the counting-mechanism 31, when the coil I9 is first energized with a current corresponding to the setting of the counter, the core 11 of the armature 18 is drawn downwardly toward the plug 13, so as to close the air gap which separates the inner ends of said armature and plug. The fluid between the core TI and plug 73 cannot move downwardly because of the pressure of the fluid flow valve 82 in the plug 13, so the fluid between the armature and plug is forced upwardly through the check valve 82 in the core 71, and hence the piston 88 remains in the position shown. The attractive force between the upper plate 14 and the upper magnetic ring 85 is enhanced by the magnetic snap ring 88 on the tube 12, and the piston 88 is thus held securely in position as the armature 18 moves downwardly.

When there is a fault on the distribution line, within the protective reach of an automatic reclosing circuit breaker, the recloser contact thereof quickly opens, and quickly again recloses, but during the moment (12 cycles or more, in a 60-cycle line) when said recloser contact was open, the sectionalizer coil I8 is deenergized, reducing the attractive force between the armature 16 and plug 13. The compression spring 19 between the core 11 and plug 13 expands, and pushes the core upward again, to the normal separation-distance. During this action, however, fluid in the armature 16 is entrapped and cannot move downwardly, because of the fluid flow valve 82 in the core 11, and hence the piston 80 and the core 11 must move upwardly together, which they are free to do, so far as fluid-action is concerned, because the lower valve 82 in the plug 13 will open during such movement. The

magnetic attraction between the upper plate 14 and the corresponding magnetizable ring 85 of the piston 88 of the armature 16 is now practically non-existent, because of the deenergization of the coil [8, and hence the piston 80 of the armature 16 is notched upwardly by a distance corresponding to approximately the amount of compression of the spring 19. Upon re-energization of the coil l9 above the rated value, the magnetic attraction between the rings 85 and 86 serves to accurately position the piston 88 and thus correct any undershoot or overshoot.

If a fault continues on the distribution system, at a point beyond the sectionalizer coil 19, the reclosure of the recloser contact re-energizes the sectionalizer coil l8 and causes a second compression of the spring 19, in the manner already described. If the fault is still on the system, as has just been assumed, the recloser-contact again opens, and a second upward stepping-movement of the trip pin 51 is obtained.' Thus the stepby-step movement of the counter mechanism continues. The ring 88 about the tube 12, being of a magnetic material, acts to concentrate the magnetic flux in the gap between the plate 14 and example, a collar 97 of the rings 85, thus increasing the effective looking power thereof, and accurately positioning the piston each time to prevent cumulative error.

When the last upward stepping of the piston of the armature I6 is obtained, depending upon the vertical positioning of the trip pin or tubular tip 51, this pin 5! comes into contact with the trigger 53 during this last upward movement, and trips out the sectionalizer contact 28. It will be noted that this last upward movement of the trip pin 51 occurs during a time when the current in the sectionalizer coil [9 is off. In the operation of the recloser, the current remains off, that is, the recloser contact remains open for a minimum of 12 cycles (on a Gil-cycle line), before the recloser contact recloses. The opening of the sectionalizer contact 20 requires something like two or three cycles, so that it is seen that the sectionalizer contact 20 opens during the current off period, so that the sectionalizer contact 20 does not have to interrupt any substantial current.

As the contact rod 38 drops, lever 43 rotates counterclockwise until it strikes roller 63, engaging arm 9! and rotating the spring counterclockwise. The foot of leg 92 is moved in under the lower edge of the trip pin 5! to prevent resetting of the counter. The counter may only reset sufliciently to permit bellcrank lever 53 to reset, so that the lever 41 is reset by being raised until roller 50 rests on the arm 52 of the lever 53, thus readying the switch for reclosing.

When the switch is reclosed by raising the handle 60, the counter 31' is conditioned for an immediate trip, thus affording the maximum protection, since the recloser counter will have at least partially reset and cannot, therefore, be locked out improperly by reason of the switch resetting first.

Referring particularly to Figs. 2 and 3 of the invention, it will be seen that in this embodiment of the invention the operating mechanism is identical with that of Fig. 1, but resetting of the counter 37 may be prevented by magnetic means, instead of the spring 98 of Fig. 1. For magnetic material such as iron, steel, or the like, may be disposed on the piston 80, being disposed about the pin 84 within the tube 12. A permanent magnet 88 having spaced pole pieces 99 and H38 may be secured to the contact rod 38, as by a set screw lfll. The magnet 98 and collar 9i may be so related that they are disposed opposite each other when the contact rod has dropped to the full open position and the counter 31 has just reset sufficiently to permit the bellcrank lever 53 to reset and latch the lever 46, as shown in Fig. 3. When the breaker is closed, as shown in Fig. 2, the magnet 98 has no influence on the collar 97 as they are relatively remote from each other.

Accordingly, when the sectionalizer switch opens, its counter will in both instances be prevented from resetting any further than is necessary to permit reclosing the switch. Thus the reclosing circuit breaker associated therewith can at least partially reset, and it will not be subject to lockout improperly as by the reclosing of the sectionalizing switch before the recloser counter resets.

While I have illustrated my invention in but two exemplary forms of embodiment, which are now preferred, it is to be understood that the invention is susceptible of considerable modification, by way of additions, omissions and substitution of various equivalents, without departing from the essential spirit of my invention, particularly in its broader aspects. It is desired, therefore, that the appended claims shall be accorded the broadest construction consistent with their language.

I claim as my invention:

1. In a circuit interrupter, separable contacts, releasable means normally operable to prevent separation of said contacts, counting means having actuating means for actuating it from an initial position in response to a predetermined number of circuit interruptions to efiect operaate said latch means to effect separation of said contacts only after a predetermined number of such interruptions, said counting means being disposed to slowly reset after an operation, an operating mechanism including a movable member operable to reclose said contacts, and releasable means including a part operable in response to separation of the contacts to prevent return of the counting means to said initial position, said part of the releasable means being operable to release said counting means in response to operation of the movable member of the operating means to reclose said contacts.

3. A circuit interrupter comprising, separable contacts, latch means normally holding said contacts closed, means movable by electroresponsive means operable from an initial position to effect operation of the latch means to effect separation of said contacts only after a plurality of interruptions of the circuit during an overload, operating means for one of the contacts including a lever operable to actuate said one contact to reclose said contacts and releasable means actuated by said lever during separation of said contacts to engage and prevent return of said means movable by the electroresponsive means to said initial position, while the contacts are separated.

4. In a circuit interrupter, separable contact means, fluid-actuated counting means operable from an initial position to efiect separation. of said contact means only after a predetermined number of interruptions or an overload, operating means connected with one of the contact means for reclosing said contact means, and having a part movable to a position to exert a restraining force on the counting means to prevent it from returning to the initial position, said part being movable to said position by said operating means when said contact means are separated.

5. In a circuit interrupter, separable contacts, releasable latch means normally maintaining said contacts closed, counting means operable in response to a predetermined number of closely successive interruptions to actuate said releasable latch means and effect separation of said con-.

tacts, operating means operatively connected with one of said contacts for actuating said contact to effect reclosing of said contacts, normally ineffective means having a movable part operable in response to movement of said operating means during separation of said contacts to a position to exert a restraining force on the counting means and prevent reset of said counting means, said movable part of said normally inefiective means being moved to a different position in which it is rendered ineffective upon operation of said operating means to reclose said contacts.

6. A circuit interrupter comprising, separable contacts, an operating mechanism supporting one of the contacts for separating and reclosing said contacts, releasable means engaging a part of said mechanism for maintaining said operating mechanism in a contact closed position, fluid pressure actuated counting means having a movable part selectively responsive to a predetermined value of overcurrent and interruption thereof to progressively advance in response to closely consecutive interruptions for operating the releasable means to release the operating mechanism and separate the contacts only after a predetermined number of closely successive overcurrents and interruptions, and restraining means having a part actuated by the operating mechanism to a predetermined position to prevent the counting means from resetting so long as the contacts are separated.

'1. A circuit interrupter comprising, separable contacts, an operating mechanism including a movable member for actuating said contacts to separate or reclose them, releasable means for maintaining said member in a position with the contacts closed, counting means having a part operable from an initial position to actuate and effect release of said releasable means in response to an overcurrent and a plurality of closely successive interruptions thereof, and a normally ineffective resilient restraining means actuated by the movable member of said mechanism to engage said part of said counting means to prevent return thereof to the initial position until said mechanism is operated to reclose said contacts.

8. A circuit interrupter comprising, separable contacts, an operating mechanism for separating and reclosing said contacts, including a contact rod carrying one of the contacts and a lever pivotally connected to said rod, a releasable support pivotally supporting said lever, counting means having an initial position to which it slowly returns, said counting means being operable progressively in response to closely successive pulses of current above a predetermined value to advance from said initial position to actuate and release said releasable support, and resilient restraining means actuated by said lever in response to movement thereof upon release of said releasable support to engage and prevent return of said counting means to the initial position.

9. In a circuit interrupter, separable contacts, releasable means normally maintaining said contacts closed, counting means having a part progressively advanced in response to closely successive interruptions of an overload to actuate the releasable means and efiect separation of the contacts after a predetermined number of such interruptions, and a spring restraining member actuated to a predetermined position in response to separation of said contacts to engage and prevent more than a predetermined resetting of said progressively advanced part so long as the contacts remain separated.

10. A circuit interrupter comprising, separable contacts, means normall maintaining said contacts closed, fluid operated counting means having a movable part operable from an initial position in response to closely successive interruptions of a current in excess of a predetermined value to progressively advance and effect separation of said contacts, said counting means being biased to return to said initial position upon separation of said contacts, and a normally inc fective resilient restraining member actuated to a predetermined position by means movable in response to separation of said contacts to maintain the movable part of the counting means in a position intermediate its operating and initial positions so long as the contacts are separated.

11. A circuit interrupter comprising, separable contacts, an operating mechanism for separating and closing said contacts, releasable means normally maintaining the operating mechanism in a contact closed position, counting means having a part progressively advanceable from an initial position in response only to a predetermined number of closely successive interruptions of an overcurrent in said circuit for actuating said releasable means and effecting operation of said mechanism to separate said contacts, and restraining means carried by the operating mechanism for exerting a restraining force on said part for preventing return of the counting means to the initial position so long as the contacts are separated.

12. A circuit interrupter comprising, separable contacts, an operating mechanism connected to at least one of said contacts including a movable contact rod, releasable means for maintaining the operating mechanism in a closed contact position, counting means having a movable part advanceable from an initial position in response to a predetermined number of closely successive interruptions of an overcurrent to actuate and release said releasable means and effect movement of said contact rod to separate said contacts, and means carried by the contact rod movable to a predetermined position in response to said movement of the rod for preventing the counting means from returning to said initial position While the contacts are separated.

13. A circuit interrupter comprising, separable contacts, an operating mechanism for effecting separation and reclosing of said contacts, latch means normally maintaining said mechanism in a closed contact position, counting means having a movable part progressively advanceable from an initial position in response to a predetermined number of closely successive interruptions of an overcurrent to actuate the latch means for permitting operation of the mechanism to separate said contacts, and magnetic means including a part actuated by the operating mechanism for preventing return of the counting means to the initial position for a predetermined time after said contacts are reclosed.

14. A circuit interrupter comprising, separable contacts, an operating mechanism for effecting separation and reclosing of said contacts, fluid actuated counting means having a movable part advanceable progressively from an initial position in response to a predetermined number of closely successive interruptions of an overload current for actuating a part of the mechanism and effecting operation of the mechanism to separate said contacts, and means including a movable part actuated in response to operation of said mechanism to separate said contacts to exert a restraining force on the counting means for preventing return of said counting means to the initial position until a predetermined time after the mechanism is operated to reclose said contacts.

15. A circuit interrupter comprising, separable contacts, an operating mechanism for said con tacts including a movable contact rod operatively connected with one of the contacts, a latch normally maintaining the rod in a closed contact position, counting means having a part movable from an initial position in response to a predetermined number of operations of the mechanism to actuate the latch and permit movement of the contact rod to separate the contacts, magnetic means on the movable part of the counting means, and magnetic means carried by the contact rod movable to a position in which it is cooperative with the magnetic means on the movable part of the counting means when the contacts are separated to prevent the counting means from returning to the initial position.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,337,713 Garlington Dec. 28, 1943 2,442,477 Wallace et a1 June 1, 1948 2,452,233 Gerard et a1 Oct. 26, 1948 2,477,067 Kyle, Jr. et a1. July 26, 1949 2,524,525 Hermann et a1. Oct. 3, 1950

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