US2828383A - Line sectionalizers - Google Patents

Description

March 25, 1958 E. o. UHRIG I 2,828,383

LINE SECTIONALIZERS Filed Dec. 16, 1953 2 Sheets-Sheet 2 Fig.2.

INVENTOR 73 Edward O. Uhrig.

BY 84 Hi 51/ ATTORNE United States Patent LINE SECTIONALIZERS Edward 0. Uhrig, Linthicum Heights, Md., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa.,- a corporation of Pennsylvania Application December 16, 1953, Serial No. 398,507

9 Claims. (Cl. 200-108) My invention relates generally to circuit interrupters, and it has reference in particular to sectionalizers.

Generally stated it is an object of my invention to provide for more readily coordinating a sectionalizer with a reclosing circuit breaker, which may be located between it and a source.-

More specifically it is an object of my invention to provide for preventing reset of the operation counter of a sectionalizer until the line in which it is connected is re-energized.

One object of my invention is to provide a releasable brake for preventing reset of a delayed reset sectionalizer counter.

Another object of my invention is to provide a direction sensitive holding device for preventing reset of the counter of a sectionalizer until the line voltage is reenergized.

It is an important object of my invention to provide a magnetically releasable restraining device for preventing reset of the counter of a sectionalizer until the line is re-energized to release the brake.

These and other objects of this invention will become more-apparent upon consideration of the following detailed description. of a preferred embodiment thereof, when taken in connection with the attached drawing in which a Figure l is a substantially central vertical section view of a line s 'ectionalizer utilizing an operation counter embodyin'g the principal features of rny invention; and

Fig. 2 is an enlarged central vertical view of the counter shown in Fig. 1.

Referring to Fig. l of the drawing, it will be seen that a sectionalizer 17 is here shown as being enclosed within a metal tank 27, which is provided with an insulating liner 28, and which is surmounted by a top casting 29. Most of the parts of the sectionalizer may be substantially similar to those described in detail in the copending application Serial No. 189,082 of James M. Wallace, of which application this one is an improvement, and which application is assigned to the assignee of the present invention. An incoming line enters through a bushing 31 which terminates inside of the tank. The circuit then continues, through a conductor 32 to a sect'ionalizerv coil 19. From the sectionalizer coil 19, the circuit continues through a conductor 33, separated from conductor 32 by insulation 30, back underneath the bush ing 31 for the incoming lead 15, 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 bridging contact 20. Ordinarily, the sectionaliz'er 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 sectiona'li'zer, bridged by contact 20, but since the drawing shows an approximate central section through the sectionalizer, the second stationary contact is not visible. The movable contact is shownas a contact bar or bridge which presses up against the underside of the stationary con- 2,828,383 Patented Mar. 25, 1958 tacts 34 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.

The sectionalizer 17 can theoretically operate either in air, or in an insulating oil, or other insulating fluid. it is sometimes desirable for the counter 37 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 34-20 also operating in oil. Consequently the apparatus, is by way of example, illustrated as having the counter 37 and the contacts 34-2t) immersed in oil 40 which is contained in the tank 27. A counter-and-lockout mechanism 23 is segregated, into its component parts, consisting of the counter 37 and the operating-mechanism 38.

The operating mechanism comprises a bellcrank trigget 53 mounted on a pivot 50 supported by a bracket 51 depending from the top casting 29, and disposed to support a lever 47 which is pivotally supported by a fixed pivot 48 carried by bracket 51, 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 43 by a pivot 45, and an operating handle 60 pivotally supported on the casting 29 by a pivot 61,- comprises the other terminal point of support for the lever 43. The pull rod 36 is connected to the lever 43 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 57 of the counter 37 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 70, which support the base plate 71 of the counter. The counter proper 37 as best shown in Fig. 2, comprises 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 73 of iron or other magnetic material, while the top of the tube 72 is open. The series current-coil 19 surrounds a portion of the tube 72, intermediate between its upper and lower ends. Immediately above and below the coil 19 are two perforated magnetizable plates 74 and 71, respectively, both of which are perforated so as to surround the tube 72. The plates 74 and 71 are joined by bolts 75 and serve as the two pole pieces of an electromagnetic circuit, the excitation of which is provided by the coil 19.

Inside of the tube 72 is a magnetizable core or armature 76, which is slidably movable, with a close fit of say perhaps 3 mils radial clearance, within said tube. The armature 7 6 normally extends partly above and partly below the level of the upper plate 74, 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 71. Both the armature 76 and the plug 73 thus extend partly within and partly Without the space between the two plates 74 and 71. I

As disclosed in the Wallace application, the armature 7 a) may comprise two relatively movable elements, namely, a core 77 of iron or other magnetic material having a cylindrical extension 77' at the upper end, and a movable cap or piston 78 of a non-magnetic material such as brass, closely surrounding the extension. Annular grooves 79 may be provided about the piston 78, in which may be disposed snap rings 80 of iron or other suitable magnetic material to provide projecting ribs which are vertically spaced from each other by a spacing which is 7 preferably approximately the same distance as the closable distance between the core 77 and the plug 73, or other such disposition which will magnetically lock the piston in its diiferent stepped positions against unwanted vertical displacement or slippage. A snap ring 81 of nagnetic'material may be disposed in a groove 82 about the tube 72 in line with the plate 74 to assist in concentrating the magnetic flux between the plate and the rings A compression spring 83 is disposed between the core and the plug 73, so that when the coil 19 is sufficiently energized, such as by a fault current, the core 77 is drawn downwardly towards the plug, storing up energy in the interposed compression spring 83, as will be more fully described hereafter.

Both the core 77 and the plug 73 are provided with central bores and the lower end of each of these bores is provided with an orifice 84 closable by means of a ball valve 85, so that the fluid which is entrapped within the closed lower end of the tube 72. resists any rapid downward movement of the piston 78, because of the closing of the ball valve 85 in the plug 73, while the valves permit the free upward movement of the piston 78 and core 77. 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 77 and piston 78 to move freely upwardly, in a step-by-step motion, as will be sub sequently described, while permitting them to drift back downwardly again, by fluid leakage, at a very slow rate.

In order to permit sectionalizers to have a relatively long effective time delay on resetting, Without running into complications of extremely close manufacturing tolerances and the like, a brake, holding or restraining device, designated generally by the numeral 86 may be provided for preventing reset of piston or cap 78 until a predetermined time after voltage has been restored to the line.

This holding device may comprise a plurality of balls 87 slidably disposed in openings 88 in the extension 77 of core 77 and having diameters greater than the thickness of the extension. Actuating means such as a tubular actuator 89 may be movably disposed within the eX- tension 77' having a tapered surface 90 at the upper end for urging the balls outwardly against the inner surface of cap 78. A spring 92 disposed beneath the actuator 89 rests on a washer 93 and biases the actuator upwardly. The actuator being of a magnetic material is attracted to the armature 77 when the solenoid coil 19 is energized, thus releasing balls 87 from the inner surface of piston 78 and allowing the piston to commence delayed reset under the influence of gravity. The inner surface of cap 78 may be counter bored as at 78' to render the holding device 86 ineffective at the uppermost position of cap 78. This permits trip pin 57 to reset sufficiently to permit bellcrank lever 53 to reset and restore the operating mechanism 38 to permit reclosing by handle on.

Each time the coil 19 is deenergized, actuator 89 will be released, and spring 92 will urge it upwardly to force balls 87 into engagement with the inner wall of piston 78. Upward movement of piston 78 is not precluded because such upward movement occurs with upward movement of core 77, but downward movement is precluded; Thus resetting of counter piston 78 is prevented until the recloser ahead of the sectionalizer is reclosed and the sectionalizer is closed, re-energizing coil 19.

At the top of the armature 76 on the piston 78, is allixed an upstanding pin 94, which extends upwardly to a point above the open top end of the tube 72. This pin 94 is surrounded by a tubular tip or trip pin 57, which is capable of serving as an adjustable vertical extension of the pin 94. This vertical adjustment is effected in any one of a plurality of vertical spaced positions corresponding to the spacing between the core 77 and the plug 73, by means of a cotterpin 96, 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 37.

in the operation of the counting mechanism 37, when the coil 19 is first energized with'a current corresponding to the setting of the counter, the core 77 of the armature 76 is drawn downwardly toward the plug 73, so as to close the airgap which separates the inner ends of said armature and plug. Since the actuator 89 is drawn toward core 77 by magnetic attraction, the brake 86 is ineflective. The fluid between the core 77 and plug 73 cannot move downwardly, in order to permit the armature and plug to come together, because of the pres ence of the fluid-flow valve 85 in the plug 73, so the fluid between the armature and plug is forced upwardly through the check valve 85 in the core 77, and hence the piston 78 must move upwardly relative to the core 77. The attractive force between the upper plate 74 and the upper magnetic ring is enhanced by the magnetic snap ring 81 on the tube 72, and the piston 78 is thus held securely in position as the armature 76 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 19 is deenergized, reducing the attractive force between the armature 76 and plug 73. The compression spring 83 between the core 77 and plug 73 expands, and the spring pushes the core upward again, to the normal separation distance. During this action, however, fluid in the armature .76 is entrapped and cannot move downwardly, because of the fluid-flow valve in the core 77, and hence the piston 78 and the core 7'7 must move upwardly together, which they are free to do, so far as fluid action is concerned, because the lower valve 85 in the plug 73 will open during such movement. The magnetic attraction between the upper plate 74 and the corresponding magnetizable ring 80 of the piston 78 of the armature 76 is now practically non-existent, because of the deenergization of the. coil 19, and hence the piston 78 of the armature 76 is notched upwardly by a distance corresponding to approximately the amount of compression of the spring 83. During the period of deenergization the piston 78 will be held in its advanced position by the holding device 86. Upon re-energization of the coil 19 above the rated value, the magnetic attraction between the rings 80 and 81 serves to accurately position the piston 78 and thus correct any undershoot or overshoot. The actuator 89 will be retracted upon re-energization of coil 19 to release the balls 87 from engaging the wall of piston 78.

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 19, releases brake 86, and causes a second compression of the spring 83, in a 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 57 is obtained, and the holding device is again activated during deenergization. Thus the step-by-step movement of the counter mechanism continues. The ring 81 about the tube 72, being of a magnetic material, acts to concentrate the magnetic flux in the gap between the plate 74 and the rings 88, thus increasing the effective locking power thereof, and accurately positioning the piston each time to prevent cumulative error.

When the last upward stepping of the piston 78 of the armature 76 is obtained, depending upon the vertical positioning of the trip pin or tubular tip '57, this pin 57- comes into contact with the trigger 53 during this last:

upward movement, and trips out the sectionalizer contact 20. It will be noted that this last upward movement of the trip pin 57 occurs during a time when the current in the sectionalizer coil 19 is OK. 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 60-cycle line), before the recloser contact recloses. During this time the actuator 89 is actuated by spring 92 to a holding position, but because of the enlarged bore of counterbor'e 78' the piston 78 is not held in the most advanced position by the holding device 86. Instead it slowly resets to the second advanced position where balls 87 can engage the normal inner wall of piston 78. The counter will thus be held in a position where but one operation is required to trip the mechanism 38, and where the bellcrank lever 53 is free to reset and permit manual reclosing of the sectionalizer. The opening of the sectionalizer contact 20 requires something like 2 or 3 cycles, so that it is seen that the sectionalizer-contact 20 opens during the current-off period, so that the sectio'rializ'er contact 20 does not have to interrupt any substantial current and the coil 19 will remain deenergized, even if the recloser recloses and stays closed.

By my new counter mechanism, I have thus provided a counter in which the magnitude or distance of the advance-steps, by which the counter is advanced each time it counts, is not only accurately fixed, but the time delay for reset is delayed until the sectionalizer is reclosed to pick up load. This action is obtained particularly by virtue of the inner magnetizable actuator which actuates the balls 87 to engage the inner surface of the piston 78 of the armature 76, and which magnetically is retracted to release the brake each time the coil 19 is energized, thus accurately extending the normal time delay of the counter until the circuit is restored and the sectionalizer reclosed. In this manner is avoided lockout of reclosers due to slightly ditferent timing characteristics of sectionalizers which may allow a recloser which has only partly reset, to lock out before a sectionalizer which has completely reset,-opens. In short, I have provided a counter mechanism which actually delays the start of its reset until the recloser and sectionalizer are reclosed, so that it will lock out in a single operation, permitting the recloser to reclose and maintain service for the rest of the system should the fault still persist. This is particularly important in view of the trend toward longer time delay used in reclosers. This permits the sectionalizer counter to reset during such time delay, resulting in a failure of the counter to properly count such delayed operations. The foregoing and other advantages are obtained in a structure which combines great simplicity, freedom from operational difficulties, and low manufacturing costs.

While I have illustrated my invention in but a single exemplary form of embodiment, which is 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.

I claim as my invention:

1. In a circuit interrupter, separable contacts, a counter having a solenoid connected in the circuit with a member advanced by successive interruptions of the circuit to efiect separation of said contacts after a predetermined number of such interruptions, said member having dashpot means for delaying reset of said member, and a holding device within the dashpot means actuated by energization of the solenoid for retaining said member in an advanced position until normal voltage is restored to the circuit.

2. A circuit interrupter comprising, separable contacts, a counter having a member advanceable to eifect separation of said contacts and electroresponsive pump 6 means operable in response to interruption of an overcurrent to effect advance of said member, and a magnetically releasable holding device preventing reset of said member operable in response to restoration of voltage to the circuit to release said member for reset.

3. In a circuit interrupter, separable contacts, a counter having a member advanceable to effect separation of said contacts, electromagnetic pump means operable to effect advance of said member by fluid pressure including one-way valve means providing slow reset of said member, and a releasable restraining device operable in response to deenergization of said electromagnetic means to prevent reset of said member until the electromagnetic means is energized.

4. A circuit interrupter comprising, separable contacts, releasable means maintaining said contacts closed, a counter having a member advanceable to release said releasable means, said counter having a solenoid with an armature biased to one position and movable to another position upon a predetermined overcurrent through the solenoid and provided with valve means for pumping a quantity of fluid each time the solenoid is deenergized following such overcurrent to advance said member, and means including a magnetically operated releasable member for permitting reset of said member to a predetermined point of advance and retaining said member advanced in any position up to said point of advance until the solenoid is reenergized.

5. In a circuit interrupter, separable contacts, an operating mechanism for said contacts including a pivotally mounted support, releasable means for supporting said support, a lever pivotally mounted on the support and connected to effect operation of said contacts, and toggle means operable to actuate said lever to different positions for opening and closing said contacts, a counter having a movable piston advanceable to effect operation of said releasable means to release said support, said counter comprising a solenoid having an armature of magnetic material biased to pump fluid in a direction to advance said piston and actuated against said bias by predetermined energization of said solenoid, and a restraining device including a magnetically retracted holding member normally operable to prevent reset of said piston.

6. In a circuit interrupter, separable contacts, releasable latch means for maintaining said contacts together, counting means having an advanceable member advanceable a predetermined amount to release said releasable means, fluid pump means including an armature and check valve operable in response to interruption of an overcurrent to advance the piston less than said predetermined amount, and a holding device including a ball and inclined plane for preventing reset of said member.

7. A circuit breaker comprising, separable contacts, operating mechanism for one of said contacts including a pivotal support and an operating lever pivotally supported on said support and operatively connected with said one of the contacts, releasable means for normally supporting said pivotal support, manual operating means including a pair of toggle levers connected to the operating lever, counting means including an advanceable member for actuating said releasable means and a releasable device for preventing reset of said member, a fluid pump for advancing said member, and means including a solenoid for actuating said pump in response to interruption of a current above a predetermined value and releasing said device in response to a current of said predetermined value.

8. In a circuit interrupter, separable contacts, a longitudinally movable pull-rod operable to separate and close said contacts, a triangular lever pivotally connected to the rod at one apex, a support lever having a fixed point of support at one end pivotally connected intermediate its ends to another apex of the triangular lever, manual operating means including a pair of levers disposed in toggle relation connected to the other apex of the triangular lever, releasable means supporting the other end of the support lever, a counter having a piston slidable in a tube and carrying an extension for actuating the releasable means to release the support lever, fluid pump means including a solenoid and an armature of a magnetic material movable to apply fluid pressure to the piston for advancing it upon interruption of an overcurrent, and a holding device including a ball carried by the armature and a member of magnetic material biased to actuate the ball to engage said piston to prevent reset, said member of magnetic material being retracted to release said ball When the solenoid is energized.

9. In a circuit interrupter, separable contacts, an operating mechanism for said contacts, releasable means for maintaining the operating mechanism in a position to hold said contacts closed, a counter having a piston advanceable to eflect release of said releasable means, fluid pump means including a solenoid and an armature of magnetic material actuated thereby for applying fluid pressure to the piston upon the interruption of an overcurrent, a ball carried by the armature for engaging a portion of the piston to' prevent reset, an actuating memher of magnetic material for moving the ball to engage said portion of the piston, said actuating member being retracted by the solenoid upon energization thereof, and means biasing the actuating member to move the ball into engagement with said portion of the piston.

References Cited in the file of this patent UNITED STATES PATENTS 414,130 Seifert Oct. 29, 1889 913,437 Schoeller et al. Feb. 23, 1909 2,337,713 Garlington Dec. 28, 1943 2,515,530 Schindler July 18, 1950 2,570,153 Phillips Oct. 2, 1951 2,587,341 Lincks Feb. 26, 1952 2,644,114 Edwards et al. June 30, 1953 2,710,320 Weinfurt June 7, 1955 2,741,726 Branflick et al. Apr. 10, 1956 2,752,453 Wallace June 26, 1956 FOREIGN PATENTS 825,324 France Dec. 8, 192

Images