US2249813A - Circuit breaker - Google Patents

Description

July 22, 1941. L w. DYE-.R 2,249,813

CIRCUIT BREAKER Filed Nov. 7, 1936 INVENToR y Joya? M/ger.

Patented July 22, 1941 CIRCUIT BREAKER Lloyd W. Dyer, Swissvale, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Penn- Sylvania Application November 7, 1936, Serial No. 109,720

17 Claims. (Cl. 175-294) My invention relates generally to electrical apparatusand more particularly to circuit breakers for opening and closing power circuits.

The principal object of my invention is to provide an improved automatic reclosing circuit breaker structure which is.entirelyfself-contained, and operated without the use of any external source of electrical energy other than that derived 'from the circuit which it controls.

A further object of my invention is to provide an improved, self-contained vautomatic recloslng circuit breaker which is simple and efficient in operation, of rugged construction, and which may b readily and economically manufactured and installed.

A further object of my invention is to provide an improved circuit breaker embodying a novel control arrangement for opening the contact means'of the breaker in response to abnormal l circuit conditions and for automatically reclosing the contact means after an opening operation.

A further object of my invention is to` provide an improved circuit breaker embodying a novel u control means for opening the contacts of the breaker 'in response to abnormal circuit condition and for automatically reclosing the same, and in which a novel means is provided for locking the contact means iii-open circuit position when a predetermined number of successive opening and closing operations of the contact means occur within a predetermined time interval.

A further object of my invention is to provide a novel control means for a circuit breaker for opening lthe contact means of the 'breaker in response to abnormal circuit conditions and for automatically reclosing the same which does not require any external electrical energy other than that derived from the circuit controlled by the breaker. y y

The principal field for immediate application of my invention is in connection with rural power distribution systemswhere it is economically impractical to install the auxiliary control networks and apparatus for controlling circuit breakers such as are used inthe more thickly populated sections. For such rural systems, it is particularly desirable to have low cost' automatic reclosing protective circuit breaker structuresA which are self-contained and operated `without external auxiliary-electric energy and which will;4 lock open in response to a predetermined number of successive-reclosures occurring within a predetermined period of time. My im. proved circuit breaker provides a particularly desirable structure for meetingvthe requirements of such application. While my invention is particularly suitable for such yuse, it is obvious that it is equally vapplicable to variousother types of installations or uses.

The novel features that I consider characteristic of my invention are set forth in particular in the appended claims. The invention, itself, however, both as to structure land operation, together with additional objects and advantages thereof, will best be understood from the following detailed description of a specific embodiment theroef when read in connection with the accompanyi-ng drawing in which:

Figure l is a vertical sectional view of my improved circuit breaker, and

Fig. 2 is an enlarged elevational view of the mechanical lock-out device and retarding means embodied in the circuit breaker shown in Fig. 1, a part of the side wall of the device being broken away in order to illustrate certain features of the device. f

Referring to Fig. 1 of the drawing, the various parts and operating mechanisms of the circuit breaker are mounted within a metal tank 5. The opposite end walls of the tank each have formed integral therewith a flange l which extends outwardly at right angles therefrom. A

metal cover 9 is removably mounted on the top I of the tank. by any suitable form of removable aligned depending metal sleeve I3 in which is inprises a stationary contact i5, a movable contact serted a porcelain lead-in bushing i4 for the conductor wires which connect the breaker in its external circuit. Thevenclosure formed by the tank k."a 'and cover 9 is adapted to be mounted on a transmission pole or other form of power line support, andthe metal sleeves I3 prevent the entrance of rain and moisture into the interior of the enclosure. A

The contact means of the circuit breaker com;

ll, and an arc extinguishing means indicated generally at; i9. The arc extinguishing means is not an important part of my invention, and any suitable structure may be used. The contact means and arc extinguishing means are immersed in 'a body of oil 2l contained in the tank 5.

'I'he movable contact i1 is secured to a switch member 2l which consists of a rod mounted for verticakmovement'within the tank by any suit-` able form of guide means. The switch member is movable upwardly to an open circuit position to open the contact means and is biased by gravity or a spring downwardly 'to a closed circuit position to cause the movable contact to engage the stationary contact.

The upper end of the switch member has associateo. therewith a mechanical device indicated generally at 24 for controlling the downward or closing movement of the switch member 23. The device 2st comprises in general, a retarding mechanism including a gear 25 for engaging y rack teeth 21 formed on the switch member 23,

and a counting lock-out device indicated generally at 29 (Fig. 2). 'The retarding device lncluding the gear 25 permits free upward or opening movement of the switch member 23 but retards the downward or closing movement of said member. Any suitable type oi' retarding means such as an escapement or dash-pot device may be used for this purpose. The counting lock-out mechanism 2S which will be hereinafter described in connection with Fig. 2 operates to loci: the switch member 23 in the open circuit position whenever a predetermined successive number of circuit interrupting operations occurl within a predetermined period of time. The retarding means and the counting lock-out mechanism 29 are mounted in a suitable casing 3| supported within the tank 5.

The control arrangement for operating the switch member comprises, in general, an operating member 33, an operating electromagnet means 35 for moving the operating member 33 to effect movement of the switch member 23 to open circuit position, a holding electromagnetic means 31 acting in opposition to the operating means 35 for normally holding the operating member 33 against movement by the operating means, and an electro-responsive means 39 for rendering the holding means 31 ineffective to hold the operating member against movement by the operating means in response to predetermined circuit conditions.

The operating member 33 comprises a rod 38 provided with a slot 4| at the lower end thereof and an angular extension 43 at the top. The operating member 33 is mounted for vertical movement within the tank by any suitable form of guiding means between a normal position. as shown in Fig. 1, and an operative position. 'I'he operating member 33 is coupled to the movable switch member 23 by means of a link 45 pivoted at one end to a fixed pin 41 and pivotally connected to the switch member at its opposite end by a pin and slot connection 43. The link 45 carries a pin 5| which engages in the slot 4| of the operating member 33. This form of loose coupling between the operating member 33 and the switch member 23 permits the operating member to gain momentum before it begins to move the switch member so as to provide ior a rapid opening of the contact means. The

,coupling means also permits movement ofv the switch member 23 by some other independent form of conventional operating mechanism, not shown, so that the switch member 23 may be moved to open and'closed circuit position independently of the control arrangement previously described if desired. The operating electromagnet` 35 consists of a stationary core 53, an operating winding or coil 55, and a moving core 51. 'I'he moving core 51 is connected at one end by a rod 59 to the angular extension 43 of the operating member 33, and at its lower end by a rod 6| to the armature 53 of the holding electromagnetic means 31..

The holding electromagnetic means comprises a stationary core 65, a holding coil 31, a short circuiting control coil 59, and the movable armature 63. The operating coil 55 and core 51, when energized, exert a force tending to move the operating member to its upper or operative position. The holding coil 61, however, produces an opposite force on the operating member 33 by means of the armature 63, which is sulcient normally to hold the operating member in its normal position against movement by the operating means 35, so that the contacts normally remain in closed circuit position as shown in Fig. l. The circuit for the winding of the short circuiting coil 63 is normally open at the contacts 1| of the electro-responsive means 39. When the contact means 1| are closed by the electro-responsive means 33, the circuit of the short circuiting winding 69 is short-circuited and acts to counteract the holding force of the hold ing coil 61, so that the holding coil is no longe: able to restrain the operating member 33 against movement to its operative position by the operating means 35. Under such conditions the operating member is moved to its operating position by the force exerted by the coil 55 and the core 51 to move the movable switch member 23 to its open circuited position.

The electro-responsive means 33 comprises a stationary core 13, a pivoted armature 15, the contact means 1| and a. control coil 16. The armature 15 is biased away from the pole face of stationary core 13 by any suitable means such as a spring 11. The operating characteristics of the electro-responsive means are such that under normal current conditions of' the circuit controlled by the breaker the magneto-motive force developed is insuiilcient to attract the armature 15 to close the contacts 1|. However, under abnormal current conditions such as overload or short-circuit the magneto-motive force developed is increased sufficiently to attract the armature 15 and close the contact means 1| to short circuit the control coil 69.

The trip characteristic of the electro-responsive control means 39 may be adjusted in any well known manner as, for example, by changing the normal tension of the biasing spring 11 which biases the armature 15 away from the core 13, or by changing the normal air gap between the armature 15 and core 13. 'Ihus the control means 39 may be adjusted to respond to different values of 'overload current.

'I'he circuit for the breaker extends from a line conductor 13 through the control coil 15 of the electro-responsive means 33, a conductor 3|, the operating coil 55 of the electro-magnetic 0perating means 35, a conductor 33 through the holding coll 51, through a flexible shunt conductor to the movable switch member 23, movable contact I1 and stationary contact I5, to a load conductor 31.

The operation of the apparatus as thus far described is as follows: 'I'he contact means comprising the contacts l5 and |1 is normally closed and the coils 16, 55 and 51 thus normally energized since they are in series circuit with the contact means. The force exerted by the operating means 35 exerts a force on the movable operating member 33 tending to move the same to its operative position to cause separation of the contacts I5 and 1. The holding coil 61, however, exertsan opposite force on the operating member 33 such as to normally hold the operating member in its normal position against movement by the operating means 35 so that the contacts remain in their closed circuit position. It an overload of sufiicient magnitude occurs in the circuit controlled by the breaker, the contacts 1| oi the electro-responsive means 39 are closed to short circuit the winding of the control coil 69. 'Ihe short circuiting of this winding counteracts the holding force exerted by the holding coil 61 so that the operating member 33 is no longer restrained by the holding coil. The electromagnetic operating means 35 then functions to move the operating member 33 to its operative position. This movement of the operating member 33 is transmitted by the link 45 to the movable switch member 23 and moves the latter to open circuit position to interrupt the circuit. The interruption of the circuit controlled by the breaker deenergizes the windings 55, 61, and 16, so that the movable switch member is permitted to return to closed circuit position by gravity or spring bias. The downward or closing movement of the movable switch member is retarded by the retarding means 25, so that the circuit remains open for a predetermined period oi?A time. When the movable switch contact reaches its closed circuit condition, the coils 55 and -61 and 16 are again energized by the circuit controlled by the breaker and if Ithe overload condition still exists, the opening operation is repeated as described above. If, during the open condition of the circuit breaker, the overload condition has ceased, the, breaker remains in closed circuit position after the contacts have closed, by reason of the fact that the holding coil 61 normally prevents movement of the operating member 33.

As has beenpointed out previously, if the overload condition persists, the contact means of the circuit breaker would ordinarily be opened and automatically reclosed as long as the ,condition exists. It is desirable, therefore, that some means be provided to limit the number of reclosures of the circuit breaker under a continuous overload condition. The means for thus limiting the number of reclosures of the circuit breaker is the counting lock-out device 29. 'Ihe counting lock-out device 29 includesv a disk 89 pivotally mounted onV a pin or shaft 9|. The disk 89 is biased in a counter-clockwise direction by means of a return spring 93 connected at one end to a pin 95 .carried by thevdisk 89 and its other end to a pin 91 secured to a wall of the casing 3|. The disk 89 also carries a plurality of pins 99, and |03, as shown in Fig. 2. The upper end of the movable switch member 23 has a recess |05 formed therein in which is pivotally mounted a latch |01. The latch is biased outwardly by a resilient steel spring |09 secured to the switch member 23 by means of a screw ||l. The upper face of the latch normally engages the pin 99 as shown in Fig. 2. A pair of locking pins ||3and ||5 extend outwardly from one face of the disk and are so positioned that when the ating hamue m, to snow the switch member The counter-clockwise rotation of the disk 89 is retarded by means of a dash pot device pivotally connected to a stationary pin |21 carried by the casing Pl and to the disk 89 by means of .a pin |29.

'llhe operation of the counting lock-out device is as follows: When the switch member 23 moves to the open circuit position, the latch |01 moves the pin 99 to the position 99'- thus partially rotating the disk 89.- After the circuit has been interrupted the switch Vmember 23 returns slowly to closed circuit position being retarded by the retarding means 25. lThe disk 89, however, is retarded to a greater extent by the dash pot |25 than the switch member is by the retarding means 25 so that the pin 99 remains in the position 99 for a predetermined period of time after the contacts close. If the overload condition which causes separation of the contacts is of a transitory nature so that it ceases to exist by the time the contact means I5 and have closed the switch member remains in closed circuit position and the disk 89 rotates very slowlyin the counterclockwise direction under the infiuence of the return spring 93, back to its normal disk 89 is rotated a predetermined distance in' the clockwise direction, the pin ||3 moves to the position ||3 where it is engaged and held-by latch ||1, and the pin 5 moves to a position beneath the lower face |3| of the latch |01, to

lock the switch member in open circuit position when al predetermined number of vsuccessive opening and closing operations have occurred in a predetermined period of time.

The latch ||1 is biased to latching position by a spring ||9. The latch ||1 may be moved about its pivot pin |2| to releasing position to release the pin ||3 by means of a manual operposition shown in Fig. 2, so that the pin 99 is returned from the position 99' to the position shown in the full lines in Fig. 2. The disk 83 is thus partially rotated each .time the circuit breaker switch member 23 moves to the open circuit position and if the opening operations are discontinuous or occur at infrequent intervals the disk 89 is returned each time to normal position. However, if a continuous overload occurs the switch member 23 in its iirst opening operation moves the pin 99 to the position 99 and then returns to closed circuit position. Immediately that it reaches the closed circuit position, it is again moved to the open circuit position by the control apparatus, since the overload condition still exists. The -switch member is moved to the open circuit position the second time before the disk 89 has returned to normal position, and in its second opening movement, the latch |01 of the switch member 23 engages the second pin |0| and imparts a further rotation to the' disk 89. The switch member again returnso to closed circuit position, and when it moves to the open circuit position for the third time. it engages the pin |03 to impart a further rotational movement to the disk 89. At this time the pin ||3 has been rotated a sufiicient distance to be engaged by the latch I i1y so that thedisk is locked against return movement to its normal position. When the'pin |3 is in the position I3 in which it is latched by the latch ||1, the pin ||5 is in a position in which it engages thexundersurface |3| of the latch |01, so that the switch operating member 23 is locked in the open circuit position. The switch member 23 cannot be moved to closed circuit position until the operating handle |23 has been moved to release the latch ||1 from its engagement with the pin ||3.

It will thus be seen that as long as the opening and closing operations of the switch member 23 occur at infrequent intervals, the disk 89`has no effect thereon and merely ret-urns after each operation toits normal position, but if the switch member moves to open circuit position three successive times within a predetermined period of time ixedby the adjustment of the dash pot |25,

, gleed means acting: o

it will be locked in the third and final open circuit position by means of the pin l l5.

if a fast reclosure is desired the retarding means may 'oe omitted so that the switch member can move freely to closed circuit position under the influence of gravity or spring bias.

While I have shown one speclilc embodiment of my invention, it is obvious that various changes may be made in the structure without departing from the spirit of the invention.

It will be seen that E have provided .an irnproved automatic reclosing protective circuit breaker structure which is entirely self-co1' ined and is operated ifthcut the use oi any external auxiliary source electrical energy. The circuit breaker operates to adequately protect the circuit in nich it is connected by opening the circuit in aesponse to an overioad condition and eut-ol"natically reclcsing the saine after a .mined time, and ir" the overload of a more or less permanent nature, the circuit breaker, after o. predetermined number of operations, is iocked in the open circuit position and cannot be reclosed except by removing the cover and moving the handle 123 to release the latch means ill.

While, in accordance with the patent statutes, have given the foregoing details of a practical embodiment of my invention, it is to be understood that many of these are merely illustra- *hat variations in their precise form irable some applications. desirv ore, the language ci the accompanys Ese accorded the broadest reasonable seri es t -s i 3er, said condin s being ole as afore- Hee ci restreint resulting from the force saisi Erst means. 2. An automati prising, a of c tion, an operating r r'cuit breaker cor.

ed toclcsed ,oc-si- .'novable to open said contacts, e. iirst elec `l27 energized acting on said operetin member to move the same to open contacts, a second electrically enersaid miser in opposition to said means lr normally preventing movenient ci said emisor, and control means for rendering saisi second electrically energized means ineicctive to preventrmovement of' said operating member by said :rst means, said first and Ineens being connected n circuit with said contact means.

3. .fin automatic reclosing circuit breaker compris ug, contact ineens movable to an open and to o. closed position and biased to the closed position, the combination of an operating member coupled said contact means movable from a norme! position to a second position. to move said contact means to the open circuit msitlon, e, ilrst electrically energized .ineens connected in ci or* with seid contact means acting to move said member to said second position, a second electrically energized means connected ln circuit with said contact means acting on said member in opposition to said first means to normally hold said member in said normal position and means responsive to predetermined conditions for rendering said second means inen'ective to prevent movement of said member by said rst means.

4. An automatic reclosing circuit breaker comprising in combination, contact means having an open and a closed circuit position, said contact means being biased to the closed circuit position, an operating member coupled to said contact means movable from a normal position to a second position to open said contact means, electrically energized means comprising an. operating coil acting to move said member to said second `position and a holding coil acting on said member in oppition to said operating coil for nor- :nelly holding said member in said normal position, both said coils being connected in circuit with said contact means, means connected in circuit with said contact means responsive to predetermined conditions i'or rendering said holding coil ineilective to hold said member from moving to said second position vto open said contact means, the separation of` said contact means etfecting deenergization ct said coils and condition responsive means to permit said contact means to reclose.

5. An automatic reclosirig circuit breaker comprising in combination, contact means having an open and o. closed circuit position, said contact means being biased to the closed circuit position, an oper ig member coupled to said contact means movable from a normal 'position to a second position to open said' contact means, electromagnetic nieans corpiising an operating coll acting to move so :neznter te said second position and e. holding coil acting on said member ln opposition to said operating coil for normally holding said ment-be' in said normal position, both said coils connected in circuit with said Contact means, connected in circuit with said oc` tact responsive to predetermined condition-c for rendering said holding coil ineffective to heid sald'member from moving to said second position to open said contact means, the separation of said contact means eectlng deenergizsticn of said coils and said condition responsive means to permit said contact means to reclose.

6. In an oil circuit breaker having a casing for enclosing oil immersed relatively movable contact means biased to the closed circuit position, the combination of control apparatus mounted in said casing for opening and recloslng said contact means comprising means including an operating coil for moving said contact means' to the open circuit position, a holding coll acting' in opposition to said operating coll to prevent movement of said contact means to the open circuit position by said operating coil, said coils being connected in circuit with saidcontact means, and means operable in response to predetermined conditions in the circuit for rendering said holding coll ineective to prevent opening of said contact means by said operating coll.

7. An automatic recloslng circuit breaker comprising a stationary contact, s movable contact biased -to closed circuit position to engage said stationary contact and movable to an open circuit position, means retardlng the movement of said movable contact to closed circuit position, an

' bel".

in circuit with said contact means acting to prevent movement of said member by said operating coil, and means responsive to predetermined conditions in the circuit for rendering said second coil ineffective to prevent movement of said mem- 8. A self-contained automatic oil circuit breaker comprising a stationary contact, a movable contact biased to closed circuit position to engage said stationary contact and movable to an open circuit position, means retarding the movement of said movable contact to closed circuit position, an operating member coupled to said movable contact movable from'a normal position to a second position to move said movprising relatively movable contact means biased to closed circuit position and movable to open circuit position, the combination of an operating member coupled to said contact means movable from a normal position to a second position to move `said contact means to the opencircuit position, said member in its normal position permitting relative movement of said contact means, electro-magnetic means including an operating coil for exerting a force on said member'to move the same to said second positionI and a holding coil for exerting a -force on said member in opposition to permit said contact means te: return to the closed circuit position.

l1. In a circuit breaker having relatively movable contact means biased to vclosed circuit position and movable to .open circuit position, the combination of an operating member coupled to said contact means movable from a normal position to an operative position to move said contact means to the open circuit position, electromagnetic means including a rst coil for exerting a force on said member to move the saine to its operative position and a second coil for exerting an opposite force on said member to normally prevent movement of said member by said iirst coil, said coils being connected incircuit with said contact means, means operable in response to predetermined conditions in the circuit for rendering said second coil ineffective to prevent movement of said member by said first coil, said coils and means being deenergized when said 4contact means has moved to the .open circuit position to permit said contact means to return to the closed circuit position, and means for retarding the movement of saidcontact means to the closed circuit position. v

12. In a circuit breaker having relatively movable contact means biased to closed circuit position and 'movable to open circuit position, the combination of an operating member coupled to said contactmeans movable 'from a normal position to an operative position .to move said contact means to the open circuit position, electrically energized means including a iirst coil for exerting a `force on said member to move the same to its operative position and a second coil y for exerting an opposite force von said member to normally prevent movement of said member t by said ilrst coil, said coils being connected in position to the force exerted by said operating coil i'or normally holding said member in said normal position, said coils being connected in circuit with said contact means, means responsive to predetermined conditionsin the circuit controlled by said contact means for so reducing the force exerted -by said holding coil that-said member is moved to said second position by said operating coil to open said contact means.

10. In a circuit breaker having relatively movable contact means biased to closed circuit posi tion and movable to open circuit position,V the combination of an operating member coupled to said contact means movable from a normal position toan operative position to move said con- -tact means to the open circuit position, means including a iirst coil for normally exerting a force on said member to move the same to its operative position and a second coil for normally preventing movement of said member by said iirst coil, said coils being connected in circuit with said contact means, means operable in response to predetermined conditions in the circuit to render said second coil ineffective to prevent movement of said member by said iirst coil, said coils and means being deenergized when said contact means has moved to .the open circuit circuit with said contact means, an electro-responsive means connected in circuit with said contact means operable in response to a predetermined condition to render said second coil ineffective to prevent movement of said member by said first coil, said coils and electro-responsive means being deenergized when said contact means lhas moved to the open circuit position to permit saidcontact means to return to the closed circuit postion, means for retarding movement oi' said contact means to the closed circuit position.

13. In a circuit interrupting device having re1- atively movable contact means biased'to closed circuit position and movable to open circuit position, the combination of an operating member coupled to said contact means having a normal position permitting relative movement of said contact means and movable to an operative position to move said contact means to the open circuit position, electro-magnetic means including an operating coil for exerting a force on said member to move it to said operative pcsition and a second coil for exerting an opposite force on said member for normally holding said member against. movement from its normal position by said yoperating coil, said coils being connected in circuit with said contact means. means operable in response to predetermined conditionsin the circuit for rendering said second coil ineiective to prevent movement of said member by said operating coil, said coils and means being deenergized when said contact means opens the circuit to permitsaid contact means to return to closed circuit position.

14. In a circuit interrupting device having relatively movable contact means biased to closed response to predetermined conditions in the circuit for rendering said second means inefclosed circuit position, and means for retardmovenient of said contact means to closed uit position.

15. in an automatic recloslng circuit breaker relatively movable contact means movable to an open and to a closed circuit position, means biasing the contact means to closed circuit position. the combination of an operating member couplet 'to said contact means movable from a position to an operative position to move contact means to open circuit position, elect' magnetic means including an operating coil for exerting s. `force on said member to move it to said second position, a. second coil for erting opposite force on said member to ncimally prevent movement thereof by said opera g coil. coils being connected in circuit with said conta-ct means, and a third coil hav mined conditions for closing the control circuit of said third coil to reduce the force exerted by said second coil a sumcient amount to allow said operating coil to move said member to its operative position.

16. In a self-contained automatic reclosing circuit breaker, a stationary contact, a. cooperating movable contact biased to closed circuit position, an operating member coupled to said movable contact movable from a normal position 'to a second position to move said movable contact to open circuit position, electrically energized means including an operating coil connected in circuit with said contacts acting to move said operating member to its second position. a holding coil connected in circuit with said contacts for normally preventing movement of the operating member by said operating coil, means operable in response to predetermined conditions in 'the circuit for rendering said holding coil ineffective to prevent movement of said operating member by said operating coil, and means retarding closing movement oi said movable contact, and a casing for enclosing all of the abovementioned means and elements.

i7. In a self-contained automatic reclosing circuit breaker, a pair of relatively movable contacts biased to closed circuit position, operating means for said contacts including a first electromagnet connected in circuit with said contacts acting to open said contacts, a second electromagnet connected in circuit with said contacts :for normally preventing opening o! said contacts by said irst electromagnet, means operable in response to predetermined conditions in the circuit for rendering said second electromagnet ineffective to prevent opening of said contacts by said iirst electromagnet, and means retarding closing of sai-d contacts.

LLOYD W.

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