US2417728A

US2417728A - Circuit breaker

Info

Publication number: US2417728A
Application number: US463623A
Authority: US
Inventors: Albert H Baylis
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1942-10-28
Filing date: 1942-10-28
Publication date: 1947-03-18
Anticipated expiration: 1964-03-18

Description

Vla:

March 18, 1947.

A. H. BAYLIS CIRCUIT BREAKER yFiled Oct. 28, 1942 Patented Mar. 18, 1947 UNITED STATES PATENT OFFICE Albert H. Baylis, North Irwin, Pa., assignor' to Westinghouse'Electric Corporation, East Pittsburgli, Pa., a' corporation of Pennsylvania Application october 2s, 1942, serial No.' 463,623

rThis invention relates to circuit breakers and, more particularly, to circuit breakers of the type that trip automatically in response to overload currents.

An object or the invention is the provision of a circuit breaker having an improved trip device which will not operate to falsely trip the breaker in response to shocks or jarring forces.

Another object of the invention is the provision of a circuit breaker with. an improved electromagnetic trip device in which means is provided to prevent tripping operation of the magnet armature in response to shocks or jarring forces.

Another object the invention is the provision of a circuit breaker with an improved electrou magnetic trip device in which a secondary arma ture cooperates lwith the main armature to prevent tripping; of the breaker in response to shocks or jarring forces.

Another object of the invention is the provision oi a circuit breaker having an improved trip de vice wherein a secondary movable armature is provided to absorb the kinetic energy of the tripping armature to thereby prevent tripping of the breaker as a result o1 shocks orjarring forces.

Another object of the invention is the provision of a circuit breaker with animproved shockproof trip device which is simple, accurateY and reliable in operationv and inexpensive to manufacture.

The novel features that are considered characteristic oi the invention are set forth in particular in the appended claims. The invention itself, howevenboth as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description oi a preferred embodiment thereof when read in conjunction with the accompanying drawing, in which:

Figure 1 is a vertical sectional View through the center pole of a multipole circuit breaker embodying a trip device constructed in accordance with the invention; and

Fig. 2 is an enlarged vertical sectionall view through the trip device showing the tripping armature and the shock-absorbing armature".

Referring to Fig. 1 of the drawing, the circuit break r is provided with an operating mechanism common to all of the poles of the breaker. The' operating mechanism is mounted in a U-shaped frame Il having sides which are rigidly connected by a cross member it. The frame I1 is mounted on the central portion of a base II of insulating material and issecured thereto by means'of bolts 13 Claims. (C1. ZOO-109) 2 2| and Z3. The outer ends of the frame are rigidly connected by a cross member 25.

The bolt 2'3 extends throughthe base and the cross member I9 `and serves to rigidly secure a connector 21 of conducting material to the cross member is and to the frame. A- shatt 2i! extendingthrough an opening. in the connector 21' and througnopenings in the sides .off the frame I1 pivotally supportsa pair of'contact' arms 3l having their free ends integralVV with a Contact arm S for the center pole. The contact armsr (not shown) for the outer polesof the breaker are identical with the` Contact arm 3ii` for the center pole, but are not provided'. with arms 3l. The contact arms are rigidly securedto a tie bar lil which has an insulating cover 69 and' extends across all of' the poles and is securely clamped to the center pole contact arm'i by meansl of a split clamp 'ill and a screw 1I.

The movable contact struct'uresand the stationary structures for the severalpoles. are alike; hence only the contacts fortbe. center pole are illustrated. The contact arm 3H pivotally' carries a main movable contact memberl andLamovable arcing Contact member55" which cooperate respectively vvith a main stationary Contact 39 and a stationary arcing contact 3l. The stationary contacts 39 and'tl/ are securedV to ar conductor 4l which extendsv through an opening' inr the base I I and forms a terminal connector 45. Contact pressure for the main contacts is providedl by a springV 53 and a spring 63 provides contactplressure-for the arcing contacts.

-When the contact arm 3e' is moved to open the contacts, the are drawn across the arcing contacts 55-31 by rupture of the current is drawn into an arc extinguisher indicated generally at 'i6 where it is cooled and extinguished.

The movable arcing contact member 55k is cone nected by a flexible shunt conductor I1 to the main movable contact member 41, and' another flexible shunt conductor 19 connects thecontact member 41 to` the connector y21. A conductor 8l, secured4 to the connector 21 bymeans of bolts 14"; extends downwardly therefrom rearwardly through the base to form the other terminal connectorv 83 which, together with the terminal connectionS-, servesto connect the/breaker in an electrical circuit.

Thecontact arms 30 are biased in aA clockwise` or opening` direction'y by means of a. pair of springs 85 (only Aone being shown). These springs are tensioned between the center pole contact arm 3l)V and a` xed. pivot 81 supported inthe main frame IT. In the closed position of the breaker, the center pole contact arm and consequently all of the contact arms are releasably restrained in the closed contact position by means of a toggle and linkage mechanism which is collapsible to cause opening of the contacts.

This collapsible linkage includes a yoke shaped lever 89 pivotally mounted on a fixed pivot 9| supported on the main frame |1. The lever 89 is operatively connected to the support arms 3| of the center pole contact arm 30 by a main operating toggle comprising toggle link 93 and 95. The toggle link 93 has one end pivoted on a pin supported on the lever 89, and the link 95 is pivoted on a pivot pin 99 in the arms 3|. The links 93 and 95 are pivotally connected by a knee pivot pin 91. The toggle link 95 comprises a pair of links rigidly connected by means of an integral cross bar H5.

The above-described linkage serves to releasably hold the movable contacts for all of the poles of the breaker in closed contact position.

In the closed position, the main operating toggle 93-95 is over center above a line through the centers of the pins 99 and |0|, and a second toggle, one link of which comprises the overcenter links 93-95 and the other link of which comprises the lever 89, is over center above a line through the centers of the pins 99 and 9|. The overcenter movement of the main operating toggle 93-95 is limited by the projecting end of the link 93 engaging the cross bar` H5 of the link 95.

With the main operating toggle 93-95 and the toggle comprising the links 93-95 and the lever 89 in the overcenter position, the springs 85 bias the lever 89 in a clockwise direction. Clockwise movement of the lever 89, however, is normally prevented by the tripping toggle |01- |09 which is over center to the left of a line through the center of the fixed pivot H3 and the point of connection of the link |01 with the lever |05. A spring |28 tensioned between the yoke H9 and the lixed pivot H3 biases the tripping toggle to its overcenter position. The overcenter position of the tripping toggle |01-I 09 is adjustably determined by the projection |25 of the yoke |23 engaging an adjusting screw |29.

The tripping toggle |01-|99 is adapted to be moved over center outwardly in a direction to cause its collapse to eiect opening of the contacts by means of an overload trip device indicated generally at |33, or by a shunt trip device indicated generally at |38. The overload trip device |33 is operable in response to overload currents in the circuit of the breaker to actuate a trip rod |35 and cause collapse of the tripping toggle H11-|09. The shunt trip device is adapted to be energized from any suitable source separate from the circuit of the breaker to actuate a tubular trip member` |40 surrounding the trip rod |35 and cause the collapse of the tripping toggle |01-|09 independently of the operation of the trip rod |35.

When operated by their respective trip devices |33 or |38, the trip rod |35 or the trip member |40 strikes the projection |21 of the yoke |23 and rocks the toggle link |09 clockwise about the fixed pivot H3. This movement of the link |09 causes collapseof the tripping toggle |01-I 09 permitting clockwise movement of the lever 89 which permits the springs B5 to actuate the movable contact structure clockwise to open the contacts.

The main operating toggle 93--95 does not immediately collapse, but the force of the springs 95 applied through the contact arms 30-3| and the main operating toggle causes collapse of the toggle comprising the links 93-95 and the lever 89 which results in a clockwise movement of the lever 89. This movement is transmitted through the link |03 and the lever |05 to complete the collapse of the tripping toggle |01-|09.

The clockwise or opening movement of the contact arms 30-3| is arrested by projections (not shown) thereon striking the frame |1. At this time, the reboiuid of the inertia of the main operating toggle 93-95 and the parts of the linkage 89, |03 and |05 starts the main operating toggle 93-95 over center in a direction to cause its collapse. By the time the knee pin 95 of the toggle has passed over center below the line 99|0 the weight of the parts acts to complete the collapse of the toggle 93-95 and causes the linkage 89, |03, |05 and the tripping toggle to be automatically reset to their normal holding positions. The main toggle 93-95 remains in collapsed condition until the contacts are closed.

The contacts are closed manually by clockwise rotation of the handle |4 This movement of the handle, through connections not shown, thrusts a link |5| downwardly, and, due to the engagement of the link with a projection |53 on a yoke shaped closing lever |45, rotates the closing lever in a clockwise direction. The closing lever |45 comprises a pair of spaced levers disposed on the outside of the frame |1 and are pivotally supported on the fixed pivot 9|. Clockwise movement of the closing lever |45 engages a roller |55 pivotally carried on the inner end of the lever with the toggle link 93 now in its collapsed position and moves the toggle 93-95 to its overcenter position. Since at this time the tripping toggle |01-|09 has been restored to its overcenter holding position, rotation of the lever 89 is prevented, and consequently the force applied by the roller |55 to straighten the operating toggle 93-95 rotates the contact arms 30 counterclockwise to close the contacts and tension the springs 85.

The circuit breaker may be tripped manually by rotation of the handle IM through a small angle in a counterclockwise direction from its neutral position. Rotation of the handle |45 in tripping direction engages a projection (not shown) on the link i5| with the extension |2| on the yoke I9 of the tripping toggle link Iii? and rocks the link counterclockwise about its point of connection with the lever |05. This moves the tripping toggle itil-439 over center in tripping direction and eiiects opening of the contacts in the previously described manner.

As previously set forth, the trip rod 35 is operated to eiiect collapse of the tripping toggle ||l`|| 139 by means of the current-responsive trip device |33. There is a trip device |33 provided for each pole of the breaker, but since the trip devices are alike only the one associated with the center pole will be described.

The trip device |33 includes a U-shaped magnet core |6| and a U-shaped frame comprising side plates |53 rigidly connected by an integral cross member |65. The frame |53 is provided with inwardly formed feet i5?, and bolts It!) passing through openings in the feet ES? and the core member itl rigidly secure these parts to the base li. An armature 'ig which cooperates with the core member |6| is mounted in one end of a trip lever |73 pivotally mounted on a pivot pin H5 supported in the frame U53. The trip lever H3 co-mprises a pair of levers rigidly connected at their right-hand ends by an integral yoke |11, The yoke |"1 carries a screw |8| which, upon operation of the trip lever |13, moves the trip rod |35 upwardly to effect tripping of the breaker in the manner previously set forth. The magnet core 6| is energized to attract the armature |19 and operate the trip lever V13 by overload currents flowing in the circuit of the breaker including the conductor 8f which, as illustrated,r passes between the legs of the U-shaped core |6|. Normal rated current traversing the conductor 8| does not energize the core member |6| enough to overcome the tension of a pair of biasing springs iai (only one being sho-wn) having one end attached to the yoke and the other end attached to a movable adjusting member |93 threadedly engaged by an adjusting screw, the knurled head |97 of which bears against the bottom of the cross member |55. Rotation of the screw moves the member |93 to adjust the tension of the springs, thereby varying the minimum overload tripping point of the breaker. The springs |9| normally bias the yoke |11 of the trip lever |73 against a stop screw Zffl which determines the open air gap of the magnet.

A trip bar 37 is rotatably mounted in arms |85 of a bracket it? secured to a iol-shaped frame |57 of the shunt trip device 33. The frame i5 which is of magnetic material secured by means of screws to iange portions |955 inte'- gral with the main frame il. The frame |57 is also secured to and spaced from a front plate |526 by means of a bar 2M and screws M53, the front plate being secured to an insulating bracket M3 suitably secured to the main il. 4rip bar 81 extends across all of the poles ci the breaker and isv provided withv avplurality of arms secured thereto by means of Screws 2M; there being an arm |85 for each pole, only the one associated with the center pole being shown. The free end of the arm |85 for the center pole is bifurcated and straddles the lower end of the trip rod |35 between nanges 265 secured to the trip rod, one above and one bef-.ow the arm |85. It can thus be seen that operation of the trip bar |87 by the trip device |33 for any pole of the breaker also operates the center pole arm 85 which thrusts the trip rod upwardly to trip the breaker. A spring 2529, having one end anchored to a spring stud 2i| in the frame |51 and the other end anchored to a spring stud 2|3 secured by means of a nut 2|5 to the upwardly extending portion of the arm |85 for the center pole, biases the trip bar iti and the arms |85 to the position shown against rotation in either direction.

The arms |86 of the bracket it'- are rigidly connected by an integral cross member 90 which is secured by means of screws 2|? to the bottom leg of the Uesiiaped frame The screws 2|? also serve to secure a member Zig of magnetic material to the center portion of the bracket ld and to the frame i5?. Supported in an opening in the member is a tube 2st' of nonmas netic material which has its upper end seated in a ccunterbore in the bottom of the upper leg of the frame A movable core of mag netic material disposed in the tube 22| is secured to the lower end of the tubular trip member Mtl which passes axially through an opening in the movable core. Disposed in the tub-e il above the movable core is a secondary movable core 225 aiso ci magnetic material. The secondary core is spaced apart from the movable core 227-2 by means of a spring 212i surrounding the tube liti?, and is movable axially relative to the core 223 and the tubular trip member iii-EB. The spring 2E? rests on top or' the core and seated in a con .terbore in the bottom of the secondary core 2..-. An energizing coil 229 is wound on an insulating spool 23| surrounding the tube Zi and is supported in the frame rEhe coil 22S is energized from any suitable source (not shown) either autonieicaliy or manually by the closure ci a switch in the energizing circuit (also not shown). When the coil 22d is energized, the movable core 223 is attracted upn wai-diy and thrusts the tubular trip member iti` upwardly to engage the projection |127 (Fig. i). This rocks the toggle link i of the tripping togn gie till-it in a direction to cause collapse of the tripping toggle, thereby effecting an opening operation ci the breaker as previously described. Upon deenergization of the coil 9i-i9, the movable core 223, the tubular trip niemeer its and the secondary core are .restored to their `anati tracte-d positions by the force of gravity.

The purpose of the separate secondary core 22d is to absorb the kinetic energy of the movable core 223 imparted thereto as the result of sl cke or jars, and thus prevent undesirable tripping of the breaker in response to shocks. The only force due to shock that would cause tripping movement or the movable core and the tube its? is in a vertical direction and cornes from the supporting structure .iL-|51?. vertical shock to the supporting structure will be transmitted to the bottoni or" the movable core 223 which results in accelerating the movable core upwardly in tripping direction. rihe spring 22'! is relatively weak and serves only to provide a desirable air gap between the two

core members

223 and 225. When the movable core 223 is moved upwardly in response to shock, the secondary core 225 will remain practically stationary until the movable core collides with it. When this occurs, the secondary core 225 is accelerated upwardly thereby absorbing substantially all of the kinetic energy of the movable core 223. At the same time, the spring 227, which was compressed as the movable core 223 came into contact with the secondary core 225, will expand and transmit its stored energy to the secondary core. The result is that after the collision of the core members, the secondary core 225, having a higher rate of acceleration than the movable core 223, will rebound from the upper leg of the frame and strike the movable core 223, thus providing an additional retarding action which is eective to prevent tripping the breaker as a result of shocks.

From the foregoing description, it will be seen that there has been provided an improved electromagnetic trip device which, when energized, will trip the breaker, but which is effective to prevent false tripping the breaker in response to shocks or jars.

Having described the preferred embodiment of the invention in accordance with the patent statutes, it is to be understood that various changes and mcdincations may be made in the particular embodiment disclosed without departing from some of the essential features of the invention. It is, therefore, desired that the language of the appended claims be given as reasonably broad interpretation as the prior art permits.

I claim as my invention:

1. In a circuit breaker comprising relativel movable contacts and operating mechanism therefor, a trip device including means operable to eTect opening cf said contacts, an electromagnet having a movable core operable upon energization of said electromagnet to operate said means, and means comprising a floating mass disposed in the path of tripping movement of said core and engageable by said movable core to absorb the kinetic energy transmitted to said movable core by sudden jarring forces to thereby oppose tripping of the breaker by said movable core in response to but only during the existence of sudden jarring forces.

2. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, a trip device including means operable to eiect an opening operation of said operating mechanism, an electromagnet having a movable armature operable upon energization of said electromagnet to operate said means, and a member disposed in the path of travel of said armature and engageable by the armature only when said armature is moved as a result of shocks or jarring forces to oppose tripping operation of the armature.

3. In a circuit breaker, the combination with relatively movable contacts and operating mechanism for said contacts, of a trip device including a member operable to eiect an operation of said operating mechanism to open said contacts, an electromagnet includinga movable armature operable upon energization of said electromagnet to operate said member, and a member movable independently of said armature and engageable by the movable armature when said armature is moved in response to but only during the existence of sudden jarring forces to oppose tripping operation of said arma-ture.

4. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, a trip device including a trip member operable to effect operation of said operating mechanism to open said contacts an electromagnet having an armature movable upon energization of said electromagnet to operate said trip member, a secondary armature movable with said armature but without opposing movement of said armature upon energization of said electromagnet, and resilient means providing a magnetic air gap between said armature and said secondary armature, said secondary armature acting in response to and only during the existence of sudden jarring forces to prevent said armature from operating said trip member.

5. A trip device for a circuit breaker comprising a tripping means movable from a normal position to a tripping position to trip the breaker, an electromagnet having an armature movable upon energization of said electromagnet to move said tripping means to tripping position, and a member disposed in the path of tripping movement of said armature and being movable independently of said armature by energization of said electromagnet to permit instantaneous tripping movement of said armature, said member being engageable by the armature when said armature is moved in tripping direction in response to sudden jarring forces to prevent said armature from moving the tripping means to tripping position.

6. A trip device for a circuit breaker comprising a trip means movable to trip the breaker, an electromagnet including an armature operable by said electromagnet to actuate the trip means, and a member engageable by said armature when said armature is moved in response to sudden jarring forces to oppose actuation of said trip means by said forces, said magnet when energiaed acting to move said member independently of said armature to permit the armature to instantaneously actuate the trip means.

7. In a circuit breaker having contact means and releasable actuating means therefor, a trip device comprising an element operable to release said actuating means and cause opening of said contacts, electroresponsive means for operating said element, and means disposed to absorb the kinetic energy of said electroresponsive means to oppose operation of said element by said electroresponsive means when said electroresponsive means is moved in response to jarring forces, said means being rendered ineiective to oppose operation of the element upon energization of the electroresponsive means.

8. In a circuit breaker having contact means and actuating means therefor, a. trip device comprising a tripping element operable to cause opening by said Contacts, an electromagnet having an armature movable upon energization of said electromagnet to instantaneously operate said tripping element, and a member of magnetic material normally disposed to oppose tripping movement of said armature in response to jarring forces, said magnetic member being moved independently of said armature to an ineifective position upon energization of said electromagnet.

9. In a shockproof circuit interrupting device, means for preventing operative movement of a reciprocably movable member of the circuit interrupter comprising a movable mass normally disposed to apply a force opposing operative movement of said reciprocably movable member, and electroresponsive means for moving said member, said movable mass being moved to an inef- Iective position by energization of said electroresponsive means to permit unopposed operation of said movable member.

10. In a sliockproof circuit making and breaking device, a movable member operable to effect operation of said device, electroresponsive means operable when energized to move said member, and means comprising a movable mass engageable by said movable member when said meme ber is moved in response to jarring forces to apply a force opposing operative movement of said movable member, said electroresponsive means when energized moving said movable mass away from said member to permit unopposed operation of said movable member.

11. An electromagnet having a movable mag netic element, means for opposing operative move ment of said magnetic element in response to jarring forces comprising a movable magnetic mass disposed to be set in motion by said magnetic element in response to jarring forces, said magnetic mass being operable when set in mo tion to apply one or more impacts opposing movement of said movable magnetic element, and said magnetic mass being operable by said electromagnet to permit operative movement of said magnetic element.

12. An electromagnet having a movable magnetic element disposed to be operated upon energization of said. electromagnet, means for opposing movement of said movable element in response to jarring forces comprising a magnetic mass disposed to be set in motion in response to jarring forces, said magnetic mass when set in motion reflecting by impact with a fixed member to impart one or more impacts to the magnetic element opposing operation thereof, and said electromagnet when energized moving said magnetic mass to an ineffective position.

13. An electromagnet having a movable armature, means for opposing operative movement of said armature in response to jarring forces comprising a member disposed to be set in motion in response te jarring forces, said member being operable when set in motion to apply one o-r more impacts opposing movement of said armature to attracted position, said electromagnet when energized moving said member and said armature 'to attracted position.

ALBERT H. BAYLIS.

REFERENCES CITED The foilov/ing references are of record in the iile of this patent:

UNITED STATES PATENTS