US2224885A - Circuit breaker - Google Patents

Description

Dec. 17, 1940. J. G. SOLA 2,224,885

CIRCUIT BREAKER vFiled Oct. 18, 1937 \NSULATION lmsuLATxpu Z5 Patented Dec. 17, 1940 UNITED STATES CIRCUIT BREAKER Joseph G. Soia, Oak Park, Ill., assignor to Sola Electric 00., Chicago, 111., a corporation of Delaware Application October 18, 1937, Serial No. 169,578

7 Claims.

My invention relates to circuit breakers of a type adapted to open .an electric circuit in case of an objectionable overload condition therein,

and it has for its object the provision of a new and improved form and arrangement of parts whereby one set of parts is effective for opening the circuit upon a heavy surge of current such as is established by a short circuit and another combination of parts is effective for opening the circuit when a moderately excessive current is carried thereby. Means is preferably provided in either case to maintain the circuit in open condition until the short-circuit or other overload has been corrected, the arrangement to be such that, when the circuit is opened independently of the circuit breaker after the abnormal condition has been corrected, the circuit through the breaker mechanism is automatically reestablished for renewed operation.

It is one of the objects of my invention to provide an improved arrangement for accomplishing the above mentioned results by the use of an electromagnet and a switch connected in series with the armature of the magnet in such relation that upon a surge of current through the magnet the switch is opened by the movement of the armature for breaking the circuit through the coil, a second coil being provided on the core of said magnet connected in the circuit in parallel arranger'nent with respect to the switch so as to be short-circuited when the switch is closed, said second coil when energized being adapted to move the armature to the limit of, its motion toward the magnet so as to open the switch completely and to hold it open until the circuit through the magnet has been broken independently of the switch.

It is one of the objects of my invention to provide in a device of this type an arrangement of parts whereby said switch may be opened independently of movement of the armature upon the passage of an overload current through the switch so as to throw said second coil effectively into operation for movement of the armature toward the magnet, such independent opening of the switch being effected preferably by thermostatic action due to the heating of a conductor part when such overload occurs.

It is one of the objects of my invention to provide an improved arrangement of stop means for the switch, comprising an arm in position to limit the movement of the armature in the direction for closing the switch, said arm being located in close proximity to the contacts of the switch at the point where they engage each other so as to be adapted to receive and carry away a great part of the heat generated by the spark produced by the current on the opening of the switch.

It is another object of my invention to improve devices of this type in sundry details hereinafter pointed out. The preferred means by which I have accomplished my several objects are illustrated in the drawing and are hereinafter specifically described. That which I believe to be new and desire to cover by Letters'Patent is set forth in the claims.

In the 'drawing-- Fig. 1 is a side view of the preferred form of my improved circuit breaker;

Fig. 2 is a top plan view of the device shown in Fig. 1;

Fig. 3 is a view similar to Fig. l but on an enlarged scale with the circuits and connections shown diagrammatically;

Fig. 4 is a view similar to the top portion of Fig. 3 but with certain of the parts in changed position; l

Fig. 5 is a horizontal sectional view taken at line 5-5 of Fig. 4; and

Fig. 6 is a schematic view showing the wiring connections. 4

Referring now to the several figures of the drawing in which corresponding parts are indicated by the same reference characters, in indicates a base memberv formed of insulating material, with a metallic standard II connected therewith and rising therefrom, the standard in the arrangement shown being mounted in position by means of a base portion I2. Upon the base l2 of the standar d l I I have mounted a block I 3 of insulation material upon which in turn I have mounted a frame member H in the form of a U, such frame member I comprising standards l5 and i6 being formed of iron or other suitable magnetic material. Upon the base of the U member Hi I have mounted a core member I! upon which are mounted two coils l8 and [9. Upon the upper end of the standard I6, I have pivotaliy mounted an armature member 2|] which is adaptedto'move toward and from the core bar ll, a coiled spring 2| being connected with the armature and with the lug 22 carried by the standard l6 serving normally to swing the armature to the limit of its motion away from the core bar II.

In the arrangement shown, the coil I9 is connected at one end with the lead 23 of an alternating current circuit comprising said lead and a lead 24, being connected at its opposite end with the U member l4 at the point 19a. The coil IS in turn is connected at one end with the. core bar I! at the'point lBa and at its opposite end with the base plate ii of the standard II at the point I81), such base plate l2 being provided at one end with a lug 25 having a lead wire 26 electrically connected thereto. Work devices in the form of lamps 21 are interposed between the lead 26 and the lead 24 whereby such work devices are fed by current from the leads 23 and 24 through said coil l9 and said lead 26. A shading v tion to thecontacts 30 and 3| as is indicated in core bar II for preventing chattering of the ar-' the electromagnet.

- Upon the turned upper end of the standard 1 have mounted a bimetallic arm 29, such arm extending from the standard into position over the armature 20, the armature and the arm being provided with contact members 33 and 3| comprising a switch connection between the armature and the arm. such switch being arranged in parallel relation to the coil It so that the switch when closed short-circuits said coil ll. The arrangement is such that when the switch is closed the current through the lead 23 passes through the coil l9, thence through the standard It, the armature 20, the switch comprising the contacts 3|) and 3|, the arm 29, the standard II, the lug 25, and the lead 26 to the load devices 21. The coil l9 comprises a fairly small number of turns so that the magnetic field established in the core of the magnet by the current through the coil is insuflicient normally for drawing the armature 20 downwardly against the action of the spring 2|. When, however, there is a heavy flux of current through the coil It, by reason of a short circuit at the load devices, for example, the strength of the magnet is correspondingly increased, and the armature is drawn downwardly serving to open the switch so as to make the coil l3 effective. Under such circumstances, with the switch open, the current passes from the lead 23 through the coil IS, the core bar H, the coil |8, and out through the lug 25 and lead 26 to the load devices 21. Since the resistance through the coil I3 is comparatively great, the current through the coil is kept down so as to protect the load devices from danger. The number of turns in the coil I3 is great enough, however, to enable the coils I8 and I9 by cooperative action to hold the armature 20 down against the action of the spring 2| until the short circuit condition has been corrected. After such correction, as soon as the circuit through the work devices has been opened independentlly of the circuit breaker, the armature 20 is moved upwardly by the spring 2| and the parts are in condition for renewed operation.

Upon the outer face of the standard ii of the core member I, .I have provided a stop plate 32 insulated by plates 33 from the frame member At its upper end the stop plate 32 is provided with an arm 34 extending into position opposite the outer face of the armature 20 for limiting the upward movement of the armature, such arm 34 being provided with a notch 35 in its end, the face of which stands in spaced rela- Fig. 5. Above the arm, 28, I have mounted a second bimetallic arm 36, extending over the arm 29 with a block of insulation 31 interposed between the arms. The arm 23 is arranged so that when it is heated it has a tendency to curl upwardly away from the armature 23. The arm 36 isreversely arranged so that when it is heated it has a tendency to curl downwardly toward the armature. As a result of this arrangement, when the two arms 29 and 36 are equally affected by the room temperature they are held in unchanged position since the tendency of one arm to curl is offset by the tendency of the other arm to curl in the opposite direction. When, however, an overload current is established and maintained for some little time through-the arm 29, the arm 23 is heated by the overload current 2,234,885 coil 23 is mounted upon the upper end of the serving to cause the arm 29 to curl upwardly against the action of the arm 33 which is not correspondingly heated since the overload current passes through the arm 23 and not through the arm 38. The contact 3| is thus moved upwardly out of engagement with the contact as is shown in Fig. 4 serving to throw the coil l3 into effective operation for drawing the armature 20 downwardly. The arrangement is such that the armature 20 is-held downwardly by the action of the coils i8 and I9 until the circuit is broken through the work devices 21. When the circuit through the work devices is broken after the correction of the overload current condition, the

By the use of my improved mechanism, the

circuit is broken Just as effectively as would be done by the melting of a fuse and the device is brought back to normal condition by the removal of the cause of the short circuit or the overload without the necessity for the replacement of parts orfor the resetting of any part of the mechanism.

While I prefer to, employ the form of device as shown in my drawing and as above described, it is to be understood that my invention is not limited to the arrangement shown except so far as the claims may be so limited, it being evident that changes might well be made in the form and arrangement of parts without departing from my invention.

I claim:

1. In a circuit breaker, the combination of a core bar, an armature movable toward and from said core bar and standing normally in spaced relation to the core bar, switch means opened by an operative stroke of said armature toward said core bar, a coil on said core bar, circuit means connecting said coil and said switch in series, a second coil of comparatively much'higher resistance value on said core bar connected in series with said first-named coil and in parallel arrangement with respect to said switch means and adapted when the switch means is standing closed to permit the armature to remain in switch-closed position and adapted when the switch means has been opened to hold the armature in switch-opened position, and thermostatically controlled means in said circuit means adapted upon the passage of a predetermined overload current therethrough to open said circuit means independently of movement of said armature.

2. In a circuit breaker, the combination of a core bar, a coil on said core bar, an armature movable toward said core barby the influence of an electric current through said coil, yielding means adapted normally to move said armature to the limit of its movement away from the core bar, an arm extending into position opposite said armature having a switching engagement therewith and limiting the outward movement of the armature, stop means limiting the outward movement of the armature independently of said arm, circuit means connecting said coil in series with the switch comprising said arm and said armature, anda second coil of comparatively much higher resistance value on said core bar connected with said circuit means in parallel arrangement with respect to said switch adapted when the switch is standing closed to permit the armature to remain in switch-closed position and adapted when the switch has been opened to hold the armature in switch-opened position, said arm being adapted by movement upon the passage of a predetermined overload current therethrough to open said switch independently of movement of the armature.

3. In a circuit breaker, the combination of a core bar, a coil on said core bar, an armature movable toward said core bar by the influence of an electric current through said coil, yielding means adapted normally to move said armature to the limit of its movement away from the core bar, an arm extending into position opposite said armature having. a switching engagement therewith and limiting the outward movementof the armature, stop means limiting the outward movement of the armature independently of said arm, circuit means connecting said coil in series with the switch comprising said arm and said armature, and a secondcoil of comparatively much higher resistance value on said core bar connected with said circuit means in parallel arrangement withrespect to said switch adapted when the switch is standing closed to permit the armature to remain in switch-closed position and adapted when the switch has been opened to hold the armature in switch-opened position,

said arm being adapted by movement upon the passage of a predetermined overload current therethrough to open said switch independently of movement of the armature and adapted when said circuit means is again closed after the overload condition has been corrected to again establish normal feed of the current through the switch.

4. In a circuit breaker, the combination of a core bar, a coil on said core bar, an armature movable toward said core bar by the influence of an electric current through said coil, yielding means adapted normally to move said armature to the limit of its movement away from the core bar, a bimetallic arm extending into position opposite said armature having a switching engagement with the armature and limiting the outward movement thereof, stop means limiting the outward movement of the armature independently of said arm, circuit means connecting said coil in series with the switch comprising said arm and said armature and arranged so that when a predetermined overload current passes through said arm the arm is distorted so as to open said switch independently of movement of the armature, and a second coil of comparatively much higher resistance value on said core bar connected with said circuit means in parallel arrangement with respect to said switch adapted when the switch is standing closed to permit the armature to remain in switch-closed position and adapted when the switch has been opened to hold the armature in switch-opened position.

5. In a circuit breaker, the combination or a core bar, a coil on said core bar, an armature movable toward said core bar by the influence of an electric circuit through said coil, yielding means adaptednormally to move said armature to the limit of its movement away from the core bar, a bimetallic arm extending into position opposite said armature having a switching engagement with the armature and limting the outward movement thereof and adapted upon the heating of the arm to be given a curvature in the direction away from the armature, a second bimetallic arm extending into position opposite said first named arm so as to apply pressure on the outer face of said first named arm and adapted upon the heating of said second arm to be given a curvature in the direction toward said first named arm, stop means limiting the outward movement of the armature independently of said arms, circuit means connecting said coil in series with the switch comprising said first named arm and said armature, said first named arm being adapted by movement upon the passage of a predetermined overload current therethrough to open said switch independently of movement of the armature, and a second coil of comparatively much higher resistance value on said core bar connected with said circuit means in parallel arrangement with respect to said switch adapted when the switch is standing closed with the armature moved outwardly with respect to the core bar to permit the armature to remain in such outwardly moved position and adapted when the switch has been opened by the movement of either member of the switch to hold the armature. moved to the limit of its motion toward the core bar.

6. In a circuit breaker, the combination of core means having two coils thereon, a movable armature normally in spaced relation to said core means and adapted upon a passage of current through one of said coils to move toward the core means, thermostatic means adapted to have movement upon the passage of an electric current therethrough, and switch means mechanically connected with and adapted to be opened by movements of said armature and said thermostatic means, one of said coils being elec.

trically in parallel relation with said switch means and the other of said coils being electrically in series relation with said thermostatic ed upon the passage of current through one of said coils to move toward said core bar against the action of said yielding means, a bimetallic arm, one end of said arm being fixed and the other having movement upon the passage of cur-- rent through the arm, and switch means comprising make and break contact members, one of said contact members being on said armature and the other on the movable end of said arm, one of said coils being electrically in parallel relation with said switch means, and the other of said coils being electrically in series'relation with said arm and said switch means. i

. JOSEPH G. SOLA.

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