US2103794A - Circuit breaker - Google Patents

Description

Patented Dec. 28, 1937 l UNITED STATES PATENT OFFICE y CIRCUIT BREAKER Fritz Rampacher, Berlin-Charlottenburg, Germany, assignor to Westinghouse Electric t Manufacturing Company, a corporation of Pennsylvania Application November 6, 1928, Serial No. 317,588 In Germany November 9, 1927 11 Claims. (Cl. 200-89) My invention relates to circuit breakers and4 the circuit-breaker apparatus mounted upon the particularly to circuit breakers of the oil-imcover, the tank being normally lled with an mers-ed type wherein the contacts are immersed insulating, arc-extinguishing liquid, such as oil in oil. or substances having similar characteristics.

5 An object of my invention is to provide a Two insulating bushings 6, that are mounted in 5 circuit breaker wherein the movable contacts the co-ver 5, serve to support the xed contacts may be moved to open position at a relatively 'l of the circuit breaker which comprise flexible high velocity in order to reduce the arcing incijaws 8 that are' adapted to yieldingly engage dent to separation of the contacts. movable contacts 9 that are movably mounted l Another object of my invention is to provide a upon a cross bar or carrier l I, in a manner to be 10 circuit breaker wherein the movable contacts are hereinafter described. mounted upon the movable carrier therefor in The crOSS bar ll iS adapted t0 Slide vertically such manner that, upon the occurrence of a seupon the guide bars l2 that are` secured to the vere overload or short-circuit, the movable concover 5 and is operated by a. pair of connecting l5 tacts are caused t0 move to Open position indelOdS I3 that are mOVed vertically through the l. pendently ofy any movement of the carrier, Inedinln 0f a cam H (Fig. 2) that is fixed to, thereby making it unnecessary to overcome the and rotates with, an operating Shaft |5- inertia of the' carrier when the circuit breaker is The bar or carrier Il is made of insulating' opened under overload and short-circuit condimaterial and Supports tWO metal cylinders i6 tions which serve to support and guide the movable A further object of my invention is to provide contacts 9, the lower ends of which are provided a circuit breaker having the above noted char- With iiat heads il that are engaged by helical acteristics wherein the carrier for the movable Springs i3 which Surround the Contact 9 and contacts is moved away from and toward the are confined within the cylinders I6, as indi- 5 fixed contacts under normal operating condicated in Fig- 1 The COntactS 9 are adapted t0 tions to move the bridging contacts of the cirbe InOVed t0 the Open DOSitiOn, indicated in dotcuit breaker out of and into operative engageted lineS in Fig- 1, by the Springs la One 0f Which ment with the fixed contacts. is shown. The contacts 9 are releasably re- A further object of my invention is to protained in their closed positions, shown in full 5,) Vide a circuit breaker having movable contacts lneS in FS- l, by means 0f the latches I9 Commounted on a, carrier in such manner that they DliSing bell-Crank leVerS that are DiVOted at 2| may move, independently of the carrier, to open 11D0n the Cylinders i5 and are DlOVided With position with a snap action when ,an overload hOIiZOntally extending limbs 22 upon which a or short-circuit condition occurs and wherein fleXible C0nnect01 23 0f U-Shape iS SllpPClted 5 means are provided for resetting the movable at its central portion, the ends of the connector contacts and wherein the operating mechanism being conductively connected to the cylinders I6 for the re-setting means and the carrier are inby Conductive brackets 24. terlocked in such manner that a predetermined In Order t0 maintain conductive Contact besequence of operation thereof is necessitated. tween the Contacts 9 and the brackets 24, conm Further objects that will be made apparent tact shoes 25 are provided for engaging the flat throughout the further description of my in.. head II of the contacts 9, regardless 0f their vention are attained by means of the apparatus DOSitiOnS in the cylinders I B, the shoes being hereinafter described and illustrated in the acyieldingly heldin engagement with the flat head companying drawing wherein: Il by leaf springs 26 connected to the brackets 7, Figure 1 is a vertical sectional view of a cir- 24- The brackets '24 alSO Carry leaf Springs 30 cuit breaker embodying features of my inven- Wi'lich Serve t0 yieldingly retain the latches Il.

tion; in engagement with the flat head ll of the con- Fig. 2 is an elevational View of the circuit taCtS 9! Y breaker carrier and re/-setting mechanism', and When a Severe Overload 0r Short-Circuit occurs Fig, 3 is an elevational View of a modified form in the circuit in which the circuit breaker is conof circuitbreakeroperating mechanism, nected, the abnormal current flow will cause dis- Referring to the drawing, the circuit breaker placement 0f the Central portion 0f the flexible comprises a metal tank or container 4 supported Connector 23 downward; thereby depressing the by a, cover 5 from which the tank may be delimbs 22 of the latches I9 and causing the latches tached for the purpose of attaining access to I9 to release the contacts 9 and permit the springs I8 to move them to open position with a snap action and at a relatively high velocity. It will be readily understood that, since the contacts 9 are relativelyI light, much less effort is necessary -to move them at a high velocity than would be required to overcomef the inertia of the entire carrier and its associated parts and move it to open position. 'Ihe actuating mechanism for operating the circuit breaker contacts under overload and short-circuit conditions is, therefore, of a lighter characterand less expensive and cumbersome than the apparatus usually required to open a circuit breaker ofthe usual type wherein the entire carrier is moved to open the circuit breaker. Furthermore, relatively high velocities of separation of the contacts are obtainable by reason of the construction above described.

It will be understood that, during ordinary normal operation of the circuit breaker, the carrier I I is moved vertically to separate the contacts 9 from the contact jaws 8, and that the contacts 9 are moved relative to the carrier only in response to overload and short-circuit conditions.

i In order to reclose the circuit breaker after it has been opened, under overload or short-circuit conditions, and to insure that a definite time interval transpiresv before the circuit breaker is again closed, provision is made for necessitating opening movement of the carrier II before the circuit breaker contacts 9 can be reset to operative position.

I have, therefore, provided a resetting bar 21 that is mounted upon the guides I2 for vertical movement and carries two resetting pins 28 axially aligned with the contacts 9 for moving them to reset position after the bar II has been moved to its lowermost position, indicated in dotted lines in Fig. 1.

As indicated in Fig. 2, the bar I I is actuated by means of a cam I4 havingan arcuate face 20,

vand the bar 21 is actuated by means of rods 29 that are operated by a cam 3| having a concave arcuate face 32. 'Ihe cams are, therefore, interilocked in such manner that a predetermined sequence of operation thereof is required.

In order that the resetting bar 21 may be raised to reset the circuit-breaker contacts 9, the cam I4 must be moved to the open position, indicated in dotted lines in Fig. 2, thus causing thebar I I to be moved to its lowermost position. After/this movement has been completed, the cam 3|' maybe rotated by a shaft 33 i n a clockwise direction to cause upward movement of the resetting bar 21. It will be seen that the cam I4 cannot be returned to its original closed position until the resettingbar 21 has been returned to its original lowermost position.

By/y reason of the interlock operating mechanism, in order to reset the circuit breaker after operation in response to an overload or short cir-v cuit, the carrier I I must rst be lowered, the resetting bar `21 then raised to reset the contact 9 and returned to its original position and then the carrier I I may be raised to bring the cony,

tacts 9 into operative engagement with the con# tact jaws 8.

In Fig. 3,I. have disclosed a modied form of circuit breaker contact operating mechanism that also laccomplishes initial movement of `the contacts without necessitating substantial movement of the movable contact carrier. [In this construction, the fixed contactmembers -1 are provided with movable contact members 34 in the form of bell-crank levers that are pivoted at 35 upon the contact members 1 and are provided pendently thereof,

with vertical .limbs 33 that are releasably retained in operative position by latches 31 com-` prising bell-crank levers 38 that are normally biased toward latching position by springs 39. Movable pawls 6I are pivotally mounted on the ends of the lever 38 and are engaged by a releasing bar i2 that is secured to the operating shaft which carries the movable contacts d4 of the circuit breaker which are mounted on a cross bar d5 secured to the shaft d3.

Springs 46, winch engagev heels 31 on the contact members 31S, serve to bias the contact members 34 toward open position and to rotate the contact members in opposite directions away from the contacts IM when the latches 31 have released the limbs 36.

The operating shaft 43 is adapted to be released by the ordinary circuit-breaker trip mechanism in response t0 a severe overload or short circuit. The initial downward movement of the shaft 153 causes the latches 31 to be released from the limbs 36 of the contacts 34, which permits their opening movement by the springs 46, with a snap action.

It will thus be seen that the contacts separate at a relatively high velocity upon a slight initial movement of the carrier for the movable contacts 34. 'I'he subsequent downward movement of the cross bar 32 serves to return the contacts 34 to their original positions, ready for the next operation.

When reclosing the circuit breaker, the shaft 43 is raised, bringing the contacts 44 into engagement with the contacts 34. The ends of the releasing bar 42 slip past the pawls 4I and reengage them. The parts of the apparatus will then occupy their original positions, as indicated in Fig. 3.

While I have illustrated only two embodiments of my invention, it will be apparent to those skilled in the art that various changes, modifications, substitutions, additions and omissions may be made in the apparatus illustrated without departirig from the spirit and scope of my invention, as set forth in the appended claims.

I claim as my invention:

1. The combination with a pair of relatively l movable contacts, of a movable carrier for one of the contacts having operating means movable te two operating positions, means for movably supoperable only when theoperating means forvthe carrier is in its other operating position.

2. The combination with a pair of relatively movable contacts, of a movable carrier for one of the contacts movable to two operating-positions,

means for movably supporting the said contact upon the carrier for disengaging movement indecurrent-responsive means mounted on the carrier for releasably retaining the saidA contact in engagement with the other contact when the carrier is in one of its operating.

positions, and means movable for resetting the said contact that is operable only when the car- U0 rier is in its other operating position. j

3. A circuit breaker comprising a .xd contact.

va movable contact for'engaging the xed contact,

a movable member having a latch portion for supporting the movable contact and for permitting relative movement of the movable contact with respect thereto, means for moving the movable 'contact to open position independently of move- 'ment of the bar, and current-responsive means the-movable contact in operative engagement .With the fixed contacts, and means movable only when said bar is in open circuit position for resetting the movable contacts.

5. Acircuit breaker comprising a pair of fixed contacts, a pair of movable contacts for engaging the fixed contacts, a movable bar for supporting the contacts and for permitting relative movement of the movable contacts with respect thereto, means for `moving the movable contacts to open position independently of movement of the bar, current-responsive means for releasably retaining the movable contacts in operative engage.

ment with the xed contacts, means for resetting the movable contacts, and interlocked operating means for the bar and the resetting means, where by a. predetermined sequence of operation thereof is required.

6. An automatic circuit breaker comprising in combination, a movable contact member biased toward its open-circuit position, a movable actuating member normally adapted to move the con-- tact member to open or close the circuit, and an electro-responsive means inherently responsive to abnormal current conditions in the circuit carried by said actuating member and constituting at least a part of a mechanical connection between the said actuating and contact members normally operative to prevent independent circuit opening movement of the latter, the said means upon the attainment of an abnormal current condition in the circuit being relatively movable by reason of its own inherent electro-responsive characteristics so as to render the said mechanical connection 'ineffective and to thereby permit the contact member to move to its open-circuit position independently of the actuating member,

7. An automatic circuit breaker as set forth in claim 6, wherein the electro-responsively movable means includes a latch carried by one of the said members and normally having a direct engagement with the other, the said latch being automatically disengaged from the said other member upon the attainment of an abnormal circuit condition so as to permit independent movement of the contact member.

8. An automatic circuit breaker as set forth in claim 6,` wherein the entire electro-responsive means is bodily movable with the said actuating and contact members during normal opening and closing of the circuit breaker.

9. An automatic circuit breaker as set forth in claim 6, wherein there are two separate circuitv breaking contacts on the contact member and wherein the entire electro-responsive means is Ainto and out of engagement with said fixed contacts, said operating rod being relatively movable y with respect to said movable contacts, means biasing said movable contacts to move towards open circuit position independently of said rod along the same line as when moved by said rod, and electromagnetic tripping means holding said switch member in closed circuit positionl said conducting switch member comprising the current-carrying element of said tripping means.

FRITZ RAMPACHER.

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