US2389999A - Circuit breaker - Google Patents

Description

Nov. 27, 1945. A. B. RYPINSKI CIRCUIT BREAKER Filed May 16, 1940 2 Sheets-Sheet 1 w yf/jldiiw uzaii INVENTOR ALBERT B. RYPINSKI ATTORN EY NW. 27, 1945., A. B. RYPINSKI 2,389,999

CIRCUIT BREAKER.

Filed May 16, 1940 2 Sheets-Sheet 2 INVENTOR ALBERT B. RYPINSKI TTORNEY Patented Nov.. 27, 1945 UNITED. s'm'r zs PATENT OFFICE mfiilim 'Albert 1:. Ryplnski, Laurelton, N. Y., assignor t Metropolitan Device Corporation, Brooklyn, N. Y., a corporation oi New York Application May 16, 1940, Serial No. 33am 6 Claims.

The invention herein disclosed relates to a relay or circuit breaker of the kind which while under normal conditions may be operated manually in the manner of an ordinary switch, operates automatically to open the circuit upon a continued overload or short circuit. vMore particularly, the invention relates to a relay or circuit breaker oi the kind disclosed in the co-pending applications for patents, Serial Nos. 309,521 and 321,022, flied December 16, 1939, and February 27, 1940, respectively, which became Patent No. 2,260,583 on October .28, 1941, and Patent No. 2,336,036 on December 7, 1943, respectively.

In the aforesaid applications for patents there is disclosed a circuit breaker that primarily includes a case and two movable elements within the case, preferably rotatably mounted about a Fig. 1 which is a plan of a circuit breaker embodying the invention;

on the line 3-3 of Fig.1}

Fig. 4 which is a sectional side elevation taken {on the line 4-4 of Fig. 1;

common axis and resiliently urged toward "ofl" Y position. The two elements comprise the primary operating parts and consist of a manually operative element or handle, and a switch element or rotor. Normally, when the handle is moved to the "011 position, it is releasably latched to the case in this position. The switch element normally moves to, and is positioned in, the "on" position with the handle as it is latched thereto through current-releasable latching means. On the existence of abnormal current conditions, the switch .element is released-from the handle and moves to "01! position and in so doing releases Fig. 5 which is a fragmentary sectional elevation of a modified form oi. switch element or rotor for the circuit breaker;

Fig. 6 which is a diagrammatic illustration 01 a modified arrangement of the circuit breaker illustrated in Figs. 1 to '4;

Fig. '7 which is a partial transverse section or a modified form of switch element for the circuit breaker;

Fig. 8 which is a sectional side elevation of the same taken on the line H 0! P18. 7;

Fig. 9 which is'a diagrammatic illustration of a modified arrangement of the circuit breaker the handle which follows the switch element to oil position.

An object of the present invention is to provide a circuit breaker of this kind in which the current-releasable means includes a coil mounted in the switch element. Another object is to provide a circuit breaker including a coil mounted in the switch element. and means to obtain time delay in operation of the core or keeper upon which the coil acts. Another object of the invention is to provide a coil arranged to effect a more rapid release of the switch element upon the flow of exceptionally large currents. A further object of the invention is to" increasethe force eilecting the release of the switch element with increases in current to secure a delayed action on slight overloads and a rapid action on short circuits.

These and other objects and certain advantages thatwill hereinafter appear are realized in the circuit breakers, illustrating by way of example, embodiments of the invention, that are disclosed in the accompanying drawings and described in detail below. The drawings include:

illustrated in Figs. '1 and 8: and

Fig. 10 which is a transverse section of the modified form of circuit breaker illustrated diagrammatically in Fig, 9.

The several circuit breakers illustrated in the drawings essentially include a. case and operating parts that are housed within the case. The case is the same for the several modified forms of the circuit breaker that are illustrated in the draw lugs, and, fundamentally, the operating parts are the same, the differences residing primarily in the mechanical and electrical arrang ment for eflecting a release 01 the circuit-controlling or switch element of the circuit breaker upon continued overload or short circuit. The case A for the circuit breaker is open at the bottom and has I an opening I through the top for a finger piece 2 by means of which the circuit breaker may be manually actuated. A base B serves as a closure.

. for the bottom or the case and as a support ior stationary contacts 3 and 4, associated with connecting pieces 5 and 6 and terminals I and 8. The case and base together form a complete enclosure tor the circuit breaker except for vents 8 and Ill extending vertically through the case to permit the free passage of gases generated by arcs formed within the case.

The operating mechanism in general includes two movable elements, a manually operative element or handle 0 fromwhich the finger iece 2 extends, and a'switch element or rotor D. The handle consists of a disk-like wall H from which a shaft i2 formed integral therewith extends. An axial flange I3 is formed at one portion oi the handle, the outer portion in the assembled circuit breaker, and extends from the wall H. The finger piece 2 extends radially from this flange through the opening in the case. The rotor is partially encased within the handle and is rotatably mounted upon the shaft I! which in turn is rotatably mounted in a slide ll received in a complementary groove in one side wall of the case, and in the arcuate end of a slot I! in the conditions, the handle, when removed to the "on" position, is restrained against the action of'the toward oiT' position, by a latching lever I! that enters in a recess 20 in the flange on the handle and engages the end wall of this recess. This lever is resiliently urged into latching relation with the end of the slot or recess 20 by the spring loop it which engages the latching end of the lever. The lever is pivoted between its ends upon a pivot pin 2| that extends from the slide H in which the shaft i2 is journaled. A cam surface 22 on the rotor is arranged to engage the end 28 of the lever when the rotor moves to "of!" position.

breaker. The end 21 of the set screw acts as a detent and is engaged, under normal conditions,

the lever. Embedded within the rotor there is i received in a groove in the rotor. Under normal spring section It, which acts to urge the handle a coil 32, One end of this coil is connected to the contact 24 and the other end is connected to the contact 25. A spring 24 coiled around the pin it acts upon the lever and normally biases it to a position in which the detent engaging end is held against the face of the rotor, in which position the end 20 engages the detent 21. By turning the set screw in the threaded opening in the handle, the extent of engagement between the lever and detent may be varied, and in consequence, the point at which the circuit breaker opens or the capacity of the circuit breaker may be varied or adjusted. Once set, the screw is preferably sealed against rotation. The engaging section or edge of the latch may be rounded to make a point contact with the detent and so minimize the drag on the lever when urged to the release. position. The opposite edge 25 of the lever is preferably bent-outwardly to form a lead-in.

It will be apparent that when the circuit breaker is closed, the current passing through the circuit passes through the coil 33. This coil is calibrated so that upon the passage of a particular current through it, theikeeper, 29 is actu- Upon engagement of the end of the lever by the cam surface 22, the lever is withdrawn from'the recess in the handle and the handle is thus released to move to "01! position under the action of the spring section ll. I

The rotor normally is latched, in a manner hereinafter described, to the handle so that when the handle is moved to "on" circuit position, the

rotor moves with the handle. Likewise, the latching arrangement is such that if the handle be moved to oil circuit position, the rotor under the action of the spring section 11 will follow the handle to the "off position. The rotor carries contacts 2i and 25 which engage respectively, in the "on" position, with, the stationary contacts 3 and I. When the rotor moves to the oil circuit position, the contacts 24 and 25 move away tripping in inverse from the stationary contacts. Normally, the

section II ofthe spring and the stationary contacts exert a force tending to rotate the rotor to the oil position. The stationary contacts are mounted and arranged so as to have a cer-"' tain amount of resiliency and are positioned with respect to the contacts on the rotor so that they are under tension in the on circuit position of the rotor. I i

The rotor is provided with current-releasable means for eflecting the release of the rotor from the handle upon continued overloads or short circuit. It is with this current releasable means,

as arranged in a circuit breaker of this kind, that .the invention of this application is primarily.

concerned.

In the circuit breaker illustrated in Figs. 1 to 4, there is provided an electro-magnetic arrange-' mentfor releasing the rotor from the handle upon the existence of abnormal current conditions.

ated or drawn to the coil causing the engaging end 28 to be released from the detent 21. When this occurs, whether by virtue of a short circuit or a continued overload, the rotor is moved to the "off" position by the action of the spring section l1. Upon'arriving at the of!" circuit position, the rotor, as previously described, trips the latchthe "oil!" position. The leadin on the latching lever permits the detent to pass the lever and since the circuit through the coil is broken, the lever will assume a position under the action of spring 3! in which it again engages the detent when the handle is moved to the on position.

Fig. 5 shows a modified form of magnetic breaker with a dashpot in the rotor to delay the shaft ll carries all the rotating parts. The handle C is cored out to form a cylinder 31' in which a piston ll travels, with a spring 39 biasing it outwardly. This spring replaces the spring 34. When keeper 2! is attracted by coil 33 it presses piston 38 in against spring 39 and also compresses the air in cylinder 31. The air leaks around the shaft 30 and piston 28 flnallyallowing the latter to move in and permit the breaker to trip. The greater the magnetic pull on the keeper 29 the faster the air will be expelled and the more rapidly the keeper moves to unlatch position.

'An alternative means for providing a time delay, in connection with the coil and keeper type breaker, is illustrated diagrammatically in Fig. 6.

Here the coil." is shunted by a resistor ll of The latching arrangement by which the rotor is.

normally secured to the handle includes a detent which consists of a dog-pointed, hardened set screw 28 that is threaded in an opening in the flange l3 and extends axially 0f the circuit high coef llcient material. When current is at. full load value it divides between the coil and. resistor in such a proportion that the coil will not pull in its keeper l0 and the resistor is relatively cool. As the current rises above full load the resistor heats, increases in resistance, and the coil carries a proportionately larger percentage of the total current. At a predetermined critical value the keeper is attracted and the breaker trips. If the overload is of brief duration the resistor does not have time to heat and a large ing lever is and the handle follows the rotor .to I

proportion to the current; A

aseaeoo alternating current supply, the current split will be affected quantitively by the inductance oi! the coil, but the net result will be the same as described below. Normally, the resistor may have a higher resistance than the coil so that the reater portion of the current passes through the coil. Under normal conditions, there will be little heating of the resistor, which may be made of nickel. However, upon increase of current passing through the circuit, heating of the resistor will occur depending upon the additional amount of current passing through the circuit. For ex-- ample, if an overload occurs in which the amount of current passing through the circuit is double the rated capacity of the breaker, the greater portion of the current will pass through the coil. However, additional current will pass through the resistor, in fact twice the normal current will pass through the resistor. This additional current will eil'ect the heating of the resistor. As it heats, its resistance becomes greater thus cutting down the amount of current that passes through it increasing the amount of the current that passes through the coil. The relation of the resistor and coil may be such that upon a condition or this kind, 1. e., a current of double the rated capacity, the breaker will trip after a period of two minutes. On the other hand, if a very heavy overload or a small short circuit occurs, causing a current over five or six times the rated capacity of the breaker, the amount of current that will. pass through the coil will immediatelycause the coil to trip the breaker and the heavier'the current, the more rapid the tripping oi the breaker will be. The keeper 40' may be a bimetal element as illus trated. In such case the action will be that, on slight overloads, the keeper will heat and warp to release the switch element. This action will be augmented by the coil as and in the manner described.

In Figs. 7 and 8, there is disclosed a modified element. The rivets 46 and 41 through which "the bimetal element is secured to the contacts on the rotor and through which it is electrically con- 65 nected to the contacts extend through insulated bushings, such as the bushing 48 extending through the ring 45. Thearrangement o! the bimetaland the ring is in the nature of atrans 70 former.

The normal operation of the circuit breaker is by heating and warping, in the usual manner ot the bimetal element; and when warped the bimetal becomes released from the detent and re-' 1 leases the rotor. This heating and releasing r the bimetal element is necessarily delayed in the case of a simple overload and should be very rapid in the case of a short circuit. when a heavy flow of current occurs through the bimetal, current is induced in the ring 45. If a heavy short circuit occurs, a relatively heavy current is induced in the ring. This current sets up its own magnetic field which causes a magnetic reaction well understood in transformer design and which results in repulsion between the bimetal element and the ring.

Power systems today are capable of supplying large short circuit currents and small circuit breakers for use on these systems. are tested with 5000 ampere short circuits through them. An appreciable force is exerted between the bimetal and the ring when the bimetal is carrying a short circuit currentoi' several thousand amperes. In consequence, the bimetal element is moved out of latching engagement much more rapidly under short circuit conditions than it would by reason or heating and warping alone.

The ring 45 may be replaced by a coil that is connected across the bimetal element. This arrangement is illustrated diagrammatically in Fig. 9. The current passing through the circuit breaker will necessarily divide in accordance with the resistance of the bimetal element 42 and the coil ll.

This arrangement is illustrated in a circuit breaker in Fig. 10 of the drawings. This circuit breaker, in construction, is in all respects the same as that illustrated in Figs. 1 to 4 of the drawings, except for the construction and attachment of the bimetal element 12. In the-construction of Fig. 10, the bimetal element 42 is positioned on, secured to the rotor and connected to the contacts and SI (Fig. 9) in the same manner as illustrated in Figs. 7 and 8. The coil 48 is preferably embedded in the rotor as illustrated and one end is electrically connected, as

illustrated in Fig. 9, to one end or the bimetal. and so to a switch element contact. The other end oi the coil is electrically connected to the other switch contact and the other end of the bimetal. The operation of this breaker should beapparent from the previous descript on.

From the foregoing, it will be apparent that by the invention herein disclosed, there is provided in a circuit breaker of the kind referred to, an arrangement wherein a coil, may be utilized to eirectively release or assist in the release or the movable element of the circuit breaker. The arrangement is such that it permits the utilization of a, circuit breaker construction that is comparatively simple and inexpensive. The arrangement provides a flexibility that may be utilized insecuring a delayed action on slight overloads with a. rapid action on heavy short circuits.

It will be obvious that'various changes maybe made by those skilled in the art in the details of the embodiments of the invention illustrated in the drawings and described in detail above within the principle and scope of the invention as expressed in the appended claims.

I claim:

'1. In a circuit controlling device of the kind described, the combination comprising a movable switch element, a movable latch carried by the switch element acting as a releasable latch therefor, bias means to move the switch element upon releasing movement of said latch, and a coil carried by the switch element and inductively coupled with the latch for eitecting relative re- 3. In a circuit controlling device oi. the kind described, the combination comprising a movable switch element, spaced switch contacts carried by the switch element, a bimetallic latch carried by the switch element, connected across the switch contacts, movable with respect to the switch element, and acting as a releasable latch therefor, bias means to move the switch element upon releasing movement of the latch and a coil carried by the switch element and inductively coupled to the latch.

4. vIn a circuit controlling device of the kind described, the combination comprising a rotatably mounted switch element, spaced switch contacts carried by the switch element, a bimetallic latch carried bythe switch element connected across the switch contacts, movable with respect latch therefor, bias means to move the element upon-releasing movement'oi the latch,

and a coil arranged concentrically with the axis of the switch element, and inductively related to the-latch.

5. In a circuit controlling device oi. the kind described, the combination comprising a movable switch element spaced switch contacts carried'by the switch element, a bimetallic latch carried by the switch element, connected across the switch contacts movable with respect to the switch element, and acting as a releasable latch therefor, bias means to move the switch element upon releasing movement up of the latch, and a coil carried by the switch element, connected across the switch contacts and inductively related to the latch.

6. In a circuit controlling device of the kind described, the combination comprising rotatably mountedswitch element; spaced switch contacts carried by the switch element, a bimetallic latch to the switch element and acting as a releasable 1 carried by the switch element connected across the switch contacts, movable with respect to the switch element and acting as a releasable latch therefor, bias means to move the switch element upon releasing movement of the latch, and a coil carried by the switch element, arranged about the axis thereof, connected across the switch contacts and inductively related to the latch.

ALBERT a RYPmsm.

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