US1467974A - Circuit-breaker-indicating device - Google Patents

Description

Sept. 11 1923. I 1.467.974

J. H. HUNT CIRCUIT BREAKER INDICATING DEVICE Filed Aug. 13, 1919 2 sheets-Sheet I Sept. 11 1923. 1,467,974

J. H. HUNT CIRCUIT BREAKER INDICATING DEVICE Filed Aug. 13 1919 2 sheets-Sheet 2 Patented Sept. 11, 1923.

UNITED sTATEs g 1,461,974 PATENT OFFICE.

TOEN H. HUNT, F DAYTON, OHIO, ASSIGNOR T0 THE DAYTON ENGINEERING LABORATORIES COMPANY, A CORPORATION OF OHIO.

` CIRCUIT-BREAKERINDICATING DEVICE. i

Application led August 13, 1919. Serial No. 317,193.

To all whom it may concern.'

Be it known that I, JOHN H. HUNT, a citizen of the United States of America, residing at Dayton, county of Montgomery,

6 State of Ohio, have invented certain new and useful Improvements in Circuit-Breaker-Indicating Devices, of which the following is a full, clear, and exact description.

This invention relates to improvements in 10 circuit breaker indicating devices for use in electrical systems, and is adapted to indicate the eXistencein said system of abnormal conditions of the current. This invention relates lmore particularly to improvements in circuit breaker indicating devices of the type disclosed in patent of C. F. Kettering,

' No. 1,336,143, dated April 6, 1920. In the patent referred to it was one of the objects of the invention to provide a circuit breaker which has rovisions for retardi'ng the op eration of t e'circuit breaker in such a manner as to rovide a clear and unmistakable signal to indicate to the operator that abnormal conditions exist in the circuit, and at the same time to prevent the waste of current. The invention disclosed in the patent referred to included an electromagnetic circuit breaker of the vibrating type including a coil connected with the electrical s stems and a core of magnetic material. Th1s electromagnetic structure e'ected .the attraction of an armature which separated a pair of contacts also connected in the system and in series with said coil. Upon interruption of the current flow through said coil the magnetic device would become demagnetized and the armature would be moved away from the magnet core through the action of a spring to eliectthe reengagement of the contacts of the circuit breaker whereupon the operation would be-repeated.

The succession of blows of one of the breaker contacts upon the other created an audible signal which would indicate to the attendant that an abnormally low resistance to current flow existed in the electrical system. In order to make this signalling device themore effective the electromagnet was provided with a retardin device in order that the engagement o the contacts would not take place too rapidly but in such a manner that a clicking rather than a buzzing sound would be lproduced. This retarding device comprise a copper.sleeve'interposed between the magnet coil and the core of magnetic material. The function of this K copper sleeve was to retard the demagnetizing of the electromagnet upon cessation of current in the magnet coil.

It has been found that under certain conditions that the copper sleeve about the magnet core tends to retard the magnetization of the core and allows the current in the system to build up to a very high value before the armature begins to move.

It is an object of the resent invention to overcome this difficulty Ey providing means by which the increasing of flux through the armature which separates the contacts will lag very little behind the increasing of current in the magnet coil. In this manner the circuit breaker indicating device will commence to function sooner upon an abnormal 'rise of current in the system than in the case where the lag of magnetization of the core is relatively great.

Other and further objects of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein preferred forms of embodiments of the present invention are clearly shown.

In the drawings:

Fig. l is a longitudinal sectional view of a structure embodying the invention together with a wiring diagram;

Fig. 2 is a side view looking in the direction of the arrow 2 of the structure shown in Fig. 1; and l Fig. 3 is a View similar to Fig. 1 showing a modified form of the invention.

In the drawings, 20 designates a frame of magnetic material provided with outwardly projecting ears 21 which are notched at 22 for a purpose to be described. Said frame supports a core of magnetic material 23 upon which is mounted a spring stud 24 of non-magnetic material. A sleeve 25 of nonmagnetic material of good electrical conductivity such as copper is placed about the vcore 23, and a second sleeve 26 or core of magnetic material such as steel is placed about the sleeve 25. An insulating sleeve 27 surrounds the sleeve 26 and around this sleeve 27 are wound the turns' of the magnet coil 28.

One end of coil 28 is connected with a terminal 29 and the other end with a conducting strip` 30 which supports a contact 31. Contact 31 is normally engaged by contact j ture.

32 mounted upon a leaf spring 33 .of conductin material which is mounted upon an insulatlng block 34 secured to the frame 20. Spring 33 is provided with a terminal portion 35 which may be connected with a switch 36 which in turn is connected with battery 37. Terminal 29 may be connected with a circuit including lamps 38 or other electrical translation devices. This circuit 38 hasa ground connection with a battery indicated by numerals 39 and 40.

An armature 41 is provided with outwardly projecting ears 42 which are located within the notches 22 provided in ears 21.

Armature 41- is provided with an aperture -43 through which the stud 24 projects and .said armature is bent around to provide a portion 44 which is arranged to engage a button of insulating material 45 mounted upon thespring 33. Armature 41 is also formed to provide a stop portion l46 normally engaging the insulating vblock 34. A leaf spring 47 is secured at one end upon 4the armature 41 by a rivet 48 and the other end of said spring 47 is apertured to pro vide for the projecting therethrough of the 'move If for any reason an abnormal flow of current through the indicating device should occur, as by reason of a short circuit existing between the indicating device and the lam circuit, this abnormal flow of current Wil cause the attraction of the arma- Since the slee-ve 26 is not surrounded by any non-magnetic conducting sleeve, such as sleeve 25, the magnet will operate quickly to attract the armature 41. Upon attraction of armature 41, the contacts 31 and 32will 4be separated and current will cease to flow through the magnet coil 28. As soon as this current ceases to flow there is a tendency for the core to become demagnetized and for the spring to draw the armature back again to its normal position, at which time the lamp circuit will be again established. By reason of the existence of the sleeve 25, which is preferably of copper, there will be a retardation of the demagnetization of the core or a 'sustaining of the flux in the core by means of an electrical effect which is set up in the closed metallic circuit formed by this oopper sleeve. The effect of this delay of demagnetization of the core 23 tends to hold the armature in its attracted position. even As previous] explained in the copending patent referre to it will be obvious that if the lamp circuit is broken and made'successively, but with a long interval between each of the successive breaks of the circuit, the clicking of the circuit breaker will tend audibly to indicate the existence of trouble in the electrical system.

The present invention possesses al1 of the advantages of the invention disclosed in theapplication referred to,.and also the additional advantage that, when the condition of the electric circuit is such as -to permit anl exceedingl rapid rise of current when the contacts c ose, the increase of the pull on the armature to a value suiicient to move it 'and separate the contacts is not delayed lby` the means provided to cause the core or cores -to have an attraction for the armature after the current has been broken. The advantage of this feature of the present'invention results from the fact that when there is a-short circuit of very low resistance, a vibrating circuit breaker constructed as 4described will limit the flow of current to a muchlower value as measured by a direct current ammeter, than will a vi rating -circuit breaker constructed according to the invention disclosed in 'the copendingv application reerred to. 4`;

A modied form of the invention is shown in Fig. 3. A frame 2()a of magnetic material is constructed in the4 ymanner similar to the construction of the frame 20 .of the first form of the invention. shown. This frame has a mounting portion which is large enough to support the core 23 and the sleeve 25 hereinbefore described, and an additional core 26a of magnetic material. A sleeve of non-conducting material 27 a is placed around sleeve 25 and core 26, around this conducting sleeve is mounted the circuit breaker winding 28". The armature 41a and the spring 47 are similar in construction with elements 41 and 47 hereinbef'ore described but are made longer in order to extend over core 26a and core 23. z

The core 26a has the same function as 4the sleeve 26 shown in Fig. 1, that s, it provides for the increase of flux through the 4armature 41 with relatively little lagging behind the increase in current in coil 28, because core 26a is not surrounded by,v a short circuited Menem to be understood that other forms might be adopted, all coming Within the scope 'oi the claims' which follow.

-What l claim is as follows:

l, ln a vibrating circuit breaker, the combination with cooperating contacts; oi means tending to maintain engagement of said con tacts; and electro-magnetic means for intermittently separating said contacts when the current passing across them exceeds certain value, said means including a mag netizable armature, a coil in circuit l"with said contacts, and a core including a path for etiecting the increase of flux through.

said armature With relatively small lag behind the increasing oi" current in said coil, and dampening means tor effecting a decrease of dux through said armature with relatively great lag behind the time of contact separation..

2,. ln a vibrating circuit breaker, the combination with cooperating contacts; of means tending to maintain engagement ot said contacts; and electro-magnetic means for in termittently separating said contacts when the current passing across them exceeds a certain value, said means including a magu netizable armature, a coil in circuit with said contacts, and a plurality. ot cores excited by said coil, one core for eidecting the increase of flux through said armature with relatively small la behind the increasing oi current in said coi, and another core having means for edecting the decrease of iiux through said armature with relatively great lag behind the time of contact separation.' i

3. ln a vibrating circuit breaker, the combination with cooperating contacts; of means tending to maintain engagement of said contacts; and electro-ma etic means for inten mittently separating said contacts when the current passing across them exceeds a certain value, said means including a magnetia able armature, a coil in circuit with said contacts, and tvvo cores excited by said coil and a short-circuited conductor in the iield oi one core but not in the field of the other. i

d. ln a vibrating circuit breaker, the combination `with cooperating contacts; of means tending to maintain engagement of said contacts; and electro-magnetic means for inten7 mittently separatingsaid contacts when the current passing across them exceeds a oeru tain value, said means including a magnetia able armature, a coil in circuit with contacts, and two cores excited by said coil, and al conducting 'sleeve oi non-magnetic material surrounding one only ot the said cores.,

5., ln a vibrating circuit breaker, the comn bination vvith cooperating contacts; oit means tending to maintain engagement of said contacts; and armature for separating said contacts; electro-magnetic means including an undampened dux path for effecting, when the current carried by said contacts exceeds a certain value, the movement oi said armature to separate said contacts, the lagging oni said movement behind the increase ot current being relatively small, and `ilux sustains ing means for causln the return movement of said armature to ta e place With relatively great lagging behind the time of contact separation,

6., ln a vibrating circuit breaker, the combination vvith cooperating contacts; an armature movable to separate the contacts; an electromagnet `including a coi-l and concentrically disposed spaced magnetic cores; and a sleeve of conducting non-magnetic material betvveen said cores.

- il lin a vibrating circuit breaker, the combination With-cooperating contacts; an an mature movable to separate the contacts; an electromagnet including a coil and concentrically disposed spaced magnetic cores; and a copper sleeve between said corean ln testimony whereof l adix my signa ture.

Jenn n. nenn Witnesses:

H, E. Somnnnnonn, WARREN SGHMUDING.

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