US1873087A - Circuit-breaker-tripping system - Google Patents

Description

Aug. 23, 1932. R. J. WENSLEY 1,373,087

.CIRCUIT BREAKER TRIPPING SYSTEI Filed May 27, 1929 fikza 12 INVENTOR x Roy J. WensZey.

BY 7 ATTORNEY to sectionalizing systems and apphed to,

magnet for maintaining has one disadvantage,

Panama Aug. 23, 1932 PATENT orrlcs I TRIO &

BOY J. WENSLEY, OI EDGEWOOD, PENNSYLVANIA,

MANUFACTURING COMPANY, A COBPORAT'IONDF PENNSYLVANIA ASSIGNOB WESTINGHOUSE ELEC- cracun--rarrrnva svs'rma Application fled Kay 87, 1929.

My invention pertains to rotective stems for electric circuits an particular y, for direct-current railway-distribution circuits.

It is the princi al object of my invention to provide a bi -speed sectionalizing circuit breaker wit means for controlling its ration in accordance with the impedance the circuit to be rotected. It is a further 0 ject of my invention to improve upon hi h-speed circuit breakers, as now applied to direct-current circuits, by the incorporation therewith of an impedance element similar to that of the well known impedance relay which has been developed for,

the protection of alternatingcurrent circuits.

The structure of the so-called high-speed circuit breaker is now well known as consisting of a contact mechanism, a holding the mechanism in closed position and a flux-shifting coil usually of one turn, called a bucking barf, for shifting the flux traversing the magnetic circuit of the holding ma et, to permit the circuit breaker to be re eased so that it will open its contacts, upon the occurrence of an overload on the circuit to which it is connected. While this structure is a great improvement over those previously known, it

not distinguish between a fault condition and a heavy-load condition.

It is another object of my invention to provide the usual high-speed circuit breaker with means for detecting the difierence between fault and heavy-load conditions;

- series with a condenser,

to be protected.

- be protected will naturally 'In accordance with my invention, I employ, in addition to the bucking bar, a second flux-shifting winding which I connect, in across the circuit Under normal conditions, the secondflux-shifting winding is deenergized, since direct current will not traverse the condenser. Upon the occurrence of a fault, however, the voltage of the circuit to be so lowered that a transient current traverses the condenser discharges through the fluxand the latter taine namely, that it does Serial No. 866,810.

shiftin winding to cause the tripping of the circuit reaker.

For a more complete understanding of my invention, reference is made to the accompanying drawing, the single figure of which is a diagrammatic illustration of the system and apparatus of my invention.

Referring particularly to the drawing, a source of irect-current energy, such as a substation bus, is indicated at 10. A distribution circuit, such. as a-feeder 11, is adapted to be connected to the bus through the contact'member of a circuit interrupter indicated generally at 12. The circuit interrugter 12-is of the type which is mainclosed by a holding dicated at 13. A spring 14, or other equivalent means, is provided toeilect the tri ing of the circuit breaker 12 when the hol ing ma et is rendered inefiective.

he olding magnet 13 consists of a core 15 havin pole pieces 16 and 17. An armature mem er 18 is adapted to cooperate with the le ieces 16 to maintain the circuit brea er c osed so long as flux traverses the pole pieces 16 and armature member 18. The olding magnet is normally excited by means of a holding coil 19 which may be connected across the circuit 11 or to a separate source of current. The bucking bar is indicated at 20 and, in the usual manner, is arranged to provide such magnetomotive force, when traversed by an electric current, as to shift the flux from the ole pieces 16 and armature acrossa reactor 21 in the circuit 11 as to be energized in accordance with the rate of change of the current traversing the ,feeder In addition to the bucking bar 20, Iprovide also asecond flux-shifting windin 22 which may, for convenience, e woun on the pole pieces 17. The winding 22 is connected across the circuit 11 in series with a condenser 23. Under normal conditions, of. course,

no current will traverse the conelectromagnet indenser 23 but it will remain charged so long as normal voltage exists across the circuit 11. Should. the voltage fall below its normal distant b calrers.

cui't biased to :r ue, the courier or to discli. e itself through the n hirting Winding 22. I employ this principle to produce a tripping impulse for the circuit breaker 12 which shall be responsive, in part, to the drop in the voltof the circuit 11 which is, of course, an indication of the severity of the fault which occurred.

If a plurality of circuit breakers provided with the operating mechanism shown and described herein, are connected in series in a distriinrtion circuit, it is obvious that the constants of the various elements of the combination may be so designed that the desired o?- erating characteristics may be obtained. f, for example, the reactor 21 is designed to shunt a large. portion of the fault current from the bucking bar 20, so that the shifting the flu? the holding magnet accomplished la y the coil 22. the circuit aer located nearest to the fault will be tripped first because its flux-shifting winding is affected by the drop in circuit voltage to a greater degree than those of more this means, it is possible to cause the isolation of a faulty section without interrupting service on remaining sections of? the svstem.

Although I hai'e shown and described but a single modification of my invention, I do not intend to be limiced thereto, since changes and modifications will be apparent to those skilled in the art, and the appended claims are relied upon to define the scope of my inention.

claim as my invention:

1. The combination with an electric circuit, a reactor and a condenser associated therewith, a circ it interrupter in said cire open position, of a normalnaguet for holding said inin closed position, means for dis- M be normal. flux of said magnet coming a bucking winding adapted to be across said reactor and a bucking adapted to be connected across said .11 series with said condenser. 21 a system for operating acircuit ini biased to the open position and d to beinaintained closed by a normalenergized electromagnet, a reactor and a nser associat d 1th the circuit conl iter, windings for traversing said electromags aid windings being connected across said reactor and another being connected across said circuit in series with said condenser.

3. A circuit-breaker-operating mechanism comprising normally energized holding electromagnet having flux-shifting windings adapted to be connected, respectively, across reactor in the circuit controlled by the circ t rid across said circuit in series with condense 4. A protective system for an electric circuit including an interrupter, a holding electromagnet for maintaining the interrupter clos d, flux-shifting coils on said electromagnet, and means for energizing said coils, respectively, in accordance with the rate of change of the current traversing said circuit and the decrease in the voltage thereof.

5. In combination, a circuit, an interrupter therein, an electromagnct for maintaining said interrupter closed, means for modifying the flux of said magnet to permit the interrupter to open, said means comprising flux-shifting windings responsive to the rate of change of the currenttraversing said circuit and to the voltage thereacross.

A device for operating a circuit breaker including an electromagnct for maintaining the circuit breaker closed and means responsive to the rate of change of the current traversing said circuit and to the voltage thereacross for rendering said electromagnet ineffective.

7. A device for operating a circuit breaker including means actuated by a winding connected across a reactor in the circuit to be interrupted, and a Winding in series with a condenser connected across said circuit.

8. In a circuit breaker, means tending to open said breaker, means for holdin said breaker closed, means for releasing sai holding means including a winding connected across a reactor in the circuit to be intcrrupted, and a winding in series with a con denser connected across said circuit.

9. In a circuit interrupter, separable ccntact means, means biasing said separable contact means to separated position, a magnetic core member having a normally energized winding for holdin said contact means closed against said lasing means, a flux shifting winding connected to the circuit controlled by said circuit interrupter for releasing said separable contact means in response to predetermined current condi f. in said circuit, said core member having thereon an additional wind iich normally deenergized and which causes the release of said separable contact means when energized, and means for energizing said normally deenergized winding.

10. In a circuit interrupter, separable contact means, means biasing said separable iontact means to separated position, an armature connected to said separable contact means and a magnetic core member for attracting said armature and holding said separable contact means closed against said biasing means, said core member having 21 normally energized winding for energizin said cone member to hold said armature, sai core member having pole pieces prwiding parallel magnetic flux paths one of which is 1.01am? v 3 shiftin the flux from said armature to the other ux ath upon the occurrence of a predetermin current condition, said core meme berv having an additional winding thereon which is normally deenergized and which causes the release of said separable contact means when energized, and means for energizirig1 said normally deenergized 11. a circuit interrupter, se arable contact means, meansbiasing sai separable contact means to separate position, an armature connected to said separablecontact means and a magnetic core member for attracting siid armature and holding said separable contact means closed against said bias- I ing means, said core member having a normally energized windinsfor ene'rgizm said core member to hold sai armature, sai core member havin pole ieces providing par, allel magnetic ux pa one of which is completed by said armature, a conductor positioned between said parallel flux paths for shiftin the flux from said armatureto the other ux path upon the occurrence of a predetermined current condition in the circuit through the circuit interrupter, said core member having an additional winding thereon which is normally deenergized an which causes the release of said separable contact means when energized, and means for energizing said normall deenergized upon the occurrence 0 an electrical condition in the circuit difierent from that which causes the flux to be shifted from the armature to the other flux ath. I In testimony whereo I have hereunto subscribed my name this 17th da of Ma 1929.

BOY J. N Y.

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