US1669493A - Circuit breaker - Google Patents

Description

May 15, 1928. 1,669,493

3. SLEPlAN CIRCUIT BREAKER Filed Oct. 15, 19,23

Fig. 1

Joseph S/ep/on.

n Y I ATTORNEY Patented May 15, 1928.

UNITED STATES 1,669,493 PATEN'r orr cs.

JOSEPH SLEIPIAN, OF SWISSVALE, PENNSYLVANIA, ASSIGNOR '10 WESTINGEOUBI ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

CIRCUIT BREAKER.

Application filed Gctober 15, 1923. serial No. 668,556.

My invention relates to circuit interrupters, and more particularly to circuit interrupters having means for controlling electrical arcs generated upon the operation thereof.

One object of my invention is to provide a circuit interrupter that is capable of normally preventing re-ignition of an are after the interrupted alternating current has passed through zero value.

It is a further object of my invention to provide a circuit interrupter having an asymmetric valve so placed as to prevent arc re-ignition after the interrupted alternating current has passed through zero value.

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It is also an object of my invention to provide a circuit interrupter that is so designed that, in its open position, the insulating dielectric medium between any one pair of relatively movable cont-act members is stressed only during each alternate halfcycle of the interrupted current.

It is a still further object of my invention to provide a circuit interrupter which em ploys the unidirectional current-transmitting characteristic of mercury rectifiers for pre= vening arc re-ignition therein.

In the accompanying drawings,

Figure 1 is a diagrammatic arrangement of apparatus and circuits embodying my in vention, the circuit interrupter being shown in the closed position.

Fig. 2 is a similar view, the circuit interrupter being in an intermediate position.

Fig. 3 is a similar view with the circuit interrupter in its open position.

In the several figures of the drawing, similar reference numerals indicate like parts.

in the preferred embodiment of my invention, an electrical transmission line 1 has therein a circuit interrupter 2, which comprises a movable bridging member 3 and a plurality of stationary contact members i, a

spring 5, an operating coil 6 and a handle 7.

These parts may be of any conventional type as they do not form a part of my invention.

in parallel circuit with the circuit interrupter 2 are placed apair of oppositelydisposed asymmetrical valves 8 and 9, such as mercury rectifier-s, although any device which has the characteristic of transmitting electrical current in but a single direction may be employed, and it is my intention to embrace any such device within the term.

asymmetric valve. A conductor 11 ex tends from a point intermediate the rectifiers 8 and 9 to'the bridging member 3 of the circuit interrupter.

In the operation of a circuit interrupter embodying my invention,'current normally traverses the conductor 1, stationary contact members 4, and the bridging member 3, and, by reason. of the higher resistance of the asymmetric valves, very little current traverses the parallel circuits. Upon the operation of the circuit interrupter 2, the bridgmg member 3 moves away from the stationary contact members 4, whereupon an arc is drawn therebetween.

The position of the are between the bridgmg member 3 and one of the stationary contact members 4 is determined by the direction of the current flow at the instant when the circuit interrupter is operated. In Fig. 2, it is assumed that the current is flowing from left to right, causing the arc to be drawn between the bridging member 3 and I the current traverses the mercury rect' er 8,

the conductor 11, the bridging member 3, and the right-hand stationary contact memher a. Substantially no arc is drawn between the left-hand contact member 4 and the bridging member 3 by reason of the parallel circuit traced above. Current is prevented from passing through the mercury rectifier 9 for the reason that it is opposltely-disposed to the mercury rectifier 8.

Upon the movement or the bridging member 3 to its fully open position, asshown in Fig. 3, the arc which existed between the bridging member 3 and the stationary contact member t is broken down by reason of the increase in the path of the intervening dielectric medium, which isgen'eraliy air, and by reason of the pamage of the current through zero value.

The voltage of the interrupted circuit builds up in the opposite direction from that indicated by the arrows in Fi 2. The potential gradient between the right-hand stationary contact member 4 and the bridging member 3 is very small for the reason that they are in parallel circuit, such potential difi'erence as may exist being due to the voltage drop in the mercury rectifier 9 and the conductor 11. However, the normal 'volta drop between the sections of the transmismedium insulating the bridging member 3 and the left-hand stationary contact member 4. The mercury rectifier 8 prevents the passage of current in the circuit paralleling the circuit interrupter 2 by reason of its unidirectional current-transmitting characteristic.

When a reversal of voltage from the direction shown in Fig. 2 takes place, there are no hot gases between the left-hand stationary contact member 4: and the briding contact member 3 to impair the dielectric qualities of the air and, accordingly, no arc is established therebetween. When electrical stresses are again applied during the next half-cycle, to the dielectric between ,the

right-hand stationary contact member 4 and i the bridging member 3, the dielectric medium will have sufiiciently cooled, clarified and increased in length to prevent are reignition.

Accordingly, the dielectric between either one of the stationary contact members 4 and the bridging member 3 is stressed only during each alternate half-cycle of the interrupted current, that is, only for half the period of any complete cycle of the interrupted current.

The advantage of this circuit interrupter will more clearly appear after a consideration of the characteristics of alternating current. As thecurrent in any 0 cle .approaches zero value, the rate of change. in value is at a maximum. This means that the interval of time'durin which no current flows is practically negligibl When an arc is drawn bet en two contact members, an ionized atmosphere is created bythe vapors incidental to such arcs, thereby aiding arc re-ignition. In my circuit interrupter, the removal of the stresses tending toward arc re-establishment at each pair of contact terminals for periods of half cycle duration permits the dissipation and cooling of the arc gases adjacent to the contact members.

In the event that current is flowing in the opposite direction from that shown in Fig. 2 at the moment of circuit interruption, the

mercury rectifier 8 will permit current to.

traverse the circuit extending through the rectifier 9, the conductor 11, the bridging member 3 to the left-hand stationary contact member 4.

It will thus be seen that, by the use of a pair of oppositely-disposed mercury rectifiers in the circuit relation here shown, any are which may be drawn between the stationary contact members and the bridging member in. the circuit interrupter 2 is destroyed when the current passes through zero value, and the relatively-movable contact members 3 and 4 have separated a sulficient distance tointerpose a suflicient dielectric medium therebetween. With the proper arrangement of mechanical parts, it is possible to insure the complete interruption of an electrical circuit in a half cycle by the use of my invention.

I do not wish to be restricted .to the specific circuit connections or arrangement of parts herein set forth, as various modifications thereof may be effected without departing from the spirit and scope of my invention. I desire, therefore, that only such limitations shall be imposed as are 1n- 1 line and a circuit interrupter therein, of a plurality of asymmetric valves in circuit with said circuit interrupter, said valves being so connected relative to said circuit interrupter that are re-ignition in said circuit interrupter is prevented after the interrupted current has passed through zero value.

4. The combination with a transmission line and a circuit interrupter therein, of oppositely disposed uni-directional means in parallel circuit with said circuit interrupter,

said' means being so connected relative to said-circuit interrupter that are re-ignition in said circuit interrupter is prevented after the interrupted current has passed through zero value.

5. The combination with a transmission line and a circuit interrupter therein, of a pair of oppositely disposed asymmetric valves in parallel circuit with said circuit interrupter, and means for. connecting a. point intermediate said valves to said circuit interrupter.

6. The combination with a transmission line and a circuit interrupter therefor comprising a plurality of relatively movable contact members, of a pair of oppositely disposed asymmetric valves in parallel circuit with said circuit interrupter, and means for connecting a point intermediate said valves to a movable contact member of said circuit interrupter.

7. The combination with a transmission line, and a circuit interrupter therefor comprising a plurality of relatively movable contact members, of a pair of oppositely disposed mercury rectifiers in parallel circuit with said circuit interrupter, and means for connecting a point intermediate said rectifiers to a movable contact member of said circuit interrupter.

8. The combination with an alternating current transmission line, and a circuit interrupter therefor comprising a plurality of contact members and a relatively movable bridging member therefor, of means for causing electrical stresses tending toward arc generation upon the operation of said circuit interrupter to be separately and consecutively impressed upon the dielectric mediums separating each of said contact members from said bridging member.

9. The combination with an alternating current transmission line, and a circuit interrupter therefor comprising a plurality of contact members and a relatively movable bridging member therefor, of means for causing electrical stresses tending toward arc generation upon the operation of said circuit interrupter to be separately and consecutively impressed upon the gaps separating each of said contact members from said bridging member, said impressions occurring once in each cycle of the electro-motive force in said transmission line. i

10. The combination with an alternating current transmission line, and a circuit interrupter therefor comprising a plurality of contact members and a relatively movable bridging member, of means for selectively determinin the location of the are drawn between said bridging member and one of said contact members upon the operation of said circuit interrupter, and means for transferrin the forces tending to are development rom said contact member to another contact member at a predetermined time.

11. The combination with an alternating current transmission line, and a circuit interrupter therefor comprising a plurality of contact members and a relatively movable bridging member, of means for selectively determining the location of the are drawn between said bridging member and one of said contact members upon the operation of said circuit interrupter, and means for transferring the forces tending to are development from said contact member to another contact member in accordance with the cyclic changes of the alternating current traversing said transmission line.

In testimony whereof, I have hereunto subscribed my name this 9th day of October,

JOSEPH SLEPIAN.

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