US1421170A - Circuit interrupter - Google Patents

Description

L. W. CHUBB.

CIRCUIT INTERRUFTER.

APPLICATION FILEDJAN.1{1.19J8.

Patented June 27, 1922.

llllll L ad INVENTOR Lew/'5 wuW/hyton C/lubb WITNESSES: 6d. fl/M ATTORNEY .matically UNITED STATES PATENT OFFICE.

LEWIS WARRINGTON CHUBB, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 WEST- INGHOUSE ELECTRIC & MANUFACTURING- GOMPANY, A CORPORATION OF PENN- SYLVANIA.

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Specification of Letters Patent. Patented J 11113 27, 1922 Application filed January 14, 1918. Serial No. 211,711.

To all whom it may camera: I Be it known that I, LEWIS WARRINGTON CHUBB, a citizen'of the United States, and a resident of Pittsburgh in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Circuit I-nterrupters, of which the followinglis a specification.

invention relates to 'circuit interrupters and particularly to means for autointerrupting electrical circuits, under predetermined conditions.

One object of my invention is to providean automatic circuit interrupter that shall be adapted to operate quickly when a short circuit, or other similar fault, obtains inthe circuit.

Another object of my invention is to pro vide a circuit interrupter of the vacuumelectric type that shall be automatic-in its operation and simple and inexpensive to construct.

In carr ing out my invention, I provide a vacuum-e ectric apparatus or vapor valve that is connected in series with the circuit. A normally charged condenser is connected in series with a spark gap and a portion of the winding of an autmtransformer. Another portion of the winding of the autotransformer is connected in series with the valve. The condenser circuit'is so connected to the valve that, when a short circuit obtains on the circuit, sufiicient voltage is induced in a portion of the transformer winding to cause the spark gap to break down and thus permit the condenser to discharge through the valve to extinguish the are in the same and thereby open the circuit. Since, under short-circuit conditions, the current in the circuit increases quickly, the transformer causes the current to be deflected through the condenser circuit, afterthe spark gap breaksdown, to insure that the arc in the valve willbe effectively extin ished. v

igure 1 of the accompanying drawings is a diagrammatic view of circuits and apparatus embodying my invention, and Figs.

'- 2, 3-and 4 are diagrammatic views of modifiedforms of circu ts and apparatus embodymyinventioni iele'ctrlc clrcuit 1 "comprises conductors or other similar transformer 6 is connected 1n series with a vapor valve or vacuum-electric apparatus 7 and the circuit, thus constituted, is connected in series with the conductor 2. A condenser 8 is connected from the cathode of the valve 7 through a relatively high-resistance resistor 9, to the conductor 3, thus permitting the condenser 8 to be charged, under all normal conditions of operation of the circuit. The secondary winding 10 ofthe transformer 6. is connected in series with a spark gap 11 .and .the condenser 8. Since the condenser 8 is operatively connected to one terminal of the valve 7, and the windings of the transformer 6 are connected together, the circuit, comprising the condenser 8, the spark gap 11 and the winding 10 of the transformer 6, is connected in shunt relation to the valve 7.

When a short circuit obtains upon the cir- ,cuit 1, the relatively quick change in current traversing the winding 5 of the transformer 6 will induce sufficient voltage in the secondary winding 10 thereof to so change the difference in potential across the spark gap 11 as to cause the same to break down. When the spark gap 11 flashes over, by reason of the increase in potential thereacross the circuit of the condenser 8, through the valve 7, the spark gap 11 and the winding 10 of the transformer, will be completed to thus permit the condenser to discharge through the. valve 7 in a direction opposite to the normal direction of flow of current therein to extinguish the arc thereof. Since the current traversing the circuit quickly increases when the fault obtains in the circuit 1, the transformer 6 will effectively deflect the current from the valve 7 through the condenser circuit and-thereby assist in extinguishing the arc in the valve.

In Fig. 2 of the drawings, a switch 12 is provided around the terminals of the spark gap 11 for. the purpose of connecting the thesame changes suddenly. In order to oifset the detrimental effect of the inductance of the transformer 6, a second valve 13, having an ionizing means 14, is connected in shunt relation to a. portion of the trans former. By this arrangement, when the switch 12 is closed manually, the current from the condenser 8 traverses the valve 13 and, since the circuit is of relatively low impedance, the arc of the valve 7 is extinguished.

If the voltage of the direct-current circuit 1 is below 600 volts, the spark gap 11 will not be reliable, and, in Fig. 3 of the drawings, I have shown a source 15 of electromotive force connected in series with the highresistance resistor 9 for maintaining the charge of the condenser higher than the voltage of the circuit 1. This permits the use of a greater gap length in the spark gap 11 and thus the spark gap will break down under a "much smaller percentage increase of voltage, or, in othen'words, under a relatively small increase of voltage.

In Fig. 4 of the drawings, a second transformer 16, the primary winding 17 of which is connected in series with the conductor 2, is provided to cause the spark gap 11 to be effective on relatively low-voltage circuits. The secondary winding 18 of the transformer 16, that has a relatively large number of turns, is connected in shunt relation to a condenser 19, and the condenser 19 is connected in series relation to a spark gap 20 and a portion of the winding of the trans former 6.". 'By this arrangement, the spark gap 11 may be set for a relatively} igh volta e and be caused to break down y reason of a high-voltage impulse produced by the transformer 16. at},

A sudden changewof current in the circuit 1 induces a high voltage in the secondary winding 18 of the transformer 16 which charges the condenser 19 and, when the condenser 19 is charged to a sufiiciently high value, it will so raise the potential across the spark gap 20 as to cause the sarne to break down. When the spark gap 20 breaks down, the sudden application of voltage across a portion of the winding of the transformer 6 will be suflicient to cause the spark gap 11 to break down and thus complete the circuit of the condenser 8 in shunt relation to the valve 7 and thereby permit the con, denser 8 to discharge through the valve 7 to extinguish the arc therein.

My invention is not limited to the specific devices illustrated, as it may be variously modified without departing from the spirit and scope of the invention, as set forth in the appended claims.

I claim as my invention:

1. In an electrical circuit, the combination with a vacuum-electric apparatus, of a normally charged condenser connected in shunt relation thereto, and a spark gap operatively connected in series with the condenser for causing the latter to discharge through the said vacuum-electric apparatus when a fault obtains on, the circuit.

2. In an electrical circuit, the combination with a vacuum-electric apparatus, of a normally charged condenser connected in shunt relation thereto, a spark gap connected in series with the condenser, and means for causing the spark gap to break down when a fault obtains on the circuit.

In an electrical circuit, the combination with a vacuum-electric apparatus, of a normally charged condenser connected in shunt relation thereto, a spark gap connected in series with the condenser, and means for causing the spark gap to break down when a short circuit obtains on the circuit.

4. In an electrical circuit, the combination with a vacuum-electric apparatus, of a normally charged condenser connected in shunt relation thereto, a spark gap connected in series with the condenser, and a transformer operatively connected to the vacuumelectric apparatus and the condenser andadapted \to break down the spark gap to cause the condenser to discharge through the vacuum-electric apparatus under predetermined conditions.

5. In an electrical circuit, the combination with a vapor valve, of a condenser normany connected across the circuit, a transformer, a portion of the winding of which is connected in series with the valve and another portion of the winding of which is connected in series with the valve and the condenser under. predetermined conditions.

6. In an electrical circuit, the combination with a vapor valve, of a condenser normally connected across the circuit, a transformer, a portion of the winding of which is connected in series with the valve and another portion of the winding of which is connected to the valve and the condenser when the current traversing the circuit changes quickly.

7 In an electrical circuit, the combination with a vapor valve, of a; normally charged condenser, a spark gap connected in circuit with the condenser across the valve, and means for increasing the potential drop across the spark gap sufficiently to break down the same when the current traversing 9. In an electrical circuit, the oombination 1 disconnect the same and to conduct the condenser discharge through the vacuum-electric apparatus when the current traversing the circuit increases uickly.

10. In an electrical circuit, the combination with a vacuum-electric apparatus, of .a normally charged condenser o peratively connected to the vacuum-electric apparatus for rendering the same inoperative, a spark gap operatively connected in series with the condenser and the vacuum-electric apparatus,

- and a transformer operatively connected in circuit relation tothe spark gap for causing the spark to breakdown when the current traversing the circuit increases quickly.

11. In an electrical circuit, the combination with a Vacuum-electric apparatus, opt a normally charged condenser operatively connected in circuit relation thereto for rendering the same inoperative, a spark gap operatively connected in series with the condenser and the vacuum-electric apparatus, and a transformer operatively connected in circuit with the spark gap to cause the latter to break down when the current traversing the circuit increases quickly and for maintaining the arc across the spark gap until the arc in the vacuum-electric apparatus is extinguished.

12. In an tion with a vacuum-electric apparatus, of a normally charged condenser connected in shunt relation thereto, a spark gap connected in series with the condenser, and means for electrical circuit, the combine;

causing the spark gap to break down under predetermined conditions in the circuit.

In testimony whereof, I have hereunto subscribed my name this 31st day of Dec., 1917.

' LEWIS WARRINGToN CHUBB.

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