US2501323A - Magnetic blowout circuit breaker - Google Patents

Description

March 21, 1950 R, E, FRlNK 2,501,323

MAGNETIC BLOWOUT CIRCUIT BREAKER ATTOREY March 21, 195o R. E. FRINK 2,501323 MAGNETIC BLOWOUT CIRCUIT BREAKER Filed March 23, 1945 2 Sheets-Sheet 2 l n 4 /Clg 2 I 33 /7 4 /e 4 V WITNESSES: fn??? INVENTOR 7a ATTORNEY Patented Mer. 2l, 195i) UNITED STATES! PATENT OFFICE MAGNETIC BLOWOUT CIRCUIT BREAKER Russell E. Frink, Wilkinsburg, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation o! Pennsylvania Application March 23, 1945, Serial No. 584,377

6 Claims. `(Cl. 20o-147) This invention relates to circuit interrupters in general and, more particularly, to arc-extinguishing structures therefor.

A general object of my invention is to provide a circuit interrupter of improved construction, which will more effectively interrupt the arc over a wider range of current values than has been obtained heretofore.

A more specic object is to provide an improved blowout magnet construction for a circuit interrupter which will be very eilective over a wide range of current values.

Another object is to provide an improved circuit interrupter in which a portion of the magnetic blowout structure is rendered ineffective during high-current operation, and in which during low-current operation the entire blowout structure may be utilized.

A more specific object of my invention is to provide an improved magnetic blowout having a plurality of serially related coils to excite the same and to render at least one of the coils inoperative during the interruption of high currents.

Further objects land advantages will readily become apparent upon a reading of the following specification, taken in conjunction with the drawings, in which:

Figure 1 is a side elevational view, partly in section, of a circuit interrupter embodying my invention and shown in the closed circuit position, the section being taken substantially on the line I-I of Fig. 3;

Fig. 2 is a plan view of the circuit interrupter shown in Fig. 1;

Fig. 3 is an end elevational view, partly in section, taken substantially along the line III-III of Fig. l; and

Fig. 4 is a diagrammatic view illustrating the principles of operation of my invention.

It has been found that it is comparatively difcult to effect the interruption of low currents with a conventional blowout structure inasmuch as relatively low magnetic forces are involved as a result of the relatively low current passing through the blowout coil of the magnet structure. Thus, a comparatively long period of time, which may approach thirty cycles, may be required to extinguish the arc. In certain instances such a long period required for the interruption of low currents is not detrimental to operation, but in other circumstances quick operation over the entire current range is desirable to eliminate the prolonged arcing period which may be encountered during low-current interruption.

I propose to speed up the interruption of low currents while maintaining quick operation on high currents by providing a plurality of serially related windings for the magnetic blowout, at least one of which may be shorted out during high-current interruption, and in which all of the coils are utilized during low-current operation. Thus, by utilizing the entire blowout winding during low-current operation, a considerable magnetic iield is present to effect extinction of the arc during low-current interruption. However, on high-current interruption, an excessive magnetic iield is not obtained for I short out at least one of the serially related windings on the blowout structure.

Referring to Fig. 4 to illustrate the principles of my invention, the reference numerals I and 2 designate serially related blowout windings of relatively heavy wire which together may be equivalent to the turns present in the blowout winding of conventional interrupters. The reference numera-l 3 designates a serially related blowout coil consisting of a, winding composed of many turns of small wire. Small wire is preferably used to get a large number of ampere turns for low-current interruption. The reference numeral 4 generally designates a breakdown gap which is in parallel with the fine winding 3. The arcing horns of the interrupter are designated by the reference characters 1, 8, between which the arc 9 may be established during interruption.

During low-current interruption the current flows through all of the coils I, 2 and 3, producing a strong magnetic field to blow out the arc 9 established between the arcing horns l and 8.

During the interruption of higher currents, the current becomes sufficiently large so that the voltage across the fine winding coil 3 causes the breakdown gap 4 to break down, and the path of current is then only through the heavy winding serially related blowout coils I, 2 and the magnetic circuit is then equivalent to that obtained in present designs. The breakdown gap 4 thus is a current responsive selective device for rendering the ne winding coil 3 inoperative during the interruption of higher currents.

Referring to the interrupter shown in Figs. 1 to 3, inclusive, which incorporates the principles set forth in Fig. 4, it will be observed that the interrupter is of a style as is more fully described in United States patent application Serial No. 514,362 now Patent Number 2,442,199, May 25, 1948, led December 15, 1943, by Robert C. Dickinson and Russell E. Frink, and assigned to the same assignee as the present application. Brieiiy, the operation of this interrupter is such that during the opening operation, the arc which is drawn between the contacts 5, 6 and transferred to the arc horns 1, B is blown upwardly by the transverse magnetic field set up by the blowout structure IU and into the interrupting chute i I where the arc is constricted by entering tapered slots I2 provided in a plurality of spaced plates I3 of insulating material. During its movement into the interrupting structure I I, the arc extends between the left-hand arcing horn I and the right-hand arcing horn 8. The aforementioned application describes the specific interrupting chute shown and may be referred to for the details of arc interruption. My invention is not concerned with the details of arc interruption, but only with the blowout structure II) in which there are serially related energizing coils disposed about the bight portion I4 of the U-shaped blowout magnet I5.

Two of the serially related coils I, 2 (see Fig. 3) are composed of a relatively few turns of heavy wire, which is preferably equivalent to that present in conventional blowout structures. However, in addition to the two windings I, 2, I provide the additional fine winding coil 3 to get a large number of ampere turns during low-current interruption, which is so connected (see Fig. 4) so as to be shorted out during the interruption of relatively high currents by the breakdown gap 4 disposed above the blowout structure I0. By having the gap 4 disposed directly above the blowout structure II), and to one side of the interrupting structure II, space may be employed which otherwise would not be utilized. Briefly, the breakdown gap 4 comprises a stationary contact I6 and an adjustable cooperable contact I1, the latter being movable toward and away from the contact i6 in adjustable fashion by the threaded stud I8, which is threadedly secured into the insulating wall I9 of the cooling structure 20 provided for the gap 4.

During the opening operation, when interrupting high currents, the electrical circuit includes movable contact 6, flexible shunt 8a. arcing horn 8, arc 9, arcing horn 1, lead Ta, coil 2, lead 2a, contact IS, arc (not numbered) in breakdown gap 4, contact Il, lead Ia, coil I, lead a to stationary contact 5. When interrupting light currents the circuit extends through movable contact 6, flexible shunt Ba, arcing horn 8, arc 9, arcing horn 1, lead 1a, coil 2, lead 2a, lead 3a, coil 3, lead 3b, lead Ia, coil I, lead 5a to stationary contact 5.

It will be apparent that the legs 2i, 22 of the blowout structure III are laterally disposed outside of the interrupting chute l I and provide the necessary transverse magnetic field to move the arc 9 upwardly into the interrupting chute I I.

By positioning the gap 4 directly above the blowout structure III in the manner shown in Fig. l, not only is space saved, but also any return flux from the blowout structure I0 passes through the gap 4 substantially longitudinally of the arc established between the contacts I5, I1 during high-current interruption when the breakdown gap 4 short circuits the fine winding 3. As a result, the magnetic field set up by the blowout structure I0, being longitudinal of the are between the contacts I6, I1 during high-current interruption, does not tend to extinguish this arc. It is apparent that it is not desirable to extinguish the arc drawn between the contacts I5, I1 at all during high-current interruption, for the arc be tween the contacts I8, I1 is necessary to short out the fine winding coil 3 during such high-current interruption.

Preferably, a plurality of -metallic plates 23 may be utilized in the construction o! the breakdown gap housing to facilitate cooling of the gases rising from the arc drawn between the contacts I5. I1. The adjustment of the contact I'I determines the effective voltage required to break down the gap between the contacts I6, I 1.

From the foregoing description, it will be apparent that I have provided an improved circuit interrupter which operates more effectively over a wider range of current values than has heretofore been achieved. During the interruption of relatively high currents the blowout winding is equivalent to that present in conventional structures, and during the interruption of relatively low currents, an additional winding 3 is inserted in the blowout winding to increase the magnetic held between the plates 2i, 22 during low-current operation.

It will also be apparent that by placing the breakdown gap 4 and its cooperating cooling structure directly above the blowout structure Il. and to one side of the interrupting chute II, not only is available space used without increasing the dimensions substantially of the circuit interrupter, but also the magnetic field resulting from the blowout structure I 0 has no tendency to eilect extinction of the arc drawn in the breakdown gap 4.

Although I have shown and described a specific structure, it is to be clearly understood that the same was merely for the purpose of illustration, and that `changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In a circuit interrupter, means for establishing an arc, a blowout structure for effecting extinction of the arc including at least one winding of relatively heavy wire and at least a second winding of a relatively large number oi turns, means electrically connecting the windings in series electrically with the arc when the latter is initially established, a current responsive selective device for rendering the second winding inoperative only during high-current interruption even before the arc has been moved substantially by the blowout structure, and the number of energizing turns when once selected by the lastmentioned device remaining constant throughout the course of movement of the arc.

2. In a circuit interrupter, means for establishing an arc, blowout means for effecting extinction of the arc comprising two winding sections, means electrically connecting the winding sections in series electrically with the arc when the latter is initially established, and a breakdown gap shunting one of the winding sections to short circuit said one of the'sections during high-current operation because of the increase of voltage thereacross even before the arc has been moved substantially by the blowout structure, and the number of energizing turns when once selected by the last-mentioned device remaining constant throughout the course of movement of the arc.

3. In a circuit interrupter, means for establishing an arc, a blowout structure including a plurality of windings, means electrically connecting the windings in series electrically with the arc when the latter is initially established, a breakdown gap structure shunting one of the windings and disposed above the blowout structure, an interrupting structure disposed laterally to the side of both the blowout structure and the breakdown gap structure, the arrangement being such that any return flux from the blowout structure passes longitudinally of the breakdown gap structure so that the arc when drawn in the breakdown gap structure during high current interruption will only be subjected to a suhstanitally longitudinal magnetic eld.

4. In a circuit interruptor, means for establishing an arc, a blowout structure including a plurality of windings, means electrically connecting the windings in series electrically with the arc when the latter is initially established, a breakdown gap structure to short circuit one of the windings during high-current operation and disposed adjacent the blowout structure, an interrupting structure disposed adjacent both the blowout structure and the breakdown gap structure, the positioning of the structures being such that the magnetic field set up by the blowout structure will be longitudinal of the gap in the breakdown structure. I V

5. In a circuit interrupter, means for establishing an arc, a blowout magnet for eil'ecting extinction of the arc including a winding of relatively i'ew turns and a second winding of relatively many turns, means electrically connecting the windings in series electrically with the arc when the latter is initially established, a current responsive selective device for short circuiting the second winding only during high-current operation even before the arc has been moved substantially by the blowout magnet, and the number of energizing turns when once selected by the lastmentioned device remaining constant throughout the course oi' movement of the arc.

6. In a circuit interrupter, means for establishingV an arc, a magnetic blowout structure including a blowout winding for causing lateral motion of the arc to effect the extinction thereof, the blowout winding including a plurality of exciting sections each of one or more turns, means electrically connecting all the exciting sections in series electrically with the arc when the latter is initially established, a current responsive selective device immediately responsive to the magnitude of the current passing through the exciting sections of the blowout winding for immediately rendering at least one of the exciting sections inoperative only during high-current operation even before the arc has been moved substantially by the blowout structure, and the number of energizing turns when once selected by the lastmentioned device remaining constant throughout the course of movement of the arc.

RUSSELL E. F'RINK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,751,205 Hellmund Mar. 18, 1930 2,381,637 Bohn Aug. 7, 1945 FOREIGN PATENTS Number Country Date 285,774 Germany July 13, 1915 540,927 Germany Jan. 7, 1932

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