US1851238A - Electric arc disrupter - Google Patents

Description

March 29, 1932. P. J. BRANCHU 398519238 ELECTRIC ARC DISRUPTER Filed April 29. 1929 Patented Mar. 29, 1932 PAUL JOSEPH BRANC HU, OF GRENOBLE, FRANCE ELECTRIC ARC DISRUITER Application filed April 29, 1929, Serial No. 359,128, and in France Hay-10, 1928.

The present invention relates to devices adapted to blow the electric arcs in circuit breakers and its object is to provide an improved device efiectiveto so modify the mag- 5 netic flux blowing the are that the field is reinforced in the regions most favorable for the good working of the circuit breaker or switch.

The invention consists in placing within the field a conductor a, b, constituting a circuit closed on itself and comprising two 0ppositely wound windings in the shape of a figure 8 of different sizes. Variations of the blowout field induce E. M. F. in each winding, but th E. M. F. of the larger loop will be larger as its linkage with the field flux is greater, consequently a current will flow in the two loops. The direction of winding is such that this current reduces the flux due to the blowout winding in the region of the upper or larger loop and increases it in the region of the small loop near the contacts.

These properties can be, for example, utilized to reinforce the field blowing the are .at the moment of working of a switch.

In the drawings:

Fig. '1 is a section of an embodiment of the invention taken on the line 1-1 of'Fig. 2;

Fig. 2 is an elevation at right angles to Fig. 3 is a detail elevation of a modified form of the coils' and showing one of the coils.

According to this latter embodiment p is the line traversed by the main current and g is the blowing coil placed inseries in this line and creating a magnetic field in a mag- I netic circuit 7.

1 In the air-gap of f are placed two contacts a, 0', the first 0 being formed by the extremity of a movable arm q pivoting around an axis 9, the working of the movable arm 9 being secured in any way.

The blowing box is formed in the usual way by insulating walls d, e.

The invention consists in that a conductor a,bclosed in itself and forming the secondary winding of a transformer whose primary winding is constituted by the blowing coil' g, is placed. in the field blowing the arc engenopening of the circuit breaken-will be dered between 0, 0'. This secondary conductor is situated outside of the blowing box and is separated from the arc.

According to the embodiment represented in Figs. 1 and 2 this secondary conductor as forms the figure 8 whose two loops a, b are therefore reversed, as to direction, and moreover are unequal in size, the greater loop a surrounding the field in a' region removed from the point where the contacts 0,0 meet 60 or are to beseparated, the small loop 5 being situated in the region of these contacts 0, o; r The device serves to' distort the field between the pole pieces, strengthening the field in the region of the initial arc and decreasing it above that point. i

If the current increases rapidly in-the coil 9 (because of a short-circuit or for any other reason), the magnetic field tends equally to augment. Owing to the increase of the flux across both loops a, b of the 8-1ike shaped conductor. electromotive forces are engendered in each loop, tending according to the lawof Lenz to oppose themselves to the variations of the flux. The great loop a trav- 7 ersed by a greater flux than the small loop I), has generated therein an electromotive force greater than the latter. These electromotive forces being each the opposite of the other, a current will be established in the sense of the greater one, which current will pass into the small loop I) in a direction inverse to the direction of the electromotive force engendered. It is obvious that the effect produced by this current with regard to 8 the fie d in the small loop b will act opposite- 1y to the law of Lenz, viz. will tend to reinforce the variations of the current instead of opposing itself to them. Consequently the field will be reinforced in the space enclosed by the small loop 6, thatis in the neighborhood of the contacts 0, c in the period of in-' crease of the currentin the coil g. Hence the roduced during the period of the increase 0 the current, and the b owing field will be reinforced in the neighbourhood of the points 0, 0'. which fact is favorable to the working of the circuit-breaker.

Fig. 3 represents an embodiment according to which the secondary conductor comprises several loops (1, b of increasing dimensions.

In this manner it is possible to obtain a reinforced field especially in the immediate neighbourhood of the contacts 0, a.

The invention is, of course, not limited to the embodiments shown and described and extends to all kinds of disjunctors and circuit breakers whose magnetic flux blowing the arc can be very favorably modified.

' What I claim is:

1. In an electric arc interrupter, a fixed contact and a movable contact traversed by the circuit to be opened, a core, a blowout coil on the core'in series with the circuit to be opened, whereby a magnetic field is created, and a second coil in short circuit disposed in the said magnetic field and having windings in the form of afigure 8 so as to deform the v blowout field. r

2. An interrupter as claimed in claim 1, in which the second coil in short circuit is in the form of a figure 8 having two loops, unequal in size and the smaller of which is located in the region of the contacts to reinforce the magnetic field in the said region.

In witness whereof I affix my signature.

' PAUL JOSaEPI-I BRANCHU.

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