US757782A - Electric-arc-rupturing device. - Google Patents

Description

PATENTED APR. 19,1904.

S. H. SHORT.-

ELECTRIG ARC RUPTURING DEVIGE.

APPLIOATION FILED FEB. 11, 1902.

N0 MODEL.

by 54 fw A5 Wl'iizesses:

UNITED STATES Iatented April 19, 1904.

PATENT ()FFIQE.

SIDNEY H. SHORT, OF LONDON, ENGLAND, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

ELECTRlC-ARC-RUPTURING DEVICE.

SPECIFICATION forming part of Letters Patent N0. 757,782, dated April 19, 1904. Application filed February 11, 1902. Serial No. 93,515.- (No model.)

To aZZ whom it may concern.-

Be it known that I, SIDNEY H. SHORT, a citizen of the United States, and a resident of London, in the county of Middlesex, England, have invented certain new and useful Improvements in Electric-Arc-Rupturing Devices, of which the following is a specification.

This invention relates to devices adapted to rupture an electric are when formed between two points, such as the switch-contacts of a current-controller for electric motors; and it has for its object to provide a magnetic blow-out arc-rupturing device which can'lbebrought close to the are without requiringfthe protection of external insulation. 4

In carrying out my invention I dispose the contact-points between which the arc will be formed between the bare pole-pieces of an electromagnet, preferably having an externally-closed magnetic circuit, these pole-pieces being electrically insulated from the magnetr core, so that when the arc is drawnout and lengthened by the flux of the electromagnet the path of the arc cannot be shortened by its striking the pole-pieces. v 1 I The invention may be applied to a single or multiple contact blow-out device, the same, general features being present under both conj-I ditions.

My invention is illustrated in the accompanying drawings, in which Figure 1 is an elevation, partly sectional, of a single-contact blow-out apparatus constructed in accordance with my invention. Fig. 2 is a similar view of a double-contact device of the same general construction, and Fig. 3 is a detail View.

In the drawings, 1 represents a switch-shaft provided with a controlling-handle 2 and having mounted upon it a sleeve 3, carrying one or more segmental contact-pieces 4 4. The contact-segments are each adapted to engage with a spring-contact 5, as shown. The parts 4 and 5 represent the terminals of an electric circuit and between them the arc is formed, which it is the purpose of the present invention to rupture. When the contacts 4 and 5 are in engagement, the circuit is closed. The point of contact between these parts or the point at which the arc is to be formed is arranged centrally between the pole-sur'faces of an electromagnet 6. This magnet may be energized by the current whose flow is to be interrupted by the switch. The magnet 6, as shown, is closed externally by an iron bar or horseshoe-frame 7, the same being made sufficiently long to prevent an are ever forming between it and the contact-points.

Each limb of the electromagnet 6 is hollowed out, as shown, and Within the hollow portion are inserted an insulating-washer9 and an insulating-ring 10, the latter being screwed into place within the hollow portion of the limb, the limb and the ring being correspondingly screw-threaded for this purpose. Each pole-piece is then similarly screwed into place within the insulating-ring, the whole forming a compact and strong mechanical structure.

Other means of connection may be selectedas, for example, that of screwing the polel-pieces over a hub in the limbs, insulation being interposed, so as to cause an electrical :separation between the pole-piece and the rnagnet-limb.

Such being the general structure and arrangement of the parts, whenever on breaking the electric circuit an arc is formed between'the contact elements 4: and 5, it is immediately drawn out by the powerful magnetic flux between the pole-pieces and becomes attenuated, taking a longer and longer path in its endeavor to embrace an increasing number of lines of force until rupture takes place. When the electric circuit is broken in one direction, the are forms outwardly away from the segment; but should the current be flowing in the other direction the arc is extended between the axes of the coil and the contactsegment.

The foregoing relates more particularly to the structures shown in Figs. 1 and 3.

In the arrangement illustrated in Fig. 2 I provide two contact segments and fingers between the poles of an electromagnet of similar character to that above described; but I so arrange the elements that the magnetic flux will pass through each contact-segment in the same direction, this being brought about by a suitable arrangement of the electrical connections of the segments and contact-fingers. Thus in the arrangement illustrated I employ three energizing-coils, one arranged between the two sets of contact-points and one on the outside of each set. The magnetic circuit of the two end coils is externally completed by an outside iron bar or horseshoe-frame as before, While the intermediate coil practically surrounds the double pole-piece formed in two parts, insulated from each other, and preferably connected in substantially the same manher as has already been described in connection with each pole-piece and its corresponding magnet-limb in Fig. 1. The pole-pieces at the ends are also insulated from the magnet-core, as already described, and for the sake of mechanical strength they are connected in the manner already indicated.

The whole structure illustrated in Fig. 2 forms, therefore, an electromagnet with three coils and two air-gaps, the contact-points being disposed within these air-gaps, so that ares formed at the contact-points will be blown out, as already described.

The number of sets of contacts and the number of magnet-coils may be multiplied at will, provided the same general arrangement is followed as indicated in Fig. 2.

By virtue of the arrangements described herein it is possible to let the magnet-poles approach the point at which the are is to be formed quite closely without requiring that the pole-pieces shall be externally insulated and without any shortening of the path of the are through its striking the pole-pieces.

I claim as my invention 1. In an electric-arc-rupturing device, the combination with the contact-points between which an arc is likely to be formed, of a polepieee in proximity to the arcing-point, the said pole-piece being insulated from the limb of the magnet to which it is attached.

2. In an electric-arc-rupturing device, the combination with the contact-pieces between which an arc is likely to be formed, of an electromagnet having a pole-piece in proximity to the arcing-point, the said pole-piece being connected to the limb of the magnet but in sulated therefrom.

3. In an electric-arc-rupturing device, the combination with contacts between which the are is likely to be formed, of an electromagnet having a bare pole-piece in proximity to the arcing-point, the said pole-piece being connected to the limb of the magnet but SOP- rated therefrom by suitable insulation.

4. In an electric-arc-rupturing device, the combination with one or more sets of contacts between which an are or arcs is or are likely to be formed, of electromagnetic pole-pieces on opposite sides of each set, the said polepieees being arranged in proximity to the are ing point or points and being safely insulated at points behind their faces, as and for the purpose set forth.

Signed at London, in the county of Middlesex, England, this 31st day of January, A. l).

SIDNEY vH. SHORT. Witnesses:

H. l). JAumsoN, A. NUTTING.

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