US2109850A - High tension fuse with high rupturing power - Google Patents

Description

March 1, 1938. L. J. SAUDICOEUR 2,109,850

HIGH TENSION FUSE WITH HIGH RUPTURING POWER Filed March 27, 1935 J0zzzr Z022 ezzz Patented Mar. 1, 1938 PATENT OFFICE HIGH TENSION FUSE WITH HIGH RUPTUR- INGP OWER

Louis Joseph Saudicoenr, Villeurbanne, France,

assignor to Ateliers de Constructions Electriques de Belle, Paris, France Application March 27, 1935, Serial No. 13,250 In Germany May 8, 1933 2 Claims.

Safety fuses are known for operation at high tensions having a high rupturing power comprising essentially a fusible wire disposed within a cylinder of insulating material filled with a 5 substance which is electrically inert. Such devices have the following disadvantages. The fusible wire of very small diameter subjected to high voltage becomes luminous due to the production of corona discharges, oxidizes and deteriorates. Moreover if the interruption of heavy currents may to a certain extent be suitably effected, it is not the same with currents of small intensity which cannot be interrupted.

The present invention permits of completely overcoming these disadvantages. It has for its object a high tension safety fuse comprising a fusible wiredisposed in an insulating cylinder containing an electrically inert material and is characterized in that the fusible wire is covered with insulating varnish or other insulating material fulfilling the same object and is in part wound in a helix on an insulating support enclosed or embedded in the inert material, the remainder of the wire being disposed in the part of the cylinder containing only air or inert material in such manner as not to contact with the said insulating support. Other characteristics will appear from the following description of the invention. to The accompanying drawing illustrates diagrammatically in elevation partly in section a fuse constructed in accordance with the invention. The fusible wire is denoted by I. It is disposed on an insulating support constituted by a glass tube 2. The whole is enclosed in a cylinder 3 containing an inert material consisting of sand or like material. This material is held in the cylinder by caps 5 which may either seal it her-' 40 metically or permit communication with the exterior through the medium of perforated plates 1 or the like.

In accordance with the invention the wire I is covered with varnish or insulating material and woundlnahelixoverpartofitslengthonthe glasstubei; theremainderofthewireisspaced from the glass andstretched'inthe air. For

this purpose the fusible wire may be passed into the interior of the glass tube which contains only air and it is held straight in this part of "its length.

The winding in a helix of the fusible wire permits of avoiding corona discharges. On the other hand the covering of varnish or insulating material prevents the oxidation of this wire. A glow discharge is avoided over the lower straight part of the wire by metallizing the outer, inner or both walls of the cylinder 3 as shown exaggerated at 5. Such an arrangement becomes in effect the same as enclosing the straight wire in a Faraday cage.

The arrangement described permits of completely avoiding deterioration of the fusible wire by corona discharge and of interrupting the whole range of currents from the weakest to the maximum currents guaranteed.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. In a high-tension high-power cartridge fuse having an elongated body, a tubular support of insulating material disposed substantially concentrically within the body and extending the full length thereof; and a uniform-section continuous fusible wire having a part wound upon said support and a part within said support, whereby said wire is adapted to start fusing at one extremity and continue melting to the other extremity thereof.

2. In a high-tension high-power cartridge fuse'having a cylindrical body permeable to gases created therein, an insulating tubular support permanently disposed inside the body and extending the whole length thereof, and a continuous uniform-section fusible wire partly wound over a portion of the support and partly extended within the remaining portion of the tubular support concentrically and parallel thereto through an aperture provided in said support, whereby when said wire is overloaded electrically it starts melting at one extremity and keeps on melting it to the other extremity.

LOUIS JOSEPH SAUDICOEUR.

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