US1829604A

US1829604A - Oil immersed fuse

Info

Publication number: US1829604A
Application number: US67013A
Authority: US
Inventors: Natalis Friedrich
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1925-01-23
Filing date: 1925-11-05
Publication date: 1931-10-27
Anticipated expiration: 1948-10-27

Description

Patented Oct. 27, 1931 UNITED STATES PATENT OFFICE FRIEDRICH NATALIS, OF BERLIN-CHARLOTTENBURG, GERMANY, ASSIGNOR TO WEST- INGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA OIL IMMERSED ruse Application filed November 5, 1925, Serial No. 67,013, and. in Germany January 23, 1925.

My invention relates to electric fuses or cutouts adapted to interrupt an electric circuit upon the passage therethrough of abnormal and dangerous currents,'and it has particular relation to oil-immersed fuses for high-tension currents.

It is an object of the present inventionto provide a fuse or cutout whereby the arc 1ncident to the rupture .of the fuse is quickly extinguished and the circuit interrupted.

Another object of the invention is to provide an oil immersed fuse wherein the oil surrounding the fuse is violently agitated and directed toward the are upon the rupture of the fuse.

A fuse constructed in accordance with my invention comprises a cylinder of insulating material closed at the ends and having large openings at the sides and fitted with a relatively light movable piston which is connected to a terminal block at one end of the cylinder by a flexible conductor and to a terminal block at the other end of the cylinder by a fusible link. The piston is moved rapidly by the pressure of gas generated by the melting of the fuse, and the arc is extinguished by the inrush of quenching liquid.

In the accompanying drawings:

Figure 1 is a longitudinal sectional view of a fuse embodying features of the invention,

Fig. 2 is a reduced sectional view of an oil filled casing enclosing the fuse structure shown in Figure 1.

An insulating casing 11 is provided with two

lateral openings

12 and 13 and comprises an arc-extinguishing chamber 15 having a fusible wire 16 located therein. The chamber is closed at the top by a cover 14, in which is located the detachable terminal member 17 to which is secured a secondary terminal member 18 for the fuse wire 16. The member 17 is secured to the cover 14 by the screw 19, which may also serve to secure the outside conductor to the device. The lower end of the fuse wire 16 is connected, by means of a terminal member 20, to a link 21 and this latter is connected to the terminal 23 by means of a flexible conductor 22.

The link 21 is carried by a cup-like piston 24 that is provided with openings 29 in its bottom and sides, respectively, the purpose of which will hereinafter appear. A tubular member 26, located within the member 11, serves as a stop for the piston 24.

A metal re-inforcing casing 27 surrounds the casing 11 in order to prevent bursting thereof, and a packing ring 28 is provided at the joint between the cover 14 and the casing 11. The piston is made very light so that it will move quickly when the fuse blows and prevent the side wall from being forced out, and. so that its movement will be dampened by the oil to prevent damage when it strikes the member 26.

The fuse structure above described is designed to be submerged in oil or other insulating liquid 30 contained in a tank 31, and, consequently, the fuse wire 16 and piston or plunger 24 are completely surrounded by insulating fluid.

In the event of the passage of current greater than the rated capacity of the fusible element, the pressure generated by the arc resulting from the rupture of the fuse will move the piston rapidly and thus quickly increase the distance between the free ends of the fuse wire.

The large openings in the casing and in the piston allow the oil to How in and quench the are formed by the melting of the fuse.

Oil also is permitted to flow inwardly through the openings 29 in the side of iston and across the are, thereby causing it to be rapidly cooled and extinguished. The rapid movement of the piston past the

openings

12 and 13 in the casing results in violent agitation of the oil and causes cool oil to flow into the space occupied by the are.

In order to replace the fuse wire 16, the casing is first removed from the tank and the terminal member 17 disengaged from the casing. A new fuse element may then be inserted between the member 17 and the link 21. The openings 29 in the sides of the piston 24 permit access to the fastening bolt or screw. I

The term electric fuse in the following claims means an electric conductor of such dimensions and other physical characteristics as to be heated to its melting point b current slightly in excess of the normal in Head current of apparatus connected in series with it, and used for the purpose of protecting such apparatus. This use of the aforesaid term is its usual and well-known significance in the electric art.

It will be apparent from the foregoing description that the fuse device is simple and inexpensive in construction and that the parts thereof are readily accessible for inspection, repair or replacement.

While I have described and illustrated a. particular form of the invention, it will be apparent to those skilled in the art that various modifications, addition and omissions may be made therein without departing from the spirit and scope thereof. as set forth in the appended claims.

I claim as my invention:

1. In an electric fuse, the combination of a receptacle adapted to contain insulating liquid, a tubular member made of insulating material and disposed within said receptacle, said tubular member having large openings providing communication between the interior of the tubular member and the liquid-containin portion of the receptacle, a

' closure for said tubular member spaced from the openings, said tubular member forinin a chamber between the closure and sa'i openings, a piston disposed within said tubular member, a fusible element disposed 'within the chamber and normally supporting the piston at the end of said chamber adjacent said openings, said fusible element being fusible by the passage of an excess electric current therethrough, whereby, upon melting of said fusible element, the pressure of the gas generated thereby will propel the piston away from said chamber to permit the insulating liquid to enter through said openings into said chamber to extin uish the are.

2. In an electric fuse, the combination with an insulating casing closed at the ends and having substantially one half of its central portion cut away, formin a large opening in its sides, of a fusible e ement and a piston therein located at one end of the opening, the said piston beingactuated t0 the other side of the opening by the pressure developed upon the rupturing of the fusible element.

3. In an electric fuse, the combination with an insulating casing having its central portion cut away leaving large openings in its sides, of a fusible element on one side of the openings, and a hollow .piston that is movable past the opened central portion of the casing when propelled by the pressure of the ases developed upon the rupturing of the f usible element.

4. In an electric fuse, the combination with an insulating casing having its upper. end closed to form a pressure chamber, the per- FRIEDRICH NATALIS.