US1696605A - Combined resistor and fuse - Google Patents

Description

Dec. 25 1928. I 1,696,605

H. P. HOLLNAGEL COMBINED RESISTOR AND FUSE Filed Jan. 1926 2 Sheets-Sheet 1 To Line Fig. 3.

/2 Inventor:

' Herbert l H0 lnugel,

His'Attorneg.

TB App orat us H. P. HOLLNAGEL COMBINED RESISTOR AND FUSE Filed Jan. 6, 1926 2 Sheets-Sheet 2 Fig. 4. FL 5.

ZII

F T0 LINE. '2 6 Inventor Herbert p. HoLLnageL T0 APPARATUS- Patented Dec. 25, 1928.

UNITED STATES PATENT orrlca.

HERBERT P. HOLLNAGEL, OF SWAMPSOOTT, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

COMBINED RESISTOR AND FUSE.

Application filed January The present invention relates to protective devices for electrical apparatus and especially for protecting against the destructive action of high potential, high frequency currents or surges of electricity having a steep characterized by transient or surge phenomena originating anywhere in the circuit 16 to thereby protect such apparatus or po'rtions of the circuit conductor as are liable to injury from such phenomena.

One of the instances Where serious troubles have been experienced, from electrical transients is in condenser installations which, as iswell known, areusually made up of a plurality of units, of substantial capacity, ]o1ned in parallel, In practice condensers probably.

fail because of-tran'sients originating from causes remote to the condenser., In the failure of a condenser, it is probable that transients are set up by the sudden breakdown of some one unit and the ensuing openin of the circuit thereto by the functioning of a se 0 I a I 1n. These transients probably cause 1ncipient failure in the other condenser unit's joined in arallel therewith, ultimately-resultingint eir breakdown,

5 It is well known that the resistance of conductors increasesi enormously with rise in diameter of the conductors, their permeabil ity and resistivit I makeuse of the constant current 0 aracteristic, of the conductors, and these characteristics in their relationto trans ents, by connecting in series tected thereby quietly and without causing ,F

orother protective device intercalated there-- with a fuse, a non-inductive resistance con-- 6, 1928, Serial No. 79,683.

sorb the energy produced by the sudden rise 1n voltage or a possible ensuing risein frequency, or both. 1

Certain embodiments of the invention are shown in the accompanying drawing, in

which Fig. 1 is a side elevation of a cartridge .fuse with a non-inductive resistor element combined therewith; Fig. 2 is a vertical section thereof; Fig. 3 is a circuit diagram;

ig. 4 is an elevation of a modification in which the cartridge fuse is mounted alongside a non-inductive resistor element provided --with dissipating'vanes; Fig. 5 is an elevation of a further modification in which non-inductive resistor elements with dissipating vanes are mounted upon both ends of the cartridge fuse, and Fig. 6 is a circuit diagram of the latter arrangement.

The resistor member, as shown, consists of a base 1 of insulation having a coil of insulated resistance wire 2 reversely or noninductively wound about the larger end of the base and protected by an incasement of tape or other fibrous material wrapped thereabout. The coil lead wires 4 and 5 are threaded through passageways 6 and 7 in the smallend of the base. 1

' The fuse member is similar to the ordinary cartridge fuse and comprises a tubular barrel 8 of insulation with a thimble-shaped. terminal 9 at .its lower end and a ferrule-shaped terminal 10 at its upper end. Theupper end of the barrel receives the smaller end of the base which is secured therein by set screws 11.

The fusible element 12 is the ordinary metal strip surrounded by a tubular envelope -13 .of sheet asbestos. The lower end of the fusible element 12 is attached to the terminal 9 and the upper end to a metal bush 1-1 secured to the lower end of the base.

The coil lead wire 4 is secured to the terminal 10 and the other lead wire 5 is attached to the bush 14, and the complete device is.

connected in circuit by insertion in the usual fuse block with the contact: terminal 10 next the power line andthe terminal 9 next the condenser unit to be protected, as indicated in Fig. 3. 1

U on the interruption of the current to the con enser unit by blowing of the fuse under short circuit, a surge of current takes place which dissipates its energy in the non-inductive resistance coil 2 without causing disturbance of other devices connected to the circuit.

To care for the situation where continued arcing or interrupted short circuit COIlFlltlQIlS persist in the line, as a consequence of which continued or interrupted transients of a relatively high frequency persist over a period of time, and resulting in the absorption of energy by the resistor, I provide the latter with dissipative means.

As shown in Fig. 4, the energy dissipative means consists of a helical vane or Archimedean spiral 1-5 of metal coiled about a core bar 16 having metal thimbles 17 at its ends adapted to enter contact clips 18, the lower of which is provided with a binding screw 19 for connection with the line wire. 'The in sulated resistance wire 2 is connectedat one end by a binding screw 20 to the lower thimble 17 and passed through the trough of the spiral 15 to the upper end thereof where it turns about a peg 21 carried by bar 16 and rep-asses through the spiral trough to the lower end thereof and joined by a binding screw 22 to the lower contact clip 23 of the enclosed fuse 8. The resistor clips 18 and the fuse clips 23 are mounted on an insulating base so as to support the resistor and the fuse beside each other and permit renewal of the latter without disturbance of the former. Vith the resistance wire 52 protected by insulation, the core bar 16 may be of either insulating or conducting material, but in case the latter material is used it is provided with a slot parallel to its axis in order that it may function as an open-c-ircuited secondary in the presence of the variable currents carried by the resistance wire. In some cases it also is advantageous to provide the radiating vanes with cross slots at intervals for a like purpose. v

As shown in Fig. 5, the end terminals of the cartridge fuse 8', are provided with-hollow insulating core bars 16", on each of which is mounted a spaced series of metal disks or washers 2-1 and the insulated resistance wire 2" is connected by a binding screw 25 to the respective fuse terminals and passed through "the innermost washer 24 and coiled rightlow bar 16''. to connect with the fusible-element as in'the first modification.

Fig. 6 shows a diagram of connections embodied in the fuse construction of Fig. 5 and from which it will be apparent, that the noninduetive resistance disposed at both ends of the fusible link serves to limit the transient efie'ct thereon in both directions. Transients arising from the continuance of an are as a result of fusion of the fuse link are dissipated not only before the entering line but also before entering theapparatus, thus. protecting against surge or transient phenomena during both alternations of each cycle of such frequenciesl \Vhile I haveshown and described the best embodiments of the invention known to me, I do not desire to be restricted thereto.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. The combination of an electric fuse, spaced metallic vanes,'and a reversely wound resistance coil connected in series with said fuse and having its convolutions distributed in the spaces between said vanes. v

2. The combination of a fuse member comprising afusible element enclosed in an insulating cartridge having external contacts, and a non-inductive resistance member comprising an insulating base mounted on said cartridge and supporting a coil of resistance conductor wound non-inductively and connected in series to said fusible element and said fusible element and said resistance con ductor having terminal connection with said external contacts, and radiating vanes so disposed as to radiate the energy developed by said resistance conductor.

3. The combination of a fusible element,

an insulating cartridge about said element,

a non-inductive resistance member mounted on said cartridge and connected in series with said element, and means also mounted on said cartridge to radiate energy from said resistance member.

4. The combination of a fusible element, an insulating cartridge about said element, a non-inductive resistance member mounted on said cartridge and connected inseries with said element, and metallic vanes also mounted on said cartridge to radiate energy from said resistance member.

In witness whereof, I have hereunto set my hand this fourth day of January, 1926.

HERBERT P. HOLLNAGEL.

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