US1657452A - Lightning arrester - Google Patents

Description

` Jan. 31,v 1928.

A. L. ATHERTON LIGHTNING ARHESTER Filed sept. 19. 1922 Figl. I

J5 .3.3 as @4 mvENToR .Alfred L. Atherton.

WITNESSES:

ATTORNEY Patented Jan. 31, 1928.

UNITED STATES PATENT carica.

ALFRED L. ATKHERTON, OF PITTSBURGH, ENNSYLVANIA, ASSIGNOR TO VIESTING- HOUSE ELECTRC & MANUFACTURNG COMPANY, A CORPORATION' OF .PENNSYL- VANA.

LIG-HTNNG ARRESTEB.

Application filed September 19, 1922. Serial No. l389,087.

My invention relates to lightning arresters, more especially to the multiple-gap type commonly employed in alternating-current circuits.

It is among the objects of this invent-ion to provide an arrester which is of simple compact structure, readily accessible and applicable to alternating-ernment transmission lines.

It is a further object of this invention to provide a struct-ure which shall be relatively inexpensive to manufacture in production quantities.

Lightning arresters of the series multigap type heretofore employed function upon the principle of obtaining a. discharge of abnormal surges from a line to ground through a series of arc gaps having a resistance in series therewith.i

My present invention is directed to a structure which comprises a relative .y large number of such discharge gaps, each having resistance in series therewith, but connected in parallel or shunt groups. rlhe structure is relatively simple and is contained wit-hin a compact unit to make it commercially applicable.

In the accompanying drawings consti- `tuting a part hereof and in which like reference characters designate like parts,

Fig. 1 is a plan view of a resistor element of a lightning arrester embodying the principles of my invention, and

Fig. 2 is a cross-sectional view of the lightning arrester taken along the lines H- H of Fig. l.

Referring to the drawing, the arrester may comprise a plurality of instal plates constituting electrodes having insulating spacer rings 31 disposed therebetween, Resistor dislrs 32, provided with surface coatings 33 or non-arcing conductor material, such as brass, and having a large number of parallel transverse slots or receses 34, are disposed between adajacent electrodes 30. The dimensions of the elctrodes 30 and the spacer rings 31 are such as to provide suitable spaces or gap 35 between the resistor surface coatings 33 and the metal-plate electrodes 30, thus establishing a plurality of individual sparking surfaces 36 in shunt to said metalplate electrodes. Any number of such constructed layers may be stacked in multiple to provide an arrester of thc desired capacit-y, as in Fig. 9,.

The function of these arresters is such that, when the device is connected in a circuit, discharge will be effected, through the individual sparking surfaces 36 and the several serially related sections of the resistors the rcsistances of which are suiiiciently high to limit the current-carrying capacity of each sparking surface 36 to a small value, so that the continued iow of the line current, after an excess-voltage discharge, is eifectively prevented, the discharge being distributed over awide area of low currentdensity, instead of being concentrated in a single point, as in a-rresters of the prior art. rlie relatively large number of gaps 35 built up in shunt groups thus increases the discharge capacity to a relatively large degree without raisingthe current across each gap and without requiring the height of construction heretofore employed in arrestors oi' the low-equivalent type.

lt will be evident from the above dccription that a lightning arrester built in accordance therewith provides an ei'iicient discharge path for abnormal voltages or surges on power 'transmission lines, thereby protecting the insulation of electrical devices embodied in such circuits.

A further advantage is that such ay device provides a plurality of spark gaps which, owing to the series resistances, are individually of a low current capacity but, as a unit, provide a relatively large current capacity for the size of the structure.

Athough have described a specific embodiment of my invention, it will be obvious to those skilled in the art that various modifications may be made in the details of construction without departing from the principles herein set forth. For instance, any arrangement of resistors to produce a plurality of spark gaps in shunt may be provided in place of the structure herein described, or the devices illustrated may be enclosed within a suitable container or in other ways modilicd to adapt them to the specific service in which they are to be used.

l claim as my invention:

l. A lightning arrester comprising a pair of electrodes having a gap therebetween, one of said electrodes comprising resistance inaterial having its gap surface divided into a large number of sparking surfaces by means of a large number of slots, the resistances of the several serially related sections of the resistance material being suffinientl),Y high to linut the current-carrying Capaoity of each of the said sparking surfaces to a small value, so that the total discharge of thea'rresteris distributed-over a ,plurality of said sparkingsurfaces insteadof 'being sparking Surfaces by ,means oi a large num-` ber of slot/s, the yresistances oit -the several serially related sections of the resistance material being sueiently high to limit the eurrentcarrying Capacityl of each of the said sparking surfaces to a small value, vso that the total discharge `of the arrester is distributed over a plurality :of said .sparking surfaces instead of being concentra-ted in a singlearo.

3. A lightning arrester comprising a group of resistor elementsarranged in sideby-sirde relation to form parallel, substan-v tially distinet'eu'rrent discharge paths, an electrode member spaced from the ends of said resistorelements to constitute a plurality of discharge gaps in series with said parallel paths, the resistance of each path being .suiliciently large to resti-ict the current in each individual path to a relatively small value, and the total number o't parallel discharge paths being sufficient to provide la relatively large discharge capacity.

In testimony whereof, have hereunto Ysubscribed my naine this 25th day of `August ALFRED L. ATHERTON.

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