US 2050334 A
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Aug. 11, 1936. D. R. KELLOGG LIGHTNING ARRESTER Filed April 8, 1953 INVENTOR DOWOEKfiV/ogg %W W ATTORNEY WITNESSES: 5%
Patented Aug. 11, 1936 LIGHTNING ARBESTER David R. Kellogg, Edgewood, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, -Pa., a corporation of Pennsylvania Application April 8, 1933. Serial No. 665,151
This invention pertains to improvements in lightning arresters.
Present types of arresters are designed to conduct lightning discarges through a path of high resistance. This path should withstand repeated discharges. Conventionally it may include a series of accurately spaced air .gaps to become conducting under high voltage, together with a high resistance conductor such as metal compounds, disposed as loose particles or as a compacted block. However on continued overload, such as imposed by a defective high-tension line, the conductivity of the path tends to increase until serious short circuit'or explosive rupture of the arrester may occur. In some types of arrester, means for protection are provided to open the arrester circuit on continued overload.
An object of this invention is to maintain the efficacy of arresters, and particularly of their high resistance elements, for extensive periods of time under normal conditions of use.
Another object is to preserve the high resistance elements under severe electrical stress.
Further objects are to improve existing protective means and assure safe operation of arresters, to minimize explosion of an arrester on continued overload, and in the event of rupture of an arrester to obviate the hazards of explosion and fire.
Other objects appear with further description of this invention, as shown in preferred embodiment in the accompanying drawing, and as particularly pointed out in the appended claims.
For illustration, but without unnecessary restriction, this invention is described with reference to a type of lightning arrester having highresistance blocks supported by frangible protective means.
In the drawing, the single figure in vertical section of a frangible lightning arrester, containing resistance blocks in fusible dielectric, illustrates a preferred embodiment of this invention.
According to the present invention the highresistance element of the arrester is embedded in consolidated but flowable material that is nonfiammable under conditions of high tension discharge. In a preferred embodiment the conductor is embedded in thermoplastic organic compound containing halogen in relatively high proportion to hydrogen.
Referring more particularly to the drawing, an arrester is shown comprising a non-conducting cylindrical shell I through which an electrical path of high resistance is interposed between line and ground connectors 2 and 3. This path comprises a series of air gaps 4 between spaced conductors 5. These are in circuit with high resistance porous conducting blocks 6, to which is soldered the connector 3. A spring I presses upon this assembly. Support for these elements 5 is provided by dished porcelain closure 8 that is secured to the bottom of shell I. The support 8 is designed with a frangible element such as thin wall portions 9 adjacent thicker walls so as to crack with appreciable rise of temperature.
According to this invention, consolidated, flowable material l embeds high resistance conductors 6, and as shown fills the space adjacent frangible element 9 and connector 3.
Various benefits result from this arrangement. For instance, alignment of the separate element is maintained as well as the air gap spacing Mechanical shock by play of the conductor elements is prevented from weakening the soldered connections or the frangible support.
Important advantages are obtainable by preferred modifications of .the invention in which the embedding material I0 comprises wax-like halogenated compound. For example, chlorinated diphenyl containing above sixty percent halogen, as about sixty to seventy-five percent chlorine, is particularly useful. In the event of its decomposition under high tension discharge, its high ratio of chlorine to hydrogen prevents combustion, or flame, and thus reduces fire hazard. Moreover, halogenated compounds are relatively stable, particularly halogenated cyclic compounds such as derivatives. of diphenyl, of naphthalene and the like. Where such high stability is not important various other waxes may be used though some waxes tend to decompose under repeated high voltage and as decomposition products yield carbon and water. Avoidance of moisture accumulation is of considerable importance to dependable operation of an arrester.
High resistance elements in conjunction with chlorinated diphenyl exhibit additional physical characteristics of value in an arrester. For example, chlorinated diphenyl containing about 68% chlorine can be poured about the high resistance blocks at upwards of 250 F. but below its fluid range sets to a hard but yielding solid. Should heat develop in the resistor block, the block may expand, and should appreciable temperature rise occur, to the melting point of the embedding material, there results attendant transfer of heat by convection to the frangible support. Moreover, combustible gases further are avoided, since both distillation and decomly chlorinated diphenyl.
position are considerably retarded. In any event there is no flash point nor fire point.
In the present description and claims, the term high resistance element designates an element of high resistance under normal conditions, though it is understood that under surge voltages the resistance diminishes as is usual in arresters.
According to the provisions of the patent statutes, I have explained the principle and mode of operation of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically illustrated .and described.
For example, it is within the contemplation of this invention to introduce various modifications in the embedding material. In some instances the resistance elements may be packed in yieldable dielectric of non-liqueflable nature. Thus sand may be regarded as an example, used either alone or retained by other medium, such as high- Boric acid may be utilized, particularly in view of its non-flammable and arc-extinguishing qualities. It may be compacted around the resistor element or may be fitted as pre-formed cylinders. Various dielectric, preferably thermoplastic, materials of nonflammable quality, are available. of the chlorinated compounds chlorinated naphthalene waxes are contemplated. In general the dielectric is of a nature to be consolidated about the resistor but is yieldable, and preferably fiowable, above normal temperatures and is substantially nonflammable.
Moreover, this invention is not limited to apaos asa plication with any particular form of high resistance elements. An important feature of the invention is a poured medium that is thermoplastic, that is, sufficiently plastic to take up expansions and contractions due to ordinary temperature-changes, but one which does not readily flow at ordinary temperatures, nor readily yield conducting deposits in normal use. The highly chlorinated diphenyl that has been mentioned congeals readily and otherwise is suitable in all modifications of the invention. Further, this invention is not restricted to the particular form of frangible element illustrated, nor even to use with a frangible element at all, since this invention imparts various qualities of strength, resilience, and stability even with other types of arrester.
I claim as my invention:
1. A lightning arrester having a loosely supported element for providing a high-resistance 20 path capable of carrying a high-current discharge without destruction, said loose element being surrounded and held firmly on all lateral sides by consolidated dielectric that is liqueflable and dispellable at above normal temperatures tha are obtainable under some operating conditions, said dielectric being substantially non-flammable.
2. A lightning arrester having a high resistance element embedded in consolidated halogen- 30 ated compound.
3. A lightning arrester having a high resistance element embedded in dyphenyl compound containing above sixty percent halogen.
4. A lightning arrester having a high resistance element embedded in diphenyl compound 35 containing about seventy percent chlorine.
I DAVID R. KELLOGG.