US669155A - Lightning-arrester. - Google Patents

Description

- No. 669,55; Patented Mar. 5, I90L H C. WIRT.

LIGHTNING ARRESTER. (A umion dim A r. so, 1897.) (no Iodol.)

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UNITED STATES PATENT OFFICE.

HERBERT c. wIR'r, or SOHENECTADY, NEW YoRK, ASSIGNOR TO GENERAL ELEcTRIc COMPANY, OF NEW YORK.

LlGHTNlNG-ARRE STER.

SPECIFICATION forming part of Letters Patent N 0. 669,155, dated March. 5, 190i;

Application filed April 80, 1897. Serial No. 684,543 \No model.)

To aZZ whom it may concern: siderably larger than those heretofore iised, Be it known that I, HERBERT O. WIRT, a so as to have a capacity for absorbing heat, citizen ofthe United States, residing at Schenand thereby keeping the temperature of the ectady, in the county of Schenectady, State pieces relatively low. By keeping the dis- 5 of New York, have invented certain new and chargers cool no conducting-gases are liberuseful Improvementsin Lightning-Arresters, ated in the air-gap and the latter is not in- (D. 551,) of which the following is a specificreased by fusing of the metal. cation. Ordinarily when a double-pole lightning Myinvention relates to lightning-arresters, arrester is used, or two single-pole arrester's I0 and has for its object to provide a lightningconnected to opposite branches of the circuit, arrester especially adapted for alternatingit forms ashunt-circuitfrom line to line, and current work which is self-contained and rewhen the lightning discharge passes it estabquires no special arc-disrupting devices. lishes a vapor between the discharge-termi- Thearresterconstructedinaccordancewith nals, so as to reduce the resistance of the 5 myinvention has a much smaller air-gap and shunt-circuit through the lightning-arrester a lower series resistance than has hitherto to a point such that there is danger of the been possible to use with certainty of prearc persisting under the potential of the alventing the continuance of arcing, and hence ternator. Especially is this true when the a better-protection for the line insulation. I metallic pieces or balls are placed close to- 2o accomplish this by the combined action of gether, so as to produce a discharge-path for metal cylinders or balls having between them the lightning at relatively low potentials and short-gap air-spaces, with a non-inductive reso insure the protection ofthe insulating desistance. The combined action of the metal vices on the circuit. cylinders and non-inductive resistance pre- It is very important, as I have found, to 25 vents the heating of the cylinders at the time keep the heating of the terminals down, for the lightning discharge passes across the gap if this is done the arc following the discharge or gapsand also prevents the forming of gas will be broken on an alternating-current cirin the spark gap or gaps sufficient to maincuit by the action of the alternator at or about tain the are by the potential of the alternathe zero-point in the Wave. Then if the tero tor. The cooperation of the cylinders ordisminals are not allowed to heat I find that chargers and the resistance liesin the fact that even though a good discharge-path for lighttogether they produce a highly-useful result ning is preserved yet the arc will not start which has not been hitherto thought possible, up again under the influence of the alternator the cooled dischargers permitting the use of potential. It is therefore,of course,desirable 3 5 a lower resistance for accomplishing the purto reduce the current which shall flow through pose of preventing re-formation of the arc than the shunt-circuit formed by the arrester after would be possible without said dischargers, the lightning discharge, for the heating effect and owing to the combination of the resistincreases with the square of the current. I ance and the cooled dischargers a much therefore use in combination with the metal- 0 40 smaller air-gap can be used than with a relic cylinders hereinbefore referred to a nonsistance alone, as hitherto. inductive resistance to limit the flow through Heretofore lightning-arresters having a the lightning-arrester circuit, thereby keepnumber of solid discharge-balls have been ing down the heating and preserving the terused, the discharge-balls being made of sominals at such a temperature that the are 5 5 called non-arcing metal. It has been suponce extinguished does not start up again.

posed that these metal pieces gave oif a non- My invention consists in a lightning-a1 conducting vapor or oxid which prevented the roster constructed and arranged as hereinafformation and continuance of arcs. My arter set forth and claimed. rester is provided with discharge cylinders 'or Referring to the accompanying drawings, I00 50 balls; but it is designed to operate in quite a Figure 1 is a front view of a single-pole lightditferent manner. The metal pieces are conning-arrester constructed in accordance with my invention. Fig. 2 is a side view thereof. Fig. 3 is a front view of the invention in the double-pole form. Fig. 4 is an end view thereof. Fig. 5 illustrates a circuit having lightning-arresters constructed in accordance with my invention connected therein.

A is an alternating-current generator, and 1 l the circuit leading therefrom to translating devices. (Not shown.) Interposed in this circuit are lightning-arresters L L, constructed in accordance with my invention.

The single-pole form of lightning-arrester (shown in Figs. 1 and 2) consists of two metal cylinders B and a non-inductive resistance Oas, for example, a rod of graphite-said cylinders and non-inductive resistance being mounted on an insulating-base D, such as porcelain. The metal cylinders B are each mounted on a metal post E, projecting from a metal plate E, secured to the base D. The metal cylinders B are each adapted to be ro- 1a ted on its post Eand can be removed therefrom. Each is secured in position by means of a screw or other suitable means. The non inductive resistance or graphite rod 0 is detachably mounted and secured on the base D by means of a removable clamping-ring F at one end, fastened to one of the plates E, and a removable clamping-ring F, fastened to a plate E secured to the base D. The metal cylinders and non-inductive resistance are arranged in series.

The arrester shown in 1 has but two metal cylinders B and one spark-gap of approximately one thirty-second of an inch and is adapted for a one-thousand-volt circuit.

As heretofore stated, the metal cylinders are considerably larger than the metal pieces heretofore used, so as to have the capacity of absorbing heat, thereby keeping the temperature of the cylinders relatively low. They are two inches in diameter and two inches long. One cylinder is connected to the overhead line and one to ground In the double-pole form (shown in Figs. 3 and i) there are cylinders or balls, connected one to each branch of the circuit, and a noninductive resistance. A third metal cylinder B is located on the plate E between the cylinders B and connected to ground 2. In this construction there are two spark-gaps of approximately one thirty-second of an inch each.

The lightning-arresters constructed in accordance with this invention may be provided with a number of cylinders in series having one spark-gap for each one thousand volts potential, and the spark-gaps are each approximately one thirty-second of an inch, except as follows: Where more than two cylinders are employed in series with a non-inductive resistance the static condition of the cylinder second to the one adjacent to line is such that there is a tendency to sparking across the gap, and to obviate this instead of making the gap between the first and second cylinders one thirty-second of an inch it is made approximately three sixty-fourths of an inch, which avoids the tendency just stated. The cylinders are rotatable on their posts to bring fresh surfaces opposite each other.

By means of the construction of lightningarrester herein set forth the operation and eifect, as hereinbefore stated, will be accomplished. The heating of the terminals will be kept down with the aid of the non-inductive resistance and the arc following the lightning discharge will be broken by the ac tion of the alternator.

What I claim is 1. In a lightning-arrester for alternatingcurrent circuits, the combination with metallic dischargers which are prevented from being heated to an intense degree by lightning discharges, and are separated by only a comparatively short air-gap, of a comparatively low resistance in series with the airgap, said elements cooperating to protect the line insulation.

3. In a lightning-arrester for alternatingcurrent circuits, the combination with metallic dischargers connected respectively to line and ground, and of sufficient mass to cause the heat generated by a lightning discharge to be conducted away from the surface adjacent the air-gap which separates them, whereby the dischargers are kept cool; of a com mratively small non-inductive resistance in series with the air-gap, said elements cooperating to protect the line insulation.

In witness whereof I have hereunto set my hand this 20th day of April, 1897.

HERBERT (J. W IRT. lVitnesses:

E. W. GADY, C. L. HAYNES.

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