US933826A - Intermittent line-switch. - Google Patents

Description

E. E, 1"". GREIGHTGN.

INTERMITTENT LNE SWITCH. APPLIOATIQH FILED 00T. a1, 1907.

' s SHEETS-SHEET 1.

\ Figi E. E. F. GREIGHTON. INTBRMITTENT LINE SWITGH.

APPLICATION FILED 00T. 3l, 1907.

3 BHEETS-SHEET S.

geses:

E. E. F. GREGETN.

INTERMITTBNT LINE SWITCH.

. APPLIUATION FILED 00T. 3l, 1907. l @3535825 Paemted Sept Mz, i909.

3 SHEETS-SECRET 3. Fi .5.

NETE@ STATES PATE ELMER CREIGHTQN, 0F SCHENECTAIDY, NEV YORK, TQ GENERAL ELEC- TRIC CMPANY, COEPORA'EIN 0F NEW YREK.

ENTERMTTENE LNE-SWTCH.

To all whom it may concern:

Be it known that l, ELMER E. F. CREIGH- yron, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful improvements in intermittent Line-Switches, of which the following is a specication.

This invention relates to lightning arresters, by which is now meant all devices which protect a transmission line from the effect of direct strokes of lightning, static charges, abnormal frequencies or potential due to surge effects or resonance, and the like.

A type of lightning arrester which l have developed is disclosed in a prior application of mine and consists of plates of aluminum immersed in a suitable electrolyte. When an electric current passeslthrough a cell of this kind it forms on the electrodes a thin film of aluminum oXid which offers a high resistance to the current, so long as the circuit is closed. have discovered that if the circuit remains open for any length of time, the film deteriorates so that it does not immediately resist current flow when the circuit is again closed, but requires a measurable time in which to re-form. l nd that the deterioration takes place very slowly, extending over a number of hours, while the re-formation can be edected in a fraction of a second,-a half-cycle of alternating current, in fact if the lm has not deteriorated too far. rlhese aluminum cell arresters are usually installed with a spark-gap in series therewith, to prevent undue leakage of current. This means that the film is liable to deterioration under normal conditions of service.

The object of the present invention is to insure the closing of the circuit and the consequent re-forming of the resistant film at predetermined intervals of time. I accomplish this by means of a switch which closes momentarily, intermittently and auto. matically without requiring special attention from the station attendant. The switch is preferably an arm or blade arranged adjacent to the spark-gap and actuated at regular intervals by a clock-work or other motor, so as to bridge said gap momentarily. Where a plurality of aluminum cell arresters is in use, connected between the conductors of a multiphase transmission line, the several switches may be grouped for ac- Speccation of Lettere Patent.

Application .filed october 3l, 19e?.

i. 7 Seal H0. 099,899.

tuation by one motor. ln case the motor falls to work, the switch can be operated by hand. in fact, the motor may be discarded and the switch installed as a hand-switch, if desired. Jin the accompanying drawing, Figure l 'is a diagrammatic perspective View of an installation embodying my invention; Fig. 2 is a detail showing its mode of operation; Fig. 3 illustrates a modification; and Figs. 4 and 5 show the two systems combined.

The transmission line selected for illustration is a three-phase line, whose conductors l, 2, 3 are severally connected by legs 1i, 5, 6 with the three aluminum cell lightning arresters 7, 8, 9, the latter being shown in section. interposed in each leg is a sparkgap, consisting preferably of horns 10, ll mounted on a block 12 of insulation. Pivoted adjacent to each gap, and preferably on one of the horns, is a switch-blade i3 adapted to be turned into Contact with the other horn and thus bridge the gap. ln order to operate all the' switches simultaneously, the blades are all mounted at the same angle on a common shaft lll, of wood or other insulating material, whereby a rotation of the shaft will close or open all the gaps at once. ln order to hold the switches normally open, i secure to the shaft a counter-weight l5, which hangs normally in the position shown in F ig. l and keeps the switch-blades away from the gaps. The switches may be operated by hand, if desired, by simply turning the counterweight clockwise to the position shown in Fig. 2, and then letting it drop through the re` mainder of the revolution. `When the weight is uppermost, the switch-blades will have nearly closed the gaps. Upon letting the weight drop, it causes the blades to sweep vup over the opposite horns, thus momentarily closing the gaps, and ermitting a rush of current through the cells for a fraction of a second: long enough to insure a reforming of the resistant films in said cells.

If it is desired to make the switch operate automatically and intermittently, a motor 1G, is located adjacent to one end of the shaft, with a rotating arbor in line `with said shaft. Said arbor rotates clockwise once in a given number of hours, say twelve. The arbor and the shaft carry coperating abutments, such as a dog 17 on the arbor and a rock-arm 18 on the shaft. The rockarm normally hangs downward and the d og comes in contact with it at the lowest point n its revolution, from which point the dog carries up the rock-arm and the counterweight until they are at the lnghest point, as shown in Fig. 2. WhenA the welght becomes overbalanced and drops, it carries the rockarm away from the dog, and the switchblades again assume the positionshown 1n Fig. l until another half revolution of the dog causes it to overtake the rock-arm.

The motor may be an ordinary sprlng clock-movement, yor an electric motor; or a combination of both, the clock bein use d to close periodically the circuit of an e ectrlc motor which rotates the arbor carrying the dog. Or an electrically-wound self-winding clock may be used, which would require almost no attention from the station attendant: the whole object of the automatic featurebeing to insure a periodic closing of the spark-gaps for a brief instant of time.

F ig. 1 shows the arrangement for a circuit in which each conductor of the line is connected directly to round through its own ligtning arrester. n this system, if one of the conductors becomes grounded, the full line potential is thrown on the arrester in one ground leg. Either this arrester must be designed with enough plates to operate under this abnormal condition, or else a fourth leg `must be introduced between the lower end of each leg shown in Fig. 1 and the ground. This method of connection is advisable from the standpoint of economy. Fig. 3 shows such an arrangement. It will be seen, however, that if the switches on the horn gaps are all closed simultaneously, as provided for in Fig. 1, the ground leg will not be thrown into operation, because it is connected in at the neutral point, which remains at zero potential. But if,.on the other hand, the horngap switches are closed only one at a time, the line connected with the switch that is closed willdischarge through its phase leg to the ground leg and in so doing will reestablish the film on the ground leg-arrester. If the ca acity current of the system is at least equa to the leakage current through the arrester, then this closing of one switchafter another will be suiiicient to reestablish the film in all four legs of the arrester up to that corresponding to the impressed voltage between line and ground.

Fig. 3 shows a switch for closing the horn gaps in succession. The driving mechanism 19 rotates the shaft 20 continuously. Said shaft is of insulating material and carries three dogs 21, 22, 23 set at angular intervals of 120 degrees. Adjacent to each dog is a sleeve 24 loosely mounted on the shaft, and carrying a light switch-blade 25, and a counterweight 26 set to hold said blade normally in an open position,`as shown at a. An arm eeaeaa 27 on the "counterweight or blade extends into the path of the dog so that the latter w1ll strike said arm and rotate said sleeve during one-half of a revolution, as shown at b. I

When the dogarrives at the upper position, as shown at c, the counterwei ht will fall over, and swee the blade quick across the horn gap 28, tlhus closin the clrcuit for a fraction of a second only, ut long enough to reestablish the film on the arrester 29 in circuit with said gap; and, if the capacity current is large enough, the film on theground leg arrester 30 will also be restablished.

It is evident that the two switches shown in Figs.. 1 and 3 can both be used in the saine circuit, if desired; as indicated in Fi .4: the two shafts being combined in a sintl shaft 31 on which are mounted lixed b ades, as blade 32, corresponding to those of Fig. 1, and also loosely mounted blades, as blade 33, corresponding to those of Fig. 3.

Fig. 5, illustrates in perspective the systems shown in Fig. 1 and that shown in Fig. 3 combined into one system. The revolution of the motor shaft causes the dog 34 to pick up the rock arm 35, which is rigidly attached to the shaft 31, and carries the arm upward, causing the shaft 31 to revolve. Its revolution causes the dog 37 to engage with its corresponding arm 38, and thus trip the blade 33, which sweeps across the gap. A further revolution of the shaft in like manner actuates the blades 39 and 40 in succession. When then these three blades have consecutively bridged their corresponding gaps, the weight 36 has moved through an angle of 180 when it falls downward through the rest of the circle by its own weight quickly sweeping the blades 32, 32A, 32B across their corresponding gaps Simultaneously, and, thereby establishing momentarily a circuit through the cells from line to line.

If the capacity current of one .leg to ground is not equal to the leakage current of the arrester, each cell, including the ground leg cell, will have its film only partly restablished during the consecutive bridging of the spark gaps; but when the blades 32, 32A, 32B bridge all the gaps simultaneously, the cells in the hase legs will have their films fully restablli vstant dynamic current flows through the cells, thus building upfthe film. The complete restablishment of the film on these phase-leg cells will be suflicient for all practical purposes, even if the ground-leg cell has its film only partially restablished.

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

:1. The combination with an electrolytic lightning arrester, of-a spark-gap in series therewith, and a switch for closing said spark-gap at will.

2. The combination with a plurality of shed, as at that in- A ating all of said blades, and one or aluminum cell lightning arresters, of sparkgaps in series therewith, and means for ybridging said gaps at will.

The combina-tion with a plurality of aluminum cell lightning arresters, or horn spark gaps in series therewith, switch-blades adapted to close said gaps, and a common means for periodically actuating all of said blades.

il. rl`he combination with a plurality of aluminum cell lightning arresters, oit horn spark-gaps in series therewith, switch-blades adapted to close said gaps, a common means tor actuating all of said blades, and means for giving said blades a quick momentary closure.

The combination with a plurality of aluminum cell lightning arresters, of horn spark-gaps in series therewith, switch-blades adapted to close said gaps, a shaft for opermore eouuterweights mounted on said shaft.

G. rlhe combination with a plurality of aluminum cell lightning' arresters, of sparkga ps in series therewith, and means 'for automatically and periodically closing said gaps.

T. rlhe con'ibination with a plurality of almninum cell lightning arresters, of sparkuaps in series therewith, switch-blades adapted. to close said gaps, and means for simultaneously and periodically actuating said blades.

The combination with a plurality of aluminum cell lightning arresters, of sparku'aps in series therewith, switch-blades adapted to close said gaps, a shaft common io said blades, and means for periodically actuating said shaft.

9. The combination with a plurality of aluminum cell lightning arresters, of sparkgaps in series therewith, switch-blades adapted to close said gaps, a shaft common to said blades, one or more counterweights adapted to give said blades a sudden impulse to cause a momentary closing thereof, and a motor arranged to rotate said shaft to a point where the weight can act.

l0. The combination with a plurality of aluminum celllightning arresters, of sparkgaps in series therewith, switchblades adapted to close said gaps, a shaft common to all of said blades, a rock-arm on said shaft, a motor having an arbor carrying a dog adapted to engage with said rock-arm, and a counterweigl'it to give a quick actuation of said shaft to close and open the switches momentarily.

1l. rlhe combination of an electrolytic lightning arrester and means for reestablishing periodically the insulating film upon the electrodes of said arrester.

l2. rlhe combination of an electrolytic lightning arrester, and means for automatically restablishing the insulating film upon the electrodes ot' said arrester.

13. The combination of an electrolytic lightning arrester connected to a line in series with a spark gap and means for periodically sending a momentary current through said arrester.

14C. rllhe combination with the line conductors of a transmission system of electrolytic condensers connected respectively in series with a spark gap to said conductors and to a common neutral, a ground connection from said neutral including an electrolytic condenser, and means for closing said gaps iirst consecutively and then simultaneously.

ln witness whereof, l have hereunto set my hand this th day of Gctober, 190'?.

El'jlilltll E. l?. CREIGHTUN. `Witnesscs Baumann* B. HULL, HELEN Gimeno.

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