US1275918A - Switch. - Google Patents

Description

E. M. HEWLETT.

SWiTCH.

APPLICATION FILED MAY 9. 1914.

Patented Aug. 13, 1918.

UNITED STATES PATENT OFFICE.

EDWARD M. HEWLETT, 0F SCHENECTADY, NEW YORK, ASSIGNOB T0 GENERAL ELECTRIC COHZPAHY,,A CORPORATION OF NEW YORK.

SWITCH.

Specification of Letters Patent. Patentefi Aug, 13, 19i8,

Application filed Kay 9, 1914. Serial Ho. $37,596.

To all whom. it may concern:

Be it known that I, EDWARD M. Hew- LE'I'I, a citizen of the United States, residing at Schenectady,- in the county of Schenectady, State of New York, have invented cer tain new and useful Improvements in Switches, of which the following is a specification.

My invention relates to switches and insulat-ing supports, and more especially to apparatus intended for very high voltages; andit comprises various novel features of construction and combinations and arrangements of parts. Among the advantages obtainable in connection with my invention are the ability to deal with voltages exceeding even the very highest at present in commercial use,180,000 to 200,000 volts, for example-and the avoidance of corona troubles. How these and various other advantages maybe obtained in accordance with my invention will appear from the detailed description hereinafterof a particular high tension switch apparatus that is the best practical application at present known to me, while the scope of the invention will be indicated'in my claims.

In the accompanying drawing, Figure 1 is a side view of a high tension disconnecting switch constructed in accordance with my invention;

Figs. 2 and 3 are similar fragmentary views on a larger scale illustrating details of construction of the insulating supporting structures, certain parts being in section;

- Fig. 4 is a fragmentary detail view of the structure shown at the right of Fig. 3 turned about thirty de ees to the left from its-posit-ion in that gure;

Fig. 5 is a plan view corresponding approximately to Fig. 3, certain lower parts being omitted;

Figs. 6 and 7 are fragmentary detail views of the switch mechanism as seen from the left nd the right of Fig. 1, respectively, certain parts being shown in section or partially broken away.

, Referring first to Fig. 1, it will be-seen that the switch comprises a cylindrical blade 1 prefera bly hollow, as-indicated in Figs. 6 and 7-pivoted at one end to a terminal or contact 2 to which the conductive cable 3 isconnected, and adapted at its other end to engage a terminal or contact 4 to which the conductive cable 5 is connected. The contacts 2 and 4 are mounted and secured 011 ill-- sulating supporting structures 6 and 7 each consisting of a plurality of post insulators arranged pyramid fashion. The structures 6 and 7 are shown in an upright posit-ion, with the switch proper uppermost, as though their bases were secured to a floor or a platform,and for clearness and convenience this arrangement will be assumed throughout the following description. In practice, however the whole apparatus may be inverted and secured to the ceiling of a powersecured to them at its side next the base by means of caps 13; another similar hollow insulator post 14. with its large end secured to the other side of the superstructure 12; and means on the other end of said insulator post 14 for securing the element to be supported theret0,this element being in the present case the contact 2. The insulator posts 11 and 14 may be of ceramic or other materiaL-as porcelain or bisque, for example, and they may be made either in one piece or in a plurality of pieces secured together as shown in my Patent No. 1,077,711,

granted November 4th, 1913, and of about the same external form as those therein shown. The-lower ends of the insulators 11 are secured to the plate 10 (see Fig. 2)-by means of clamps 15 externally engaging them, as shown in my patent aforesaid, and the caps 13, also, (see Figs. 3 and- 1) are the angularly adjustable caps of my said patent. The superstructure or platform 12 is preferably a rigid circular casting having outstanding ear portions 16 (see Fig. 5) which overlie the upper ends of the insula-hirs 11 and to which the caps 13 are screwed; bolted or otherwise secured. The lower end of the insulator 1 is, again, secured to the superstructure 12 by means of a clamp 17 externally engaging it (Figs. 3 and 5), as shown in my aforesaid patent, and the contact 2 18 secured on the upper end of said insulator 14 by means of a cap 18 (see Fig. 6) such as shown in said patent Referring to Figs, 1 and 6, it will be seen that the left-hand switch'contact 2 is an upwardly opening U-shaped part, and that the contact or end piece 21 of the switch blade 1 fits between the sides of the U and is pivotally secured by a bolt or pin22. It

will also be seen that from the bottom portion of the U projects a sleeve 23 in which the conductor of the cable 3 is soldered or otherwise secured and connected. The edges of the contact part 2 are swelled into round beads to avoid corona, and all the other parts are rounded as much as possible for the same purpose.

Referring, now, to Fig. 7, it will be seen that the right-hand switch contact 4 is in general form and arrangement very much like the contact 2-, and that the cable 5 is similarly connected to it. It will be seen, however, that the movable contact or end piece all of the blade 1 does not engage directly with the sides of the U shaped part d0, but is received between contact springs 42 conductively secured to the part 40. The lowerends of these springs 42 fit in slots in ridges on the bottom of the U and are held in place by pins 43, while their free upper ends are curved apart to facilitate entrance of the movable contact 41 between them. At thesides of the U are chambered bosses 44 in which are round ended catches 4:5 and helical springs 46 that act between the removable covers 47 of the boss chambers and ilanges on the catches 15 to force the catches inward. The inner ends of the catches 45 extend through holes in the contact springs 42 and engage in depressions in the sides of the movable contact piece 41 so as to resist accidental opening of the switch without pre venting intentional opening,for which latter purpose the contact piece 41 is provided with an apcrtured lug 48. A projection 49 on thclower side of the piece tl prevents the switch from being closed beyond the positlon for the proper engagement of the spring actuated catches 45. The edges of the part 40 are enlarged and rounded even more than those of the part 2, since the part 10 is intended to serve as a sort of corona shield for the contact springs 42, catches 15 etc.; and the edges of the other switch parts are roundedas far as possible for the same purpose.

It will be understood that the various parts of the supporting structures 6 and 7 all have their edges rounded as much as pos sible to prevent corona,especially the screws, nuts, etc, of the clamps 15 and 17 and the caps 13 and 18 and the superstructure platform 12. While this and the overlying of the caps 13 by the platform 12 will generally suffice to prevent corona, it is desirable to employ special measures to prevent it on the caps 18, which are at the same high potential as the switch itself. shown, therefore, sheet metal corona hoods 50 of rounded Derby hat-like form are mterposed between the contacts 2 and 1- and the parts beneath (see Figs. 1, 6 and 7),

these hoods extending down around the caps and the upper ends of the insulators 14 and having their lower edge or brim portions turned over and inward and then down, though not necessarily forming a completely closed bead.

For a 300 ampere switch for 1%,000 to 150,000 volts, the insulators 11 may be about 20 inches high, the insulators 14 about 24:

inches high, and the switch blade 1 about d8 inches long, the dimensions or the other parts being in about the proportions shown 'to those of the insulators.

hat I claim as new and desire to secure by Letters Patent of the United States, is z- 1. An insulating supporting structure for high voltage electrical apparatus comprising a base plate, a plurality of hollow insulator posts mounted thereon in polygonal relation and each secured thereto at its end next the same, a rigid superstructure above the other ends of said insulator posts secured thereto at its side next the base plate,

another hollow insulator post above those first mentioned mounted on the other side of saidsuperstructure and secured thereto at its end next the same, and means on the other end 01' said last-mentioned insulator post for securing the element to be supported thereto.

2. An insulating supporting structure for high voltage electrical apparatus comprising a plate, a plurality of hollow externally ribbed insulator posts mounted thereon and each secured thereto by means externally engaging its end next the plate, a platform superstructure overlying the other ends of said insulator posts and secured thereto at its side next the base, another hollow externally ribbed insulator post mounted on the other side of said superstructure and secured thereto by means externally engaging its end next the same, means for securing the element to be supported to the end of the post externally engaging the same, and a rounded, smooth-surfaced metal corona hood surrounding said last-mentioned securing means and the end of the insulator post.

3. The combination of an insulator, means on its end for securing the element to be supover said securing means and the end of ported, means externally engaging the inthe insulator. I 'sulator for securing said means thereto, and In witness whereof, I have hereunto set a metal corona hood having a rounded, hatmy hand this eighth day of May, 1914.

5 like form and having its edge or brim por- EDWARD M. HEWLETT.

tion turned over and inwar interposed be- Witnesses: tween the supporting means and the secur- SAMUEL W. MAUGER.

ing means aforesaid and extending down H LEN ORFORD.

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