US1696573A - Electric switch - Google Patents

Description

Dec. 25, 1928. 1,696,573

J. D. HILLIARD ELECTRIC SWITCH Filed May 27. 1924 :5 1 2 5; {1 1 *1 4 n 3 5 5 .I 2 u Header common 39 39- to allphases. 25 6g 6 60 25 fl] W I n n 11 6 rdohn DlfiiLLiord 6'2 :5 F F 63 65 fiis Attdrney Patented Dec. 25, 1928.

UNITED STATES PATENT OFFICE.

JOHN D. HILLIABD, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, .A. CORPORATION OF NEW YORK.

ELECTRIC swrrcn.

Application filed May 27, 1924. Serial No. 716,271.

My invention relates to electric switches, particularly those for controlling high potential currents of large capacity.

For the control of high potential power circuits, switches of the oil break type heretofore have been almost universally employed and as the development of the art has been accompanied by the use of power circuits of ever increasing voltage, the construction of switches for the satisfactory control of such circuits has presented many difiicult problems and has involved great expense. Large ca acity oil switches have required the use 0 vlarge quantities of oil and, because of the generation of great volumes of highly heated gas by the arc within the oil when the switch is opened under a heavy load, the switch contacts and oil have been enclosed in strong steel tanks capable of withstanding the high pressures generated in order to avoid the loss of oil and the risk of fire and personal injury. Notonly is the cost of manufacture of such apparatus excessive, but because of its size serious transportation difliculties often arise in placing the apparatus after it is manufactured.

It is an object of my present invention to provide a construction of switch for control-.

ling high voltage circuits which shall avoid the above mentioned dangers, shall comprise parts of moderate dimensions facilitating transportation, shall be manufactu'rable at a relatively low cost, and be eiiicient in operation.

My invention will be better understood by reference to the accompanyin specification and drawing and its scope will be pointed out in the appended claims.

In the drawing Fig. 1 is a diagrammatic sketch showing one manner of carrying out my invention as applied to a multiphase switch and Fig. 2 is a similar sketch on a larger scale of the mechanism for controlling each phase.

Before roceeding with the detailed description, desire to point out that in illustrating my invention, I have made no attempt to show the various parts in their relative proportions but have sought only to show them in a purely diagrammatic manner.

Referring to the drawing which in Fig. 2 illustrates the individual switch mechamsm for interruptin one phase only of a polyphase switch, t e stationary contact 1 is a socket member and the movable contact 2 is a rod. The stationary contact is shown mounted on the cross member 3 which is suspended by insulators 4 of the suspension type from a supporting truss 5. The ends of this truss are carried on cross channels 6 supported on standards 7 reaching to the ground. The line controlled by the switch is shown connected to opposite ends of the truss by insulators 8. The movable contact rod 2 together with operating mechanism therefor is shown carrried by a second cross member 10 which is also suspended from the truss 5 by the insulators 4 but at a lower level than cross member 3. An open vessel 11 of comparatively small diameter and. having its side walls constructed of insulating material contains a liquid of fairly high dielectric strength, as for example water or a mixture of water and glycerin'e, the vessel being kept supplied by a connection 12 with a reservoir 13. The vessel 11 is located directly beneath the stationary contact 1 and contact rod 2 extends up through the insu lating liquid in vessel 11 into engagement with stationary contact 1. Attached to an extension of contact rod 2 are shown two pistons 14 and 15 operating respectively in Cylinders 16 and 17 which may be supported from the cross member 10 by a frame in the manner shown. Air pressure admitted above the former piston withdraws the contact rod 2 from contact 1 and air pressure admitted below the latter piston raises the contact rod 2 into engagement with contact 1. Bleed holes 18 and 19 allow the air to escape to permit the return movement of pistons 14 and 15. The lower portion of cylinder 16 is provided with openings 20 and the adjacent portion of the cylinder is enclosed by a casing 21 to constitute a chamber for holding a fluid such as oil which, in escaping through the openings 20 as piston 14 descends, is adapted to impede the downward movement of the piston and finally bring it to rest. A bleed hole 22 in the top of casing 21 permits the escape of air therein.

A reservoir 25 for compressed air or other suitable fluid may be supplied from a suitable source, not shown, through the pipe 26 and leading from this reservoir are two passages 27 and 28 controlled respectively by valves 29 and 30. Valve 30 is adapted to be actuated by the rod 31 which is shown having an insulating section 32 and may extend to a point near the ground where it terminates in a handle 33. The valve 29, the opening of which admits air to the piston 14 to open the switch may be operated either manually or automatically in response to some predetermined condition of the circuit controlled. Actuating lever 35 having a pin 36 at its free end connects with valve rod 37 and with the rod 38 at the lower portion of which is the core 39 of solenoid 40. Rod 38 is normally held in its raised position by the spring 41 and at its upper end has a slotin which slides the pin 36 on lever 35. One end of the solenoid 40 is connected with the line through a disconnecting switch 42, the opposite end is shown for convenience connected with the reservoir 25- through which and the attached metallic parts the current may travel to the brushes 43 bearing upon the contact rod 2. A second disconnecting switch 44 is shown in the connection between the cross member "3 and line.

For the manual actuation of the switch, a valve 47 is provided to admit air from the reservoir 25 through pipe 48 to the header 49 .from' whence it flows through pipe 50 to cylinder 51. In this 0 'linder slides the piston 52 having piston r0 53 which is slotted for a portion of its length to receive the lever 35. Cylinder 51 is provided with bleed holes 54 and 55 and above it is mounted a spring 56 to normally hold the lever 35 in its elevated position. A dash pot 58 is shown operatively connected through a lever 59 with an enlarged portion 60 of the valve rod 61. Like the valve rod 31, valve rod 61 may have an insulation section 62 therein and may reach to a point near the ground where it terminates in a handle 63.

The header 49 serves as an interconnection between the single pole individual switch mechanism of the separate phases, each switch and mechanism therefor being a duplicate of that illustrated. Pipes 48 and 50 of each individual switch mechanism connect with the header as illustrated so that all the switches will be opened either upon the occurrence of a predetermined overload on any one phase or as a result of the manual operation of a valve 47 as more fully described in the following paragraph. Since the pipes 26, 48 and 50 are subject to the full line potential, suitable insulating sections may be provided therein as indicated for example where those pipes are shown broken away. If desired the disconnecting switches 42 and 44 may be constructed to be operated by any well known pneumatic means, suitable connections being made for example to the header by means of a pipe 64.

The operation of the polyphase switch is as follows: The main and disconnecting switches being closed and the parts otherwise being in the relative positions shown,

the occurrence of an overload of predetermined value on any phase excites the corresponding solenoid to an extent suflicient to overcome the force of the spring 41. Downward movement of the rod 38 moves the lever 35, thereby opening the valve 29 to admit air pressure directly from the reservoir 25 to cylinder 16. The resulting sudden downward movement of the contact rod 2 from the stationary contact. 1 opens the circuit at this point, the contact end'of the rod being finally submerged in the insulating liquid contained in the vessel 11. The

rod 38 in descending under the influence of the solenoid 40 engages the enlarged end 60 of the valve rod 61 and in moving it downwardly opens the valve 47 to admit air pressure to the header 49 from which it is conveyed by pipes 50 to the cylinder 51 of each single pole switch mechanism.- All three switches are thereby actuated in response to an overload in any one phase. The dash pot 58 functions to holdvalve 47 open a sufficient length of time to insure the passage of the necessary amount of air into the header for the operation of the switches.

When the polyphase switch is to be opened by hand, a downward movement of the' handle 63 will open the valve 47 to admit air to the header 49 and cause the operations of the individual switches in the manner already described. To reclose the switch, each handle 33 either individually or by a common operating mechanism, not shown, is pushedupward to open valve 30 whence air pressure is admitted to the cylinder 17 against the underside of piston 15.

While I have described only one embodiment of my invention, I do not wish to be limited to the particular form shown and described as it will be apparent that many modifications therein may be made without departing from the scope of my invention as set forth in the appended claims.

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

1. A multiphase switch comprising cooperating stationary and movable contacts, a separate fluid pressure operated contact actuating mechanism and a separate fluid pressure reservoir for each phase, a header connecting the mechanisms of the several phases, means for varying the pressure in said header and means responsive to pressure change therein for admitting pressure from each of the several reservoirs to the corresponding contact actuating mechanism.

2. A multiphase switch comprising cooperating stationary and movable contacts, separate fluid pressure operated contact actuating means including a fluid pressure reservoir and a connection therebetween for each phase, a header connecting the mechanisms of the several phases, load responsive means for varying the pressure in said header, a

valve controlling said connection and means responsive to a pressure change in said header for operating said valve.

3. A multiphase switch comprising a stationary contact and a cooperating movable contact for each phase, separate actuating mechanism for each movable contact comprising a pressure actuated member, a reservoir, and a valve for admitting pressure from the reservoir to the member, a header connecting the mechanism of the several phases, load responsive means for admitting pressure from one of said reservoirsto said header and means responsive to a pressure increase in said header for operating all of said valves.

4. A multiphase switch comprising a plurality of stationary contacts, a plurality of movable contacts, a fluid pressure actuated operating member for each of said movable contacts, a separate reservoir adjacent each of said members, a load responsive means in each of said phases for controlling the flow of fluid to the corresponding operating member from the adjacent reservoir.

5. A multiphase switch comprising a support, a stationary contact and a cooperating movable contact for each of said phases, insulators of the suspension type for attaching said contacts to said support, fluid pressure actuated means for operating each of said movable contacts, a reservoir and a valve for each of said means, means responsive to a predetermined overload on each of said phases for operating the corresponding valve and separate means comprising an intel-connecting header for causing the actuation of all of said valves in response to a predetermined overload on any one of said phases.

In witness whereof, I have hereunto set my hand this 26th day of May, 1924.

JOHN D. HILLIARD.

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