US1882728A - Electric switch - Google Patents

Description

Oct. 18, 1932. A. o. AUSTIN 1,382,728

ELECTRIC SWITCH Filed June 1, 1928 2 Sheets-Sheet l noooo o o o INVENTOR Arfhur 0 AA/Jf/h BY /iwi ATTORNEY Oct. 18, 1932. A. o. AUSTIN 1,832,723

ELECTRIC SWITCH I Filed June 1, 1928 2 Sheets-Sheet. 2

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INVENTOR Ar/hz/r 0 flush/1.

B Y% y, flan/Q V ATTORNEY Patented Oct. 1 8, 1932 UNITED STATES PATENT OFFICE ARTHUR. O. AUSTIN, OF NEAR BARBERTON, OHIO, ASSIGNOB, BY MESNE ASSIGNMENTS, TO THE OHIO BRASS COMPANY, OF MANSFIELD, OHIO, A CORPORATION ,OF NEW JERSEY ELECTRIC SWITCH Application filed June 1, 1928. Serial No. 282,214.

This invention relates 'to switching mechanism for high voltage currents and especially to oil break switches and has for one of its objects the provision .of an oil break switch which shall be simple and econom cal to manufacture, which shall have a minimum number of operating parts and which shall be of improved construction and operation. Other objects and advantages will appear from the following description.

The invention is exemplified in the combination and arrangement of parts shown in the accompanying drawings and described in the following specification, and it is more particularly pointed out in the appended claims.

In the drawings:

Fig. 1 is an elevation with parts in section showing one embodiment .of the present invention.

Fig. 2 is a fragmentary, horizontal section on line 2.2 of Fig. 1.

Fig. 3 is a view similar to Fig. 1 showing a slightly modified formof the invention.

Fig. 4 is a horizontal section on line 1 i of Fig. 3.

Fig. 5 is .a fragmentary elevation partly in section showing a detail of the construction.

Fig. 6 is a somewhat diagrammatic top plan View of the operating mechanism.

In order to open the circuit on high .voltage transmission lines, it is usually necessary to make use of an oil circuit breaker or a device which opens the circuit beneath the surface of .oil. Oil circuit breakers are the source of an appreciable part of the expense on a system and cause 211101'8 or less (trouble owing to :their failure under heavy short on:- cuit conditions. In order to improve the operation of the .circuitbreaker and lower its cost of manufacture, I have devised a new type of circuit breaker and method of opermake contact beneath the surface of the oil 17 filling the tank 18. The bushings have flanges 19 which operate on a seat or bearing '20, the arrangement being such that the bushings are free to rotate on their axes. Gear segments 21 are secured to the bushings 12 and 13 respectively and are operated by beveled pinions 22 or other suitable driving mechanism. The bushings rotate in the same angular direction in opening which moves the contact arms and 16 in opposite directions. This tends to make or break the contact in the shortest possible time-and gives the maximum opening for a given length of arm. The contact arms 15 and 1 6 may be provided with a series of contact members and arcing points or the arm may be provided with an expansion chamber .as in some types of circuit breakers.

lVith this type of construction, it is seen that the only insulating members required for the switch mechanism are the bushings which are required in any case. WVith this type of switch or circuit breaker, it is possible to do away with insulated operating rods and posts used for supporting contact members.

If the upper portion of the bushing, within the housing, is above oil level and is provided with an insulating member which is internally screened, there will be no direct leakage over the bushing, even though the insulating value ofthe oil may fall off greatly. Where the insulating zone above the oil issufli -iently large, it will take a very high voltage to bridge this Zone, particularly as c this zone is in series with that below the oil. The fact that this zone is above the oil level and'prevents a direct leakage will do much to prevent the coating up of the insulating portion of the bushing below the surface of the oil.

This scheme may be readily carried out, even :though current transformers are required in the bushings, as the current transformers can be readily installed inside the bushings so that the insulating surface will not vbe cut down. The secondary .winding of a curren transformer is shown at 23, the

ends ,of the winding being carried out through flexible conductors '24. The construction is similar to that of my prior Patent Number 1,699,342, issued January 15, 1929. The construction reduces the size of the circuit breaker tank and oil contents for a given amount of insulation and, furthermore, the number of paths to ground is reduced to a minimum so that the danger of break-down is materially reduced over that of the ordinary circuit breaker. This is of considerable advantage, particularly at very high voltages, for one source of trouble is the break-down of the operating rod or insulators holding live parts. The construction also has the advantage that the operating mechanism is very simple and inexpensive.

A somewhat different form is shown in Fig. 3. In this case the operating arms 30 and 31-are attached to members 32 and 33 which permit of an appreciable torsional movement. The operating gears 22 first bring the contact portion of the arms 30 and 31 together. The further movement of the gears 22 rotates the bushings 12 and 13, but as the contacts are against each other they remain stationary, the torsional movement being taken up by the members 32 and 33. The members 32 and 33 may be rods or pipes free to rotate in tubes 34 which are fixed by tight joints at their lower ends to their respective bushings. The upper ends of the embers 32 and 33 are connected by springs 35 to washers 36 which are held from rotation by engagement with notches 37 in the upper ends of tubes 34. If one of the torsional members 32 is provided with a shorter arm or requires a higher torsional moment for a given angular displacement, it will tend to carry the other contact arm 31 with it. WVhere the arms have the proper length and the torsional members 32 and 33 the proper relation, the bushings may be given an appreciable angular rotation after the contact members 30 and 31 have closed the circuit. A still further angular rotation or displacement of the bushings will tend to force the weaker arm back and allow the contact members to spring past each other. By properly proportioning the members 32 and 33, or the springs controlling these members, the circuit breaker may be set or closed at a comparatively slow speed and the circuit opened at a high speed due to the energy stored in the torsional members 32 and 33, only a slight additional movement in the bushings being required to cause the contacts to open after the springs have been placed under stress.

One form of operating mechanism is illustrated in Figs. 3 and 6 of the drawings. A lever or handle 40 is attached to the gear 22 in position to move the gear through an are. A spring catch 41 is arranged to engage the handle 40 after it approaches one extremity of its arc of movement. The catch is so located that it will engage the handle 40 after the contact members 30 and 31 have been brought into engagement and the springs 35 have been put under tension but before the springs have been sufiicient'ly stressed to cause the contact arms 30 and 31 to pass each other. lVhen the handle is moved to this position, it will be retained in this position by the spring catch 41 and the switch will be closed and the contacts held in place by spring pressure. The adjustment is such that a very slight additional movement of the handle 40 will cause the contact arms to pass each other so that they will. spring apart with a quick action. This may be effected by a slight movement of the handle 40 by hand or a relay may be employed to move the handle to open the switch. In the drawings this relay is shown at 42 and is connected with the current transformer 23 inside one of the bushing insulators.

The parts are so related that in case of an overload passing through the circuit, the solenoid 42 will exert sufficient force on the handle 40 to move the handle a suilicient distance to open the switch.

The catch 41 may be provided with an additional holding means for retaining the handle in its new position, although this feature is not essential since the arms will be sepa rated widely due to the distortion of the springs 35. It will be apparent that the relay 42 and catch 41 may be duplicated at the opposite extremity of the arc of movement of the handle 40 so that the operation may be effected by movement of the lever to each side of its path of movement. This will close the switch by bringing the arms 30 and 31 together from each direction.

It is obvious that other means may be used to permit the opening of the circuit breaker such as a solenoid within the bushing or located in the contact arm. The arms may be released magnetically or mechanically as desired. By the proper use of bailies attached to the arms or bushing parts, and by using breaks in series to open the are, it is possible to provide an effective oil gap be tween the current-carrying parts very quickly.

It is evident that the type of construction does away with all necessity of providing truss parts in the breaker cover which tend to cut down the insulation. In fact, the case of the breaker may be of sheet metal construction which will withstand very heavy pressures. The comparatively small amount of oil required with the construction and the simplicity in the operating mechanism and insulation, all tend to make a breaker of low cost for a given service.

It is evident with this type of construction that it is possible to place the bushing-,s in the sides of the tank or in the cover. Where the bushings are placed in the side of the tank, it is possible to inspect all opof switch contacts, yielding means for moving said contacts into mechanical and electrical connection with each other to close said switch, a movable operating member for applying force to said yielding means to move said contacts, said yielding means being placed under stress by the application,

after said switch is closed, of further force in the same direction as that employed to close said switch, one of said contacts being arranged to yield to the other when the stress in said yielding means exceeds a predetermined-amount to permit quick separation of said contacts under the stress of said yielding means and locking means for holding sa-i-c switch closed indefinitely with said yielding means under stress.

3. An electrlc swltch comprising a bushing insulator, a switch contact y-l'eldingly connected to said insulator, a cooperating contact, means for rotating said bushing insulator 'to close said switch and to press said contacts together and locking means for retaining said switch indefinitely in its closed position,'one of said contacts being arranged to yieldto the other after further rotation of said insulator in the same direction to permitquick separation of said contacts under the stress set up by relative movement between said insulator and said first named contact produced by said further rotation of said insulator.

4. An electric switch comprising a housing, a bushing insulator extending through the wall of said housing and rotatable about an axis extending through said wall, a switch contact yieldingly connected with said bushing insulator and operable by rotation of said insulator, a cooperating contact arranged to intercept the movement of said first named switch contact and thus effecting closing of said switch and to displace said switch contact relative to said bushing insulator upon further rotation of said insulator, said contacts being movable out of engagement with each other upon a given displacement of said switch contact, to permit quick separation of'sa-id contacts under the stress set up by the displacement of said tact in a given position relative to said bushing insulator, a cooperating contact arranged to intercept said switch contact when said bushing insulator is rotated to close said switch and to cause said resilient means to be placed under stress when said insulator is further rotated in the same direction, one oi said contacts being arranged to yield to the other to permit said contacts to pass, said resilient means being arranged to eiiect quick separation of said contacts when they have passed each other and lacking means for retaining said switch indefinitely in its closed position. I

6. An electric switch comprising an oil-containing housing, 'a pair of bushing insulators extending through the wall of said housing,

contact members projecting laterally from said bushing insulators, and means fo rotating both of saidbushing insulators each about its own axis extending through said wall to move said contact members together.

7. An electric switch comprising an oilcontaining housing, a pair of bushing insulators extending through the wall of said housing and rotatable about their respective axes extending through said wall, contact members extending laterally from said bushing insulators within said housing, yielding means connecting said contact members with said bushing insulators, and means for rotating said bushing insulators in the same an- :gular direction about their respective axes to bring said contact :members into engage ment and thus closing'said switch, said yielding means being arranged to permit said contact members to pass under the stress set up by further rotation of said insulators in the same direction as before and to effect quick separation of said contact members when they have passed each other.

8. An oil break switch comprising an oilcontaining housing, a pair of bushing insulators rotatably mounted in said housing and rotatable about axes extending through the wall of-said housing, conductor leads extending through said insulators, switch contacts carried by said insulators respectively beneath the oil level in said housing and arranged to engage each other when said bushing insulators are rotated, and means disposed outside of said housing for rotating said insulators to effect connection and disconnection of said contacts.

9. An oil break switch comprising a housin a )air of bushin insulatorsextendin 7 b O through the top of said housing and having their longitudinal axes in fixed position relative to said housing, conductor leads extending through said bushing insulators, switch contacts carried by said bushing insulators beneath the surface level of the oil within said housing and electrically connected with said conductor leads respectively, means disposed outside of said housing for rotating said bushing insulators about their respective longitudinal axes to make and break connection between said switch contacts, and a secondary winding disposed about one of said conductor leads within the associated bushing insulator, and a dielectric covering for the errremities of said secondary winding.

10. An electric switch comprising a housing, a bushing insulator extending through the wall of said housing and having its longitudinal axis in fixed position relative to said housing, a contact member carried by said insulator within said housing, operating means for said contact member disposed outside of said housing, a resilient connection between said operating means and contact member arranged to be placed under stress by said operating means when said switch is closed and to effect quick movement of said operating member about the axis of said insulator hy the energy stored in said connection,

locf'ng means for holding said swich closed c t the stress of said resilient connection and elec rical means for controlling the U stored energy in said connection to permit quick movement of said contact member.

11, An electric switch. comprising a housing, a bushing insulator extending through the wall of said housing, a contact member carried by said insulator within said housing, operating mechanism for said contact member arranged by movement in one direction first to close said switch; second, to place said operating mechanism under stress to e potential energy therein for actuating said contact member to open said switch; and third, to free said contact member to porn it quick opening of said switch under said stored energy; and over-load means for producing the final movement of said contact member to effect opening of said switch under said stored energy.

12. A switch comprising a pair of contact members, operating means for moving one of said members into contact with the other to close said switch, yielding means connecting said operating means with its contact member for exerting further force on said contact in the direction of its closing movement, sa d yielding means being placed under stress by said force, locking means for retaining said contacts indefinitely in engagement with each other in the closed position of said switch, one of said contacts being arranged to yield to the other to permit said contacts to pass and open said switch by relative movement in the same direction as the closing movement and by a quick action under the stress in said yielding means when additional force is exerted on said operating means in the same direction as that for closing the switch.

13. A switch comprising a pair of rotary members having spaced axes, radially extending contacts on said members arranged to be moved into engagement by rotation of said members to close said switch, yielding connection between one of said contacts and its rotary member, said yielding connection being placed under stress by further rotation of its rotary member after engagement of said contacts, one of said contacts being arranged to yield to the other to permit said contacts to pass, the energy stored in said yielding means by said further rotation after engagement of said contacts acting to produce quick separation of said contacts after they have passed each other.

14. An insulator comprising an oil containing housing, a pair of bushings extendingthrough the wall of said housing and having fixed axes spaced apart, radially extend ng contact members carried by said bushings within said housing, operating means for said contacts rotatable about the axes of said bushings respectively, yielding connection between one of said contacts and its operating means, arranged to be placed under stress by continued rotation of said operating means after engagement of said contacts, one of said contacts being arranged to yield to the other to permit said contacts to pass, said yielding connection operating to efiect quick separation of said contacts bv means of the energy stored therein due to thb stress in said connection.

15. An electric switch comprising an oil containing housing, a pair of insulator bushings mounted in said housing and rotatable about their longitudinal axes respectively, contact members disposed within said housing and connected with said bushings respectively, means connected with said bushings outside of said housing for rotating said bushings to bring said contacts into engagement by movement toward each other from opposite directions, said contacts being movable into engagement with each other so as to intercept temporarily relative movement thereof, yielding means connecting said contacts with said bushings, said yielding means being placed under stress when the movement of said bushings is continued after engagement of said contacts, a catch for holding said bushings in fixed position with said contacts in engagement with each other and with said yielding means under stress, one of said contacts being yieldable to the other to permit said contacts to pass and to separate with a quick movement when the stress in the connection between said contacts and insulators has reached a predetermined amount.

16. A switch comp-rising a housing, a pair of insulator bushings extending through the wall of said housing, a contact carried by each bushing within said housing, a conductor connected with each contact and extending through its bushing to the outside of said housing, operating means disposed outside of said housing for rotating said contacts about the axes of their respective bushings to bring said contacts together, yielding means interposed between said operating means and the respective contacts and placed under stress by further movement of said operating means in the same direction after said contacts have been brought together, means for holding said contacts in engagement with each other in the closed position of said switch with said yielding means under stress, one of said contacts being arranged to yield to the other upon application of further force to said operating means in the same direction as the closing force.

In testimony whereof I have signed my name to this specification this 26th day of May, A. D. 1928.

ARTHUR O. AUSTIN.

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