US2856480A - High voltage switch - Google Patents

Description

Oct. 14, 1958 E. wEsTERHoFF 2,856,480

HIGH VOLTAGE SWITCH Filed sept. 9, 1954 \\l l 37 fp ///V// A\ i@ 35 fa 56 lINVENTOR.

z5 2; EUGEN WESTERHOFF `ATTORNEY United States Patent O 2,856,480 man voLTAeE SWITCH Eugen Westerhotr, deceased, late of Kassel, Germany, by Luise Gertrud Charlotte Westerhofr, nee Stalin, heir, Kassel, Germany, assigner to Licentia Patent-Verwaltungs-G. n1. b. H., Berlin-Grunewald, Germany Application September 9, 1954, Serial No. 454,886

6 Claims. (Cl. 20082) This invention relates to an improved high voltage switch and more particularly to an improved high voltage switch driven by compressed gas and having contacts in free air.

In prior art high voltage switches having contacts in free air there is the problem of making sure and positive contact disconnection. In these switches, the switch arms are biased, usually by means of a spring, so that when the switch is closed the switch contacts make positive engagement. In order to open the switch, a source of compressed gas is directed against a portion of the switch arm which causes the switch arm to retract a distance sufficient to prevent arcing between switch contacts. However, since the switch arms are biased, when the gas pressure is removed, the arm tends to return to its original closed position. In order to prevent this, in one prior art device, the switch is mounted on a rotatable or tiltable insulator so that as soon as contact is broken, the switch chamber may be rotated to a new position. The disadvantage of this type of switch is that it is rather expensive to manufacture and is somewhat complex.

Another solution for the problem above is to place a second switch in series with the pressure driven switch. The procedure for opening the switch is to apply pressure to a portion of the spring biased switch arm so as to cause the arm to retract a distance sucient to prevent arcing between the switch contacts and then to open the second switch in series with the pressure driven switch. The disadvantage of this type of switch is that a great deal of gas pressure is required rst to open the switch and then to maintain the switch in its open condition for a length of time suflicient to permit the series connected switch to be opened.

It is an object of the present invention to provide a high voltage switch which has none of the foregoing disadvantages.

It is a further object of the present invention to provide a high voltage switch which is quite simple to manufacture and operate and yet which is highly efficient.

It is still another object of the invention to provide a high voltage switch which includes a unique arrangement for quickly disposing of noxious gases formed by the high voltage arc generated when opening the switch.

It is still another object of the invention to provide a number of novel means for locking a high voltage switch in its retracted position, that is, when the switch contacts are opened.

With the above objects in view, there is provided a high voltage switch which mainly consists of a pair of contacts at least one of which is movable to and from a closed position engaging the other of the contacts. Fluid pressure means are operatively associated with the movable contact for moving the same from the closed position to an open position where the movable contact is spaced from the other contact by a distance suicient to prevent arcing between the contacts, and means are provided for holding the movable contact in its open position.

In a preferred embodiment of the invention the switch ice arm is mounted in a switch chamber and projects from a nozzle in the end of the chamber. The arm is provided at its projecting end with a contact and at its other end with a piston. Gas pressure directed against the piston causes the arm to be withdrawn into the chamber, and a locking device actuated by the movement of the piston then locksl the switch arm in its retracted position.

In a second preferred embodiment of the invention the switch arm is mounted in a switch chamber which projects from a nozzle in the end of the chamber. The arm is provided at its projecting end with a contact and near the center portion thereof with a piston. Gas pressure directed against one end of the piston causes the arm to be withdrawn into the chamber,l and a locking device then locks the switch arm in its retracted position. Gas pressure directed against the other end of the piston causes the switch arm to be moved to its closed position and a locking device then locks the switch arm in this position. v

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. l is a plan view of a high voltage switch;

Fig. 2 is a cross sectional view through a switch charnber; and

Fig. 3 is a cross sectional view through a switch chamber of a second embodiment of the invention.

Referring now to Fig. l there is shown a tank 1 lled with compressed gas and mounted on wheels. Fixedly secured to the tank are a plurality of stand-off insulators 14. Switch chambers 9 and 12 are mounted on the two outermost insulators and switch chambers 10 and 11 are mounted on the center insulator. Switch arms 50, 51, 52 and 53 form a series connection between current carrying switch terminal 54 and 55. The switch is actuated by means of compressed gas which is made to ow through one channel in the insulators through compressed gas lines 3, 4, 7, 63 and 8 respectively and through another channel in the insulators through compressed gas line 13. Relay coils 15 and 16 which are mounted in control box 2 are the break and make relays respectively. They may be actuated by connecting the relays to a source of current (not shown) and placing between the relay coils and the current source a switch such as a doublepole, double-throw switch, for example. Lines 3 and 4 are connected directly to the source of compressed gas. When relay 15 is actuated it causes air valves 5 and 6 to be opened and this allows compressed gas to be forced through compressed gas channels 7, 63 and 8 into one channel in the insulators. When relay 16 is actuated it causes a gas pressure valve in the common branch of line 13 (this valve is not shown in the drawing) to be opened and compressed gas from the tank to flow through the ducts 13 into the second channel through the insulators 14.

Referring now to Fig. 2, there is shown a metal switch chamber 9 having disposed therein a switch arm 50 with a piston 18 at the end thereof. The switch arm 50 is shown in its retracted position so that the space a `between its contact end and the contact end of switch arm 51 is sufficient to prevent arcing. Member 26 is a conductor which is fixed to the metal wall of the switch chamber and in slidable engagement with the switch arm S0. Member 26 forms the current carrying contact between terminal 54 and the switch arm. Member 27 consists of three small sections spaced at intervals. It is fixed to the insulator and serves 'as a guide for switch arm 50. The three sections making up member 27 are spaced sufficiently apart so as to offer little impedance to the ilow of compressed gas from channel 7. There is an aperture 56 at the center of the switch. arm whichleads to a chamber behind the piston 18 and to the silencer apertures 43 leading to the outside. The switch arm is biased by means of a coil spring 49 which is mounted on pin 42.

The switch arm is retained in its retracted position by means of a locking arrangement comprising a pin 22 secured to a piston 20 which is spring biased by means of a coil spring 21. Posts 40 and 41 mounted to the metal switch chamber wall are limit devices to prevent the pin 22 from extending any further into the switch chamber than as shown in the figure. Pin 22 is provided at its free end with a sloping surface 6d. The switch is opened by causing compressed gas to flow through channel 7 and the switch is closed by causing compressed gas to flow through channel 13. The switch nozzle through which compressed gas may escape is indicated by the numeral 57.

In operation, in order to cause the switch arm to move from its closed position as indicated in Fig. 1 to its open position as indicated in Fig. 2, relay coil 15 is energized. This causes air valves and 6 to open and compressed gas to ow through channels 7, 63 and S in the stationary stand-off insulators. In the closed position of the switch, the switch arm 50 forms a fairly tight fit with the nozzle 57 and substantially the complete pressure of the gas in channel 7 is directed against piston 1S. This causes the piston and the switch arm 5l) secured thereto to move to the left against the lbias of spring 49 until the piston rides over the sloping surface 60 at the `end of pin 22. Pin 22 is forced down against the bias of spring 21 and when the p-iston 18 moves past the pin to the position shown in Fig. 2, spring 21 then forces the pin to spring back to its original position and engage an edge ofv the piston 18.

When the switch arm is moved to the position shown in Fig. 2, compressed` gas from channel 7 escapes through nozzle 57 and this flow of gas causes the arc between the contacts at the ends of arms 50 and 51 rapidlyy to be v extinguished. A portion of the compressed gas is also forced through the aperture 56 in the switch arm 50 and out through the silencer openings 43. This last path provides a convenient exit for noxious gases.

In order again to close the switch, relay 16 is actuated and this causes an air pressure valve (not shown) in line 13 to be opened and gas to be forced into channel 13 in the various stand-off insulators. As can be seen in Fig. 2, the gas pressure is directed against piston 20 and forces the piston to move against the bias exerted by spring 21. When the pin 22 and piston 20 are moved in a downwardly direction the pin is disengaged from piston 18 and spring 49 forces the piston 18 and switch arm 50 to be propelled to the right. Similarly, arm 51 inl chamber 10 is propelled to the left and the contact at the end of arm 50 engages the contact at the end of arm 51. Posts 40 and 41 prevent the pin 22 from projecting into the switch chamber a distance sufficient to become entangled with the spring 49.

Fig. 3 illustrates a second embodiment ofthe invention. It includes a switch chamber 57 having disposed therein a switch arm 62 which has mounted on an intermediate portion thereof a piston 58. The switch arm has a groove 36 around the circumference thereof and a sloping end portion 37. Spring 29 is located within the spring chamber about the switch arm 62 and serves as a shock absorbing means. The locking arrangement for maintaining the switch arm in the closed or open position thereof comprises cylindrical housings 35 having mounted therein elongated members 32. These members are spring biased by means of springs 30 which are compressed between the caps 59 and one end of the elongated member. At the other end of the elongated members are rollers 31 which are of proper size to engage the groove 36. Channel 23 and apertures 56 provide the gas pressure path through which gas ows for opening the switch and channel 28 provides the gas pressure path through which gas ows for closing the switch.

In operation, in order to open the switch, gas is forced into channel 23, through apertures 56 and against piston 53 forcing the piston and the switch arm to move toward the left. When this occurs, the elongated members are caused to move against the bias of springs 343 and the rollers 3l then ride up surface 37. The switch arm then moves to the left and the rollers roll over the switch arm until they are forced by the bias of springs 36 into the groove 36. -ln the latter position, they lock the switch arm in its retracted position.

in other respects the opening of the switch results in operations similar to that described in connection with Figs. l and 2. For example, when the switch is in its fully retracted position, gas from channel 23 is forced through the nozzle opening 64 formerly occupied by the switch arm 62 and this flow of gas causes the arc rapidly to be extinguished. As in the embodiment of Fig. 2, switch arm 62 may be provided with a central axial aperture and wall 34 of the switch chamber provided with a plurality of apertures as exit points for compressed gas.

To close the switch, compressed gas is forced through channel 28 into the switch chamber and this causes piston 58 and the switch arm to move to the right into the position shown in Fig. 3. When in the closed position, the rollers 31 engage the sloping end surface 37 of the switch arm and lock the switch arm in the closed position. Caps 59 on housings 35 are threaded so as to provide a means for adjusting the tension of springs 30.

I-t will be understood that each of the elements described above, or two or more together, may also nd a useful application in other types of high voltage switches differing from the types described above.

While the invention has been illustrated and described as embodied in high voltage switch driven by compressed gas and having contacts in free air, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A pressure actuated high voltage switch comprising, in combination, a support member; a plurality of spaced insulators ixedly mounted on said support member, each of said insulating members being formed with at least one switching chamber therein having an opening in one wall thereof for communication with the free air; and a plurality of pairs of mating elongated switch arms connected in series, each of said switch arms being movably mounted in one of said switching chambers respectively for movement through said opening and being coaxially movable between an extended position wherein it makes electrical `Contact in free air with its extended mating switch arm of its respective pair, and a retracted position wherein each of said switch arms is spaced from its mating switch arm whereby the total distance between pairs of retracted switch arms is sufficient to prevent breakdown between said switch arms.

2. A pressure actuated high voltage switch comprising, in combination, a support member; a plurality of spaced insulators xedly mounted on said support member, each of said insulating members being formed with at least one switching chamber therein having an opening in one wall thereof for communication with the free air; a plurality of pairs of mating elongated switch arms connected in series, each of said switch arms being movably mounted in one of said switching chambers for movement through said opening and being coaxially movable between an extended position wherein it makes electrical contact in free air with its extended mating switch arm of its respective pair, and a retracted position wherein each of said switch arms is spaced from its mating switch arm whereby the total distance between pairs of retracted switch arms is suflicient to prevent breakdown between said switch arms; and means disposed in each of said chambers respectively for respectively holding the switch arm thereof in both of its positions.

3. A pressure actuated high voltage switch comprising, in combination, a support member; a plurality of spaced insulators iixedly mounted on said support member, each of said insulating members being formed with at least one switching chamber therein having an opening in one wall thereof for communcation with the free air; a plurality of pairs of `mating elongated switch arms connected in series, each of said switch arms being movably mounted in one of said switching chambers respectively for movement through said opening and being coaxially movable between an extended position wherein it makes electrical contact in free air with its extended mating switch arm of its respective pair, and a retracted position wherein each of said switch arms is spaced from its mating switch Iarm whereby the total distance between pairs yof retracted switch arms is suihcient to prevent breakdown between said switch arms; locking means disposed in each of said chambers respectively for respectively locking the switch arm thereof in its retracted position; and actuating means arranged on each of said switch arms respectively for actuating said respective locking means in response to the movement of said switch arm to its retracted position.

4. A pressure actuated high voltage switch comprising, in combination, -a support member; at least two spaced insulators xedly mounted on said support member, each of said insulating members being formed with at least one switching chamber therein having an opening in one wall thereof for communication with the free air; a plurality of elongated switch arms, each of said switch arms being movably mounted in one of said switching chambers respectively for movement through said opening and being coaxially movable between an extended position wherein each of said arms extends through the opening of its respective chamber to make electrical contact with an extended mating switch arm from another switching chamber, and a retracted position wherein each of said switch arms is spaced from its mating switch arm a distance sucient to prevent breakdown between said switch arms; resilient means arranged in each of said switching chambers respectively for normally urging the switching arms into their extended positions; and holding means disposed in each of said chambers respectively for respectively holding the switch arm thereof in its retracted position against the action of said resilient means.

5. A pressure actuated high voltage switch comprising, in combination, a support member; a plurality of spaced insulators xedly mounted on said support member, each of said insulating members being formed with at least one switching chamber therein having an opening in one wall thereof for communication with the free air; a plurality of pairs of mating elongated switch arms connected in series, each of said switch arms being movably mounted in one of said switching chambers respectively for movement through said opening and being coaxiaily movable between an extended position wherein it makes electrical contact in free Iair with its extended mating switch arm of its respective pair, and a retracted position wherein each of said switch arms is spaced from its mating switch arm whereby the total distance between pairs of retracted switch arms is suicient to prevent breakdown between said switch arms; resilient means arranged in each of said switching chambers respectively for normally urging the switching arms into their extended positions; holding means disposed in each of said chambers respectively for respectively holding the switch arm thereof in its retracted position against the action of said resilient means; and pneumatic means communicating with the interior of each of said switching chambers respectively for releasing said holding means whenever desired and for moving said switch arms from the extended position thereof to its retracted position, whenever desired.

6. A pressure actuated high voltage switch comprising, in combination, a support member; a plurality of spaced insulators xedly mounted -on said support member, each of said insulating members being formed with at least one switching chamber therein having an opening in one wall thereof for communication with the free air; a plurality of pairs of mating elongated cylindrical switch arms connected in series and having an annular groove in the outer surfaces thereof, each of said switch arms being movably mounted in one of said switching chambers respectively for movement through said opening and being coaxially movable between an extended position wherein it makes electrical contact in free air with its extended mating switch arm of its respective pair, and a retracted position wherein each of said switch arms is spaced from its mating switch arm whereby the total distance between pairs of retracted switch arms is suicient to prevent breakdown between said switch arms; and holding means disposed in each of said chambers respectively for respectively holding the switch arm thereof in its retracted position, said holding means including roller members arranged on opposite sides of each of said switch arms and engaging said annular groove in the outer surface of said cylindrical switch arm when said Varm is in its retracted position.

References Cited in the tile of this patent UNITED STATES PATENTS 695,118 Read Mar. 11, 1902 1,043,014 Jackson Oct. 29, 1912 1,895,907' Baum Jan. 31, 1933 1,904,577 Uebermuth Apr. 8, 1933 2,230,735 Verse Feb. 4, 1941 2,250,208 Schulz July 22, 1941 2,250,216 Biermans July 22, 1941 2,290,320 Duiiing July 21, 1942 2,382,786 Foulds Aug. 14, 1945 2,449,518 Strom Sept. 14, 1948 2,480,553 Cooper et a1. Aug. 30, 1949 2,747,055 Forwald May 22, 1956 FOREIGN PATENTS 716,684 Germany Jan. 31, 1942 582,687 Great Britain Nov. 25, 1946

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