US2281337A - Circuit breaker fluid pressure operated system - Google Patents

Description

April 289 i942, H. STEGELHTZ mmm y 231,337

v BREAKER FLUID PRESSUREv OPERATED SYSTEM CIRCUITv Filed Feb. 26, 1958 2 ShEatS-Shcae'l l OPEL/yA/G 53 I A i l Invehtrs: Hams 5tege\itz,-

Wilhehh Sch her; by T eh Att-,ovh ey.

April 28, 1942. H. sTEGELlTz. Erm. 2,231,337

CIRCUITBREAKER FLUID PRESSURE OPERATED SYSTEM Filed Feb. 26,- 1938 2 SheetsPSheet 2 IhvehtOP-SI Hans Stegeltz, Wilhelm Schreiner; )e2/7a The'n` Attorh ey.

Patented Apr. 28, 1942 OFFICE CIRCUIT BREAKER FLUID PRESSURE OPERA'EED SYSTEM Hans Stegelitz, Berlin-Johannisthal, and Wilhelm Schreiner, Berlin-Niedersehonhausen, Germany, assignors to Gener-ai Electric Company, a corporation oi New York Application February 26, 1938, Serial No. 192,804 In Germany April 3, 1937 11 Claims.

Our invention relates to circuit breaker uid pressure operated mechanisms, such as, for example, pneumatically actuated mechanisms for operating the Icontacts of an electric circuit breaker between open and closed circuit positions.

It has been recognized that the operating mechanism for closing a large capacity electric circuit breaker, for example, should include a so-called seal for automatically insuring continuation of the operating impulse throughout substantially the entire closing stroke of the breaker, and for discontinuing the impulse substantially at that point. Burning of the breaker contacts due to incomplete closure is therefore precluded and the usual trip-free feature assures short circuit protection. Methods heretofore used have generally included electric relays and auxiliary circuits which have not always worked satisfactorily and which often complicate the operating mechanism.

The principal object of our invention is the provision of an improved huid-operated mechanisrn of the piston type for electric circuit breakers wherein the opening and closing control. valves for admitting fluid pressure to the actuating plston are provided with interlocking means for rendering inoperative means for opening the closing valve when the opening valve is operated and for providing trip-free operation of said circuit breaker.

Our invention will be more fully set forth in the following description 4referring to the accompanying drawings, and the features of novelty which characterize our invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawing Fig. 1 is a partly diagrammatic layout of a pneumatically operated mechanism for actuating an electric circuit actuating impulse.

The pneumatic system illustrated by Fig. l comprises a suitable source of uid pressure, such as a conduit I connected to a gas reservoir (not shown), circuit breaker means adapted to be y actuated by fluid pressure, such as a doubleacting piston generally` indicated at 2, and a main valve 3 for controlling the fluid connection 4 between the source and the actuating piston structure.

As shown the piston structure 2 comprises a pair of pistons 5 and 6 rigidly interconnected at l for reciprocal operation within the cylinder portions 5' and 6 respectively. The piston structure is operatively connected in any suitable manner such as by a link 8 and pin 9 to the movable contact structure I0 of an electric circuit breaker. The circuit breaker may be of any suitable typeand in the present case wherein a source of gas pressure is available, the gas blast type may advantageously be used. As shown, the circuit breaker is in the open position, the contact I0 being elevated during the closing operation to engage the fixed contact structure at II. In the arrangement so far described it will be apparent that opening of the main valve 3 admitsfluid pressure by way of the connection 4 to the lower piston 5 so as to close the breaker.

For the purpose of sealing this operating impulse an auxiliary pressure responsive device I2 is disposed in communication with the fluid connection 4 and is operatively related to the valve 3 through a suitable mechanical connection for holding the valve open. Likewise, a second auxiliary pressure responsive' device I3 adapted to be placed in communication with the connection 4 after predetermined movement of the piston 5 is located with respect to the aforesaid mechanical connection so as to render the same inoperative and permit closing of the valve 3 when the circuit breaker has substantially completed its closing stroke.

To this end the pressure responsive device I2 comprises a piston I2 directly in communication with the iluid pressure connection 4 and operatively connected through a bell-crank I4 and toggle linkage I5 to the main valve stem I6. The pressure responsive device I3 likewise includes a piston I3' having an extension I3" for engaging the knee I5 of the toggle and serving as a support for holding the same in thrusttransmitting position.

It will therefore be apparent that when the valve 3 is initially opened in response to any suitable operation or impulse, such as by manual operation at Il. or by suitable and well-known remote control means, the fluid pressure in connection 4 operates simultaneously the pistons 5 and I2. As the piston 5 moves upward to close the breaker the piston I2' through togglelinkage I5 forces the valve stem I6 toward the open position and holds it in that position as long as the piston I2' is under :luid pressure and the toggle I is in the thrust-transmitting position. When, however, the closing stroke is substantially completed as shown by Fig. 1a the piston I uncovers the'port in the cylinder 5' communicating with the conduit I1 for admitting pressure to the piston I3.' This causes upward or buckling movement of the toggle knee I5 and subsequent collapse ot the toggle thereby rendering the pressure responsive .device I2 inoperative with respect to the main valvev 3 and permitting closing of lthe valve under inuence of the conduit pressure or other suitable biasing means.

The pneumatic operating means above described therefore is effective to seal a pneumatic actuating impulse, once initiated, through a pre-a determined operation, and automatically to dis-I continue the impulse upon completion of the operation.

The means for opening the breaker, although shown as pneumaticallyoperated, can obviously be selected in accordance with the particular breaker requirements. For example, the-breakerl can be opened by the usual compression spring that is unlatched in response to a tripping impulse. In the pneumatically operated means shown the upper or opening piston 6 is also adapted to be in communication with the pressure source I through a fluid connection 20 controlled by a valve 2I. In this case opening of the valve 2l causes downward movement of the adapted to be operatively connected to the valve stem 2| through a thrust transmitting toggle 25.

The toggle 25 in the reset position shown is spaced from the valve stem 2l for a reason presently Y described.

For the purposes of interlocking the closing and opening operations so that the breaker cannot be inadvertently closed after the opening operao tion has been initiated there is provided a mechanical connection 26 between the bell-crank lever 24 and the toggle I5. Accordingly, when the bell-crank lever 24 is rotated clockwise in response to an initial impulse and admission of uid pressure to the opening piston 3, the knee I5 of the toggle yI5 is raised to the collapsed position so that an actuating impulse cannot be transmitted to the valve 3. When, however,

, the breaker is opened and the mechanism in the position shown, buckling of the toggle I5 at the end of the closing stroke is not suiiicient to cause opening of the valve 2| by reason of the lost motionv between the toggle 2 stem 2|'.

The opening operation may be initiated, either manually as at 24 or by suitable remote control means such as an auxiliary pressure line 2l having a one-way valve 23 relating to the nuid connection 20. It will be apparent that when the remote control means is operated to admit gas under pressure to the line 21, the device 22 will 5 and the valve and closing of the valve 3. Thus, even though the piston 5 may not have reached the end of its closing stroke, actuation of the remote control means'can be effective to cause premature reversal of the piston from an intermediate point in the closing' stroke.

It win be noted that a mud-operated mechanism as described permits trip-free operationof the breaker during closing by reason ot .the collapsible connection to the closing valve 3. and also prevents pumping" or repeated reclosures of the breaker in addition to the interlocking 3 to close. The compressed gas acting on piston 5 is thus cut off and the piston cylinder simultaneously vented to atmosphere through pipe 4 vas shown by Fig. 1a.

In the modification shown by Fig. 2 a timedelay device is used in lieu of the piston controlled connection for automatically eiIecting closure of the main valve. In this case the valve 3 controlling communication between the source I and uid connection 4 is adapted to be actuated by a lever 30 having suitable actuating means, such as, for example a push button shown at 3l. The lever 33 can be adjustably related to the valve stem I6 as at 32.

For the purpose of sealingthe valve 3 after loperation of the push button, a differential piston having two portions 33 and 34 is connected as at 35 to the lever 30. The differential piston operates within a housing 36, one end of which forms a cylinder for the piston portion 33 connected vat 31 with the main fluid connection 4. The other part of the housing forms a cylinder for the large piston 34, that is adapted to be in communication at 38 with the connection 4 through a time-delay device 39. The device 39 may comprise simply a fluid reservoir, the entrance of which at 40 can be suitably restricted in combination with an adjustable escape at 4I, so that fluid pressure builds up in the cylinder of piston 34 only after a predetermined time.

The operation of this device is believed to be apparent from the above description, the rst opening of the valve 3 transmitting pressureto the first fluid responsive deviceat 33 for sealing A open the valve 3, and the large portion 34 ofthe be operated to open the valve 2| in the manner previously described. At the same time, the rod 26 will be lifted, causing collapse of the toggle I5 differential piston, or the second fluid responsive device, serving after a predetermined time to return the lever to its initial position thereby permitting closing of the valve 3 spring at 3l.

-It should beunderstood that our invention is not limited to specific details of construction and arrangementthereof herein illustrated, and that changes and modifications may occur. to one skilled in the art without departing from the spirit of our invention.

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

l. Fluid operated actuating mechanism com- I prising a source of fluid pressure, piston structure adapted to be actuated by fluid pressure. a main valve for controlling a fluid connection between said source and piston, an auxiliary pressure operated device communicating with said connection, means for opening said main valve,

means mechanically interconnecting said aux- -iliary device and main valve whereby said device under bias of the.

is operative to maintain said main valve in open position when fluid pressure is first admitted to said connection, and means for rendering inoperative the connection between said device and main valve after a predetermined working stroke of said piston.

2. Fluid operated actuating mechanism comprising a source of fluid pressure, a piston adapted to be actuated by fluid pressure, a main valve controlling the fluid connection between said source and piston, anauxiliary pressure operated device in communication with said connection, means for opening said main valve, a mechanical connection between said auxiliary device and main valve for holding said main valve in open position upon admission of fluid pressure to said connection, and a second auxiliary pressure operated device controlled by said piston for rendering inoperative said mechanical connection substantially upon completion of the working stroke of said piston.

3. Fluid operated actuating mechanism comprising a source of fluid pressure, piston structure operatively connected to the means to be actuated, a valve for controlling a fluid connection between said source and said piston structure for initiating a piston stroke, a second valve for controlling another iluid connection between said source and said piston structure for initiating a reverse stroke, an auxiliary pressure responsive de'vice actuated by fluid pressure in accordance with opening of said first valve, said auxiliary device being effective to hold said first valve in open position until substantial completion of said first piston stroke, means responsive to fluid pressure controlled by said piston structure for rendering inoperative said auxiliary device with respect to said valve whereby said valve may be closed upon completionof said ilrst piston stroke,

' a second auxiliary pressure responsive device also adapted to maintain open said second valve upon initial opening thereof, means for rendering inoperative said device with respect to said second valve substantially upon completion of said reverse stroke, and interlocking means inter-relatI ing said va'lves for rendering inoperative said first auxiliary device with respect to said first valve when said second auxiliary device is actuated in response to said first piston stroke.

4. Fluid operated actuating mechanism comprising a source of fluid pressure, a piston adapted to be actuated by fluid pressure, a valve for controlling a fluid connection between said source and said piston for causing a working stroke thereof, and means for automatically maintaining said valveV in open position only during said working stroke comprising a pressure responsive device in communication with said fluid connection, means including a collapsible mechanical connection between said fluid responsive device and said valve for maintaining said valve in open position substantially during said working stroke, and a second pressure responsive device operated by fluid pressure from said connection in accordance with predetermined movement of said piston for causing collapse of said mechanical connection thereby permitting closing of said valve.

5. Fluid operated actuating mechanism comprising a source of fluid pressure, a piston adapted to be actuated by fluid pressure, a valve for controlling a fluid connection between said source and said piston for causing a working stroke thereof, and means for automatically maintaining said valve in open position only during said Working stroke comprising a pressure responsive device in communication with said fluid connection, means including a collapsible mechanical connection between said fluid responsive device and said valve for maintaining said valve in open position substantially during said working stroke, and a second pressure responsive device operated by fluid pressure from said connection in accordance with predetermined movement of said piston for causing collapse of said mechanical connection thereby permitting closing of said valve, and means for effecting a reverse working stroke of said piston and interlocking means inter-relating the aforesaid means and said mechanical connection for rendering said connection inoperative during said reverse operation.

6. A circuit breaker pneumatic operating system of the trip-free type for opening and closing the contacts of said circuit breaker comprising a source of fluid pressure, fluid motor means operable by said fluid pressure operatively connected to said circuit breaker contacts, a closing Valve for connecting said source of fluid pressure with said fluid motor means for closing said circuit breaker, a tripping valve for connecting said source of fluid pressure with said fluid motor means for opening said circuit breaker, and interlocking means operatively interconnecting said closing and tripping valves for causing in response to a tripping operation during the closing stroke of said breaker closing of said closing valve upon opening of said tripping valve to cause premature reversal-oi said fluid motor means and trip-free operation of said circuit breaker.

7. A circuit breaker pneumatic operating s ystem of the trip-free type for opening and closing the contacts of said circuit breaker comprising a source of fluid pressure, a piston operable by said fluid pressure connected to one of the breaker contacts, a closing valve for connecting said source of fluid pressure with said piston for clos- Y ing s aid circuit breaker, a tripping valve for connecting said source of fluid pressure with said piston for opening said circuit breaker, and interlocking means including meansA for rendering inoperative the actuating means for said closing valve operatively interconnecting said closing and tripping valves for causing in response to a tripping operation during the closing stroke of said breaker closing of said closing valve upon opening of said tripping valve to cause premature reversal of said piston and trip-free operation of said circuit breaker.

8. A circuit breaker pneumatic operating system of the trip-free type for opening and closing the contacts of said circuit breaker comprising a source of fluid pressure, a piston operable by said fluid pressure connected to one of said circuit breaker contacts, a closing valve including a collapsible actuating means for connecting said source of fluid pressure with said piston for clos- .ing said circuit breaker, a tripping valve for connecting said source of fluid pressure with said piston for opening said circuit breaker, and mechanical interlocking means operatively interconnecting sald closing and tripping valves for causing in response to a tripping-operation during the closing stroke of said breaker collapse of said closing valve actuating means and closing of said closing valve upon opening of said tripping valve to cause premature reversal of said piston and trip-free operation of said circuit breaker.

Y ated by air pressure fromv said source,` a closing valve for controlling a connection between said source and piston for causing a closing stroke of said breaker, means for opening and holding open said valve to insure a full closing stroke of said piston under normal operating conditions,

a tripping valve for admitting air pressure to- Y said piston for causing a reverse circuit opening stroke thereof, and interlocking means operatively interconnecting said valves so as to insure a predetermined sequence of operation thereof, said interlocking means being arranged to cause in response to a tripping operation premature closing of lsaid closing valve at an intermediate point in the closing stroke substantially coincident with opening of said tripping valve for causing immediate reversal of said piston and tripfree operation of said breaker.

l0. A circuit breaker having relatively movable contacts and air-operated actuating mechanism of the trip-free type for operating said contacts comprising a source of air pressure, a piston op` eratively connected to one of said contacts actuated by air pressure from said source, a closing valve for controlling a connection between said source and piston for causing a closing stroke of said breaker, means for opening and holding open said valve to insure a full closing stroke of said piston under normal operating conditions,

a tripping valve for admitting air` pressure to' said piston for causing a reverse circuit opening stroke thereof, and interlocking means including a link member operatively interconnecting said valves so as to insure a predetermined sequence of operation thereof, said link member being arranged to'engage in response to a tripping operation the actuating means of said closing valve during the closing stroke during opening of said tripping valve for causing immediate reversal of said piston .and trip-free operation of said said piston under normal operating conditions' a tripping valve for admitting air pressure to said piston for causing a reverse circuit opening stroke thereof, and interlocking means including a lost-motion connection operatively interconnecting the actuating means of said valves so as to insure a predetermined sequence of operation thereof, said interlockingv means being arranged to cause in response to a tripping operation premature closing of said closing valve at an intermediate point in the closing stroke by and in accordance with the opening of said trpping valve for causing immediate reversal of said piston and trip-free operation of said breaker.

HANS STEGELITZ. WILHELM SCHREINER.

Images