US3358103A - Anti-pump control scheme for fluidactuated circuit interrupters - Google Patents

Description

Dec. 12, 1967 Filed Oct. 5, 1964 W. A. FISH, JR ANTI-PUMP CONTROL SCHEME FOR FLUID-ACTUATED CIRCUIT INTERRUPTERS 4 Sheets-Sheet 1 v INVENTOR William A. Fish. Jr.

-BY M m 4% ATTORNEY Dec. 12, 1967 w. A. FISH, JR 3,358,103

ANTI-PUMP CONTROL SCHEME FOR FLUID-ACTUATED CIRCUIT INTERRUPI'ERS Filed Oct. 5, 1964 4 Sheets-Sheet 2 Dec. 12, 1967 w s JR 3,358,103

ANTI-PUMP CONTRO L SCHEME FOR FLUID-ACTUATED CIRCUIT INTERRUPTERS Filed Oct. 5, 1964 4 Sheets-Sheet 02 FIG. 6.

gOL 4(Bil Dec. 12, 1967 w. A. FISH, JR 3,353,103

ANTI'PUMP CONTROL SCHEME FOR FLUID-ACTUATED CIRCUIT INTERRUPTERS Filed Oct. 5, 1964 4 SheetsSheet 4 a w j FlG. 7. d 4-:

CST 0a L L IL i w 1 TC I *0 o J C80 CC a? o- FIXED THROTTLE United States Patent 3,358,103 ANTI-PUMP CONTRQL SCHEME FUR FLUID- ACTUATED CIRCUIT INTERRUPTERS William A. Fish, .lr., Wilkins Township, 1821., assignor to Westinghouse Electric Corporation, Pittsburgh, Pa, a

corporation of Pennsylvania Filed Oct. 5, 1964, Ser. No. 401,298 7 Claims. (Cl. 20t)148) ABSTRACT OF THE DISCLOSURE To prevent pumping in the pneumatic operating mechanism of a circuit interrupter, a non-pumping relay having seal-in contacts in series With the actuating coil of the trip relay is provided. Other contacts responsive to the pressure of the outlet fluid connection of the closing valve of the circuit interrupter are arranged in series with the actuating coil of the non-pumping relay.

This invention relates, in general, to improved antipump control schemes for circuit interrupters and, more particularly, to an improved simplified-type non-pumping control scheme for use with a control valve controlling the operation of a fluid motor of a circuit interrupter.

A general object of the present invention is the provision of an improved non-pumping control scheme for a circuit interrupter having a fluid motor associated therewith.

Another object of the present invention is to provide an improved non-pumping control scheme for use with a particular type of control valve as set forth in United States patent application filed July 18, 1963, Ser. No. 296,015, by William A. Fish, Jr. and Charles B. Wolfe and assigned to the assignee of the instant application.

The fluid control valve of the aforesaid patent application has the unique characteristic of pneumatically latching in either the open or closed positions without the necessity of employing mechanical latches. The construction of the valve is such that the pneumatic forces operable in the open and closed positions of the valve retain the valve in such position without reliance upon mechanical latching.

Still a further object of the present invention is the provision of an improved non-pumping control scheme particularly applicable to an improved control valve of unique construction wherein the opening operation will take place in precedence to the closing operation, and wherein pumping, or alternate closing and opening of the circuit breaker, cannot occur.

Another object is to provide an improved non-pumping electrical control scheme for a circuit interrupter using a fluid motor for contact operation, in which the closing operation of the closing device is continued when once initiated.

Further objects and advantages will readily become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

FIGURE '1 illustrates in vertical crosssection, and partially diagrammatically, an application of the improved anti-pump control scheme of the present invention as applied to a fluid-blast circuit interrupter, the contact structure being shown in the closed-circuit position;

FIG. 2 illustrates a fragmentary view of the fluid-blast circuit interrupter of FIG. 1, and the improved nonpumping control circuit therefor;

FIG. 3 is a sectional view through the control valve in the exhaust position;

FIG. 4 is a line diagram of the control connections for the pneumatic control arrangement in FIG. 2;

3,358" 1 Patented Dec. 12, 1967 ICC FIG. 5 illustrates a modified arrangement of control connections which may be utilized for supervising reliability of the trip coil and relay coil circuits;

FIG. 6 is a diagrammatic view of the improved fluidoperating control of the present invention as applied to a circuit breaker, the circuit breaker being shown in the open-circuit position, and all coils being deenergized;

FIG. 7 is a line diagram of the electrical control for the valve elements illustrated in FIG. 6; and,

FIG. 8 is a diagrammatic view similar to that of FIG. 6, but showing the position of the several parts upon initiating a closing operation, with the circuit-breaker parts being shown in their closed position.

Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral 1 generally designates a fluid-blast circuit interrupter of the type of which a blast of fluid, obtained by putter action, is forced across the separating contact structure 2 to bring about are extinction. As shown, generally the circuit-interrupting structure 1 includes an upstanding frame support 3 and a generally horizontally extending pressurized casing 4. The pressurized casing 4 has a terminal cap 5 at one end thereof, which serves to support a relatively stationary contact post 6. The movable cooperating contact structure 7 comprises a plurality of circumferentially-disposed contact fingers 8 and an arcing tip portion 9, which extends interiorly within a cooperable recess 10 provided at the extremity of the stationary contact 6. Serving the purpose of opening and closing the movable contact structure 7 and an associated piston device 11 is a driving piston 12 operable within an operating cylinder 13, the latter comprising a casting structure 14, which additionally serves as a terminal end plate 15, as shown.

Movable within the operating cylinder 13 is the driving piston 12, having a piston rod 12a which has a contact finger collector 16 associated therewith. It will be noted that the piston rod 12a functions as a movable contact rod. The piston rod has an extension 12b on the other side of the piston 12, which may be guided by an aperture 15a in a weatherproof shield casting 15b affixed in any suitable manner to the terminal end plate portion 15, as shown.

To effect the alternate pressurizing and exhausting of the region to the right of the driving piston 12 there is provided a valve-control device 17. The valve-control device 17, as shown more clearly in FIG. 2, includes an exhaust valve 18, a valve stem 19 and an actuating piston 2i) fixedly secured together as a unit, and operable by the pressurizing of the space 21 below the actuating piston 20. FIG. 2 more clearly shows a fluid connection 22 from the closing pilot valve 23, which connects with a bypassing channel 24 having a relatively restricted upper bleeder portion 25. i

In more detail, the valve-control device 17 comprises a valve cap 17a, a valve body 17b and a lower valve cover 170. The valve cap 17a has an exhausting aperture 17d provided therethrough, which is controlled by the operation of the exhaust valve 18.

The valve body 17b is provided with the axial bore 24 having the restricted portion 25. Additionally, there is provided a first enlarged space 36 and a second enlarged space 37 communicating with the exhaust aperture 17d and with a control port 38, the latter communicating with the interior 28 of the driving cylinder 13.

As mentioned hereinbefo-re, there is reciprocally movable interiorly of the valve body 171) the piston-actuated exhaust valve 18 having as a unitary portion thereof a valve stem 19 having an intermediate piston portion 39. As shown, O- rings 40, 41 are provided to prevent fluid escape. Carried with the exhaust valve 18 is a sealing gasket 42, which seals against a sealing portion 172 of the valve cap 17a in the presurized condition of the control valve 17, as shown in FIG. 2 of the drawings.

As shown in FIG. 2, the lower end of the valve system 19 has fixedly secured thereto the actuating piston 20 operable within an operating cylinder 43 defined by the aforesaid first enlarged space 36.

A control pressure connection 44 enters the space 21 below the actuating piston 20. The pressure condition within the restricted portion 17 of the axial bore 17g is constantly maintained by a permanent pressure connection 45 from a high-pressure tank HP1.

Carried with the valve stem 1% is a sealing gasket 46, which seals against a sealing portion 4 7 of the restricted opening 17f in the exhausted condition of the control valve 17. The bypassing channel 25 is of relatively small bore and parallels the axial bore 17g and has an inlet port 48 associated therewith. A three-Way opening valve 26 is associated with the inlet port 49 leading to the space 21 below the actuating piston 20.

To measure the current passing through the interrupter 1 for relaying functions, a plurality of current transformers GT1, GT2, etc. may be utilized encircling the casing 4 on opposite sides of the clamping portion 3a of the upstanding frame support 3. The present interrupter retainsthe advantage of maintaining the circuit transformers at ground potential. One of these current transformers GT1, for example, may be used to actuate an overload or protective relay OL, as shown in FIG. 1.

To effect opening of the circuit interrupter 1, the coil 50 of the opening pilot valve 26 is energized. This may be obtained by momentarily pressing a trip button 51, or by the actuation of the overload relay L closing the contacts 0L1 thereof as a result of excessive current flow through the current transformer GT1. This momentarily transmits high pressure from a high-pressure source of fluid HPZ into the space 21 below the actuating piston 20 forcing the latter upwardly to open the exhausting valve 18 and sealing the lower sealing gasket 46 against the valve seat 47 of the valve body 1711. Since the volume of the space 21 is relatively small, and the actuating area of piston 20 is large, only a very small build-up of pressure in the space 21 is required to start the exhausting operation of the valve 18. As mentioned hereinbefore, only a momentary application of pressure from the opening switch 51 is required. Inasmuch as the area N, exposed to the constant high pressure within the axial bore 17 is greater than the area it of the sealing gasket 46 exposed to the same pressure in the exhausted condition, pneumatic latching is thereby achieved in the exhausted condition of the control valve 17 shown in FIG. 3.

When the exhaust valve 13 has been moved upwardly to the exhausting position, fluid pressure, such as air pressure at a pressure of 150 lbs. per sq. in., is exhausted from the space 28, through exhaust port 38 and out exhaust opening 170. of the control valve 17. This will enable the high-pressure gas within the space 54 within casing 4 to act through openings 35 and on the left-hand face 12c of the piston 12 forcing the latter to the right, as viewed in FIG. 1. This opening movement of the driving piston 12 to the right will correspondingly cause rightward movement of the fluid-driving piston 11a within the fluid cylinder 29 and thereby compress fluid within the space 110 to force such compressed fluid out through openings 30 and through the orifice 31 of a nozzle, or orifice structure 32 causing extinction of the established arc between contacts 6 and 9.

To eifect a closing operation of the circuit interrupter 1, the coil 34, associated with the closing pilot valve 23, is energized by pressing closing contacts 23a to thereby effect a momentary pressurized condition through the pipe 22 and inlet port 48 into the bypassing channel 25. Since the restricted portion of the bypassing channel 25 is of only small dimensions, the exhausting of the pressure -is less than the entrance of the pressure into the space 36 above the actuating piston 21), so that the piston 20 is nevertheless forced downwardly to the position illustrated in FIG. 2 of the drawings. This action closes the exhaust valve 18 sealing the gasket 42 against the valve seat 17.2 and permitting high pressure to feed into the operating cylinder 13 of the circuit interrupter 1 through bypassing channel 25 from the high-pressure gas tank HP3. Since the pressure supplied by the high-pressure tank HP?) is greater than the pressure supplied within the space 54 interiorly of the casing means 4, the driving piston 12 will be forced pneumatically toward the left to thereby effect closure of the separable contact means 2 to the closed position as shown in FIG. 1 of the drawings.

Inasmuch as the area M exposed to the operating pressure is greater than the area m exposed to the same pressure, the exhaust valve 18 will remain in the closed position shown in FIG. 2. Thus, pneumatic latching is thereby achieved in the pressurized condition of the control valve 17, as shown in FIG. 2.

The control valve 17 has the particular advantage of remaining in its pressurized or exhausted condition without any mechanical latches due to the pressurized condition of the axial bore 17f and the particular arrangement of the component parts. The result is extremely high speed opening and closing operations of the circuit-interrupting device 1. From the foregoing, it will be apparent that there is provided pneumatic latching, in the pneumatic operating mechanism thus eliminating the need for delicate and troublesome adjustments of mechanical latches. Pneumatic seal-in on the cylinder-pressurizing operation is obtained since momentary application of pressure from the closing pilot valve 23 will cause the valve device 17 to complete its closing operation and seal-in with the cylinder 13 remaining pressurized. This eliminates the need for seal-in contacts in the associated electrical control circuit.

A very important characteristic of the control valve 17, particularly as applied to circuit-breaker operation, is the pneumatic trip-free operation, which is obtained since pressure from the cylinder exhausting opening pilot valve 26 will drive the exhaust valve 18 open, and exhaust the operating cylinder 13 regardless of the energization of the cylinder pressurizing closing pilot valve 23. This eliminates the need for mechanical trip-free linkages to assure circuit-breaker tripping even though the closing coil is energized.

More specifically, with the exhaust valve 18 closed, as shown in FIG. 2, and with both pilot valves 23, 26 energized, there will be an upward unbalanced opening force tending to unseat valve 18 equal to the pressure in space 37 times the entire opening area of exhaust outlet 17d. Once the exhaust valve 13 has opened the exhaust opening 17d slightly, the pressure will drop in the space 37. Now the forces acting on the intermediate piston portion 39 will be unbalanced, since high pressure exists below piston 39 and the pressure is dropping above piston 39 in the space 37. In addition, at this time there is an additional upward exhausting force equal to the stem area X times the high pressure below the actuating piston 26 in the volume 21. And, moreover, to supplement this force, there will be the differential force on the exhaust valve 18 itself, this force, however, dropping as the valve 18 moves to its upper and exhausting position.

The pneumatic control circuit set forth in FIG. 2 of the drawings includes an anti-pump control scheme. As shown, the coil and contacts designated as Z and Z1 indicate a standard relay, or contactor so connected that it will pick up on a momentary contact of the controlswitch tripping contact 51 and maintain itself and the trip coil 51) in an energized condition until the circuit is broken by a series-connected auxiliary switch contact. Such a contact is designated as aa in this scheme, and is a pressure-operated switch actuated by pressure from a connection 60 between the cylinder-pressurizing pilot valve 23 and the bleed hole 25. This contact will therefore be closed at all times when the operating cylinder 13 is pressurized, that is in the circuit-breaker closed posi tion, and also at all times when the closing coil 34 is energized, thus applying pressure to the control valve 17 in an attempt to pressurize the cylinder 13. The reference letters R and G designate conventional red and green indicating lights; and contacts a and b are auxiliary switch contacts used in the conventional sense to indicate the closed or open-circuit positions of the circuit breaker l.

An important feature of the control circuit, as illustrated in FIG. 2, is the use of the aa contact in the trip coil, or Z coil circuit 61 to provide non-pumping operation with a very simple control circuit, thus eliminating the need for the conventional X and Y relays, which are useful in conventional control schemes of the prior art.

The closing coil 34 can be energized at any time by closing the control switch contact 23a. Since the pneumatic latching device 17 seals in pneumatically, only a momentaly contact of the closing button 23a is required to assure completion of the closing operation of the interrupter 1.

Closing .the control switch contact 51 energizes the Z coil provided the an contact is closed, indicating either that the circuit breaker 1 is closed, or the closing valve 23 is energized in an attempt to close the circuit breaker 1. Energizing the Z coil closes the Z1 contacts, thus sealing the Z relay in. In the illustrated control circuit of FIGS. 2 and 4, the trip coil 51) is energized simultaneously with the Z coil. A momentary contact of the control switch 51, or a tripping relay contact 0L1, energizes the Z coil and trip coil 50 which remain energized until the aa contact opens, thus assuring completion of the tripping operation.

If both closing and tripping contacts 23a, 51 are closed at the same time, the trip circuit 61 will be energized through the aa contact, and will remain energized until the closing contact 23a is opened, thus permitting the an contact to open. The design of the pneumatic latching device 17 is such as hereinbefore described, that pressure from the tripping valve 26 will drive the exhaust valve 18 open, and open the circuit breaker 1 regardless of the closing valve condition 23. Thus, if the trip circuit 61 is energized at any time while the closing switch 23a is closed, both close and trip coils 34, 56 will remain energized, and the circuit breaker will open and remain open until the closing switch 23a is opened and again closed. Therefore, positive tripping is assured regardless of the closing switch position; and the pumping (alternate closing and opening of the circuit breaker 1) cannot occur.

As shown in FIG. 1, the high-pressure tanks, tripping and closing pilot valves, non-pumping relay and the electrical supply 63, 64 may be housed in a grounded metallic mechanism housing 65 supported on the upstanding frame support 3 with the pneumatic lines 22, 44, and 4S composed of a suitable insulating material, such as plastic or ceramic tubing to hold the voltage.

By way of recapitulation during the opening operation the exhaust valve 18 of the control device 17 is opened by the application of pressure below the actuating piston 20. This will force the exhaust valve 18 upwardly to exhaust the region 28 to the righthand side of the driving piston 12 to thereby effect rightward opening movement of the movable contact structure 7. An arc will be drawn between the separated contact structure 2, and the compression of fluid within the operating cylinder 29 Will force fiuid' through apertures 30 associated with the contact structure 2 and through the orifice 31 of a nozzle 32 and into the arc to eifect the extinction thereof. In the open-circuit position of the interrupter, not shown, the fluid will be exhausted from the rear of the driving piston 12, and the pressure within the housing 4 will act upon the lefthand face 120 of the driving piston 12 and insure that the contact structure 7 will remain open. As set forth in the aforesaid United States patent application Serial No. 296,015, the pneumatic control device 17 has the automatic feature of latching into the open or closed positions with no mechanical latches necessary.

To effect the closing operation of the interrupter, energization of the closing solenoid 34 by pressing the closing button 23a will force pressure into the valve device 17 through the pressure line 22 and will effect closing of the exhaust valve 18 and a consequent pressurizing of the region 28 to the righthand side of the driving piston 12. This will close the contact structure 7 and will position the parts in a closed position, as shown in FIG- URE 1.

FIG. 4 is a line diagram of the control connections for the pneumatic control arrangement of FIGS. 1 and 2, and FIG. 5 illustrates a slightly modified type of control arrangement which may be utilized for supervising reliability of the trip coil and relay coil circuits. It will be noted here that the relay Z has an extra set of contacts Z2 and that the red indicating light R is connected to supervise the trip coil 50 and Z coil circuits. In other words, the trip coil 50 and Z coil are connected in series and if for any reason they are open-circuited, the red indicating light R will not light in the closed circuit position of the interrupter 1. If, on the other hand, the light R is lit in the closed position of the interrupter 1, this will indicate that both coils S0 and Z are in proper condition and ready to operate.

Although for diagrammatic illustration in FIG. 2 the high-pressure tanks HP1, HPZ and HPS have been indicated as separate high-pressure reservoir tanks, in fact, the three tanks could, of course, be combined as one tank disposed within the mechanism housing 65 of FIG. 1.

FIGURE 6 shows a modification of the invention in which the reference numeral 101 generally designates a circuit interrupter having a pair of stationary contacts 102, 103 and a movable bridging contact 194. A transmission line 105 is connected to the stationary contact 1112 and a transmission line 106 is connected to the other stationary contact 1&3. For the purpose of eifecting the closing and opening operations of the movable bridging contact 104 relative to the two stationary contacts 102, 1113, there is provided a fluid-operating mechanism, generally designated by the reference numeral 107, and including an operating cylinder 108, within which is reciprocally movable an operating piston 199. Secured to the operating piston 109 is a piston rod 110, which, in turn, is secured to the bridging contact 104 so as to cause the opening and closing movements thereof.

An accelerating spring 112 is arranged within the operating cylinder 108 and functions to bias the piston 109 and movable bridging contact 104 to the open-circuit position, as illustrated in FIG. 6.

With a view to effecting closure of the bridging contact 104 into engagement with the stationary contacts 102, 103, a pressurized fluid may be introduced into the operating cylinder 108 to the left of the operating piston 109, as shown in FIG. 8, thereby effecting closure of the contact structure against the bias exerted by the opening accelerating spring 112. A main operating valve 114 is provided to control the admittance of fluid under pressure into the left-hand end of the operating cylinder 108, and also to effect the exhausting of this region, as shown in FIG. 6, to bring about an opening operation. It will be noted that the main operating valve 114 is a three-way normally-closed, pressure pilot-operated valve. More specifically, the main operating valve 114 has an outlet connection 115 leading to the left-hand end of the operating cylinder 108. In addition, the main operating valve 114 has a pressurized region 116 connected, by a conduit 117, to a source of high-pressure fluid 113. Another region 119 of the main operating valve is at a relatively low pressure, having an exhaust connection 120.

As shown in FIG. 6, the main operating valve 114 has a pair of valve elements 122, 124 operable therewith in, being connected by a valve rod 126 to a pilot piston 127 operable within an operating cylinder 128. As shown, the lower end of the operating cylinder 128 has a connection 129 to the central region 138 of a trip valve, generally designated by the reference numeral 131. As shown in FIG. 6, the trip valve 131 is a three-way, normally-open, solenoid-operated valve. More specifically, the trip valve 131 has a pair of valve elements 132, 133 interconnected by a valve rod 134, the latter being secured to an armature 135. A tripping coil TC is arranged, when energized, to eifect upward movement of the armature 135, thereby opening the valve element 132 and closing the valve element 133. The outlet connection 134Aof the trip valve 131 is connected to the pilot inlet port 137 by way of the conduit 129.

The trip valve 131 has an inlet conduit 138, which connects with a lower region 139 of the trip valve 131, and connects with the upper region 140 of a closing valve, generally designated by the reference numeral 141. As shown in FIG. 1, the closing valve 141 is a straight-Way, normally-closed, solenoid-operated valve. The closing valve 141 has a valve element 142 connected by a valve stem 143 to an armature 144. The armature 144 is actuated by a closing solenoid CC, the latter being connected to the closing-control button CSC by a connection 146. The other contact of the closing button CSC is connected, by a connection 147, to the positive side of the line 148. The negative side of the line 150 is connected by a line connection 151 to the lower terminal of the closing coil CC.

The closing valve 141 is provided with a lower region 149, which is connected by a conduit 152 to the highpressure storage reservoir 118.

The improved fluid-operating mechanism of the present invention has an auxiliary-switch operating cylinder 154 having a piston 155 reciprocally operable therewithin. The piston 155 has a piston rod 156 carrying two bridging contacts 157, 158. The bridging contacts 157, 158 respectively engage stationary contacts b, a, which are respectively connected by connections 159, 169 to indicating lights G, R. The other terminals of the indicating lights are connected by connections 161, 162 to the positive side of the line 148.

It will be noted that the region 154a of the operating cylinder 154 is pneumatically connected by a conduit 164, to the high-pressure fluid source 118. In addition, the operating cylinder 154 has a region 154b, which is in fluid connection, by a line 166, with the outlet connection 115 of the main operating valve 114. A branch connection 168 interconnects the fluid line 166 with the region 108a of the operating cylinder 108. A bleeder connection of restricted size 170 interconnects the fluid connection 115 with the region 128a below the pilot piston 127 of the pilot section for the main operating valve 114.

With further reference to FIG. 6, it will be noted that there is' provided a cutoff-switch operating cylinder 180 having a region 188a in fluid connection, by means of a fluid conduit 181, with the fluid conduit 164 previously described. In addition, the cutoff-operating cylinder 180 has a region 180b, which has a fluid connection 184 with the fluid connection 138. There is provided a fixed-throttle fluid-connection 190 interconnecting the fluid connections 129 and 184, the purpose of which will appear more fully hereinafter.

Certain features of the electrical control circuit will now be described. It will be noted, that there is provided a current transformer CTl, which provides an indication of the magnitude of the current flowing through the line L L The current transformer CTI has a pair of branch leads 195, 196, which are connected to an overload coil OL, which actuates overload contacts L1. It will be noted that the overload contacts 0L1 are in electrical parallel, by means of connectors 198, 19?, with a tripping button CST. The positive side of the line 148 is connected to the connection 199 and to one of the contacts of the tripping button by means of a connector 201. The other contact of the tripping button CST is connected, by a connection 203, to the tripping coil TC and also to the coil 205 of a relay Z having a pair of contacts Z1. The contacts Z1 of the relay Z are connected to the positive side of the line 148 and also by a connection 208 to additional connections 209, 210, which are connected to the coils TC and Z.

The closing operation is initiated by energizing the closing coil CC, thus moving the closing valve 141 to the open position. Pressure admitted through the closing valve 141 and the normally-open trip valve 131, to the pilot section of the cylinder-actuating valve, or main operating valve 114, causes the main operating valve 114 to move to the open position, thereby admitting pressure to the operating cylinder 108 and closing the circuit breaker 101. When the closing valve is deenergized, pressure trapped in the passages between the closed closing valve and the cylinder-actuating valve pilot will maintain the cylinderactuating valve in the open position. Thus, pressure is continuously supplied to the operating cylinder 108 to maintain the closed position of the circuit-breaker 101. Any possible leakage of trapped pressure from the pilot of the cylinder-actuating valve will be replenished through the internal bleed connection from the outlet side 115 of the main operating valve 114.

The tripping or opening operation is initiated by energizing the trip coil TC, thus moving the trip valve 131 to the closed position. This closes the inlet port of the trip valve 131, and connects the outlet to the exhaust port, thus exhausting the pilot of the cylinder-actuating valve 114. The deenergized cylinder-actuating valve will move to its normally-closed position, thus closing the inlet port and connecting the outlet to the exhaust port. The operating cylinder is thus exhausted permitting the circuit breaker to move to the open position. When the trip coil is deenergized, the trip valve will return to its normally-open position, however, the inlet is blocked by the closed closing valve, the pilot section of the cylinderactuating valve has no source of pressure feed, and the circuit-breaker will remain open. Any possible leakage into the pilot passages will be exhausted through the internal bleed to the outlet and exhaust port of the cylin der-actuating valve.

In the event that the closing valve and tripping valve are both closed at the same time, in any sequence, or simultaneously, the pilot passage is blocked by the closed inlet port of the trip valve, and the closing valve will be ineffective. Pneumatic trip-free operation is thus assured under all conditions.

The cut-off (aa) switch-operating cylinder is actuated by pressure at the output of the closing valve. Thus, it will indicate the closed position at any time the closing valve is energized, or at any time the circuitbreaker 101 is closed. The fixed throttle is a restricted passage provided between the inlet and outlet of the trip valve for the purpose of exhausting the cutoff-switch actuating line when the closing valve is deenergized, and the trip valve is energized. It must be smaller than the passages in either of these valves in order to permit pressure build-up in the cutoff-switch actuating line, and not interfere with proper exhausting of the cylinder-actuating valve pilot when the closing valve and trip valve are both energized.

The auxiliary-switch operating cylinder 154, actuated by pressure at the operating cylinder inlet, is a direct indication of the position of the circuit breaker.

From the-foregoing description it will be apparent that conventional pneumatic or hydraulic operating mechanisms and which use mechanical latching, require complicated and costly latches, links and levers to provide the necessary mechanically and pneumatically or hydraulically-trip features, are unnecessary.

From the foregoing description, it will be apparent that there is provided an improved non-pumping control circuit to prevent rapid repeated opening and closing operations of the interrupter 1, 101, which could result in damage thereto.

Although there has been illustrated and described specific structures, -it is to be clearly understood that the same were merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the invention.

I claim as my invention:

1. A circuit interrupter having separable contacts and a fluid motor for actuating said contacts, said fluid motor having a movable pressure-responsive member connected to the contacts, control valve means for pressurizing or exhausting one side of said pressure-responsive member, electrically-actuated trip valve means for effecting an exhausted status of said control valve means and having an actuating coil associated therewith, a non-pumping relay (Z) having seal-in contacts (Z1) in series circuit with said actuating coil and also having an actuating coil, a closing valve for'eflecting a pressurized status of said control valve, a non-pumping contact (aa) in electrical series with said actuating coil of the non-pumping relay (Z) and being pressure-responsive to the outlet fluid connection of the closing valve, whereby non-pumping operation of the circuit interrupter is achieved.

2. A circuit interrupter having separable contacts and a fluid motor for actuating said contacts, said fluid motor having a movable pressure-responsive member connected to the contacts, control valve means for pressurizing or exhausting one side of said pressure-responsive member, said control valve including a valve body having an axial bore With a restricting portion therein, a piston-actuated exhaust valve having a valve stem portion extending through said axial bore, said valve body having an enlarged space defining an operating cylinder on one side of said restrictingv portion and an enlarged space on the other side of said restricting portion, high-pressure fluid supply means for constantly supplying high-pressure fluid to said axial bore, an actuating piston disposed at one end of said valve-stem portion and reciprocally operable Within the first mentioned enlarged space, a gasket seal carried by said valve stem and arranged for sealing against said restricting portion in the exhaust position of the fluid-control valve, an intermediate piston portion secured to the valve stem and disposed on said other side of the restricting portion, the annular piston area of said intermediate piston portion being larger than the annular area of the gasket seal exposed to the constant high-pressure fluid when in the exhausting position of the control valve, a bypassing channel paralleling said axial bore and interconnecting the two enlarged spaces, the annular area of the exhaust valve exposed to fluid pressure being greater than the exposed annular area of the actuating piston when in the pressurized condition of the control valve, electrically actuated trip valve means for eifecting an exhausted status of said control valve means and having an actuating coi-l associated therewith, a nonpumping relay (Z) having seal-in contacts (Z1) in series circuit with said actuating coil and also having an actuating coil, a closing valve for eflecting a pressurized status of said control valve, a non-pumping contact (aa) in electrical series with said actuating coil of the nonpumping relay (Z) and 'being pressure-responsive to the outlet fluid connection of the closing valve, whereby nonpumping operation of the circuit interrupter is achieved.

3. A circuit interrupter including separable movable and stationary contact means, a fluid-operated mechanism for actuating the movable contact means to the engaged and disengaged positions, said fluid-operated mechanism including a main operating cylinder having an operating piston reciprocally operable therewithin, means connecting the movable contact means to the operating piston, means biasing the movable contact means to the opencircuit piston, a three-way normally-closed pressure pilot operated main operating control valve, said main operating control valve having its intermediate outlet portion connected by a fluid connection to the closing side of the operating piston, a high-pressure fluid reservoir connected to the inlet portion of said main operating valve, an exhaust region connected to the other end of said main operating valve, a three-way normally-open solenoid-operated tripping valve having its intermediate outlet portion in fluid connection with the pilot section of the main operating control valve, the inlet portion of said tripping valve being in fluid connection with a straight-way normally-closed solenoid-operated closing valve, a highpressure fluid connection to the inlet portion of said closing valve, electrical closing means for energizing the closing valve to permit the passage therethrough of highpressure fluid, electrical tripping means for energizing the tripping valve, said electrical tripping means having an actuating coil, a non-pumping relay (Z) having a sealin contacts (Z1) in series circuit with said actuating coil and also having an actuating coil, a non-pumping contact (aa) in electrical series with said actuating coil of the non-pumping relay (Z) and being pressure-responsive to the outlet fluid connection of the closing valve, whereby non-pumpin operation of the circuit interrupter is achieved.

4. The combination of claim 3, wherein a fluid bleeder connection is provided between the outlet side of the main operating valve and the pilot section of said main operating valve to replenish any loss of pressure in the fluid passages between the closed closing valve and the main operating valve in the closed position of the circuit interrupter.

5. The combination of claim 3, wherein an auxiliaryswitch operating cylinder has its closing side in fluid communication with the outlet of the main operating valve.

6. The combination of claim 3, wherein a cutoff switch is provided including an operating cylinder with its closing sidle in fluid communication with the outlet side of closing va ve.

7. The combination of claim 6, wherein the tripping valve solenoid is electrically serially connected with the cutoif contacts of the cutoff switch.

References Cited UNITED STATES PATENTS 2,447,656 8/1948 Ludwig et a l 200-148 3,185,180 5/1965 Fish, Jr. et a1. 137-625.66 3,062,990 11/1962 Brown 317-23 3,324,265 6/1967 Fish Jr. 200-148 ROBERT S. MACON, Primary Examiner

Claims (1)

1. A CIRCUIT INTERRUPTER HAVING SEPARABLE CONTACTS AND A FLUID MOTOR FOR ACTUATING SAID CONTACTS, AND FLUID MOTOR HAVING A MOVABLE PRESSURE-RESPONSIVE MEMBER CONNECTED TO THE CONTACTS, CONTROL VALVE MEANS FOR PRESSURIZING OR EXHAUSTING ONE SIDE OF SAID PRESSURE-RESPONSIVE MEMBER, ELECTRICALLY-ACTUATED TRIP VALVE MEANS FOR EFFECTING AN EXHAUSTED STATUS OF SAID CONTROL VALVE MEANS AND HAVING AN ACTUATING COIL ASSOCIATED THEREWITH, A NON-PUMPING RELAY (Z) HAVING SEAL-IN CONTACTS (Z1) IN SERIES CIRCUIT WITH SAID ACTUATING COIL AND ALSO HAVING AN ACTUATING COIL, A CLOSING VALVE FOR EFFECTING A PRESSURIZED STATUS OF SAID CONTROL VALVE, A NON-PUMPING CONTACT (AA) IN ELECTRICAL SERIES WITH SAID ACTUATING COIL OF THE NON-PUMPING RELAY (Z) AND BEING PRESSURE-RESPONSIVE TO THE OUTLET FLUID CONNECTION OF THE CLOSING VALVE, WHEREBY NON-PUMPING OPERATION OF THE CIRCUIT INTERRRUPTER IS ACHIEVED.

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