US3324265A - Fluid-operating mechanism for a circuit interrupter - Google Patents

Description

June 6, 1967 w. A. FISH, JR 3,

FLUID-OPERATING MEC HANISM FOR A CIRCUIT TNTERRUPTER Filed Oct. 5, 1964 2 Sheets-Sheet 1 LI 9 7 .L t 2 FIG. l.

M N csc -Z-l -CST FIG. 2. 50 00 INVENTOR T T William A. Fish, Jr

ATTORNEY June 6, 1967 w. A. FISH, JR 3,32 I

FLUID-OPERATING MECHANISM FOR A CIRCUIT T.NTERRUPTER Filed Oct. 5, 1964 2 Sheets-Sheet 2 FIG. 3.

United States Patent 3,324,265 FLUID-OPERATING MECHANISM FOR A CIRCUIT INTERRUPTER William A. Fish, Jr., Wilkins Township, Allegheny County, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Oct. 5, 1964, Ser. No. 401,454 Claims. (Cl. 200148) This invention relates to fluid-operating mechanisms for circuit interrupters and, more particularly, to a simple, low-cost and trouble-free operating mechanism utilizing a minimum of component parts.

A general object of the present invention is the provision of an improved and simplified-type of fluid-operating mechanism for a circuit interrupter.

A more specific object of the present invention is to provide an improved fluid-operating mechanism in which the tripping function will take precedence over the closing operation by a highly-effective arrangement of the component parts.

Another object is to provide :an improved fluid-operating mechanism for a circuit interrupter having fluid tripfree operation under all operating conditions.

Still a further object of the present invention is the provision of an improved fluid-operatingmechanism utilizing a minimum of readily-available component parts.

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

FIGURE 1 is. a diagrammatic view of the improved fluid-operating mechanism 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. 2. is a line diagram of the electrical control for the valve elements illustrated in FIG. 1; and,

FIG. 3 is a diagrammatic view similar to that of FIG. 1, 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 circuit interrupter having a pair of stationary contacts 2, 3 and a movable bridging contact 4. A transmission line 5 is connected to the stationary contact land a transmission line 6 is connected to the other stationary contact 3. For the'purpose of eflecting the closing and openingoperat ions of the movable bridging contact 4 relative to the two stationary contacts 2, 3, there is provided a fluid-operating mechanism, generallydesignated by the reference numeral 7, and including an operating cylinder 8, within which is reciprocally movable an operating piston 9. Secured to the operating piston 9 is a piston rod 10, which, in turn, is secured to the bridging contact 4 so as to cause the opening and closing movements thereof.

An accelerating spring 12 is arranged within the oper-' ating cylinder 8 and functions to bias the piston 9 and movable bridging contact 4 to the open-circuit position, as illustrated in FIG. 1. I

With a view to eifecting closure of the bridging contact 4 into engagement with the stationary contacts 2, 3, a pressurized fluid may be introduced into theoperating cylinder 8 to the left of the operating piston 9, as shown in FIG. 3, thereby eifecting closure of the contact structure against the bias exerted by the opening accelerating spring '12. A main operating valve 14 is provided to control the admittance of fluid under pressure into the lefthand end of the operating cylinder 8, and also to effect the exhausting of this region, as shown in FIG. 1, to bring about an opening operation. It will be noted that the main operating valve 14 is a three-way normally-closed, pressure pilot-operated valve. More specifically, the main operating valve 14 has an outlet connection 15 leading to the left-hand end of the operating cylinder 8. In addition, the main operating valve 14 has a pressurized inlet region 16 connected, by a conduit 17, to a source of high pressure fluid 18. Another exhausting region 19 of the main operating valve is at a relatively low pressure having an exhaust connection 20.

As shown in FIG. 1, the main operating valve 14 has a pair of valve elements 22, 24 operable therewithin, being connected by a valve rod 26 to a pilot piston 27 operable within an operating cylinder 28. As shown, the lower end of the operating cylinder 28 has a connection 29 to the central region 30 of a trip valve, generally designated by the reference numeral 31. As shown in FIG. 1, the trip valve 31 is a three-way, normally-open, solenoid-operated valve. More specifically, the trip valve 31 has a pair of valve elements 32, 33 interconnected by a valve rod 34, the latter being secured to an armature 35. A tripping coil TC is arranged, when energized, to eifect upward movement of the armature 35, thereby opening the valve element 32 and closing the valve element 33. The outlet connection 36 of the trip valve 31 is connected to the pilot inlet port 37 by Way of the conduit 29.

The trip valve 31 has an inlet conduit 38, which connects with a lower region 39 of the trip valve 31, and connects with the upper region 40 of a closing valve, generally designated by the reference numeral 41. As shown in FIG. 1, the closing valve 41 is a straight-way, normally-closed, solenoid-operated valve. The closing valve 41 has a valve element 42 connected by a valve stem 43 to an armature 44. The armature 44 is actuated by a closing solenoid CC, the latter being connected to the closing-control button CSC by a concentration 46. The other contact of the closing button CSC is connected, by a connection 47, to the positive side of the line 48. The negative side of the line 50 is connected by a line connection 51 to the lower terminal of the closing coil CC.

The closing valve 41 is provided with a lower inlet region 49, which is connected by a conduit 52 to the highpressure storage reservoir 18.

The improved fluid-operating mechanism of the present invention has an auxiliary-switch operating cylinder 54 having a piston 55 reciprocally operable therewithin. The piston 55 has a piston rod 56 carrying two bridging contacts 57, 58. Thebridging contacts 57, 58 respectively engage stationary contacts b, a, which are respectively connected by connections 59, 60 to indicating lights G, R. The other terminals of the indicating lights are connected by connections 61, 62 to the positive side of the line 48. a

It will be noted that the region 54a of the operating cylinder 54 is pneumatically connected, by a conduit 64, to the high-pressure fluid source 18. In addition, the operating cylinder 54 has a region 54b, which is. in fluid connection, by a line 66, with the outlet connection 15 of the main operating valve 14. A branch connection 68 interconnects the fluid line 66 with the region 8a of the operating cylinder 8. A bleeder connection of restricted size 70 interconnects the fluid connection 15 with the region 28a. below the pilot piston 27 of thepilot section for the main operating valve 14. 1

With further reference to FIG. 1, it will be noted that there is provided a cutoff-switch operating cylinder having a region 80a in fluid connection, by means of a,

fluid conduit 81, with the fluid conduit 64 previously described. In addition, the cutoif-operating cylinder 80 has a region 80b, which has a fluid connection 84 with the fluid connection 38. There is provided a fixed-throttle, fluid-connection 90 interconnecting the fluid connectors 29 and 84, the purpose for 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 CT1, which provides an indication of the magnitude of the current flowing through the line L L The current transformer CTl has a pair of branch leads 95, 96, 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 98, 99, with a tripping button CST. The positive side of the line 48 is connected to the connection 99 and to one of the contacts of the tripping button by means of a connector 101. The other contact of the tripping button CST is connected, by a connection 103, to the tripping coil TC and also to the coil 105 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 48 and also by a connection 108 to additional connections 109, 110, 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 41 to the open position. Pressure admitted through the closing valve 41 and the normally-open trip valve 31, to the pilot section of the cylinder-actuating valve, or main operating valve 14, causes the main operating valve 14 to move to the open position, thereby admitting pressure to the operating cylinder 8 and closing the circuit-breaker 1. 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 8 to maintain the closed position of the circuit-breaker 1. Any possible leakage of trapped pressure from the pilot of the cylinder-actuating valve will be replenished through the internal bleed connection 70 from the outlet side of the main operating valve 14.

The tripping or opening operation is initiated by energizing the trip coil TC, thus moving the trip valve 31 to .the closed position. This closes the inlet port of the trip valve 31, and connects the outlet to the exhaust port, thus exhausting the pilot of the cylinder-actuating valve 14. 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 cylinder-actuating 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 cylinder-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 80 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 circuit-breaker 1 is closed. The fixed throttle 90 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 plot when the closing valve and trip valve are both energized. H

The auxiliary-switch operating cylinder 54, 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, which use mechanical latching, require complicated and costly latches, links and levers to provide the necessary mechanical and pneumatically or hydraulicallytrip features, are unnecessary. The principal advantage of the present invention is its simplicity and resulting lowcost and trouble-free operation.

Certain features of the electrical control circuit are set forth and claimed in U.S. patent application filed Oct. 5, 1964, Ser. No. 401,298, by William A. Fish, In, and assigned to the assignee of the instant application.

It will be noted that by the selection of suitable valves and cylinders, the instant fluid-operating mechanism can be designed for use with any fluid, either gas or liquid.

Although there has been illustrated and described specific structures, it is to be clearly understood that the same were merely provided 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: p 1. 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 (8) having an operating piston (9) reciprocally operable there- A within, said operating piston (9) having a closing side and an opening side, means connecting the movable contact means to the operating piston (9), means biasing the movable contact means to the open-circuit position, a three-way normally-closed pressure pilot-operated main operating valve (14) having a high-pressure inlet portion (16) adjacent one end thereof, an intermediate outlet portion and an exhaust-ing portion (19) disposed adjacent the other end thereof, saidmain operating valve (14) additionally having a pilot section, said main operating valve (14) having its intermediate outlet portion connected by a fluid connection (15) to said closing side of the operating piston 9), a high-pressure fluid reservoir (18) connected to said inlet portion (16) of said main operating valve (14), a three-way normally-open solenoid-operated tripping valve (31) having an inlet portion (39) disposed adjacent one end thereof, an intermediate outlet portion and an exhausting portion disposed adjacent the other end thereof, said tripping valvehaving an actuating solenoid (TC), said tripping valve (31) having its intermediate outlet portion in fluid connection with said pilot section of the main operating valve (14), the inlet portion (39) of said tripping valve (31) being in fluid connection with a straight-way normally-closed solenoid-operated closing valve having an inlet portion (49), a high-pressure fluid connection (52) connected to said inlet portion (49) of said closing valve (41), electrical closing means for energizing the closing valve (41) to permit the passage therethrough of high-pressure fluid, and electrical tripping means for energizing the tripping valve (31).

2. The combination of claim 1, wherein a fluid-bleeder connection (70) is provided between the outlet side of main operating valve (14) and the pilot section of said main operating valve (14) to replenish any loss of pressure in the fluid passages between the closed closing valve (41) and the main operating valve (14) in the closed position of the circuit interrupter.

3. The combination of claim 1, wherein an auxiliaryswitch operating cylinder (54) is provided having a clos- 5. The combination of claim 4, wherein the tripping Valve solenoid (TC) is electrically serially connected with the cutolf contacts (aa) of the cutoff switch.

No references cited.

ROBERT K. SCHAEFER, Primary Examiner. R. S. MACON, Assistant Examiner.

Claims (1)

1. 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 (8) HAVING AN OPERATING PISTON (9) RECIPROCALLY OPERABLE THEREWITHIN, SAID OPERATING PISTON (9) HAVING A CLOSING SIDE AND AN OPENING SIDE, MEANS CONNECTING THE MOVABLE CONTACT MEANS TO THE OPERATING PISTON (9), MEANS BIASING THE MOVABLE CONTACT MEANS TO THE OPEN-CIRCUIT POSITION, A THREE-WAY NORMALLY-CLOSED PRESSURE-PILOT-OPERATED MAIN OPERATING VALVE (14) HAVING A HIGH-PRESSURE INLET PORTION (16) ADJACENT ONE END THEREOF, AN INTERMEDIATE OUTLET PORTION AND AN EXHAUSTING PORTION (19) DISPOSED ADJACENT THE OTHER END THEREOF, SAID MAIN OPERATING VALVE (14) ADDITIONALLY HAVING A PILOT SECTION, SAID MAIN OPERATING VALVE (14) HAVING ITS INTERMEDIATE OUTLET PORTION CONNECTED BY A FLUID CONNECTION (15) TO SAID CLOSING SIDE OF THE OPERATING PISTON (9), A HIGH-PRESSURE FLUID RESERVOIR (18) CONNECTED TO SAID INLET PORTION (16) OF SAID MAIN OPERATING VALVE (14), A THREE-WAY NORMALLY-OPEN SOLENOID-OPERATED TRIPPING VALVE (31) HAVING AN INLET PORTION (39) DISPOSED ADJACENT ONE END THEREOF, AN INTERMEDIATE OUTLET PORTION AND AN EXHAUSTING PORTION DISPOSED ADJACENT THE OTHER END THEREOF, SAID TRIPPING VALVE HAVING AN ACTUATING SOLENOID (TC), SAID TRIPPING VALVE (31) HAVING ITS INTERMEDIATE OUTLET PORTION IN FLUID CONNECTION

Images