US2346147A - Pumpproof switch control system - Google Patents

Description

April 11, 1944. BO EA 2,346,147

PUMP PROOF SWITCH CONTROL SYSTEM Filed Feb. 13, 1942 Fig.1.

a TO 04055 c/ncu/r INTERRUPTER Pi .2. T

To CLO-SE v i CIRCUIT INTERRUPTER H His Attonneg.

Patented Apr. 11, 1944 2,346,147 A PUMPPROOF SWITCH CONTROL SYSTEM Alexander C. Boisseau, Lansdowne, Pa., assignor to General Electric Company, a corporation oi.

New York Application February 13, 1942, Serial No. 430,773

8 Claims. (Cl. 175294l My invention relates to an electric control sys-' tem for controlling a single predetermined operation such as a circuit-interrupter closing operation so as not only to insure completion thereof but also to prevent recurrent operations when only a single control operation has been initiated by the operator. More particularly, my invention is in the nature of an improvement on the invention disclosed and claimed in copending application, Serial No. 410,980, filed jointly for Benjamin S. Beall and me, and assigned to the same assignee as the present application.

It is a common expedient in control systems for circuit interrupters to initiate the closing operation by closing a manual switch of some sort. Generally, the closing of this switch initiates the operation of suitable motiv means for moving the circuit interrupter to the closed position. If this switch remains in the closedposition after the closing operation has been completed and the circuit interrupter immediately opens due to an abnormal condition on the power circuit which it controls, obviously, the closing circuit of the circuit interrupter is again completed as soon as it reaches its open position and the cloisng operation is repeated. Under these conditions, a circuit interrupter continues to open and close rapidly while the abnormal condition persists and the manual switch remains in its circuit-closing position. This so-called pumping action if allowed to continue may result in serious damage to the associated apparatus.

Many antipumping arrangements have been proposed which usually depend upon electromagnetic means for rendering the control circuit ineffective at the completion of a closing operation if the manual initiating switch remains closed. However, in most such arrangements, the closing operation could be initiated even though such electromagnetic. means or antipumping means were defective and considerable damage to associated apparatus might result due to such defect, which permitted pumping of the device or the like. It would be desirable to provide an improved arrangement like the copending application referred to above in which no closing operation which might damage the actuating portions of the apparatus could occur if, for any reason, the electromagnetic means failed to respond when the manual switch to initiate the closing operation is actuated.

The previous arrangements often required complicated mechanisms in order to relate the mechanical motion of the main operating mechanism with the cutoff switch. It would be desirable to provide an arrangement in which a considerable simplification of the mechanism is possible.

Accordingly, it is an object of my invention to provide a new and improved control system for an electric circuit interrupter.

It is another object of my invention to provide an improved control system in which a considerable simplification of the mechanism may be obtained without any necessity for locating the cutoff switch in a manner convenient. to the main operating mechanism so that the mechanical motion of the latter may be related to the cutoff switch.

It is a further object of my invention to provide an arrangement for preventing the repeated opening and closing of a circuit interrupter even though reversal of the circuit-breaker operating mechanism occurs at any time during the operating stroke.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with pen ticularity in the claims annexed to and forming a part of this specification. v

For a better understanding of my invention, reference may be had to the accompanying drawing in which Fig. 1 is a partly diagrammatic layout of an electric control system and apparatus illustrating a specific embodiment of my invention, and Fig. 2. is a partly diagrammatic layout illustrating another modification of my invention.

As will be understood by those skilled in the art, any suitable motor means may be utilized for moving to a predetermined position, such as the closed position, the device to be operated, such as the circuit interrupter. Such motive means, as has been set forth in the copending application referred to above, may comprise motors of various sorts, such as fluid motors, pneumatic motors, dynamoelectric machines, solenoid motors, and the like, all of which may be controlled directly or indirectly by electric control means. In order to illustrate my invention, I have chosenin Fig. 1 to illustrate this motive means as comprising a fluid motor, generally indicated at l0, comprising a cylinder H and a piston I2 reciprocally mounted therein. Piston I2 is preferably connected to means to be actuated by longitudinally movable connecting rod l3. Preferably, connecting rod 13 is connected to an electric circuit breaker not shown, so that upward movement thereof causes closing of the circuit breaker.

' Fluid motor l0 may be operated with any suitable fluid, such as air under pressure, for example, and, accordingly, the lower end of cylinder H is connected through conduit ll, valve l5 and conduit IE, only a portion of which is shown, to a source of fluid under pressure, not shown. When valve I5 is open to interconnect the source of fluid under pressure with the lower end of cylinder ll, upward movement of piston l2 and consequent closing of the circuit breaker results. For this reason, valve 15 will hereinafter be referred to as the circuit-breaker closing valve.

In order to open the circuit breaker, not shown, I provide mean including conduit l1, circuitbreaker opening valve l8, and conduit l9, only a portion of which is shown, which is preferably connected to the same source of fluid under pressure as is conduit l8.

Circuit-breaker closing valve l8 may be oper-, ated in any suitable manner and is indicated as being provided with a solenoid 28 having a winding 2|, which is energized to open valve l8 whenever opening of the circuit breaker not shown is desired. As will be understood by those skilled in the art, winding 2| is preferably automatically controlled in response to the conditions on the. circuit controlled by the electric circuit breaker and, furthermore, should be manually controllable so that opening of the circuit breaker at the will of the operator may also be obtained. In order to maintain circuit-breaker opening valve in the closed position whenever the winding 21 of solenoid 28 is deenergized, I provide suitable means, such as spring 22, for biasing the valve member to the position indicated in Fig. l.-

- The circuit-breaker closing valve I is also indicated as of the solenoid-controlled type including a solenoid 23, having a winding 28'. Valve I5 is normally biased to the closed position indicated in Fig; 1 by suitable spring means 24.

In order to control the closing operation of the circuit breaker, not shown, I provide an electrical control circuit including a suitable source of electrical energy, such as supply circuit 25. The energization of winding 23' of solenoid 23 from supply circuit 28 is controlled by electromagnetic means, generally indicated at 28. Electromagnetic means 28 includes a magnetic structure 21 having a single winding 28 thereon which controls two independent armatures 29 and 38, re-

.. spectively, pivotally mounted about a common pin or pivot point 3|. The inner armature 29 is light and constructed so as to be moved with a -relatively small force acting thereon and is always maintained within the coercive zone of the electromagnet comprising magnetic structure 21 and winding 28 by means of a suitable stop 32 engaging an extension 33 of armature 29. Armature 29 is arranged to move so as to assume a vertical position against the pole piece of magnetic structure 21 upon energization of winding 28 so as to cause a-switch 34 to bridge contacts 35 which are connected in series with the energization circuit of winding 23' or solenoid 23 so that, when armature" approaches its fully attracted position, winding 23' is energized to open circuit-breaker closing valve [5, thereby initiating the closing stroke of the circuit interrupter. The second armature 38 is much heavier than the armature 29 and is normally held outsidethe coercive zone of the electromagnet comprising magnetic structure 21 and winding 28 by spring means 38 connected so as to cause armature 88 to pivot about pin 8| in a counterclockwise direction. Armature 38 is provided with an ex,- tension 31 connected to support a limit switch 88 which normally bridges contacts 89., When armature 28 is in the position indicated in Fig. 1, contacts 88 which are connected in the control circuit of winding 22' of solenoid 28 in series with the contacts 85 mentioned above, are closed.

Theparticular construction of armatures 28 and 38 is not important insofar as my invention is concerned and several diflerent arrangements can be'used. For example, armature 38 might be channel shaped so as to embrace armature 28 when both armatures are in the vertical position or, as indicated in the drawing, armature 88 may be arranged in adjacent relationship to arma ture 29.

, Although armature 38 in the unattracted position of Fig. 1 outside the coercive zone of electromagnetic means 28 cannot be pulled into the vertical or attracted position by energization of winding 28, nevertheless, it armature 38 were once it has been moved by anvextemal force to I this position.

Winding 28 of electromagnetic means 26 is preferably energized from supply circuit 25 through a push-button control or operator's switch 48 which may be manually closed by the operator to initiate the closing operation of the circuit breaker. This operation may also be automatically initiated by automatic reclosing switch 4! par alleling switch 48 which may be controlled in a manner well known to those skilled in the art. Seal-in contacts 42 controlled by switch member 43 are provided to parallel push button 48 to seal in the circuit of winding 28 of electromagnetic means 28 when the push button 48 is released.

The control circuit described thu far is disclosed and claimed in the copending application referred to above.

In order to deenergize the control circuit for the closing operation of motive means i8 in accordance with a predetermined operation thereof without requiring a, predetermined relationship with respect to the position of armature 88 and connecting rod l3 as was required heretoi'ore, I provide an auxiliary fluid motor, generally indicated at 44, including a cylinder 45 and a piston 48. Cylinder 45 is positioned that, when piston 46 is moved to the right as viewed in Fig. l, a'longitudinally guided operating rod 41 connected to piston 46 moves armature 98 into the coercive zone ofv electromagnet 26 so that it may be held electrically in the vertical position until deenergization of winding 28 occurs. In order that this movement of armature 38 occurs when connecting rod l3 reaches a predetermined position during the closing stroke of the circuit interrupter, thereby moving member 41 against heavy armature 38 heretofore unresponsive in lying beyond the coercive zone of the electromagnet comprising magnetic structure 21 and winding 28, I connect the left-hand end of cylinder 45 of auxiliary fluid 'motor 44 through conduit- 48 and conduit 48 to cylinder II at a point indicated at 49 intermediate the ends thereof. When piston I2 moves beyond the point 49 at which conduits 48 and 48' interconnects cylinders H and 45, fluid under pressure is permitted to enter the left-hand end of cylinder 45 and consequent-movement of heavy armature 88 results. Just as'heavy armature 38 isabout to reach the vertical position against magnetic structure 21, limit switch 38 is moved condition on the system with which it is associated. The instant during the closing cycle of In order that the opening operation of the circuit breaker may be given preference over the closing operation, I interconnect the upper end of cylinder H with cylinder 45 through conduit 48 and conduit 48 so that, whenever circuitbreaker opening valve I8 is opened, fluid under pressure is immediately admitted into cylinder 45 to move heavy armature 30 against magnetic structure 27 thereby opening limit switch 38 and, consequently, deenergizing the winding 23' of solenoid 23 controlling circuit-breaker closing valve l5.

In order to prevent fluid from flowing around the piston l2 in cylinder I when in the dotted position indicated in Fig. 1 tluough conduits 48' and 48", I provide check valves 50 and 5|, respectively, which permit fluid to flow only from cylinder to cylinder 45.

It will be o served that, with the arrangement disclosed in Fig. l, the motion of piston I2 may be reversed from the closing to the opening operation at any time during the operating stroke without danger of pumpingsince the moment opening valve I8 is opened, heav armature 30 is moved so as to open cutoff switch 38 and it is not necessary to wait until a predetermined position of piston |2 has been obtained before this results as in the prior-art construction.

The operation of m invention will be well understood by those skilled in the art in view of the detailed description included above. A closing operation of the circuit breaker connected to rod l3 may be initiated by depressing push button or by automatic closure of switch 4|, whereupon the winding 28 of electromagnetic means 26 is energized to attract armature 29 which is within the coercive zone thereof. Such operation of armature 29 causes switch 34 to bridge contacts 35, thereby energizing solenoid 23 to open circuit-breaker closing valve l5 and initiate the closing operation of fluid motor Hi. When the circuit breaker controlled by the motiv means comprising fluid motor In approaches its closed position, piston It has reached a position in cylinder I2 above point 49 so that fluid under pressure may enter conduit 4B'.a'nd flow through check valve and conduit 48 to cylinder 45,causing piston 46 to move member 41 so as to move heavy armature 30 against armature 29 which is in the attracted position with respect to magnetic structure 21, thereby opening limit switch 38 and deenergizin winding 23? of solenoid 23. As long as the operators switch Ml or automatic reclosing switch 4| remains closed, winding 28 remains energized to hold heavy armature 30 in the attracted position so that only a single operation can occur and repeated (-10- sures or pumping of the circuit breaker will not result if the circuit breaker were closed on an abnormal current "condition existing on the circuit which it controls. In the event that electromagnetic means should become defective, the circuit-breaker closing operation would not be initiated as in prior-art devices so that the danger of improper operation of the limit switch would not arise as was the case in such prior-art arrangements.

Where electromagnetic means 26 may be positioned close to the fluid motor l9 and connecting rod i3, mechanical means, as illustrated in the copending application referred to above, may be utilized to operate heavy armature 30 directly in response to the position of connecting rod l3. Accordingly, in Fig. 2, I have illustrated such an arrangement in which the corresponding parts of the apparatus and control system are designated by the same reference numerals as in Fig. 1. I have provided a cam 52 mounted on longitudinally movable connecting rod l3 which engages with a horizontally movable member 53 whenever connecting rod l3 reaches a predetermined position so as to move heavy armature 30 in the same manner as was accomplished by member 41 in Fig. 1. In order to permit reversal of piston l2 at any time during the closing operation without pumping and also in order to give the opening operation of the circuit interrupter. not shown, preference over the closing operation. I again provide an auxiliary fluid motor. generally indicated at 54, comprisinga cylinder 55 and a piston 55 operatively connected to a member 51 which engages an extension 58 on heavy armature 30. Cylinder 55 is connected by means of conduit 59 to the upper end of cylinder ll so that, whenever opening valve I8 is opened upon energization of winding 2| of solenoid 20, heavy armature 30 is immediately moved so as to open limit switch 38. It will be understood by those skilled in the art that the arrangement disclosed by Fig. 2 operates similarly tothat disclosed in Fig. 1 although the arrangement in Fig. 1 has the advantage in that the locationof the cutoff switch and electromagnetic means 28 is not limited as in Fig. 2 where it is necessary to obtain mechanical motion directly from the main operating mechanism.

It should be understood that my invention is not limited to the specific details of construction herein illustrated and that changes and modiflcations may occur to one skilled in the art without departing from my-invention. I, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

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

1. In a circuit-interrupter controlling system comprising motive means for moving said circuit interrupter to the closed position, on electric control circuit for eii'ecting the operation of said motive means, means including a first switch for rendering said electric control circuit effective to initiate operation of said motive means to move said circuit interrupter to the closed position, electromagnetic means having an armature for operating. said first switch, means including an operators switch for energizing said electromagnetic means to operate said flrst switch and initiate closing of said circuit interrupter, and fluid operated means responsive to a predetermined operation of said motive means for causing deenergization of said control circuit, said electromagnetic means being so constructed and arranged to maintainsaid control circuit in the deenergized condition as long as said operator's switch is closed regardless of the position of said c cuit interrupter.

2. In a circuit-interrupter controlling system comprising motive means iormoving said circuit interrupter to the closed position, an electric control circuit for effecting the operation of said motive means, electromagnetic operated means for causing energization and deenergization of said control circuit to render said motive means efiective and ineffective to close said circuit interrupter, means including an operator's switch for controlling the energization of said electromagnetic means to initiate the closing operation of said circuit interrupter, fluid operated means including a cylinder and apiston operative in response to a predetermined closing movement of said circuit interrupter for deenergizing said control circuit, and means responsive to the continued energization of said electromagnetic means for maintaining said control circuit in a deenergized condition as long as said operator's switch remains closed regardless of the position of said circuit interrupter.

3. In a circuit-interrupter controlling system comprising motive means for moving said circuit interrupter to the closed position, an electric control circuit for efiecting the operation of said motive means, means including a first switch for rendering said electric control circuit effective to initiate operation of said motive means to move said circuit interrupter to the closed position, electromagnetic means including a plurality of armatures, one of which is arranged for operating said first switch, means including an operators switch for energizing said electromagnetic means to operate said first switch and initiate closing of said circuit interrupter, and fluidoperated means responsive to a predetermined operation of said motive means' 'for rendering said first switch ineiIective to control the enerization of said control circuit! 4, In a circuit-interrupter controlling system comprising a fluid motor including a cylinder and a piston for moving said circuit interrupter from one position to another, an electric control circuit for controlling the circuit-breaker closing operation of said fluid motor, electromagnetic operated means for causing energization of said' control circuit to render said fluid motor efiective and ineffective to close said circuit interrupter, means including an operators switch for controlling the energization of said electromagnetic means to initiate the closing operation of said circuit interrupter, fluid-operated means responsive to a predetermined position of the piston of said fluid motor in said cylinder for deenergizing said control circuit, means for causing opening movement of said circuit interrupter, and means responsive to the operation of said last-mentioned means for rendering said control circuit ineflective to control said fluid motor so that opening of said circuit interrupter takes precedence over the closing operation thereof regardless of the position of said fluid motor.

5. In a circuit interrupter controlling system comprising a fluid motor including a cylinder and a piston for moving said circuit interrupter to the closed position, a first means for causing said piston tomove in a direction to open said circuit breaker, a second means for causing said piston to move in a direction to close said circuit breaker, an electric control circuit for controlling the operation of said second means, fluidoperated means connected to a predetermined intermediate point on said cylinder for rendering said control circuit ineflective to cause further closflig operation of said circuit breaker when said piston reaches said predetermined point in said cylinder during the closing operation, and

means for connecting said fluid-operated means to another point on said cylinder of said fluid motor to give said first means precedent over said second means.

5 6. In a circuit interrupter controlling system comprising a fluid motor including a cylinder and a piston for moving said circuit interrupter to the closed position, a first means for causing said piston to move in a direction to open said circuit breaker, a second means for causing said piston to move in a direction to close said circuit breaker, an electric control circuit for controlling the operation of said second means, fluid-operated means connected to a predetermined intermediate point on said cylinder for rendering said control circuit inefiective to cause -further closing operation of said circuit breaker when said piston reaches said predetermined point in said cylinder during the closing operation, means for connecting said fluid-operated means to another point on said cylinder of said fluid motor to give said first means precedent over said second means, and a check valve interposedin the connections between said fluid-operated means and said cylinder to prevent interchange of fluid between said points on said cylinder.

'7. In a circuit interrupter controlling system comprising a fluid motor including a cylinder and a piston for moving said circuit interrupter from one position to another, an electric control circuit for controlling the circuit breaker closing operation of said fluid motor, electromagnetic operated means for causing energization of said control circuit to render said fluid motor effective and inefiective to close said circuit interrupter, means including an operator's switch for controlling the energization of said electromagnetic means to initiate the closing operation'of 40 said circuit interrupter, means responsive to a predetermined position of the fluid motor for deenergizing said control circuit, means for causing opening movement of said circuit interrupter, and fluid-operated means responsive to the operation of said last-mentioned means for rendering said control circuit ineffective to control said fluid motor so that opening of said circuit interrupter takes precedence over the closing operation thereof regardless of the position of said fluid motor.

8. In a circuit interrupter controlling system comprising a fluid motor including a cylinder and a piston for moving said circuit interrupter from'one position to another, an electric control circuit for controlling the circuit breaker closing operation of said fluid motor, lectromagnetic operated means for causing energizaticn of said control circuit to render said fluid motor effective and ineffective'to close said circuit interrupter, means responsive to a predetermined position of thefluid motor for deenergizing said control circuit, means for causing opening movement of said circuit interrupter, and fluid-operated means responsive to the operation of said last-mentioned means for rendering said control circuit inefiective to control said fluid motor so that opening of said circuit interrupter takes precedence over the closing operation thereof.

' ALEXANDER C. BOISSEAU.

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