US2319632A

US2319632A - Reclosing circuit breaker system

Info

Publication number: US2319632A
Application number: US334596A
Authority: US
Inventors: William K Rankin
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1940-05-11
Filing date: 1940-05-11
Publication date: 1943-05-18
Anticipated expiration: 1960-05-18
Also published as: GB544092A

Description

y 8, 1942 w. K, RANKIN 2,319,632

RECLOSING CIRCUIT BREAKER SYSTEM Filed May 11, 1940 2 Sheets-Sheet 1 ITWVETWtOTL William K.F\ n 'm,

by jv wwyifiwz HIS Attorney y 1943 w. K. RANKIN 2,319,632

REGLOSING CIRCUIT BREAKER SYSTEM Filed May 11, 1940 2 Sheets-Sheet 2 ITWVETItOT": WiHicrm K. Rom kin,

by His Attorney.

Patented May 18, 1943 2319,632 aEoLosING cmom'r BREAKER SYSTEM William K. Rankin, Lansdowne, Pa., assignor to General Electric Company, a corporation of New York Application May l1, 1940, Serial No. 334,596

13 Claims. (Q1. 175-294) I My invention relates to electric circuit breakers, and more particularly to circuit breakers of the reclosing type and Control arrangements therefor.

It is an object of the invention to provide an improved reclosing circuit breaker arrangement characterized by its high operating speed, rugged construction and reliability in service.

Another object of this invention is to provide an improved reclosing circuit breaker control system for a multiphase system which provides for opening the breaker in only one phase, in the first instance, upon the occurrence of a phase to ground fault and for opening the breakers in all the phases if the fault breaker is reclosed.

Further objects and advantages of the invention will become apparent as the following description proceeds, reference being had to the accompanying drawings, in which Fig. 1 is a perspective view partially in section of a reclosing circuit breaker arrangement constructed in accordance with the present invention; Fig. 21s a schematic diagram showing the control arrangement employed in a three-phase installation of the reclosing breaker arrangement of Fig. 1, and Fig. 3 is an elevational view of a detail of the control system.

Referring to Fig. 1 of th drawings I have shown my invention in connection with an 'oil circuit breaker of the impulse type comprising a container having spaced upwardly extending cylinder portions i and H connected at their lower ends by a conduit l2 and partially filled with a quantity of insulating liquid :3 such as oil. A driving piston 14 having a rod 15 of insulating material connected thereto is slidably mounted in the cylinder 10. The piston is biased downwardly by a heavy coil operating spring l6 which bears at its opposite ends on a shoulder ll on the rod l and the under surface of a fixed plate or abutment l8. a

In the cylinder H is mounted a movable contact H in the form of a conducting rod having a hollow enlarged end portion 20, to which is secured a disk 2| of insulating material. disk slidably engages the walls of the cylinder H and forms a piston for actuating the movable contact vl9. A fixed contact 22, electrically connected with the container, is located concentrically with the cylinder H and cooperates with the lower end of the contact rod ii! to complete an electrical circuit through the breaker in the closed circuit position thereof. The hollow end of the contact rod defines a passage 23 which is persists when the i The closed at its lower end by the stationary contact in the closed circuit position of the breaker. When the movable contact moves upwardly in response to fluid pressure applied to the lower side of the disk 2|, a blast of fluid is forced through the passage 23 and into the cylinder ll above the piston through the ports 24. The blast of fluid is effective to extinguish the are drawn between the relatively movable contacts.

The movable contact rod 19 is slidably mounted in an insulating bushing 25 which is suitably mounted in the cover 26 of the cylinder H. An extension 21 of the movable contact rod passes through a fixed plate 28 and: is provided with a shoulder 29 located in spaced relation to the lower face thereof. A helical coil closing spring '30 surrounds the extension 21 and engages at its opposite ends the plate 28 and shoulder 29 to bias the movable contact rod toward its closed circuit position. Means for holding the contact rod releasably in raised or open circuit position is provided by a ratchet 3i and a cooperating spring biased pivoted pawl member 32 which is electromagnetically controlled by the core 33 and associated coil 34.

In order to maintain the fluid level substantially the same in the cylinders l0 and l l a conduit 35 having its opposite ends communicating with the cylinders in and H, respectively, is provided. A vent 36 in the cover of cylinder ll provides for the escape of gases formed during circuit interruption of the breaker. The driving piston l4 is'provided with ports 37 and a check valve 38 which allows the oil which returns to the upper portion of cylinder l0 through the conduit 35 to pass through the piston during its upward travel.

The operation of the breaker thus far described may be readily understood from an inspection of the drawings. With the parts in the position indicated in Fig. 1 the breaker is in its closed circuit position. Upon the occurrence of an abnormal circuit condition the piston rod I5 is released by a tripping arrangement to be described at a later point in the specification and the driving piston 14 is forced downwardly by the energy stored in the charged operating spring i8. Downward movement of the piston causes a pressure surge in the liquid in the container between the lower face of the piston I4 and the disk 2| and causes the movable contact to move upwardly. As soon as the contacts separate the insulating liquid is forced through the passage 23 in the hollow end of the movable contact and through the ports 24 to the upper side of the disk 2!. This blast of arc-extinguishing fluid is effective to extinguish the are drawn between the fixed and movable contacts upon separation. The oil transferred to the upper side of the disk is returned to the cylinder ill through the conduit 35. Upward movement of the contact rod l9 compresses the closing spring 30, which is held in charged condition by the pawl and ratchet 3i, 32.

In accordance with the present invention a novel arrangement is provided for controlling the movement of the operating piston i l and for controlling the operation of all of the breakers in a multiphase installation in response to reopening of any one of the breakers. In accordance with the illustrated embodiment of Fig. 1 the upper end of the piston rod i5 is provided with an extending rack portion 39 secured in fixed relation to a circuit-controlling panel all which moves in timed relation with the operating piston id. The rack 39 is connected to a suitable prime mover such as an electric motor iii through a pinion M, a planetary gear system illustrated generally by the numeral 53, and worm gearing it. The planetary gearing comprises a ring gear 55, planet gears t6 and a sun gear ll. The motor is connected through the worm gearing to the planet gears at by parallel shafts 68 which are secured to opposite ends of a cross-arm 49, while the pinion lZ is secured in fixed relation to the ring gear bya sleeve so and yoke 5i. The sun gear Ill is secured to the end of a latching shaft 52 which is mountedfor rotation in the sleeve 50 and has a stop member 53 and a resetting cam 54 secured thereon in fixed relation thereto. A pivoted latching arm 55 cooperates with the stop member 53 to hold the sun gear M and latching shaft 52 from rotation under the influence of the charged operating spring it acting through the piston rod i5 and the rack 39. The latching arm 55 is held in latching position against the biasing force of an adjustable spring means 56 by an extending armature portion 57 which cooperates with a core 58 of an electromagnetic tripping device illustrated generally by the numeral 59. A slotted resetting arm til cooperates with a pin 6! carried by the latching arm 55 and is moved by the resetting cam 5% to return the arm 55 to latching position once for each revolution of the latchins shaft.

transformer cores changes to a large extent while the flux in the core of the other current transformer changes very little. In the core of this latter current transformer the flux produced by the current in the power line is in the same direction as the flux produced by the direct current winding while in the core of the other current transformer these iiuxes are opposed. The result is that the current through the tripping coil 63 increases for an increase in current in the power line above a predetermined value. The coil 63 is wound in direction to oppose the flow of flux through the armature 57 resulting from the holding coil 62. By a proper adjustment of the resistor 69 and the biasing spring 5%, it is possible to cause the armature to be released and upon the occurrence of a predetermined fault current in the power line. The particular form of device utilized for securing the release of armature 5? in response to abnormal circuit condi- I tions forms no part of the present invention and The electromagnetic tripping device may be I any suitable arrangement which responds to the circuit conditions to be controlled in such a manner as to release the latching arm 55. In the arrangement illustrated in Fig. 2 the core is provided with a holding coil 62 and a trip coil 63 which are both energized from the supply lines normal circuit conditions by the net flux the core 58 resulting from the holding coil 62 and the tripping coil 63. The direct current through reversely connected transformer windings 85 normally saturate the cores (not shown) of current transformers 67. The occurrence of a fault in the power line the flux in one of the current it is apparent that any suitable arrangement may be used. A system of the general type described above is described in detail and claimed in the copending application of D. C. Prince, Serial No. 327,616, filed April 3, 1940, and assigned to the same assignee as the present invention.

The controller it, which is arranged to move in unison with the operating piston id of the circuit breaker is provided with four laterally spaced conductive inserts iii to it, inclusive, having differing lengths and positions which cooperate with contacts it to so, inclusive, to accomplish the desired switching operations for the control of the circuit breaker. the power supply line 5d through the coil 35 of the tripping device which cooperates with the movable contact rod ii to latch the breaker in open circuit position. The contacts l5 and ii are connected directly to the other power supply line of the control circuit. The contact 56 is connected to the same terminal of the coil 34 as the contact i l through a normally open push button ti which provides for manual closing of the circuit breaker. One terminal of the driving motor ii is connected directly to supply line 64 by conductor 513a while the other terminal thereof is connected to contact it in order to control theenergization of the motor in accordance with the position of the control panel to.

The above description has been limited to the equipment required for a single-phase installation. In the drawings I have illustrated my invention applied to a S-phase system having a novel arrangement for coordinating the operation of the breakers in the different phases which will now be described.

In order to trip the breakers in all phases of a I source of control potential, while the other termi nals of these coils are connected together and to the supply line 65 through a circuit including the normally closed contacts 82, 83 and 84 of relays 85, 8t anddl. A normally closed manual switch 88 is also included in the series circuit to provide for manual tripping of the breaker by deenergizing the coils 62 of the overload devices 59.

The contact id is connected to I The relays 82, 83 and 84 are each energized in accordance with the position or the control panel 43 of the breaker with which it is associated by means of the brush contacts 19 and 80 which are bridged by the conductive insert '13 when the control panel moves from position B to position C.

In order to provide for resetting of the breakers after the breakers in all phases have been tripped out, means are provided for reenergizing the coils 62 from the control circuits S4 and 85. As illustrated in the drawings, a time delay relay 89 is provided with an actuating coil 96 connected in series with normally open contacts SH, 92 and 93 of the relays 85 to 81', inclusive. When theselatter relays are all energized as they are when the breakers in all phases of the system are moving from position B to position 0, a circuit is completed from control line 64 through the contacts 9!, 92 and 93 and through the coil 80 of the time delay relay to the other supply line 85. The normally open contacts 94 of the time delay relay are closed to complete a circuit from the common terminals of the coils 62 to the supply line 55. This latter circuit parallels the circuit in cluding the contacts 82, 83 and 84 of the relays 85 and 81. The energization of the coils 52 is effective to move the latching member 55 into latching engagement with cam 53 so that operation of the motor M is effective to return the breaker and associated control panels to the reset position illustrated in Figs. 1 and 2 as will be described in more detail at a laterpoint in the specification.

The operation of the circuit breaker arrange ment of the present invention will now be described. With the three-phase installation illustrated in Fig. 2 and with the breaker and its associated operating mechanism in the closed position illustrated in both Figs. 1 and 2 a circuit is completed through the circuit interrupterin each phase through the contact rod l9 and the stationary contact 22 and the operating spring it is held in charged condition by the latching arm 55 which engages the stop member 53 on the latching shaft 52. Upon the occurrence of an abnormal condition in any one of the phases, the increased current through the tripping coil 63 of the electromagnetic tripping device 59 associated.

with that phase decreases the flux through the armature portion of the latching member an-d permits the latching arm to move out of engagement with the stop 53 under the action of the biasing spring 58. At the moment of release the control panel 40 and the operating piston l4 are both in the position indicated by the letter A. Immediately upon release of the latching shaft 52 the charged spring moves thepiston I4 and also the control panel 40 downwardly until they reach the position indicated by the letter B. During this movement the fluid pressure caused by the movement of piston i4 is effective to raise the movablecontact 29 from the stationary con tact 22 to draw an arc therebetween which is extinguished by a blast of oil passing through the passage 23 in the movable contact. The movable contact rod is moved upwardly and is retained in its'uppermost position against the bias of the closing spring 38 by the spring biased latching pawl 32. During the first portion of the move-- ment ofthe panel 40 from the position A to the position B, the brushing contacts 11 and 18 come into engagement with the conductive insert 12 to complete a circuit from the control circuit supply lines 64, and 85 through the driving motor 4|. As long as the latching shaft is free to rotate, the rotation of the motor is ineffective to appreciably retard the movement of the operating piston H under the action of the operating spring 16 since the only force transmitted from the motor to the pinion 42 is due to the resistance of the gearing. Assuming that the circuit is interrupted during the opening movement of the contact 20 the current in the tripping coil 63 returns to the value determined by the direct current control circuit and the latching arm is returned to its latching position at the end of one-half a revolution of the latching shaft by the resetting cam 53 and the slotted arm associated therewith. The gearing is appropriately proportioned so that one revolution of the latching shaft will take place while the panel 0 and piston l4 move from position A to position B. When the control panel reaches the position B, the conductive insert 10 bridges the contacts H and to connect the closing coil 34 across the supply lines 64 and 65 of the control circuit to release the pawl 32 and allow the movable contact is to return to its closed position under the influence of the closing spring 30. If the fault has been removed during this first opening of the breaker the latching arm 55 will remain in engagement with the stop 52 on the latching shaft and the driving motor II will continue to be energized through the conductive insert 72 and will rotate the pinion 42 in a direction to return the control panel 40 and driving piston H to its initial position A. This returnmovement is also efiective to charge the operating spring iii. If the fault persists after the first opening of the breaker the latching arm 51 is immediately released from its latching position upon the reclosing of the breaker so that the latching shaft is free to rotate and the motor H is ineffective to return the piston H and control panel 40 from the position B to the position A, and these members continue their downward movement from the position B to the position C. In moving from the position B to the position C, the piston 14 is again effective to move the movable contact to the open circuit position where it is again latched by the sprlng biased pawl member 32.

As the control panel 40 moves from position B to position C, the conductive insert 13 bridgesthe contacts l8 and to complete a circuit from the direct current supply lines 54 and G5 through the coii of one or the relays -81 inclusive associated with the particular phase on which the fault has occurred. Opening of this relay. opens one pair of the contacts 82-84 to interrupt the circuit of the holding coils 62 of the electromagnetic tripping devices of all of the phases and release the latching arm 55 of the remaining breakers so that all of the breakers are opened. When the breakers in certain phases are tripped in response to a fault in another phase they will not reclose as the control panel 48 and operating pistons l4 thereof pass through the position 33 since the circuits for the holding coils 62 have been opened in response to the movement of the first breaker from position B to position C. As the breakers of all of the phases move from position B to position C the relays 85, 86 and 8! are all energized and the series contacts 8! 92 and 93 terminals of the holding coils 62 to the supply line 65 to energize them and cause the latching member 55 to engage the latch 53 of the latching shaft 52. As soon as shaft 52 is latched the rotation of the motor 4! returns the operating mechanism of the circuit breakers from position C to position A. As the control panels approach position A the circuit of the driving motor H is interrupted as the contacts 11 and 18 leave the end of the conducting segment 12. The conducting segment ll bridges the

contacts

15 and 16 in the fully reset, or A position, of the circuit breaker so that the breaker may be closed by closing the manual switch 8| which is effective to complete a circuit from line 64 to line 65 through the tripping coil 34.

In order to prevent reclosing of the breakers during movement of the control panel from position C to position A means are provided .to

prevent the conducting segment 10 from bridging the contacts 14 and 15 and thereby completing a circuit from the control lines 64 and 65 through the closing coil 34. In the particular arrangement illustrated I have provided a specially constructed contact 14 for accomplishing this result. Referring to Fig. 3, the contact is in the form of a roller of insulating material 95 of relatively small diameter having a conductive insert 96 embedded in the face thereof. The insert is electrically connected to a supporting arm 91 in any suitable manner, as by the inwardly projecting portion 98. arm 91 is pivoted at its lower end and biased by a spring 99 to engagement with the surface of panel 49. The roller 95 is provided with a suitable stop member I90 which prevents the roller from making a complete revolution in either direction. Since the diameter of the roller is relatively small as compared with the distance between the control positions A, B and C of the control panel, it is clear that the roller will reverse its position during a relatively short travel of the panel, 1. e., the conducting segment will be located on the side of the roller away from the panel when the panel moves upwardly as it does during the resetting operation. Upon reversal of the direction of the panel the roller is moved to the position illustrated so that the conducting segment is efiective to engage the insert 10 as the panel is moved from position A to position B.

From the foregoing'description it is apparent that the present invention provides a novel arrangement for controlling electric circuit breakers which permits the opening and one reclosing of a breaker in any phase of a multi-phase system without operating the breakers in the remaining phases but, which is effective to open the breakers in all phases if the fault persists after one reclosing operation. The invention also provides an arrangement of this type in which practically all of the equipment is associated with each individual breaker so that the coordinationof the breakers requires only a very small amount of interconnecting control wiring. As a result of this featureit is possible to install breakers at the opposite ends of a power line so that it may be completely isolated and to control the operation of the breakers in accordance with a tripping of any one of the breakers without extensive interconnecting of the control arrangements located with the. individual breakers.

While I have shown and described a particular embodiment of my invention, it will be ap- The supporting parent to those skilled in the art that many modifications may be made, and I intend in the appended claims to cover all forms thereof which fall within the true scope and spirit of my invention.

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

1. In combination, an electric circuit breaker for controlling a power line comprising relatively movable contacts normally biased to closed circuit position, contact operating means having a plurality of operative positions, means operable in response to abnormal conditions in the power line with which the breaker is associated for effecting movement of said contact operating means from a first operative position to a second operative position to open said contacts, means effecting automatic reclosure of said contacts after the first opening thereof, means for returning said operating means to its first operative position if the abnormal condition is removed during the first opening of said breaker, and means for rendering said last mentioned means ineffective if the abnormal condition persists *when said contacts are reclosed and permitting said operating means to reopen said contacts by movement of said operating means from said second operative position to a third operative position.

2. In combination, a plurality of power lines, an electric circuit breaker associated with each of said power lines, each of said breakers comprising relatively movable contacts, means normally biasing said contacts to closed circuit position and contact operating means having a plurality of operative positions, means operable in response to an abnormal condition in the power line with which the breaker is associated to render said contact operating means effective to move said contacts to open circuit position, means rendering said biasing means effective to reclose said breaker after the first opening thereof, means for returning said operating means to its first operative position if the abnormal condition is removed during the first opening of said breaker, means for rendering said last men-' tioned means ineffective if the abnormal condition persists when said contacts are reclosed and permitting said operating means to reopen said contacts, and means responsive to the operative position of said contact operating means for causing opening of the contacts of the breakers associated with the remaining power lines in response to reopening of said breaker.

3. In combination, a plurality of electric circuit breakers each associated with a different power line and each comprising relatively movable contacts normally biased to closed circuit position, contact operating means, means responsive to an abnormal condition of one of the power lines for moving said contact operating means from one operative position to a second operative position to operate said contacts to open circuit position, circuit controlling'means, means for operating said circuit controlling means in response to movement of said operating means, said circuit controlling means being effective to cause reclosure of said contacts and return of said operating means to its original operative position if the abnormal condition causing opening of'said breaker has been removed during movement of said operating means from said one operative position to said second operative position, said contact operating means being mov- 75 able from said second operative position to a third operative position to reopen said contacts if the abnormal condition persists after the first opening of said breaker, said circuit controlling means including means for effecting opening of the remaining of said breakers in response to a reopening of any one of said breakers.

4. In combination, a plurality of power lines, an electric circuit breaker oi the impulse type associated with each of said power lines, each of said breakers comprising relatively movable contacts normally biased to closed circuit position, fluid pressure creating means having a plurality o1 operative positions, energy storage means normally biasing said fluid pressure creating means in a direction to cause separation of said relatively movable contacts, latching means for restraining said fluid pressure creating means from movement under the influence of said ener y storage means, means operable in response to abnormal circuit conditions for releasing said latching means and permitting said fluid pressure creating means to move from one operative position to another to separate said relatively movable contacts, an electric power means for retuming said fluid pressure-creating means to said flrst operative position and recharging said energy storage means, and a circuit controller operated in response to movement of said pressure creating means and eflfective to cause reclosure of said contacts after the first opening thereof and to energize said power means to return said fluid pressure creating means to said flrst operative position it the abnormal condition has been removed during the flrst circuit interrupting operation, and means including said latching means for rendering said power means ineffective to interrupt the movement of said fluid pressure creating means under the influence of said energy storage means if the abnormal conditions persist after said contacts are reclosed so that the continued movement of said fluid pressure creating means is effective to reopen said contacts, said circuit controller including means for causing operation of the breakers associated with the remainder of said power lines to open circuit position in response to the reopening of said one breaker.

5. In combination, an electric circuit breaker cf the impulse type comprising relatively movable contacts normally biased to closed circuit posi tion, fluid pressure-creating means having a plurality of operative positions for operating said contacts to open circuit position, means including energy storage means for moving said fluid presmre-creating means from one operative position to a second operative position to open said contacts in response to a controlling influence,

means responsive to opening of said contacts for eflfecting the automatic reclosure thereof, said fluid pressure-creating means being movable by said energy storage means from said second operative position to a third operative position to reopen said contacts if the controlling influence persists after said reclosure.

6. In combination, an electric circuit breaker of theimpulse type comprising relatively movable contacts normally biased to closed circuit position, fluid pressure-creating means having a plurality of operative positions, biasing means tending to move said pressure-creating means in a direction to separate said contacts, means including latch means for restraining said fluid pressure-creating means and operable in response to abnormal conditions in the circuit with which the breaker is associated to release said fluid pressure-creating means to open said contacts by movement of said fluid pressure creating means to a second operative position, means responsive to opening of said contacts for effecting their reclosure, power means operated in response to movement of said breaker to open circuit position for returning said iluid pressure-creating means to said first operative position if the abnormal condition is removed during the flrst opening of said breaker, means for rendering 1 said last mentioned means inefiective to return said fluid pressure-creating means if the abnormal condition persists and said fluid pressurecreating means being movable under the influence of. said biasing means to a third position to reopen said contacts..

'7. In combination, an electric circuit breaker of the impulse type comprising relatively movable contacts normally biased to closed circuit position, fluid pressure-creating means having a plurality of operative positions for operating said contacts to open circuit position, energy storage means normally biasing said fluid pressure-creating means for movement in a direction to cause separation of said contacts, latch means for restraining said fluid pres'sure-creating means from movement under the influence of said energy storage means and means operable in response to abnormal circuit conditions for releasing said latch means and effecting movement on said fluid pressure creating means in a direction to effect separation of said contacts, power means for returning said fluid pressure-creating means to said first operative position and recharging said energy storage means, and switching means operated in accordance with the movement of said fluid pressure-creating means for effecting reclosing of said contacts after the first opening thereof and operation of said power means to return said fluid pressure-creating means to said flrst operative position if the abnormal circuit condition has been removed during the first circuit interrupting operation.

8. In combination, an electric circuit breaker for controlling a power line comprising relatively movable contacts, operating means having a plurality of operative positions for operating said contacts, means including energy storage means for moving said operating means from one operative position to a second operative position to open said contacts in response to abnormal conditions in the power line, with which the breaker is associated, circuit controlling means, means for operating said circuit controlling means in response to movement of said operating means for effecting reclosure of said contacts, motor means energized under the control of said circuit controlling means for returning said operating means to its flrst operative position if the abnormal condition is removed from the line with which the breaker is associated during the first opening of said contacts, means for rendering said motor means ineffective to return said operating means to said flrst operative position if the abnormal condition persists after reclosing of said contacts, said operating means being operated from said second operative position to a third operative positionunder the action of said energy storage means to reopen said contacts, said motor being energized under the control of said circuit controlling means to return said operating mechanism from said third operative position to its first operative position.

9. In combination, an electric circuit breaker comprising relatively movable contacts and operating means therefor having a plurality of operative positions and effective upon movement from a first operative position to a second operative position to open said relatively movable contacts and effective upon movement from a second operative position to a third operative position to reopen said contacts, switching means operated in response to movement of said operating means for efiecting automatic reclosure of said contacts after the first opening thereof, electric power means energized under the control of said switching means for returning said operating means to said first operative position after the reclosure of said contacts, and means for rendering said electric power means ineffective to return said operating means to said first operative position under predetermined conditions and to permit said contacts to be reopened by movement of said operating means from said second to said third operative position.

10. The combination of an electric circuit breaker comprising relatively movable contacts with an operating system therefor comprising operating means having at least three operative positions and movable in one direction to operate said contacts to one position, energy storing means for moving said operating means in said one direction from one operative position to another, an electric motor for moving said operating means in the opposite direction, differential gearing interconnecting said motor and said operating means, latching means for restraining one of the rotatable members of said differential gearing to render said gearing effective to drive said operating means, switching means operable in response to movement of said operating means from one of said operative positions to either a second or a third operative position for energizing said motor, and means for controlling said latching means to determine the time that said one direction under the influence of said energy storage means while said motor is rotating in a direction to move said operating means in the opposite direction, and means for rendering said mechanical means effective to return said'operating means to its first operative position by operation of said motor.

12. An operating system for an electric circuit breaker having relatively movable contacts normally biased to closed circuit position comprising an operating member having a plurality of operative positions, energy storage means for moving said operating means in one direction from one operative position to another to move said contacts to open circuit position, an electric motor for moving said operating means in the opposite direction, switching means operated in response to movement of said operating means for energizing said motor, latching means and means responsive to abnormal conditions of the circuit with which the breaker is associated for controlling said latching means to control the operative connection between said motor and said operating means.

13. A polyphase electric circuit and a single pole electric circuit breaker connected in series with each phase conductor of said polyphase circuit, fluid pressure-creating means associated with'each of said breakers and movable in one direction to effect opening operation of the asso- {ciated electric circuit breaker, means including means responsive to a fault on one of said phase conductors for effecting operation of the operating means of the breaker connected in series therewith in a direction to open said circuit breaker, means for effecting reclosure of said breaker, means for returning said fluid pressurecreating means to its original operative position if the fault has been removed during the first circuit interrupting operation of said breaker, means for rendering said last mentioned means inefiective if the fault persists after the first opening of said breaker and permitting said fluid pressure-creating means to continue in the direction to open said contacts to effect reopening of said circuit breaker, and means responsive to the reopening of the circuit breaker connected in series with any of said phase conductors for effecting opening operation of the breakers connected in series with the remaining phase conductors.

WILLIAM K. RANKIN.