US2287041A - Circuit breaker control system - Google Patents

Description

June 23, 1942. D. JOURNEAUX 2,237,041

CIRCUIT BREAKER CONTROL SYSTEM Filed Feb. 25, 1959 5 Sheets-Sheet l June 23, 1942. D. JOURNEAUX 2,237,041

CIRCUIT BREAKER CONTROL SYSTEM Filed Feb. 23, 1939 3 Sheets-Sheet 2 June 23, 1942.. JQURNEAUX 2,287,041

CIRCUIT BREAKER CONTROL SYSTEM Filed Feb. 23, 19559 3 Sheets-Sheet 3 52 L? I %Q 652 r-M r194 6 36 LY H01 H441 J a s J 2) gm 064L011 0 r j I o .52.

Patented June 23, 1942 CIRCUIT BREAKER CONTROL SYSTEM Didier Journeaux, Wauwatosa, Wis ascignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wia, a corporation of Delaware v Application February 23,1939, Serial No. 258,017

18 Claims. (01. 175-294) fiow of current through the several phase conductors of a polyphase electric circuit, it is frequently required to interrupt transient disturbances afiecting less than all the conductors of the a circuit. Each disturbance is caused to cease by momentary opening of the circuit breaker and normal operating condition of the circuit is restored by reblosure of the circuit breaker. The circuit breaker thus causes unnecessary momentary interruption of the flow of current through the conductors which are not aflected by the disturbance and thus unnecessarily disturbs the functioning of the generating and current consuming apparatus connected with the circuit. On. the other hand if the disturbance is of a permanent nature and necessitates permanent opening of the circuit breaker, all contacts of the circuit breaker should ultimately be opened to avoid continued operation of the sound conductors of the circuit either as a single phase circuit or at the most as an unbalanced polyphase circuit.

The circuit should therefore be so controlled that only the faulty conductors of the circuit are disconnected in response to the occurrence of a disturbance in the operation thereof and that all conductors are opened upon a predetermined number of disconnections and reconnections of the faulty conductors within a limited time. If the circuit breaker is of the type-having serially connected arcing and disconnecting contacts, only the arcing contacts controlling the faulty conductors should be opened in response to the occurrence of a disturbance therein, and all areing and disconnecting contacts should be opened alter a predetermined number of openings and reclosures 'of the arcing contacts controlling the faulty conductors. The actuating means for the contacts are preferably operable by fluid under pressure and are preferably provided with interlocks for preventing faulty operation of the con:

tacts when the pressure of the fluid falls below a predetermined value or when the source of energy for actuating the control valves fails, as well as for rendering the circuit breaker trip free.

, The arcing contacts may be closed as well as opened by 'fluid actuated means selectively operable by varying the pressure of the fluid supplied thereto.

It is therefore an object of the present invention to provide a circuit breaker control system by means of which the sound conductors of the circuit controlled by the circuit breaker are caused to be unaffected by theterminaticn of a transient disturbance in any faulty conductor thereof.

Another object of the present invention is to provide a circuit breaker control system for rendering the circuit breaker operable in response to a transient disturbance in the circuit controlled thereby to disconnect momentarily only the faulty conductors, and operable in response to a permanent disturbance to disconnect all the conductors of the circuit.

Another object of the present invention is to provide a circuit breaker control system for causing the disconnecting contacts of the circuit breaker to open only upon-repeated openings of any of the arcing contacts thereof during a limited time.

Another object of the present invention is to provide a circuit breaker control system for preventing faulty operation of the circuit breaker as a result of an abnormal condition of the control system.

Another object of the present invention is to provide a circuit breaker control system by means of which fluid under pressure above and below a predetermined value may be supplied to the circuit breaker to cause selective actuation thereof.

Objects and advantages other than those above set forth will be apparent from the following description when read in connection with the accompanying drawings, in which:

Fig. 1 diagrammatically illustrates an embodiment of the present invention in which the actuating means for the arcing and disconnecting contacts are interlocked by means of a time delay relay;

Fig. 2 is a view in axial cross-section through one of the arcing chambers of the embodiment illustrated in Fig. 1;

Fig. 3 diagrammatically illustrates a modified embodiment of the present invention in which the disconnecting contacts are controlled by interlocked counting relays and in which the arcing contacts are selectively actuable in response to variations in the pressure of the fluid supplied thereto;

Fig. 4 is a view in axial cross-section through the arcing chamber of the embodiment illustrated in Fig. 3; I

Fig. 5 diagrammatically illustrates a portion of a modified embodiment of the present inven-.

conductors of a polyphase electric circuit tion differing from the embodiment illustrated in Figs. 3 and 4 by the use of a single relay of the operation counting type instead of interlocked counting relays.

Elements having the same function in the difierent embodiments are designated therein by the same reference characters although such elements may be of different configuration in the several embodiments "shown. It will be understood that elements illustrated in some of the figures may also be utilized in combination with elements illustrated in other figures to form further embodiments of the present invention.

Referring 'more particularly to the drawing by characters of reference, reference numeral 8 generally designates a circuit breaker of the fluid actuated type having a plurality of pole portions each comprising cooperating arcing contacts 1,

3 serially connected with cooperating disconnecting contacts 9, it in a difierent one of the phase ii. Circuit breaker 3 comprises a reservoir l2 serving as a source of supply of fluid under pressurelators l3, ll mounted on reservoir l2 and serving tosupport contacts 9, l0; Insulator I3 is hollow and also serves to conduct airfrom reservoir '2 to another insulator l6 defining an arcing chamber containing contacts I, 3. Contact 3 is preferably of the 'hollow tubular type forming an outlet from thearcing chamber, contact 1 abuttingfagainst one end of contact 8 to substantially close the arcing chamber. Contacts 1,

' 3 are preferably bridged by cooperating current v opening of contacts l1, l3 and of contacts l, 3.

Insulator i3 is closed by an upper. flange 26 cooperating with insulator l6 and with flange 22 in defining the arcing chamber and connected with contact 3 through a flexible conductor 21.

Flange-.26 preferably supportsan arc deionizing and sound muiiiing device 23. One of the flanges 22, 26 is connected with one of the disconnecting contacts and the other flange is connected with one of the conductors of circuit ll.

Admission of air under pressure from reservoir" to pistons 2| and 23 to causefopening of the arcing contacts is controlled by a valve 23 actuable by a suitable motor such as an air motor 30 of the spring biased reciprocating type.

Opening of the arcing contacts connected in one of the conductors of circuit ii is controlled in response to an operating condition, such as the magnitude of the flowof current through the same conductor, by means of a current transformer 3| connected therein andsupplying'cure rent to the coil'of a relay 32. Each relay 32 by the lower of itstwo sets of contacts controls the connection of a suitable auxiliary source of energy such as a battery 33 with the coil 31 of a magnet valve 36. This circuit extends 'from the upper side of battery 33 through the lower contacts of any relay 32, any coil 34 to the lower end of battery 33. Valve 36 connects the associated motor 3|) with atmosphere..when the coil 34 thereof is deenergized and connects the motor with reservoir I! when the coil is energized from battery 33. r I

In the embodiment illustrated in Fig. 1 .the several relays 32 also control the connection of battery 33 with the coil and with the contacts of a single relay 31 of any suitable known time delay type. This circuit extends from the upper side of battery 33 through the upper contacts of any relay 32, conductor 68, coil 31; conductor 65 to the lower side of battery 33. Relay 31 may carrying contacts l1, l8 when the contacts are required to carry relatively large currents. Con tact I1 may consist of a length of resilient conducting tubing arranged about contact 1 and divided by saw cuts into a plurality of segmental portions independently engaging contact I3. Contact I8 is preferably fastened to contact 8 and is provided with an annular groove ii for engaging the tips of the segmental portions of contact l1. Contacts l1, l3 are normally maintained closed by means of a spring I? operable to reclose 'the contacts upon opening thereof.

When contacts l1, it are closed, contact l is urged into engagement with contact 3 by another spring 23 which is not, however, of a sufficient strength to cause separation of contacts l1, it.

Contact I is fastened to a plunger type piston' varranged 'forreciprocating movement in an apertured flange 22 joining insulators l3 and I6. Piston 2| is preferably connected with flange 22 through a flexible conductor Y23 and is arranged to be actuated by fluid under pressure contained within insulator l3. Piston 2| simultaneously actuates contacts 1,3 and II to impart a joint 76 for the left be adjusted in a suitable manner as by the conventional dashpot shown to close the contacts a result of a permanent disturbance in the'operation of circuit H. The dashpot on relay 31 also provides suitable timing means for c'aus ing'the contacts thereof to remain closed for a predetermined length of time after closing thereof. The contacts of relay 31 control the. connection of battery 33, through the contacts of any one of relays 32. with all coils 33 and with the, coil 33 of a valve 39 common to all three pole portions of the circuit breaker. This circuit for the coil 38 extends from the upper side of battery 33 through the upper contacts of any relay-32, conductor 66. the upper contacts of relay 31; coil.

33 to the lower side of battery 33 The circuits for the coils 34 similarly extend through the second; third and fourth contacts of relay 31 hand, center and right hand coils 34, respectively. Valve 39 is similar to valve 39 and controls admission of air from reservoir 2 to a suitable contact actuating means such as an air motor 40 for causing joint opening of the different disconnecting contacts l9 of the circuit breaker. Operation of relay 31 may also be obtained independently of relay 32 by means of a hand switch 4|, which closes a circuit from the upper side of battery 33,.through switch 4|, coil of relay 3], conductor 95 to the lower side of battery 33.

Contacts ||I may be reclosed by suitable closing means such as an air motor 42 which may be supplied with air under pressure from reservoir l2 through a valve 43 similar to valves 39 and 39. Valve 43 may be actuated by a coil 44 connected with battery 33 through a switch 48 and through the contacts of an air relay 41 responsive to the pressure of the air. contained within the air motor 40.

Relay 41 serves as an interlock between valves 39 and 43 to prevent operation of motor 42 during operation of motor 48 and to thus render the circuit breaker trip free.

Fig. 1 illustrates the circuit breaker in the normal operating condition thereof, contacts 1,8, 9, l and l1, l9 being closed to complete circuit Since the different-pole portions of the circuit breaker are similar to one another and are severally operable, in the following description only the elements associated with a single pole will be referred to unless otherwise specified.

Upon occurrence of an operating condition such as an overload or a short circuit in one of the conductors of circuit resulting in an ex--' cessive flow of current therethrough, the current transformer 3| associated with such conductor supplies sufiicient current to the coil of the associated relay 32 to cause the relay contacts to close. Operation of relay 32 causes energization of the coil of relay 31 and connects coil 34 with battery 33 to actuate valve 36. The valve admits air from reservoir l2 to motor 39 which opens valve 29 to admit air from reservoir |2 into insulator l3 and through the apertures of flange 22 into insulator IS. The air acts first on the lower faces of piston 2| and of contact to impart thereto an initial acceleration which is also transmitted by contact to contacts 9 and I9. Substantially simultaneously therewith the air contained within insulator l9 exerts an upward thrust on piston 24 to continue the actuationof contacts 8 and I8 independently of contact 1.

During the upward movement of contacts 9 and 9, contact I9 is first separated from con-- tact while contacts and 9 remain in mutual engagement and carry the entire current flowing through the associated conductor H. When contact 1 reaches the end ofits stroke, contacts 8 and I8 continue their upward movement. Contacts 1 and 8 are then separated and an arc is drawn therebetween. At the same time the gap between contacts and 9 forms a path for the fiow of air contained in reservoir I2 and in insulators l3, l6 and which issues therefrom as a violent blast. The air blast causes such lengthening of the are that, at the beginning of the half cycle next following opening of the arcing contacts, the arc path is readily deionized and the current cannot be reestablished between the contacts. The flow of current through the faulty conductor is interrupted and relay 32 returns to the position shown. Coil 34 is deenergized and causes valves 39 and 29 to return to the position shown to discontinue the opening operation of contacts 9, I9, whereupon spring |9 becomes operable to reclose contacts 9, l8.

Contact 8 first reengages contact I, which is thereby displaced downward against the action of spring 28 and recloses conductor Contact |9 finally reengages contact H, the segmental portions of which first enter into resilient sliding engagement with the inner side of the groove of contact l8 and thereafter also abut against the bottom of the groove to cause contact l9 to stop. Relay 3! is assumed to be so adjusted as to close the contacts thereof between the return of relay 32 to the position shown and the subsequent reclosure of contacts I, 8. i

The above described operation of the circuit breaker takes place regardless of whether or not the disturbance in circuit H has been terminated by opening of contacts I, 9. If the disturbance is of a transient nature such as a single phase are to ground from an otherwise sound conductor of a grounded circuit following a -stroke of lightning, and if the disturbance is caused to cease upon opening of contacts I, 9, reclosure of the contacts restores the system to the normal operating condition thereof. Relay 3l returns to the position shown within a limited time without performing any functionin the system. It will be observed that the disturbance has been removed and the faulty conductor reclosed without causing any interruption in the continued operation of those conductors ofthe circuit which were not affected by the disturbance.

If, however, the disturbance is of a permanent nature, such as a short circuit resulting from rupture of a conductor of circuit H, the excessive flow of current through the faulty conductor is reestablished therethrough immediately upon reclosure of contacts I, 8, i. e. within a short time following the first occurrence thereof. Relay 32 is actuated a second time in response thereto while the contacts of relay 31 are closed. Battery 33 is then connected through the contacts of the relays with the coils 34 of all the pole portions of the circuit breaker and with coil 39 to initiate opening operation of all the contacts of the circuit breaker. I Coils 34 open valves 36 which admit air from reservoir |2 to motors 39 to cause opening of valves 29. Air is admitted therethrough to the arcing chambers to actuate all pistons 2| and 24 and for momentarily -,opening all contacts I, 8 and l1, l8. The flow of current through all conductors H is interrupted at the arcing contacts by the air blasts issuing from the arcing chambers, Coil 38 opens valve 39 which admits air to motor 40 for causing Joint opening of all disconnecting contacts I9.

The different contact separating means of the circuit breaker are so constructed. that themeing contacts and the disconnecting contacts open sequentially, the disconnecting contacts being opened only after interruption of the flow of current through the circuit and while contacts 1, 8 are still open. Relays 32 and 31 are therefore operable in response to the flow of excessive current through one of conductors within a predetermined time following an occurrence of such flow and within a limited time following a reclosure of contacts I, 9 of one pole portion for causing opening of all the contacts of the circuit breaker. Relay 31 operates in response to the operation of one of relays 32 for causing the same one of the relays 32 to control motor 48 within a limited time and forms an interlock between the contact opening means of contacts 1, 3 and motor 43 to render the latter effective only during a limited time following opening operation of contacts I, 3.

Upon interruption of the flow of 'current' through circuit ll, relay 32 returns to the position shown, thereby deenergizing coils 34 and 38.

.Valves 23 reclose to enablesprings iii to reclose value, valve 43 is actuated torelease the. pressure above piston 24 and to admit air from cylinder I3 to the arcing chamber. Contacts '3, l3 therefore cannot open when the pressure within reservoir i2 falls below the selectedpredetermined value, and it is accordingly desirable to connect motors 40 and 42 with'reservoir l2 through a .pressure responsive valve or air relay 3| which replaced by a plurality of interlocked counting two or more of the conductors of circuit II, the

relays and the pole portions severally associated therewith will function simultaneously and independently of one another in the manner above described, any conductor not aflected by the disturbance remaining in normal. operation until eventual opening of contacts Ill. Relay 31 may also be 50 adjusted as to close the contacts thereof in the full time necessary for the completion cooperates with relay 32 in controlling the ener-,

of a predetermined plurality of consecutive openings and reclosures of the arcing contacts, but care must be taken that the contacts of the relay close only while relays 32 are momentarily all in the deenergized position shown.

In the embodiment illustrated in Figs. 3 and 4, motor 43 is not under the control of relays 32 and therefore always tends to maintain contacts ID in the open position. Motor 421s of such construction as to be operable upon actuation of valve 43 to the position shown to overcome the action of motor 43 and to close contacts l0. When valve 43 is released by coil 44, motor 42 is rendered ineffective and motor 40 is therefore enabledto open contacts H).

To prevent untimely opening of contacts III as a result of a failure of battery 33, the connection of motor with reservoir i2 is again controlled by valve 33 which is normally maintained open by direct connection of coil 33 with battery 33. Upon failure of battery 33 both coils 33 and 44 are deenergized and both motors 43 and 42 are therefore rendered ineflective so that contacts 10 remain in the position previously assumed thereby.

In the present embodiment contacts 3, l3 are relays, there-being only two relays 32 and 33 if all the contacts of the circuit breaker are to be opened following a single reclosure of the arcing contacts of one pole. Relay 32 is of the instantaneous closing and delayed opening type and gization of the coil of relay 33. Relay 33 cooperates with relay 32 in controlling the energization of the coil of relay 52 and of coils 34 and 44. A self-locking relay 54 maintains coil 44 deenergized after any momentary opening of the circult thereof.

The operation of the present embodiment is generally similar to that of the embodiment illustrated in Fig. 1 and is therefore described'herein only briefly. The circuit breaker being in the closed position shown, valves 43 admit airunder reduced pressure into insulators l3 and, through valves 43, into the spaces above pistons 24 to cooperate with springs l3 in maintaining contacts l1, l3 closed under relatively high pressure. Upon occurrence of a fault in one of conductors ii, the corresponding relay 32, through its center .set of contacts, energizes the associated coil 34 to cause opening of valve 23 of the same pole portion. Valve 29 admits air under full pressure from reservoir i2 into insulator i3, thereby causing valve 43 to be lifted. The air in the space above piston 24 is discharged through valve 43 pressure above the same predetermined value for Flange 22 contains valve 43, which is a-slide valve closing the connection between the arcing chamher and insulator I: when the-pressure in the insulator is below a predetermined value. This value is preferably the lowest value which will enable contacts 3, l3 to open and to interrupt current satisfactorily. from insulator i3 through valve 43 and flange 22,

- through an insulating pipe 30, flange 23 and insulator. l3'to the'upper face of piston 24 to cause the latter to cooperate with spring I3 in closing contacts I, 3 and i1, I3.

When' the pressure within insulator I3 is raised above the previously considered predetermined A passage is provided and air under pressure is admitted to the arcing chamber to cause opening of contacts 1, 3 and interruption of the flow of current therethrough:

contacts of any relay 32, coil of relay 32, the

lower contacts of relay 33, conductor 35 to the lower side of battery 33. Relay 32 immediately closes the contacts thereof, the lower contacts energizing the coil of relay" independently of relay 32, through conductor 33. Upon interruption of the disturbance in circuit ll, relay 32 is deenergized to enable contacts 1, 3 to reclose. Upon return of relay 32 to the position shown, the coil of relay becomes energized through contacts of relay 32 and 32. This circuit extends from the upper side of battery 33, through the lower contacts of allthree relays 32, the upper contacts of relay 32,coil of relays 53, conductor 33 to the lower side of battery 33.; Relay 33 by opening its lower contacts disconnects the coil of relay 32 from battery 33 but relay 32 remains in thecontact closing position for a limited time the normal operating condition thereof by reclosure of the contacts. Relay 52 returns to the position shown after a predetermined time delay and deenergizes the coil of relay 53 which will likewise return to the position shown.

If, however, the disturbance is still present upon reclosure of contacts I, 6, relay 32 is again actuated while relays 52 and 53 are in the energized position. Relays 32 and 53 jointly connect all coils 34 with battery 33 and cooperate to disconnect coil 44 from the battery. The circuit closed through coils 34 extends from the upper side of battery 33, through conductor 69, center contacts of left hand (for example) relay 32. Here the circuit splits two ways, one through left hand coil 34, conductor 65, to the lower side of battery 33, and the other through conductor 13, upper contacts of relay 52 where the circuit again splits, energizing the center coil 34 through the lower contacts of relay 52 and conductor 65, and energizing the right hand coil 34 through conductors H and 65. Coils 34 actuate valves 29 to cause all contacts I, 8 to open momentarily while coil 44 releases valves 43 to enable motors 40 to open all disconnecting contacts l while the arcing contacts are open. The arcing contacts are thereafter reclosed and relays 32, 52 and 53 return to the position shown. Contacts I9 may subsequently be closed by manually resetting relay 54 or by closing switch 55.

The embodiment partially illustrated in Fig. differs from the embodiment illustrated in Figs. 3 and 4 mainly in that relays 52 and 53 are replaced by a single operation counting relay 56. Relay 56 may be of any known type andmay comprise a latch 51 actuable by means of a coil 58 to engage the teeth of a ratchet 59. Ratchet 59 may be instantaneously raised one step by latch 51 but returns towards the position shown with atime delay. After a predetermined number of operations of latch 51 within a limited time, ratchet 59 engages the contacts 60 of the relay.

Coil 58 is connected with battery 33 through the upper contacts of one of relays 32 so that operation of any relay 32 causes ratchet 59 to be raised one step. Subsequent deenergization of the same one of relays 32 enables ratchet 59 to.gradually return towards the position shown. It a disturbance in circuit ll having caused operation of a relay 32 is of a permanent nature, reclosure of the arcing contacts causes immediate reactuation of the relay 32 which causes latch 51 to raise ratchet 59 another step. Relay 56 thus counts the number of operations of relay 32 within'a limited time and, after a predetermined number of consecutive operations of relay 32, rack 59 engages contacts which cooperate with the contacts of relays 32 in causing opening of all the contacts of the circuit breaker. This is done by energizing coils 34 through a circuit similar to that traced for similar action in the embodiment of Fig. 3, except that the contacts 69 replace those of relay 53. Relays 32 and 56 then return to the position shown.

Although but a few embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various modifications and changes may be made therein without departing from the spirit of the invention or from the scope of the appended claims. Some of the features of the invention disclosed herein are claimed in a copending application of Didier Journeaux, Serial No. 443,259, filed May 16, 1942.

It is claimed and desired to secure by letters Patent:

1. In combination, a polyphase electric circuit comprising a plurality of phase conductors, a circuit breaker havinga plurality of pole portions each comprising cooperating arcing contacts and cooperating disconnecting contacts serially connected with said arcing contacts in a different one of said phase conductors, means responsive to an operating condition of one of said conductors for opening only certain of said arcing contacts connected in said one of said conductors, means operable upon opening of said certain arcing contacts for causing reclosure thereof, and means responsive to said operating condition within a limited time following a reclosure of said certain arcing contacts for opening all said contacts.

2. In combination, a polyphase electric circuit comprising a plurality of phase conductors, a circuit breaker having a plurality of pole portions eachcomprising cooperating arcing contacts and cooperating disconnecting contacts serially connected with saidarcing contacts in a different one of said phase conductors, means responsive to an operating condition of one of said conductors for opening only certain of said arcing contacts connected in said one of said conductors, means operable upon opening of said certain arcing contacts for causing reclosure thereof, and means responsive to said operating condition within a limited time following a reclosure of said certain arcing contacts for sequentially opening all said arcing contacts and all said disconnecting contacts.

3. In combination, a polyphase electric circuit comprising a plurality of phase conductors, a circuit breaker having a plurality of pole portions each comprising cooperating arcing contacts and cooperating disconnecting contacts serially connected with said arcing contacts in a different one of said phase conductors, means responsive to an operating condition of one of said conductors for opening only certain of said arcing contacts connected in said one of said conductors, means operable upon opening of said certain arcing contacts for causing reclosure thereof, and means responsive to said operating condition within a limited time following a reclosure of said certain arcing contacts for sequentially opening all said arcing contacts, opening all said disconnecting contacts, and reclosing all said arcing contacts.

4. In combination, a polyphase electric circuit comprising a plurality of phase conductors, a circuit breaker having a plurality of pole portions each comprising cooperating arcing contacts and cooperating disconnecting contacts serially connected with said arcing contacts in a different one of said phase conductors, means responsive to an operating condition of one of said. conductors for opening only certain of said arcing contacts connected in said one of said conductors, means operable upon opening of said certain arcing contacts for causing reclosure thereof, and means responsive to said operating condition and to occurrence of a plurality of openings of said certain arcing contacts and or reclosures thereof within a limited time for opening all said contacts.

5. In combination, a .polyphase electric circuit comprising a plurality of phase conductors, a circuit breaker having a plurality of pole portions each comprising cooperating arcing contacts and cooperating disconnecting contacts serially connected with said arcing'contacts in a difierent one oi. said phase conductors, means responsive cause momentary opening of only the second said means for opening the remainder of said contacts.

6. In combination, a polyphase electric circuit comprising a plurality of phase conductors, a circuit breaker having a plurality of pole portions disconnecting contacts comprising a second conoperating condition within a limited time foleach comprising cooperating arcing'contacts and cooperating disconnecting contacts serially connected with said arcing contacts in a different one of said phase conductors, means responsive to an operating condition of one of said conductors for opening only certain of said arcing contacts connected in said one of said conductors, means operable upon opening of said certain arcing contacts for causing reclosure thereof, means responsive to said operating condition for-opening all said contacts, and means operative between the first and second said contact opening means for rendering the second said contact opening means effective only during a limited timeiollowing operation of the first saidcontact opening means.

7. In combination, a poly'phase electric circuit comprising a plurality of phase conductors, a circuit breaker having a plurality of pole portions each comprising cooperating arcing contacts and cooperating disconnecting contacts serially connected with said arcing contacts in a diiierent one of said phase conductors, means responsive to an operating condition of one of I said conductors for opening only certain of said arcing contacts connected in said one of said conductors, means operable upon opening of said certain arcing contacts for causing reclosure thereof, means operable after said reclosure for opening all said contacts, a relay'responsive to an operating condition of said one of said conductors for controlling the first said contact opening means, and means responsive to operation of said relay for causing said relay to control the second said contact opening means withlowing a predetermined number of openings of the second said arcing contacts for actuating the second said valve to cause opening of said disconnecting contacts. I

10. In combination, an electric circuit, a circuit breaker comprising cooperating. arcing contacts and cooperating disconnecting contacts serially connected with said arcing contacts in said circuit, means for causing opening of said arcing contacts comprising a source of fluid under pressure, c ntactseparating means, and a valve for connecairg said source with said contact separating means, means for actuating said valve to cause momentary opening of said arcing contacts, means for opening said disconnecting contacts comprising a second contact separating means and a second valve for connecting said second contact separating. means with said source, means for actuating the second said valve to cause opening of said disconnecting contacts while said arcing contacts are open, means for reclosing said disconnecting contacts comprising contact-closing means and a third valvefor connecting-said contact closing means with said source, and an interlock between the said second and third valves for preventing operation of said contact closing means during operation of the second said contact opening means.

11. In combination, an electric circuit, a circuit breaker comprising cooperating arcing contacts and cooperating disconnecting contacts serially connected with said arcing contacts in tacts andcooperatlng disconnecting contacts seriaily connected with said arcing contacts in a different one or said phaseconductors, means severally associated with each one of said conductors and. each responsive to an operating condition of the associated one of said conductors to cause opening of the arcing contacts connected therein, means operable upon opening of any of said arcing contacts for causing reclosure thereof, and means responsive to said operating condition or any one of said conductors within a limited time following a reclosure of any of said arcing contacts for opening all said contacts.

9. In combination, a polyphase electric circuit comprising a plurality of phase conductors,

a circuit breaker having a plurality of pole'portions each comprising cooperating arcing con tacts and cooperating disconnecting contacts serially connected with said arcing contacts in a different one or said phase conductors, means ior opening only the arcing contacts connected said circuit, means for causing opening of said arcing contacts comprising a source of fluid under pressure, contact separating means, and a valve for connecting said source with said contact separating means, means for actuating said valve to cause-momentary opening of said arcing contacts, means for opening said disconnecting contacts comprising asecond contact separating means connected with said source, means for reclosing said disconnecting contacts comprising contact closing means and a second valve for connecting said'contact closing means with said source to overcome the action of the second contact separating means, and means for actuating the said second valve to render said contact closing means ineffective and to cause the second said contact separating means to open said disconnecting contacts while said arcing contacts.

valve for connecting said source with said con-' tact separating means, means for actuating said valve to cause momentary opening ofsaid arcing contacts, means for opening said disconnecting contacts comprising a second contact separating means connected with said source, means for reclosing said disconnecting contacts comprising contact closing means and a second valve for connecting said contact closing means with said source, and means responsive to the pressure of the fluid oi said source below a predetermined value for rendering said contact separating and v closing means ineffective.

13. In combination, an electric circuit, a circuit breaker comprising cooperating 'arcing'contacts and cooperating disconnecting contacts serially-connected with said arcing contacts in said circuit, means for causing opening of said arcing contacts comprising a source oi'fluid under pressure, contact separating means, and 'a valve for connecting said source with said contact separating means, means for actuating said valve to cause momentary opening of said arcing contacts, means for opening said disconnecting contacts comprising a second contact separating means connected with said source,.means for reclosing said disconnecting contacts comprising contact closing means and a second valve for connecting saidcontact closing means with said source to overcome the action of the second/ said contact separating-means, means comprising a source of energy for controlling, the operation oi said second valve, a third valve for controlling the connection of said second contact separating means with said source oi fluid, and means connected with said source of energy for maintaining said third valve open, whereby said second contact separating means is rendered ineflective upon failure of said source of energy.

14. In combination, an electric circuit, a circult breaker comprising cooperating arcing conpressure for selectively controlling the operation of said contact actuating means.

15. In combination, an electric circuit, a circult breaker comprising cooperating arcing contacts and cooperating disconnecting contacts serially connected with said arcing contacts in said circuit, means operable'by fluid under pressure for closing said arcing contacts, means operable by fluid under pressure for opening said arcing contacts, means comprising a source of fluid under pressure and a pressure responsive valve for causing selective actuation of the said contact closing and opening means, and means operable by fluid under pressure from said source ior opening said disconnecting contacts while said arcing operable-by fluid under pressure conrfected with said source for relatively actuating said contacts, means operable by fluid pressure to overcome the action of the first said means, a valve for controlling the connection oi' the second said means with said source, means comprising a source of 1 failure of said source of energy.

17. In combination, a polyphase electric circuit comprising a plurality of phase conductors, a circuit breaker having a plurality oi pole portions each comprising contacts connected in a different one of said phase conductors, means responsive to an operating condition oi one of said conductors for opening only contacts connected in said one of said conductors, means operable upon opening of the second said contacts ior causing reclosure thereof, and means responsive to said operating condition within a limited time following a reclosure of the second said contacts for opening all said contacts.

18. In combination, an electric circuit, a circuit breaker comprising cooperating contacts connected in said circuit, means operable by fluid under pressure for closing said contacts, means operable by fluid under pressure for opening said contacts, and means comprising a source oi fluid under pressure and a valve operatively responsive at a predetermined fluid pressure for causing selective actuation of said contact closing and opening means dependent upon the fluid pressure acting upon-said valve being above or below said predetermined value.

DIDIER JOURNEAUX.

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