US2383288A - Circuit breaker - Google Patents

Description

` Aug? 21, T1945.

s. H, BODEN EVAL l C IRQUI T BREAKER FiledMay` 19, 1942 Sheets-Sheet l 'ug. 21', 11945. s. H. BODEN* efr-AL CIRCUIT I BREAKR y Fileday 419, v1842 Y 4 Sheets-Sheet 2 x .4 MN

21, 1945. s. H. BODEN Erm.

` CIRCUIT BREAKER 4 4 Sheets-Sheef 5 Filedv may 18. 1942 lNVNToRs Allg. 2 1, 19445. is'. vH.4 Bom-5N ErfAL 2,383,288

CIRCUIT BREAKER Filedlay 19, 1942 4 Sheets-Sheet 4 o, .9-7 la .51 /77 /69 75 lNvENToRs 'amue/ fr. Boden and Henry L Peel( Y Il .B A

WITNESSES:

Patented Aug. 21, 1945 CIRCUIT BREAKER Samuel H. Boden, Turtle Creek, and Henry L. Peek, Edgewood, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a. corporation of Pennsylvania Application May 19, 1942, Serial No. 443,550

Claims. (Cl. 20o-82) The invention relates to circuit breakers in general and, more particularly, to automatic reclosing circuit breakers of the type which are adapted to be reclosed substantially instantaneously upon the initial opening thereof vin re`- sponse to abnormal conditions. f,

In order to obtain quick reclosing of a circuit breaker, it is desirable to f initially trip the breaker in response to a faultcondition by a non-trip-free tripping means which leaves the breaker operatively connected to Vthe closing means or under the immediate control of the closing means, so that reclosing movement can be initiated before the breaker reaches full open position or at least by the time. the breaker reaches full open position. This is permissible, however, only when the closing means is in deenergized condition and Will not retard opening of the breaker. If a fault condition is present when the breaker recloses the circuit, ity is important that the breaker be tripped by tripfree tripping lmeans. free `of the closing means, so that opening of the breakerwill not be retarded or prevented by the closingmeans which is usually in energizedcondition at this time. In Patent No. 2,150,587, issued to A. J. A. Peterson March 14, 1939, there is discloseda solenoid circuit breaker mechanism ,which accomplishes the aforementioned I selective tripping by means of a magnetic selector lever operated by they magnetic flux or force produced by the closingysolenoid. The copending application of H. L. Peek, Serial No. 443,040,1fi1ed May 15, 1942, also discloses a quick reclosing circuit breaker mechanism which accomplishes the selective tripping by a selector switch for selecting the trip-free or non-trip-free trip coils provided on the mechanism.

The present invention has for an object the provision of a circuit breaker operating mechanism having a different automatic selecting arrangement from that disclosedfin the abovementioned patent and copendingapplication, and a different type of mechanism from that of the aforementioned patent.

An object of the present invention is the provision of a circuit breaker having a trip-free tripping means, a non-trip-free tripping means, and an automatic trip selecting device energized simultaneously with the closing means, but independently of any force produced by the closing means, said device when deenergized preventing operation ofthe trip-free tripping means, even if a tripping forcefis applied to the trip-free tripping means, and said device when energized permitting operation of thetrip-free tripping means. Another object of theinvention is the provision of a circuit breakerl having a fluid or gas pressure operated closing means, a trip-free tripping means, a non-trip-free tripping means and an automatic trip selecting device energized and deenergized simultaneously with said closing means, said device being effective when deenergized to prevent operation of the trip-free tripping means, even though a tripping force is applied thereto, and said device being operative when energized to permit operation of the trip-free tripping means.

. Another object of the invention is the provision of a circuit breaker mechanism as described in the preceding paragraph, wherein the trip selecting device is energized or operated by fluid or gas pressure whenever iiuid or gas pressure in said closing means is above a predetermined value.

Another object of the invention, in accordance with a modication thereof, is the provision of a circuit breaker having a trip-free tripping means, a non-trip-free tripping means, and an automatic trip selecting device comprising an electromagnet separate from the closing means and energized and deenergized simultaneously with the closing means for selecting the proper tripping means.

Another object of the invention is the provision of a circuit breaker as described in the preceding objects, wherein each of the two tripping means comprises a releasable latch, and the two latches are both mechanically operated by a single tripping electromagnet, operation of the trip-free latch being prevented or permitted by the automatic trip selecting device.

Another object of the invention is the provision of an improved circuit breaker operating mechanism for obtaining high speed opening and reclosing of a circuit breaker.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself both asto structure and operation, together 'with additional objects and advantages thereof,

will be best understood from the following detail description of several embodiments thereof When read in conjunction with the accompanying drawings, in which:

Figure 1 is a side elevational View, partly in section of a circuit breaker operating mechanism constructed in accordance with the invention, the parts being shown in the breaker closed and latched position and the closing means in deenergized condition;

Fig.- 2 is a plan view of the operating mechanism shown'in Fig. l;

Fig. 3 is a side elevational View, partly in section, of the circuit breaker operating mechanism showing a. momentary intermediate open position of the parts after the mechanism has been tripped by the non-trip-free tripping means or latch, the circuit breaker being shown somewhat schematically in this figure;

Fig. 4 is a fragmentary sectional view taken substantially along the line IV-IV of Fig. l showing the trip coil plunger and the rocking trip bar for loperating either of the two latching means of the mechanism;

Fig. 5 is a View similar to Fig. 3, but showing another momentary position of the parts an instant after the breaker has been tripped by the trip-free tripping means or latch; and

Fig. 6 is a fragmentary view showing a modication of the trip selecting arrangement.

Referring to the` drawings, the reference nu ineral 9 indicates generally a metal casting which is formed to provide an operating cylinder I and a plate I3 which closes the upper end of the operating cylinder and forms a support for the various parts Iof the mechanism. An operating piston I5 adapted to be operated by iluid pressure, such as compressed air, is reciprocably movable in the cylinder and this piston together with the cylinder constitutes a fluid motor or closing means for closing the circuit breaker. The lower end of the operating cylinder is closed by a closure member |1 secured in any suitable manner to the cylinder.

A lever mechanism of the trip-free type, indicated generally at I9, is mounted on the support portion I3, and this mechanism serves to normally connect the circuit breaker with the closing means or fluid motor ||-|5. The lever mechanism comprises a closing lever 2| which is pivoted at its right-hand end on the support I3 and a. breaker lever 23 which is pivoted at its left-hand end to the free end of the closing lever 2|. The closing lever 2| consists of a pair of spaced parallel outer levers 25 (Fig. 2) which have their right-hand end pivoted about a common axis by means of a pair of aligned fixed pivot studs 21 carried by two spaced vertical plates 29 secured to the support portion I3. 'I'he breaker lever 23 consists of a pair of spaced parallel inner levers 3| which have their left-hand ends pivoted on a pivot pin 33 carried by and connecting the free ends of the outer levers 25. The inner levers 3| which form the breaker lever 23 are spaced so as to be movable into the space between the outer levers 25 which form the clos ing lever 2|. The right-hand end of the breaker lever 23 carries a trip-free roller 35 which is mounted on a pin carried by and connecting the free ends of the inner levers 3|.

The circuit breaker may be of any suitable construction, either 'of the liquid or air break type, and is shown schematically in Figs. 3 and 5 as comprising stationary main and arcing contacts 31 and 39 and a movable bridging contact assemblage 4| which consists of a main bridging contact 43 and a pair of spring biased arcing contacts 45. The arcing contacts are arranged to engage prior to the main contacts during closing of the circuit breaker and to separate after separation of the main contacts during opening of the breaker. The movable Contact assemblage is carried by a rod 46 which is connected to the mid-portion of the breaker lever 23 through the agency of a pivoted lever 41 and an operating rod 49, the lower end of the operating rod 49 being pivotally connected to the breaker lever by a pivot pin 5| which extends between the inner levers 3|. The circuit breaker is biased to open position by an opening or accelerating spring 53. It will be understood that the circuit breaker may be of any conventional type and may have any suitable form of contact means.

The breaker lever 23 is biased upwardly by the opening bias of the circuit breaker, and the trip-free roller 35 carried by the free end of the lever 23 is normally engaged and releasably held in a position of alignment with the fixed pivot axis 21 of the closing lever 2| by a trip-free latching mechanism indicated generally at 55. When the trip-free roller 35 is held in latched position, the breaker lever 23 is operatively connected to the closing lever 2| for movement thereby. The closing lever 2| is connected to the operating piston |5 of the closing means by means of a pair of connecting links 51 and a connecting rod 58 which extends into the cylinder through a fluid-tight opening in the head of the cylinder. The free end of the closing lever 2| is adapted to be releasably held in closed position, as shown in Fig. l, by means of a non-trip-free latch mechanism indicated generally at 59 which engages a non-trip-free roller 6| carried by the pivot pin 33. The closing lever is biased in a clockwise direction about its fixed pivot axis 21 by means of a pair of strong helical retrieving springs 63 which are disposed in compression between each of the outer levers 25 and the support portion I3.

When the trip-free roller 35 on the free end of the breaker lever 23 is released by a releasing operation of the trip-free latch mechanism 55, the operative connection between the circuit breaker and the piston I5 of the closing means is released, and the breaker moves to open circuit position under the iniluence of the accelerating spring 53 free of any restraint by the closing means. The opening movement of the circuit breaker causes the breaker lever 23 to rotate in a counterclockwise direction toward the open position about the pivot pin 33 which is held down by the non-trip-free latch mechanism 59. The breaker lever 23 during a portion of its opening movement eiects an automatic releasing operation 0f the non-trip-free latch mechanism 59 to thereby cause the release of the free end of the closing lever 2|. For this purpose, the breaker lever has a projecting pin 65 adjacent its pivoted end which, during a portion of the opening mover ment of the lever 23, engages and rotates a pivoted bell-crank lever 61 to effect release of the non-trip-free latch mechanism 59 and consequently the free end of the closing lever 2|. The

bell-crank releasing lever 61 is pivoted on a pivot pin 91 supported between a pair of spaced vertical plates 98 secured to the support portion |3, and this lever has a projection |00 for releasing the latch mechanism 59. The bell-crank releasing lever 61 is biased in a counterclockwise direction, as viewed in Fig. 1, by means of a compression spring 68 interposed between a projection on the bell-crank lever and a xed support.

When the free end of the closing lever 2| is thus released, the retrieving springs 63 rotate the closing lever in a clockwise direction about its iixed pivot axis 21, and this clockwise rotation eifects a clockwise rotation 0f the breaker lever 23 about the pivot pin 5| as a center to thereby return the trip-free roller 35 into latching engagement with the trip-free latch mechanism 55. At this point, the breaker is in full open position, and the two levers 2| and 23 are latched together to form, in effect, a single lever, the breaker lever thus being again operatively connected to the closing lever 2| and through the same to the operating piston |5 of the closing means. When the closing means is energized, that is, when compressed air is admitted to the upper end of the cylinder, the operating piston |5 is moved downwardly and rotates the two levers 2| and 23 in a counterclockwise direction about the common axis of the pivot studs 21 to the closed position shown in Fig, 1, thereby effecting closing of the circuit breaker. When the two levers reach closed position, the non-trip-free roller 6| is reengaged and latched by the non-trip-free latch mechanism 59.

The circuit breaker may also be tripped open by a releasing operation of the non-trip-free mechanism 59. This allows the circuit breaker to be moved to open position by its accelerating spring, thereby causing the two levers 2| and 23 to rotate in a clockwise direction about the cornmon axis of the pivot studs 21 to the open position. In this instance, however, the circuit breaker remains operatively connected to the closing lever 2| and through the same to the operating piston of the closing means, so that the circuit breaker can be reclosed instantly, preferably from some intermediate open position after the are is extinguished and' before the contacts reach full open position. This quick reclosing Operation is initiated by admitting compressed air to the cylinder I I at an intermediate point in the opening movement of the breaker so as to initiate the reclosing movement before the breaker reaches full open position.

' 'I'he trip-free latch mechanism 55 (Fig. l) comprises a main latch 69 of the slip-oil? type pivoted on a pivot pin 1I carried by the support portion I3, and thelatch 69 is biased by means of a compression spring 13 to latching position in which it engages and restrains the trip-free roller 35 in the position shown in Fig; 1. A block 15 carried rby the support portion I3 serves as a seat for one end of the latch spring 13. A stop pin 11 is positioned to prevent movement of the latch 69 beyond its latching position. In order to hold the latch 69 in latching position against the upward or opening bias exerted on the breaker lever 23, an auxiliary latch 19 is provided. The latch 19 ispivoted by means of a pin 8| carried by the framework on the support portion I3, and this auxiliary latch is biased to latching position by means of a light spring 83. The auxiliary latch 19 in latching position effectively locks the main latch 69 in its latching position. The auxiliary latch 19 is adapted to be moved in a clockwise direction about its pivot axis 8| to effect a releasing operation of the trip-.free latch mechanism by means of a tripping solenoid which will be hereinafter described.

When the auxiliary latch 19 is released, the trip-free roller 35 moves upwardly under the opening bias of the breaker, forcing the main latch 89 in a clockwise direction until the roller 35 clears the nose of the latch. The spring 13 then returns the main latch 69 to latching position. The main latch 69 is provided with a rounded nose to allow the roller 35 to force the latch back and clear the salme during resetting or retrieving of the breaker lever 23 and the roller 35. As soon as the trip-free roller 35 has cleared the nose of the latch 69 during a retrieving operation, the spring 13 returns thelatch 69 to latching position, and the auxiliary latch 19 returns to its latching position toengage and hold the main latch 69. l

In order to ensure complete retrieving of .the breaker lever 23 and the trip-free roller 35 to latching position, it is necessary that the auxiliary latch 19 be held in its released position free of the main latch 69 until the trip-free roller has been returned toits latching position. Otherwise the trip-free roller would jam against the rounded nose of the main latch 69 during a retrieving operation. For holding the auxiliary latch 19 in its released position during the release and retrieving of the breaker lever 23, there is provided a holding lever 81 pivoted on the pivot pin 8| and biased in a clockwise direction by a strong spring 89 which is stronger thanA the latch spring 83. The lever 81 is provided with one extending arm 9| which lies. in the path of the final retrieving movement of the free end of the breaker lever 23. When the trip-free roller 35 is in latching position, the free end of the breaker lever 23 holds the lever 81 down in an inoperative position t0 allow the auxiliary latch 19 to assume its latching position. However, when the trip-free roller moves upwardly following a tripping operation by the latch mechanism 55, the holding lever 81 rotates in a clockwise direction and a crosspiece 93 carried thereby engages and holds the auxiliary latch 19 in its released position until the trip-free roller has been retrieved to its latching position.

The non-trip-free latch mechanism 59 is substantially similar to the trip-free latch mechanism previously described. The latch mechanism 59 comprises a main latch 95 pivoted on the pin 91 carried by part of the frame, and the latch is biased by means of a spring 99 to latching position in which it engages and restrains the nontrip-free roller 5| carried by the closing lever 2 I. A block IUI carried by the frame serves as a support for one end of the spring 99. A stop pin |53 prevents movement of the latch beyond its latching position. The main latch 95 is held in latching position by means of an auxiliary latch |05. The auxiliary latch |05 is pivoted on a pin |01 'carried by a portion of the frame, and the latch |05 is biased to latching position by means of a light spring |09. The main latch 95 is provided with a rounded nose to permitfit to beA forced back and cleared by the non-trip-free roller 6| during closing movement of the closing lever 2|. In order to permit the closing lever 2| to be moved to its completely closed position and to be relatched by the latch mechanism 59, there is provided a holding lever ||3 which is similar to the holding lever 81 of the trip-free latch mechanism 55. The holding lever ||3 is pivoted on the pin |01 and is biased in a counterclockwise direction by a spring ||5 which is stronger than the latch spring |09. The lever ||3 is provided with an arm I|1 which extends into the path of the final closing movement of the free end of the closing lever 2|. When the closing lever 2| is in the closed position shown in Fig. l, the levei` ||3 is held down in an inoperative position to permit return of the auxiliary latch |05 to latching position. However, when the free end of the closing lever 2| moves upwardly following a tripping operation of the latch member |05, the holding lever ||3 rotates in a counterclockwise direction and a cross-piece |20 carried thereby engages and holds the auxiliary latch |05 in released position clear of the main latch 95 until the closing lever 2| has been returned `to the fully closed and latched lever 2| has been returned to the fully closed and latched position by the closing means.

yBoth of the latching mechanisms 55 and 59 are adapted to be operated by a single trip coil or trip solenoid 9 (Fig. l). The trip coil ||9 is mounted on a portion of the frame beneath the trip-free latch mechanism 55 and is provided with a trip plunger |2I. The

operating. winding of the trip coil vis adapted to be energized in response to predetermined overload conditions in the circuit controlled by the breaker, or in response to any other circuit fault conditions under which tripping of the breaker is desired. Energization of the trip coil causes upward movement of the trip plunger |2|. A trip bar |23 (Fig. 4) rests freely on a plate |25 carried by the frame above the trip coil H9. The plate |25 is provided with an opening for receiving the upper end of the trip plunger |21 and with suitable guides |29 for guiding the trip bar |23 and for preventing longitudinal and lateral displacement thereof. The trip plunger |2|, when moved upwardly, engages the center of the underside of the trip bar |23 to cause upward movement thereof to effect release of both latch mechanisms 55 and 59, if a trip selecting means, to be hereinafter described, does not prevent release of the trip-free latch mechanism 55. If release of the latch mechanism 55 is prevented by the trip selecting device, upward movement of the trip plunger |2| causes the trip bar to rock about the end which is held down so that only the non-trip-free latch mechanism 59 is released under these conditions. The auxiliary latch 19 of the trip-free latch mechanism 55 is disposed over one end of the trip bar |23, and the free end |3| of a pivoted bell crank lever |33 is disposed over the opposite end of the trip bar |23. The bell crank lever |33 (Fig. 1) is pivoted intermediate its ends on the pivot pin 8| carried by the frame, and the upper end of the bell crank lever is pivotally connected by means of a pivot pin |31 to the right-hand end of a horizontal connecting link |39. The lef*- hand end of the connecting link |39 engages the upper end of the releasing lever 61 through the agency of a pin and slot connection |4|.

If the trip plunger |2| is moved upwardly at a time when the auxiliary latch 19 is prevented from moving in a clockwise direction, the upward movement of the plunger |2| causes the rocking trip bar |23 to rock about its end which engages the auxiliary latch 19 to eiect clockwise rotation (as viewed in Fig. l) of the bell crank lever |33. The clockwise rotation of the bell crank lever |33 moves the horizontal connecting link |39 towards the right and rotates the releasing lever 61 in a clockwise direction to effect release of the latch |95 and the non-trip-free latch mechanism 59. If neither the bell crank lever |33 nor the auxiliary latch 19 are held against movement, the upward movement of the plunger |2| effects release of both the trip-,free and the nontrip-free latch mechanisms.

If an overload or fault condition occurs in the circuit controlled by the breaker when the breaker has been standing closed and the closing means is deenergized, that is, when the air pressure in the cylinder on the upper side of the operating piston is substantially at atmospheric pressure, it is desirable that the circuit breaker be tripped only by means of the nontrip-free latch mechanism 59, because when the breaker is tripped by the non-trip-free latch mechanism 59. it is moved to open circuit position without releasing the operative connection between the breaker and the closing means. This permits the circuit breaker to be reclosed in the shortest possible time. The closing means is preferably energized at a predetermined intermediate point in the opening movement of the breaker, that is, compressed air is admitted to the cylinder at a predetermined intermediate point in the opening movement of the breaker so as to initiate the reclosing movement of the breaker before the breaker reaches full open position, preferably shortly after the arcs drawn by the contacts have been extinguished. This may be accomplished by energizing the inlet air valve controlling electromagnet by a control circuit similar to that disclosed in the copending application of J. M. Cumming and R. C. Cunningham, Serial No. 410,686, filed September 13, 1941, and assigned t0 the assignee of the present invention. However, if the overload condition occurs at a time when the closing means is in energized condition, that is, when the air pressure in the cylinder above the operating piston is above a predetermined value, it is important that the breaker be tripped open by means of the tripfree latch mechanism 55 in order to permit high speed opening oi the breaker unretarded by any opposing force of the closing means.

Compressed air for moving the operating piston i5 downwardly to close or reclose the circuit breaker is supplied from an auxiliary air reservoir tank |45. The auxiliary tank |45 is connected to a main air storage tank (not shown) in which compressed air is stored and maintained by a suitable motor driven compressor unit (not shown). The supply of compressed air to the upper end of the operating cylinder is controlled by an inlet valve mechanism indicated generally at |41. The inlet valve mechanism comprises a valve housing |5| which is secured to the side of the cylinder casting 9 by a plurality of bolts (not shown), and this valve housing is provided with inlet passages |53 and |55, the former communicating with an inlet port |56 in the upper end of the cylinder and the latter communicating with the auxiliary air reservoir i45. The main inlet valve element |51 disposed in the valve housing has a stern |59 slidably mounted in a guide sleeve |6| carried by bushing |63. The bushing |63 is threaded in an opening and a wall of the valve housing between the passages |53 and |55, and this bushing serves as a valve seat for the valve element |51. 'I'he valve element |51 is biased to closed position, as shown in Fig. 1, by means of a helical compression spring |65 which surrounds the guide sleeve 16|. The lower end of the valve spring bears against spider legs on the bushing IBI, and the upper end bears against a spring support |61 secured to the upper end of the valve stem.

The main inletvalve element |51 is adapted to be opened by means of a valve piston |69 to admit compressed air into the upper end of the operating cylinder yt0 close or automatically reclose the circuit breaker. I'he valve piston |59 is movable in a valve cylinder |1| formed in the valve housing, and this valve piston is biased upwardly to an inoperative position against the head of the valve cylinder by means of a helical compression spring |13 surrounding a. portion of the valve biasing spring and disposed between the underside of the valve piston and a shoulder formed in the valve housing. The valve operating piston |69 is adapted to be moved downwardly to open the main inlet valve element |51 by compressed air from the auxiliary air tank |45 through passages |15 and |11 formed in the valve housing. Communication between the auxiliary air tank and the upper end of the valve cylinder |1| is normally shut oi, however, by a pilot valve |19 which is biased to closed position and which is adapted to be opened by means of an electromagnet |3| when the electromagnet is energized. The cylinder portion |1| of the main-inlet valve is provided with one or more atmosphere exhaust 'ports |83 which areclosed `by a skirt on the valve piston when the valve mechanism is in open position. When the valve mechanism is in closed position, as shown in Fig. l, however, the atmosphere exhaustports |83 communicate with the interior of the main operating cylinder Il, 'and thereby serve to exhaust the air pressure in the' reciprocably movable in the cylinder |81, and' this piston has a plunger |9| which extends in a fluid-tight manner throughan opening provided therefor in the upper end of the cylinder |81. The plunger |9| is disposed directly beneath an extended tail portion |93 of the auxiliary latch or trigger 19 of the trip-free latching mechanism 55. The piston |89 is biased to and normally held in the upper position shown in Fig. 1 by means of a helical compression spring |95 disposed within the cylinder |81. The upper end of the cylinder |81 is connected by means of an air conduit or pipe |91 to the inlet passage |53 of the inlet valve mechanism, so that compressed air is admitted to the upper end of the cylinder |81 .simultaneously with the admission of compressed air to the main operating cylinder II. Sincethe inlet passage |53 is in direct communication with the operating cylinder II, the interlock or trip selecting piston |89 is responsive-to air pressure conditions within the main circuit breaker operating cylinder |I. If the air pressure in the main operating cylinder |I above the breaker operating piston I5 is substantially at atmosphericy pressure,l

the spring `|95 holds the trip selecting or interlock piston |89 in its upper or locking position, as shown in Fig. l, thereby preventing release of the auxiliary or trigger latch 19 of the trip-free latching means 55. The strength of the spring |95 is such that it will prevent release of the auxiliary latch 19 even though the trip coil-H9 is energized and acts to move the auxiliary latch to released position.y Thus if the trip coil ||9 is energized at any time when the air pressure within the trigger operating cylinder I| is substantially at atmospheric pressure, the trip selecting or interlock piston |89 prevents release of the auxiliary latch 19 of the trip-free latching mechanism. Under these conditions, the upward movement of the trip plunger |2| causes the trip bar to be rocked about .the end thereof engaged by the latch 19 to rotate the bell crank lever |33 in a `clockwise direction as viewed in Fig. 1.l The clockwise rotation of the rbell crank lever |33* moves the horizontal link |39 towards Ithe right to cause `clockwise rotation of the releasing lever 61, thereby effecting release of the non-trp-free latch vmechanism 59. It will thus be seen that the occurrence of an overload when the closing means is in deenergized condition, that is, when there is no compressed air in the main breaker operating cylinder, results in the breaker being `tripped only by lthe noni means 55.

trip-free latching mechanism 59, the trip-free latch mechanism being locked in latching position by the automatic trip selecting device. Tripping of .the breaker under these conditions is illustrated in Fig. 3. When compressed air is admitted to the breaker operating cylinder II by opening of the inlet valve |51 to effect a closing or reclosing operation of .the circuit breaker, compressed air is also simultaneously admitted to the upper end of the cylinder |81 of the automatic trip selecting device through the pipe |91.

Under these conditions, .the trip selecting or.

interlock piston |89 is moved downwardly, compressing the spring |95, and is thus moved away fromthe tail portion of the auxiliary latch 19 so as to permit operation of the trip-free latching Since the compressed air is applied until vthe `breaker operating piston reaches closed position, the trip selecting piston |89 will be maintained in its depressed or unlocking position throughout the entire closing stroke ofthe breaker operating piston, and thus will permit the operation of the trip-free latching means 55 if the trip coil ||9 should be energized when the breaker recloses the main circuit. The upper endy of the operating cylinder |81 is in direct communication with the breaker operating cylinder and the strength of the spring is so selected that the .trip selecting interlock piston |89 will be maintained in its downward or unlocking position at any time when the air pressure within the main operating cylinder is above a predetermined value, tha-t is, substantially above atmospheric pressure.

From the foregoing, it will be seen that if the trip coil I9 is energized at any time when compressed air or air above a predetermined pressure is in the breaker operating cylinder I I, the piston |89 and plunger |9| will `be in the lower or unlocked position, as shown in Fig. 5, thereby permitting release of the auxiliary latch 19, allowing the mechanism to trip from the trip-free end and thus permitting the circuit breaker to be tripped free of the closing means.A The mechanism is, therefore, trip-free at all times that suilicient air pressure is present above the main breaker operating piston I5 to retard opening movement of the breaker, and is non-trip-free at all other times.

A .modiiication of the invention is illustrated in Fig. 6. In Fig. 6, the main parts of the operating mechanism have been omitted since they are of the same construction as vshown in the original embodiment. In this modification of the iinvention, the automatic trip selecting device is ;iliary latch 19 of the trip-free latch mechanism 55. The core 205 is biased to the upperk position shown in Fig. 6 by means of a compression spring 209so as to prevent release of the auxiliary latch 19 when the solenoid 20| is deenergized. The winding of the solenoid 20| is arranged to be energized simultaneously with the energization of the `inlet valve controlling electromagnet -|8| which controls the admission of compressed air to the breaker operating cylinder, as disclosed in the original embodiment. For this purpose, the winding of the solenoid 20| is connected in parallel with the winding of the inlet valve controlling electromagnet |8I. Thus the device 20| will :be energized simultaneously with the inlet valve controlling electromagnet |8|, and consequently simultaneously with the energization of the iiuid motor for closing the breaker. When the solenoid 28| is energized, the moving core and plunger move downwardly to the unlocked position, thereby permitting release of the auxiliary latch 19 of the trip-free latch mechanism 55 whenever the closing means is energized. When the closing means is deenergized, the solenoid 20| is also deenergized and prevents operation of the trip-free tripping means, so that under these conditions tripping of the breaker is placed under the control of the non-trip-free tripping means only and quick reclosing can be obtained.

In both embodiments of the invention the biasing spring 89 of the holding lever 81 is stronger than the biasing spring of the trip selecting device so that the trip selecting device will not interfere with the retrieving operation of the breaker.

It will thus be seen that the invention provides an improved circuit breaker operating mechanism which is operable to trip the breaker by a non-trip-free tripping means if the fault condition or overload occurs when the closing means is in deenergized condition, thereby permitting quick reclosing of the breaker, and which is operafble to trip the breaker free of the closing means if the fault condition occurs when the closing means is in energized condition.

While the invention has been disclosed in accordancewith the patent statutes, it is to be understood that various changes in the structural details thereof may be made without `departing from some of the essential features of the invention. It is desired, therefore, that the language of the appended claims be given the broadest reasonable interpretation permissible in the light of the prior art.

We claim as our invention:

l. In combination, a circuit breaker, a motor for closing the breaker, tripping means for effecting opening of the breaker irrespective of the energized condition of the motor, additional tripping means for effecting opening of the breaker only when said motor is deenergized, a single trip coil operable in response to predetermined conditions for operating either of said tripping means, a source of power for energizing said motor, a device effective when deenergized to prevent operation of said iirst mentioned tripping means and operable when energized to permit opera-tion of said first mentioned tripping means, and stationary power transmitting means having parallel connections to said motor and to said device for energizing said device simultaneously with said motor.

2. In combination, a circuit breaker, a fluid pressure operated motor for closing said breaker, trip-free tripping means for effecting opening of the breaker irrespective of the energized condition of said closing motor, non-trip-free tripping means for effecting opening of the breaker only when said motor is deenergized, a single tripping electromagnet for operating both said tripping means, means including a source of fluid under pressure for energizing said motor, and a device effective when deenergized to prevent operation of said trip-free tripping means and operable when energized to permit operation of said tripfree tripping means, said device being energized by fluid pressure from said source simultaneously with the energization of said fiuid motor.

3. In combination, a circuit breaker, a fluid pressure operated motor for closing the breaker, trip-free tripping means for effecting opening of the breaker irrespective of the energized condition of said motor, non-trip-free tripping means for effecting opening of said breaker only when said motor is deenergized, a single tripping electromagnet for operating both of said tripping means, means including a source of uid under pressure for energizing said motor, and a device normally effective to prevent operation of said trip-free tripping means by said tripping electromagnet, said device being operable by iiuid pressure when the fluid pressure in said motor exceeds a predetermined value to permit operation of said trip-free tripping means.

4. In combination, a circuit breaker, a fluid pressure operated motor for closing the breaker, trip-free tripping means for effecting opening of the breaker irrespective of the energized condition of said motor, non-trip-free tripping means for effecting opening of said breaker only when said motor is deenergized, a single tripping electromagnet for operating both of said tripping means, means including a source of fluid under pressure for energizing said motor, and a device effective to prevent operation of said trip-free tripping means by said tripping electromagnet when the iiuid pressure in said motor is below a predetermined value and operable to permit operation of said trip-free tripping means when the fluid pressure in said motor is above said predetermined value.

5. In combination, a circuit breaker, a iiuid pressure operated motor for closing said breaker, trip-free tripping means for effectingv opening of the breaker irrespective of the energized condition of said motor, non-trip-free tripping means for effecting opening of the breaker only when said motor is deenergized, means including a source of fluid under pressure for energizing said motor, and a device effective to prevent operation of said trip-free tripping means when said motor is deenergized even though a tripping force is applied to said trip-free tripping means, said device being operated by iluid pressure whenever fluid pressure in said motor exceeds a predetermined valve to permit operation of said trip-free tripping means.

6. In combination, a circuit breaker, a fluid pressure operated motor for closing the breaker, trip-free tripping means for effecting opening of the breaker irrespective of the energized condition of said motor, non-trip-free tripping means for effecting opening of said breaker only when said motor is deenergized, a single tripping electromagnet for operating both of said tripping means, means including a source of iiuid under pressure for energizing said motor, a iiuid pressure operated device effective when deenergized to prevent operation of said trip-free tripping means by said tripping electromagnet and operable when energized to permit operation of said trip-free tripping means, and means for simultaneously admitting fluid pressure to said device and to said motor.

7. In combination, a circuit breaker, a fluid motor for closing said breaker, trip-free tripping means for effecting opening of the breaker irrespective of the energized condition of said motor, non-trip-free tripping means for effecting opening of the breaker only when said motor is substantially deenergized, means including a source of iiuid under pressure for energizing said motor. a device effective when deenergized to prevent operation of said trip-free tripping means even though a tripping force acts on said trip-free tripping means, said device being operative when energized t permit operation of said trip-free 'tripping means, and means for energizing said v device when the fluid pressure in said motor is above a predetermined value.

8. In combination, a circuit breaker, closing means for closing the breaker, trip-free tripping means for effecting opening of said breaker irrespective of the energized condition of said closing means, non-trip-free tripping means for effecting,

opening of said breaker, means including a source of power and power transmitting means for energizing said closing means, a device effective when deenergized to prevent operation of saidl trip-free tripping means even though a tripping force acts on said trip-free tripping means, said device being operative when energized to permit operation of said trip-free tripping means, and stationary energy transmitting means having parallel connections to said device and to said closing means for energizing said device simultaneously with energization of said closing means.

9. In combination, a circuit breaker, a fluid motor for closing said breaker, a trip-free tripping means for effecting opening of the breaker irrespective of the energized condition of said motor, non-trip-free tripping means for effecting opening of the breaker only when said motor is substantially deenergized, means including a source of fluid under pressure for energizing said motpr, a fluid pressure operated device effective When the fluid pressure in said motor is below a predetermined value to prevent operation of said trip-free tripping means even though a tripping force acts on said trip-free Itripping means, said device being operative to permit operation of said trip-free tripping means when fluid pressure in said motor is above said predetermined value.

10. In combination, a circuit breaker, a fluid pressure operated motor for closing the breaker, a rst latch releasableto cause opening of the breaker free of the closing motor and independently of the energized condition of the zmotor, a second latch releasable to cause opening of the breaker Whilethe breaker remains operatively connected to the motor and under the immediate influence of the motor, tripping means for releasing said latches, means including a source of fluid under pressure for energizing said motor, a device effective when deenergized to prevent release of said first latch even though a tripping forceis applied to said latch by said tripping means, said device being operative when energized to permit release of said first latch and being connected to said source for simultaneous energization with said motor.

1l. In combination, a circuit breaker, a fluid f pressure operated motor for closing said breaker, trip-free tripping means for effecting opening of said breaker irrespective of the energized condition of said motor, non-trip-free tripping means for effecting opening of said breaker, an inlet valve for controlling the flow of fluid under pressure from a source of fluid under pressure to said motor, an electromagnet for controlling said inlet valve, and a device normally effective to prevent operation of said trip-free tripping means even though a tripping force is applied to said tripping means, said device being operative to permit operation of said trip-free: tripping means when said electromagnet is energized.

12. In combination, a circuit breaker, a, fluid pressure operated motor for closing the breaker, trip-free tripping means for effecting opening of said breaker irrespective ofthe energized condition' of said motor, non-trip-free tripping means for effecting opening of said breaker only when said motor is substantially deenergized, means including a source of fluid under pressure and an inlet valve vfor supplying fluid under pressure to said motor for closing the breaker, an electromagnet for controlling, said inlet valve; and an electromagnetic means independent of said valve electromagnet effective when deenergized to prevent operation of said trip-free tripping means and operative when energized to permit operation of said trip-free tripping means, said electromagnetic means being energized simultaneously with said inlet valve controlling electromagnet.

13. In combination, a circuit breaker, a fluid pressure operated motor for closing the breaker, trip-free tripping means for effecting opening of the breaker irrespective of the energized condition of said motor, non-trip-free tripping means for effecting opening of the breaker While leaving the breaker subject to immediate control by the motor, means including a source of fluid under pressure and an inlet valve for supplying fluid under pressure to said motor to close the breaker, and a device .effective at times When said inlet valve is in closed position to prevent operation of said trip-free tripping means even though a tripping force is applied to said trip-free tripping means, said device'being operative to permit operation of said trip-free tripping means when said inlet valve is open.

14. Ina compressed gas operated circuit breaker, an operating cylinder and a movable piston therein for closing the breaker, means including a source of gas under pressure and an inlet valve for supplying compressed gas to said cylinder, trip-free tripping means for effecting opening of the breakerl free of said piston, non-trip-free tripping means for effecting opening of said breaker while leaving the breaker under the immediate control of said piston, a singley tripping electromagnet fcr mechanically operating both said tripping means, a gas pressure operated device communicating with said cylinder and effective when the gas pressure in said cylinder is below a predetermined value to prevent operation of said trip-free tripping means by said tripping electromagnet, said device beingoperable by gas pressure to permit operation of said trip-free trpping ymeans whenever the gas pressure in said cylinder is above said predetermined value.

y15. In a compressed gas operated circuit breaker, an operating cylinder and a movable piston therein for closing the breaker, means including a source of gas under pressure and an electromagnetically controlled valve for supplying compressed gas to said cylinder to close the breaker, an electromagnet for controlling said valve, tripfree tripping means for effecting opening of said breaker free of said piston, non-trip-free tripping means for effecting opening of said breaker while

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