US2676285A

US2676285A - Reclosing system for circuit breakers, including variable stroke disconnect switch means

Info

Publication number: US2676285A
Application number: US245724A
Authority: US
Inventors: Gustav E Jansson; Salzer Erwin
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1951-09-08
Filing date: 1951-09-08
Publication date: 1954-04-20
Anticipated expiration: 1971-04-20

Description

April 20, 1954 E. JANSSON ET AL RECLOSING SYSTEM FOR 01 VARIABLE STROKE DISCONNECT SWITCH MEANS Filed Sept. 8 1951 4 Sheets-Sheet l 2,676,285 RCUIT BREAKERS. INCLUDING April 20, 1954 G. E. JANSSON ET AL 2,676,285

RECLOSING SYSTEM FOR CIRCUIT BREAKERS, INCLUDING VARIABLE STROKE DISCONNECT SWITCH MEANS Filed Sept. 8, 1951 4 Sheets-Sheet 2 Aprll 20, 1954 G. E. JANSSON ET AL 2,676,285

RECLOSING SYSTEM FOR CIRCUIT BREAKERS, INCLUDING VARIABLE STROKE DISCONNECT SWITCH MEANS Filed Sept. 8, 1951 4 Sheets-Sheet 5 Aprll 1954 G. E. JANSSON ET AL 2,676,235

RECLOSING SYSTEM FOR CIRCUIT BREAKERS, INCLUDING VARIABLE STROKE DISCONNECT SWITCH MEANS Filed Sept. 8 1951 4 Sheets-Sheet 4 Patented Apr. 20, 1954 RECLOSING SYSTEM FOR CIRCUIT BREAK- ERS, INCLUDING VARIABLE STROKE DIS- CONNECT SWITCH MEANS Gustav E. Jansson, Salzer, Brookline,

North Quincy, and Erwin Mass., assignors to Allis- Chalmers Manufacturing Company, Milwaukee, Wis.

Application September 8, 1951, Serial No. 245,724

Claims. 1

This invention relates to automatic reclosing systems for electric circuit interrupters and. more particularly to means for controlling fluid blast circuit breakers having serially connected arcing and disconnect contacts for automatic high speed reclosing duty.

Heretofore, circuit breakers have been provided which remove a fault from a line and reclose within about ten to twenty cycles of a sixty cycle current wave. If the fault was not removed upon initial opening, th breaker would open a second time and would then remain permanently in the open position.

In fluid blast circuit breakers of standard design the weight and the stroke of the arcing or interrupting contacts are relatively small and. the weight and stroke of the disconnect contacts are relatively large. Consequently, the speed of operation of the interrupting contacts is relatively rapid and that of the disconnect contacts relatively slow. Therefore, it is possible to fully separate the interrupting contacts in the order of 2.5 to 3.5 cycles of the current wave, while it takes about fifteen cycles of the current wave to achieve full separation of the disconnect contacts. In the case of rapid reclosing the reclosing time must be in the order of ten to twenty cycles, thus the movable disconnect contact of a fluid blast circuit breaker of conventional design is incapable of achieving the required speed of operation.

Rapid reclosing of a circuit breaker may be achieved by interlocking the arcing or interrupting contacts and the disconnect contacts so as to preclude opening of the latter upon initial opening of the former, but permitting opening of the latter upon repeated opening of the former.

A circuit breaker which is provided with such an interlock recloses the circuit upon initial opening thereof by means of the arcing or interrupting contacts rather than the disconnect contacts. Reclosing of the circuit by means of the interrupting contacts is a serious drawback since it imposes an additional heavy duty upon the interrupting contacts, for which they are generally not suited.

Therefore, in the invention claimed new and improved controlling means are provided for a circuit interrupting device which employs a plurality of cooperating arcing contacts in series with a plurality of cooperating disconnect contacts. Upon initial opening of the power circuit the arcing contacts separate followed by the separation of the disconnect contacts a predetermined distance. The are is extinguished by a blast of fluid under pressure and upon are extinction the arcing contacts reengage followed by the reengagement of the disconnect contacts. If the circuit difl'iculty still exists the arcing contacts again separate followed by the separation of the disconnect contacts a second predetermined distance. The disconnect contacts separate the second time a greater distance than the first time to provide upon permanent interruption a sufiicient amount of circuit insulation to keep the are from restriking across the gap in the power circuit.

It is, therefore, one object of the present invention to provide a new and improved control system for a fluid blast circuit breaker having serially connected arcing and disconnect contact means to provide high speed reclosing service in which the electric circuit is interrupted by one pair of contacts and closed by another pair of contacts.

Another object of this invention is to provide a new and improved control system for high speed reclosing duty of a circuit interrupting device in which one pair of contacts interpose upon initial interruption a certain amount of circuit insulation and upon repeated interruption a larger amount of circuit insulation.

A further object of this invention is to provide a new and improved control system for a circuit breaker in which the electric circuit is interrupted by one pair of contacts in a medium of substantially higher dielectric strength than air at atmospheric pressure and is closed by 'a second pair of contacts arranged at atmospheric pressure.

A still further object of this invention is to provide a new and improved circuit breaker structure in which contact means are serially connected into a circuit with a pair of cooperat ing arcing contacts and are adapted to insert selectively into the electric circuit a relatively small amount of circuit insulation at a gap of relatively small length in a medium of relatively high dielectric strength and a relatively large amount of circuit insulation at a gap of increased length formed at least in part of air at atmos pheric pressure.

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

Fig. 1 is a diagrammatic view partly in elevation of a circuit breaker and operating system therefor embodying the present invention, the circuit breaker being open;

Fig. 2 is an enlarged view of the blast valve and arcing contact operating mechanism of Fig. 1 showing the contacts closed;

Fig. 3 is a View in cross section taken along the line IIIIII of Fig. 2 looking in the direction of the arrows;

Fig. 4 is a view of the latching mechanism shown in Fig. 1 but showing the mechanism in the disconnect contact closed position;

Fig. 5 is a diagrammatic view partly in elevation of a circuit breaker and operating system therefore employing another embodiment of the invention, the circuit breaker being open; and

Figs. 6 to 8, inclusive, show in front elevation three different positions of the linkage by which the disconnect contact of the circuit breaker illustrated in Fig. 5 is operated and restrained in closed position.

Referring to Fig. l of the drawing, the circuit breaker operating system comprises a supporting frame structure (not shown) topped by a platform it. A storage tank lit for air under pressure is arranged below platform l2. Platform 1% supports four insulating columns one of which, column i l, houses a disconnect switch comprising a stationary tulip contact it? and a cooperating movable bayonet contact it. An insulating column l1 houses a current transformer another insulating column i8 is adapted to be rotated by a fluid motor it to cause opening and closing of a pair of cooperating arcing contacts and 2 l. The contacts 29, 2 i, which are shown open in Fig. l, are housed in a fourth insulating column which is generally designated Column 22 comprises a lower insulator in. which an insulating blast tube as is arranged. A1netallic blast tube connects tank 3 with insulating blast tube 24. A casting Z6 is supported on one end thereof by the hollow insulators 23 and 2E. Attached to the other end of casting 25 is a disconnect and reclosing switch structure generally designated 3t. The disconnect and reclosing switch structure is supported on the left side thereof by column li. Casting 25 houses a differential type blast valve 3i under control of an auxiliary valve and an operating linkage 33 for contact 2i. Casting Zii supports in turn the hollow insulator (i i in which the tubular contact 2% is arranged. Insulator 3 2 is topped by a hood 35 defining two venting passages 3% for the exhaust of are products. Stacks of parallel spaced plates 3? serve to cool the are products before they are released to atmosphere. An electric line terminal it forms an integral part of hood Insulating column is is likewise topped by a hood 35! of which electric line terminal ill forms an integral part. Column M consists of two tubular insulators 33 and ie between which a casting G5 is arranged. Casting defines an internal cylindrical surface id for a piston 47 supporting contact i6. Piston ill is adapted to be operated by an insulating rod which, in turn, is adapted to be operated by a metal rod 19.

Casting 45 of column M is conductively connected to the current transformer til within column H by a bridging member 5?. r'l. member 53 connects the current transformer within column ll withthe disconnect and reclosing switch 3ll.

The current path through the entire breaker structure is as follows: terminal hood 35, stationary contact 26, movable contact 2|, casting 26, disconnect and reclosing switch 39, member 5a. current transformer 55 within column l1, bridging member 5!, casting d5, bayonet Conta t 16, tulip contact 55, hood 39, terminal cc.

Referring more particularly to Figs. 2 and 3 in which the arcing contact mechanism is shown in contact closing position, casting it forms a housing for a blast valve generally designated 3|. Blast valve 3| comprises movable valve element 55 which is acted upon by helical biasing spring 56 tending to press valve element b5 against valve seat 57. Normally, air under pressure act upon both the right and left end surfaces of valve element 5%. In the closed position of valve iii the effective area of the right fluid pressure reactive surface of valve element is larger than the effective area of the left pressure reactive surface thereof The air pressure tending to move valve element 55 from its normal position shown in Fig. l to the rightis much less than the sum of the air pressure and the pressure of spring ts both tending to press valve element 553 to the left against valve seat 51. The space situated at the right side of valve element adapted to be vented by means of pipe 58, auxiliary valve chamber 55 and an orifice iifi controlled by valve element 6 i.

Valve element iii is adapted to be operated by means of stem 62 resting in slide bearings 63. Stem 62, in turn, is adapted to be operated by a crank mechanism which has generally been indicated at iii. Crank mechanism it is associated with an operating shaft 6t adapted to be operated by insulating column iii. The right end of stem 82 is surrounded by a helical biasing spring of which one end rests on a collar 86 on stem 62, while the opposite end rests against valve housing 55 Upon rotation of shaft 54 in the clockwise di rection (as seen in Fig. 3) stem 62 moves to the right against the action of biasing spring E5 and moves valve element 6! from the left valve seat 68 to the right valve seat 63 of valve housing 58. Consequently, pipe 12 interconnecting a blast passage 73 with valve housing ts is blocked and valve housing 59 vented, to atmosphere. This causes the pressure on valve element directed from left to right to exceed that directed from right to left, resulting in rapid opening of blast valve 3i. The blast of air under pressure which is admitted from blast passage 3 to the gap formed between separated contacts 28, El tends to extinguish the arc which is initiated upon parting of movable contact 2i from stationary contact 20.

Separation of contacts and 2| is effected by an arm T4 of crank mechanism '50. Arm 2'4 extends into a U-shaped abutment member i5 forming an integral part of rod l is for actuating a contact operating toggle mechanism generally designated 33. That toggle mechanism comprises link HS adapted to operate links '57 and i8, of which the former is adapted to operate two links it and 8%). Links ii and it are joined together at SI and link it is fulcrumed at B2, in casting 26. Links 11 and T9 are joined together at 83, and link 19 is fulcrumed at 84, in casting 26. Links is and 89 are joined together at B5, and link Bil is pivotallyv connected at to movable contact 2!. Arm 74 and U-shaped abutment member 15 form a lost motion connection between shaft 64 and link 16 which is responsible for a small time delay between opening of blast valve 3! and separation of contacts 2c and 2!.

When crank mechanism in is rotated in the clockwise direction (as seen in Fig. 3), arm 14 moves a predetermined distance before acting upon rod H4; then it engages the left abutment surface of member 15 moving rod H4 from right to left. Rod'I I4 acts upon a piston 89'which,

in turn, acts upon spring 90 in spring housing 9|. Spring 90 provides the necessary contact pressure in the closed position of the breaker and is compressed by the action of arm I4 during the circuit interrupting operation. When link I is actuated by rod I I4 to the left, toggle TI, I8 collapses. This causes rotation of link 19 about pivot 84 in the clockwise direction resulting in downward movement of the movable contact 2|.

Movable contact 2I comprises a radially inner portion 92 and a radially outer portion 93. The outer portion 93 is telescopically arranged in a cylindrical guiding member 94. The inner por tion 92 is, in turn, telescopically arranged in the outer portion 93. Spring 95 which is arranged between

portions

92 and 93 biases the former upward. As clearly shown in Fig. 2, there is a certain axial play or lost motion between

portions

92 and 93 and these two portions are provided with cooperating abutments 96 and 91, respectively, which limit relative movement of portions 92 and 83 when the latter is disengaged from tubular stationary contact 20.

Guiding member 94 is provided with spring biased contact segments 98 for reducing the contast resistance between that member and outer portion 93. In a similar way, outer portion 93 is provided with contact segments 99 for reducing the contact resistance between that portion and the inner portion 92. The inner portion 92 serves as arcing contact or interrupting contact while the outer portion 93 serves as current carrying contact. When the outer portion is ac tuated downward by toggle mechanism 33, the outer portion 93 separates first from stationary nozzle contact 20. Upon a predetermined downward travel of portion 93 abutment 91 thereof engages the flange or abutment 90 of portion 92, thus compelling the latter to separate from nozzle contact 20.

In order to cause reclosing of the blast valve 3i at the end of the circuit interrupting operation, an intermediate link I00 is arranged between arm '1 and connecting rod 8? of crank mechanism I0,

rod 8! is provided with an abutment member 88 adapted to be engaged by a stationary abutment 08a. Abutments 8B and 88a cause buckling of the toggle formed by members 87, 00 at the end of the circuit opening operation. This in turn permits spring 65 to move stem 62 to the left, thus moving valve element 0! from right valve seat 69 to left valve seat 58. Consequently, compressed air is being admitted to blast valve 3! through passage I2 and 58, resulting in closing of blast valve 3|, thus precluding continued consumption of compressed air upon interruption of the circuit and interposition of a suificient amount of circuit insulation by the dis connect and reclosing switch 30.

The disconnect and reclosing switch generally indicated at 39 comprises a stationary tulip type contact I0 I made up of a plurality of spring biased contact fingers and a cooperating movable rod contact I02.

The pair of contacts I M and I02 is arranged in a chamber I03 defined by an insulator I04. The left end of insulator I0; is supported by member 52! resting on the current transformer column I! while its right end is supported by a cylinder 5&5 of a pneumatic motor comprising a piston I05. The piston I00 arranged in cylinder I05 operates contact I02 and is biased to contact closed position by a helicalspring I01. Admission of air un- ,der pressure from casting 20 to cylinder I 05 may biased auxiliary latch hi2.

occur through duct I08, a. check valve I20, port I09 and ports H0 and I23 in the left head of cylinder I05.

The flow of compressed air through duct I00 and ports I09, H0 is controlled by auxiliary piston valve I II operated by a lever Il2. Lever I I2 cooperates with an abutment II3 secured to the operating rod H4 of the operating linkage 33 of interrupting contact 2|. Piston valve III is provided with a venting port I I5 and a spring I It normally biasing valve III to the left, to open or venting position. Valve III begins to close upon engagement of lever II2 by abutment H3 and rotation of the former in the clockwise direction, as seen in Fig. 1. Cylinder I05 is provided with two lateral openings I I1 and H8 of which one is arranged relatively close to contact IM and the other relatively remote from contact IOI.

0n occurrence of a fault motor I9 rotates column I0, resulting in separating interrupting contact 2I from interrupting contact 20, opening of the blast valve 3| to produce an arc extinguishing blast across the gap formed between the separated contacts 20, 2| and closing of the auxiliary valve comprising a piston II I. Upon opening of blast valve 3I casting 20 is filled with air under pressure. Air under pressure is allowed to flow from casting 26 through duct I00 and ports I05, I50 into chamber I03, thus filling chamber I03 with a medium having a relatively high dielectric strength. Closing of valve I II by abutment H3 and lever I I2 occurs substantially simultaneously with the separation of the interrupting contacts 20, 2 I. Pressure rapidly built up in chamber I03 and cylinder I05 results in separation of contacts Idi and I02 by spring pneumatic motor I05, I05.

The operating and control arrangement for contacts I5 and I B is as follows:

The operating mechanism for contact I0 comprises a spring biased pneumatic motor generally designated I25. Motor I25 and the motor comprising cylinder I05, piston I 06 and spring I01 constitute an operator for the disconnect contact means IOI, I02 and I5, I0. Motor I25 effects separation of contacts I 5, IB by spring means I20, and reclosing of contacts I5, I6 by pneumatic action. The helical spring I20 is arranged between a piston I21 and a cylinder I28 of motor I25. A piston type dump valve I29 which opens to atmosphere is provided to dump motor 525 when piston I21 approaches the top end of its stroke and also while it is impelled downward by the action of spring I26.

The operating linkage for contact It comprises two levers I30 and I3l. The former is pivoted at I32 and the latter at I33. A tie link 134 interconnects levers I30 and I3l. An operating rod I35 and a link I44 interconnect piston I 21 of motor I25 and lever I3I. Lever I3I carries a pin I36 which is provided with a roller I31 adapted to be engaged by cam surface I38 of a latch I39. Latch I39 is biased by a spring I40. Latch IE9 is pivoted at I4! and controlled by a spring Auxiliary latch M2 is in turn controlled by tripping solenoid I43.

The pneumatic control system of the breaker includes pipeline I00 leading from the tank I3 to magnet valves I4? and I 40. Both these valves are of the solenoid type; the former is a tripping valve energized when the breaker is to open; the latter is a closing valve energized when the breaker is to close. Pipeline I49 leads from tripping valve !41 to one end of pneumatic motor I9 and to one end of a piston valve I53. A pipeline I5! leads from closing valve I08 to the other amazes end of pneumatic motor I9 and to the other end of piston valve I58. Pipeline Ito connects one ta of the fluid motor piston valve unit it, lbs with fluid motor I25. This pipeline is under the control of spring biased solenoid operated valve I52. The dump valve I25) of fluid motor M is operated by a lost motion mechanism and a rod I53 attached to lever I3I.

The control circuit for the disconnect contact includes an auxiliary switch it l adapted to be directly operated by the piston Hit of fluid motor I9.

The manual reclosing cutout switch comprising a pair of switch arms insulated from each other is placed in the lower positon shown to pro-- pare the energizing circuit of tripping solenoid I43 when an automatic reclosing cycle is not desired.

Relay I5! is a conventional fault responsive time delay relay for initiating the operation or" the breaker at the occurrence of a fault along the line for the protection of which the breaker is provided. Relay IE8 is a conventional reolosing relay and is used for energizing closing solenoid valve I48 upon an initial separation of interrupting contacts 2i} and ill and for energizing tripping solenoid I43 upon repeated separation of interrupting contacts 2' 3 and 25. Pushbut'ton 'li ifii enables manual tripping and pushbutton switch I62 manual closing of the breaker; both reopen with a time delay.

The system being in the condition shown. in Fig. l, the open circuit breaker is closed by closing switch I62. This results in sect. closing of interrupting contacts 2i and disconnect contacts I5, It. More particularly, the operation of switch 52 causes energisation of solenoid valve I43 from a battery bit through switches I62 and I54. Valve Hit admits com pressed air through pipe IEiI to the left ends of motor I?) and of valve I50. Valve 1% moves to the right, thereby closing the left dumping p it of motor I9, opening the right dumping port of motor It, and opening pipe 159. Piston also moves to the right to cause column it to rotate counterclockwise (as seen in Fig. 2-) to close contacts Ell, 2%. Upon movement to the left by spring H 3, valve II! opens to vent cylinder liit and contacts lei, I82 reclose if they were still open. Link Itii and connecting rod iii are rose in the position shown while blast valve ti remains closed. Switch id iopens the energized circuit of valve I43, and the valve recloses.

When piston ifill reaches a predetermined position air may pass from the cylinder of motor is through pipe I59 and valve I52 to motor 125, causing upward movement of piston i2'l against the bias of spring I26 and closing of contacts IE, it. When piston i2l approaches the top end of its stroke, rod l53 moves valve its to dump the air contained in cylinder IZii. The actuating means of contact I6 completes its stroke by mementum, roller I31 rolling on cam surface H33 during such movement. When contacts 55, it are closed, roller 536 reaches the notch in surface Itt. Spring Mil causes latch use to pivot to cause engagement of the roller with the notch. Latch I42 is pulled into latching position to maintain latch 39 in the position reached there by, in which it maintains contacts it, iii closed. The above referred to sequence of closing of contacts 2i], 2i and I5, I55 isdue to the interlocking of motors I 9 and 125 through pipe its and to the time required to build up sufficient pressure 12 low piston I21 to move it against the bias of spring I26.

Manual opening of the circuit breaker is eifected by actuating opening switch IEI, causing energization of trip solenoid valve it! from battery it through switches ltI and 54. Valve Ml admits air, through pipe use, to the right ends of motor I9 and of valve I50. Valve I59 moves to the left, thereby opening the left dumping port of motor I9, closing the right dumping port of motor is and closing pipe 159.

Piston 555 also moves to the left to cause column It to rotate clockwise (as seen in Fig. 3). Blast valve BI is thereby opened and

contacts

20, 25 are separated to open the circuit. After the last between contacts 2t, 2| has had time to extinguish the arc, valve IIi admits air to cylinder its to cause opening of contacts till, I02. Switch I5 3 opens the energizing circuit of valve ml, and the valve recloses.

Switch [5 t also completes a circuit from battery M53 through switch it I, switch Itt, solenoid i and switch I54, back to the battery. Sole- .oid M3 withdraws latch M2. The latter releases latch 539. Under the action of gravity and of spring 25, the disconnect contact actuting means moves latch 39 back to the un i lied position shown, roller i3? rolling on cam E355 while disconnect contact iii returns 0 the open position shown.

Wl'ien piston r55 approaches the end of its e formed by link tilt and connecting rod 81 to reclose blast valve 3i. In order to preclude a reclosing operation when his desired to manually a permanent interruption of the circuit, switches its and 162 may be provided with an interlock iii so that switch H32 cannot be operated as long as switch 256 is in the upper or reclosing position.

The circuit breaker being closed, relay I51 is energized upon occurrence of a fault condition. If switch i56 is in the lower position shown, relay merely causes tripping of circuit breaker if switch It! had been closed as above de scribed.

If switch W8 is placed in the upper (reclosing) position, relay i5? likewise connects the solenoid of valve Ml to the battery. in addition, the motor of reclosing relay IE3 is connected to the batterry through rela I5! and switch I55. Reclosing relay i558 starts and closes a circuit maintaining its motor energized while its drum completes a full revolution. Energization of the circuit of solenoid valve Nil causes admission of compressed air to the right side oi fluid motor 59 and piston valve I59. Consequently, piston or" motor Iii and the movable valve element of valve I59 are moved from right to This movement of piston I55 causes a rotation of column it which in turn causes opening of blast valve 3i and separation of contacts and 2|. Upon separation of contacts 252 and 2 contacts and Hi2 are separated by the action of fluid motor 185, I05, as previously described. Toggle 3i, collapses and 'recloses blast valve 3|. However, check valve I20 retains the air in cylinder Hit and thus prevents premature reclosure of contact 382. Relay I5? returns to the position shown.

The movement of piston Iii: to the crates the auxiliary switch 15:3, gizes solenoid valve i4! and closes the circuit of solenoid valve #48 through switch 553. Consequently the flow of compressed air through pipe left als opic I49 is interrupted and a flow of compressed air is established through pipe II. The latter flow causes a motion of the piston I55 of motor I 9 and of the movable element of valve I59 from left to right. This movement of piston I55 results in a rotation of insulating column I8 whereby interrupting contacts 26 and 2I are reclosed. The auxiliary valve I II for controlling the operation of contacts IIIII, I02 is opened by the biasing spring IIS substantially simultaneously with reclosure of interrupting contacts 20, 2I as abutment H3 is moved to the right by column I3. This results in venting of fluid motor I 65, I55 through vent opening I I5 and closing of contacts I05, I82 after contacts 21), 2I have reclosed.

The movement of the valve element of piston valve I55 to the right causes admission of air under pressure from the cylinder of fluid motor is to pipe I59. Pipe I59, however, is sealed by solenoid valve I52 since, as piston I55 moves from left to right, auxiliary switch I54 energizes solenoid valve I52 from battery I63 through relay I58. Solenoid valve I52 closes against the action of its biasing spring. Switch I54 also deenergizes solenoid valve I48, which returns to the closed position shown.

What happens further depends on whether or not the fault still prevails at the time when contacts WI and I82 reengage. Relay I58 returns to the position shown but if the fault does not prevail during that time, nothing else happens, i. e., service continuity is maintained. If the fault still persists at the time when contacts IIII and I82 reengage, the operating cycle of the breaker continues and a permanent interruption of the circuit is effected by the breaker.

Permanent interruption is initiated by reenergization of relay I51, resulting in reopening of solenoid valve M? and readmission of compressed air to motor I9. Piston I55 of motor I9 then moves from right to left,-which results in momentary opening of blast valve 3i and separation of interrupting contacts 28 and 2I, and, therefore, reinterruption of the faulted circuit. Relay I57 again returns to the position shown. Thereafter contacts iIlI and H52 part under the action of fluid motor I95, I06. At that time the reclosing relay ISt energizes the tripping relay M3 through switch I, whereby latch I42 is moved in counterclockwise direction, thus releasing main latch I 39. Roller I37 is deprived of its support and spring I255 is free to move linkage I30, I34, I3I from its upper position, shown in Fig. 4, to its lower position, shown in Fig. 1. This completes the opening operation of the circuit breaker and results in the formation of a gap of required length between contacts I5 and I6.

Upon permanent interruption contacts 25, 2! and IE, IS remain separated. Contacts IIlI and IIIZ reclose when contacts I5, I6 are separated a safe distance from each other. The time at which contacts IHI and I02 reclose is determined by the size of a bleed hole I 2I by which chamber IE3 is vented. To be able to vary that time, bleed hole I2! may be provided with an adjustable needle valve I22.

It will be obvious from the foregoing that this embodiment of the invention shown comprises three principal pairs of contacts, 1. e., a pair of arcing or circuit interrupting contacts 20, 2|, a separate pair of circuit closing contacts IUI, I22 and a separate pair of disconnect contacts I5, I

It will also be apparent from the foregoing that each pair of contacts has a. separate operator.

The pair of arcing or interrupting contacts 20, 2| is separated and closed by the fluid operator I9, the pair of closing contacts IIII, I02 is separated and closed by the combined fluid and spring motor 38 and the disconnect contacts I5, I6 are separated and closed by the combined fluid and spring motor I25.

Fluid motor IS! and combined fluid and spring motor I25 are arranged at ground potential, whereas combined fluid and spring motor 30 is arranged at the same elevated potential as housing 25 and all the metallic parts that are associated with it, including the blast valve 3i.

Fig. 5 illustrates another embodiment of the invention as appiied to an air blast circuit breaker structure of the same type as illustrated in Fig. 1. The circuit breaker structures of Figs. 1 and 5 are identical except that the disconnect and reclosing switch 39 and its operating mechanism have been omitted from the embodiment of Fig. 5 and the operating means for the disconnect switch 45, It has been modified so that the disconnect contacts I5, Iii may be opened to provide a plurality of air gaps of varying size. Structural elements of Fig. 5 which are identical with those of Fig. 1 have the same reference characters.

On the occurrence of a fault on the power circuit controlled, motor it rotates column I8, resulting in the separation of arcing contacts 26] and iii and the opening of the blast valve 3i to produce an arc extinguishing blast across the gap formed between the separated contacts 20, 2i. Disconnect contacts I5 and I6 separate instantly after the extinction of the are formed between arcing contacts ZII, 2i. Contacts 25, 2I are caused to reengage by the action of motor I9 and rotating column It. The lowest position of contact I5 during the initial arc extinguishing operation is illustrated in Fig. 5 by dotted lines. If the fault condition still prevails at the time contacts I5 and It reengage, the circuit breaker is tripped again, resulting in sequential separation of contacts 20, 2! and I5, I6. This time, however, disconnect contact IE3 is actuated to the position shown in full lines in Fig. 5.

The operating and control means for achieving this particular type of operation is as follows:

The operator or operating mechanism for contact I5 comprises two spring biased pneumatic motors I'it and I25. Motor 570 effects the short opening stroke of contact I6 and recloses contacts I5 and I6. Motor I25 effects the long opening stroke of contact I6 and recloses contacts I5 and Iii after contact I5 has reached its lowermost position shown in Fig. 5. Motor Ilil effects separation of contacts I5, It by spring means I?! and eifects reclosing of contacts I5, It; by pneumatic action. Spring means III are arranged between piston H2 and cylinder H3.

The operating linkage for contact it com-- prises two levers I14 and I15. The former is pivoted at I76 and the latter at I'Ii. Tie link I78 interconnects levers iii and I75. Operating rod H9 interconnects piston rod I35 of motor I25 and lever I75. Lever I75 is provided with a roller I89 adapted to be engaged by the main latch I35 under the action of biasing spring lei). Main latch I39 is pivoted at It! and controlled by the spring biased auxiliary latch I42. Auxiliary latch I 52 is in turn controlled by tripping solenoid M3.

The piston rod I8! of fluid motor I'i't is connected to lever I74 by a link I82. A roller I'Id on the pin interconnecting link I82 and lever IN is guided by cam surface I83 and held in position by spring biased latch I54. Latch I84 is in turn controlled by a latch 555 adapted to be operated by a tripping solenoid I55. Pipeline I88 connects one tap of the fluid motor piston valve unit I9, I56 with fluid motor Ilil. This pipeline is under the control of solenoid operated valve I81. Pipeline I59 connects another tap of the fluid motor piston valve unit I9, 559 with fluid motor l25. This pipeline is under the con trol of latch checking valve I59 which insures that the main closing motor I25 cannot be supplied with fluid under pressure unless the latch mechanism I84, I85 is in locked position.

The energizing circuit of solenoid operated valve I81 includes an interlock switch I99 adapted to be operated by piston rod ltl of fluid motor I by means of an operating rod I9I. Switch I99 is spring biased to open position in which it prevents the solenoid oi solenoid operated valve I81 from being energized. When the piston I12 of fluid motor I18 moves to its upper position, piston rod I8I acts upon operating rod lill to close interlock switch I99.

The circuit breaker illustrated open in Fig. 5 is manually closed by means of pushbutton I52. This results in operation of valve I45 to permit fluid under pressure from tank it to actuate piston I55 of motor I9 and valve i5!) from left to right. After piston i55 has completed. part of its stroke air flows from the cylinder of mo tor I9 through valve I59 and pipeline I59 to inotor I25. Piston I21 is actuated upward against the bias or spring I26 to close the disconnect contacts I5 and I6 through the levers I14, E and I18 and is latched in place by latches I39 and I42. Dump valve E29 remains closed during most of the closing stroke of the breaker as a result of the lost motion connection associated with rod I53 and the dump valve actuating rod. At the end of the stroke of piston I55 from left to right, switch I54 interrupts the energizing circuit of valve I48.

Manual opening of the circuit breaker illustrated in Fig. 5 may be efieoted by actuating pushbutton I6I, causing energization of tripping valve I51 and the same sequence of operation as described above for the embodiment illustrated in Fig. 1. During manual opening, switch I56 is moved to its lower position to preclude automatic reclosing of the breaker.

If reclosing cutout switch I55 is in the upper position an automatic reclosing sequence of operation of the circuit breaker system will occur. The circuit breaker being closed, energization of relay I51 starts reclosing relay I58, which looks itself in circuit. Energization of relay I51 also results in closing of the circuit of solenoid valve I41 through switch I54 and consequently in admission of compressed air to the right side of fluid motor I9 and piston valve I59. Piston I55 of motor I9 and the movable valve element oi valve I50 are thereby moved from right to left. This movement of piston 55 causes a rotation of column I8 which in turn causes momentary opening of blast valve 3i and separation or con tacts and 2|. The movement of piston I55 to the left operates auxiliary switch I54.

When piston I55 of motor I9 reaches its left position, switch I54 energizes the circuit of solenoid I86 through reclosing relay I53. Solenoid I86 unlatches latch 154 and spring I'll or motor I10 expands, thereby causing lever I14 to rotate counterclockwise about the point where it is hingedly connected to link I18. Roller I16 moves up along the cam surface I83 as disconnect oontact I6 is moved a reduced stroke to the position shown in dotted lines in Fig. 5. The position of the latch members I84, I85, I42 and I39 for the reduced stroke of the disconnect contact I6 is illustrated in Fig. 8. At that time piston rod I8I closes valve I89 and switch I90. Relay I51 returns to the position shown.

Switch I54 in its movement from right to left also deenergizes solenoid I86 so that latch I may reset. However, while piston I12 moves downward roller I16 moves along an extension of latch I84 so that latches I84 and I85 are prevented from returning to the latching portion of Figs. 5 and '1 until piston I12 has completed its downward stroke.

When piston I55 of motor I9 is in its left position, switch I54 causes opening of the solenoid valve I41 and closing of the circuit of the solenoid valve I48 through relay I58. Consequently, the flow of compressed air through pipe I49 is interrupted and a flow of compressed air is established through pipe I5I. The latter flow causes a motion of the piston I55 and of the movable element of valve I58 from left to right. This movement of piston I55 results in arotation of insulating column I8 which, in turn, recloses contacts 25 and 2 I.

Movement of the valve element of piston valve I59 to the right causes admission of air under pressure from the cylinder of fluid motor I9 to the pipes I59 and I88. Compressed air admitted to pipe I59 remains ineffective since that pipe is blocked by latch checking valve I89 moved to closed position through the previous operation of spring I1! and rod I8I.

As piston I55 of motor I9 moves from left to right auxiliary switch IE4 is moved from right to left and closes the circuit which energizes solenoid valve I51 through switches lei! and I56 and relay I58. Valve I81 is thereby opened and compressed air is then admitted to the cylinder I13 of fluid motor I15, causing the downward movement of piston I12 against the action of spring ill, thus reclosing contacts I5 and I5. Reclosing of contacts I5 and I5 results in reclosing of the controlled power circuit.

What happens further depends on whether or not the fault still prevails at the time disconnect contacts I5 and I5 reengage. If the fault does not prevail at that time the continuity of the system is maintained. If the fault still persists, the circuit breaker proceeds to effect a permanent interruption of the power circuit.

Upon reclosure of contacts I5, I5, permanent interruption is initiated by reenergizing relays I51 and I41, resulting in admission or compressed air to motor I9. Piston I55 of motor I9 then moves from right to left, resulting in momentary opening blast valve 3| and in separation of arcing contacts 20, 2%. The power circuit is again interrupted.

During the initial interrupting sequence, motor controlled relay I58 moved so that at this time the control circuit passing therethrough and through switch I54 will energize solenoid I43 but not solenoid I86.

Solenoid I43 causes auxiliary latch I42 to move counterclockwise and release main latch I39. Roll I89, as shown, in Fig. 7 is deprived of its support and spring I26 is free to move linkage I14, I15, I18 from its position shown in Fig. 7 to its position shown in Figs. 5 and 6. This completes the opening operation of the circuit breaker and results in separating the disconnect 13 contacts their full strok as distinguished from part stroke separation.

Although but two embodiments of the Dresent invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims. In particular, while the specific structures shown in the drawing are high voltage air blast circuit breakers of th axial type, the invention is also applicable to circuit breakers of other types such as for instance oil poor or small volume oil circuit breakers.

Features disclosed but not claimed herein are claimed in U. S. Patent No. 2,568,008, granted upon the application of Gustav E. Jansson.

t is claimed and desired to secure by Letters Patent:

1. In combination, an electric circuit, a circuit breaker comprising serially connected cooperating arcing contact means and. disconnect,

contact means, said disconnect contact means arranged to insert circuit insulation into said circuit selectively at relatively small gap length and at relatively large gap length, means respontive to an overload condition of said circuit for causing separation of said arcing contacts and interruption of said circuit at the gap formed between said arcing contacts, means operative upon initial interruption of said circuit at said arcing contacts for causing said disconnect contact means to open and to insert circuit insulation at said small gap length into said circuit, means operative upon said insertion of circuit insulation at said small gap length for causing said arcing contacts and said disconnect contact means to be reclosed sequentially, and means operative only upon repeated interruption of said circuit at said arcing contacts for causing said disconnect contact means to insert circuit insulation at said large gap length into said circuit.

2. In combination, an electric circuit, a circuit breaker comprising serially connected arcing contacts and disconnect contacts connected in said circuit, an arcing contact operator for providing relative short stroke movements between said arcing contacts, a disconnect contact operator for providing selectively relative short stroke and. long stroke movements between said disconnect contacts, means responsive to an overload condition of said circuit for actuating said arcing contact operator to separate said arcing contacts, means for actuating said disconnect contact operator to separate said disconnect contacts at small gap length upon initial opening of said arcing contacts, means for actuating said arcing contact operator to reclose said arcing contacts upon separation of said disconnect contacts at small gap length, means for actuating said disconnect contact operator to reclose said disconnect contacts upon separation thereof at small gap length, and means operative only upon repeated interruption of said circuit at said arcing contacts for actuating said disconnect contact operator to separate said disconnect contacts at large gap length.

3. An electric circuit breaker comprising in combination, a source of gas under pressure, a pair of relatively movable cooperating arcing contacts, means for actuating said arcing contacts, means for establishing and maintaining a blast of gas from said source adjacent said arcing contact when separated by said actuating means, a pair of relatively movable disconnect contactsconnectedin series with said arcing contacts, a first disconnect contact operator provided to eiiect small relative movements between said disconnect contacts, a second disconnect contact operator provided to effect large relative movements between said disconnect contacts, tripping means for actuating said arcing contact operator to separate said arcing contacts, means for actuating said first disconnect contact operator to separate said disconnect contacts upon initial separation of said arcing contacts, means for actuating said arcing contact operator to close said arcing contacts upon separation of said disconnect contacts, means for causing said first disconnect contact operator to close said disconnect contacts upon reengagement of said arcing contacts, and means operative only upon repeated opening of said arcing contacts for actuating said second disconnect contact operator to separate said disconnect contacts.

i. In combination, an electric circuit, a circuit breaker comprising a pair of cooperating arcing contacts, contact means in series with said arcing contacts for selective insertion into said circuit a relatively small amount of circuit insulation at a gap of relatively small length formed in a medium of relatively high dielectric strength and of a relatively large amount or circuit insulation at a gap of increased length formed in air at atmospheric pressure, means responsive to an overload condition of said circuit for separating said arcing contacts to interrupt said circuit, means operative upon initial interruption of said circuit at said arcing contacts for causing said contact means to insert circuit insulation at small gap length into said circuit, means operative upon insertion of circuit insulation at small gap length for reengaging said arcing contacts, means for reclosing said additional contact means upon reclosing of said areing contacts, and means operative only upon repeated interruption of said circuit at said arcing contacts for causing said additional contact means to insert circuit insulation at large gap length into said circuit.

5. In combination, an electric circuit, a circuit breaker comprising a pair of circuit interrupting contacts, a pair of circuit closing contacts, and a pair of disconnect contacts, all said contacts being serially connected in said circuit, an interrupting contact operator for eiTecting relative short stroke movements between said interrupting contacts, a closing contact operator for efrecting relative short strok movements between said closing contacts, fault responsive tripping means for causing said interrupting contact operator to open said interrupting contacts en the occurrence of a fault in said circuit, means for causing said closing contact operator to open said closing contacts upon initial opening of said interrupting contacts, means for causing said interrupting contact operator to reclose said interrupting contact upon opening of said closing contacts, means for causing said closing contact operator to reclose said closing contacts upon reclosing of said interrupting contacts, a disconnect contact operator for effecting relative long stroke movements between said disconnect contacts, and means operative onl upon repeated opening of said interrupting contacts for causing said disconnect contact operator to open said disconnect contacts.

6. In combination, an electric circuit, a circuit breaker comprising a pair of cooperating interrupting contacts of the nozzle and plug type,

a pair of closing contacts of the engageable finger type, and a pair of disconnect contactsof the engageable finger type, all said contacts being serially connected into said circuit, an interrupting contact operator for effecting relative short stroke movements between said interrupting contacts, a closing contact operator for effecting relative short stroke movements between saidclosing contacts, fault responsive tripping means for causing said interrupting contact operator to open said interrupting contacts to draw an arc therebetwecn, means for producing an are extinguishing blast of fluid across the gap formed upon opening of said interrupting contacts, means for causing said closing contact operator to open said closing contacts upon opening of said interrupting contacts extinction of said are, means for causing said interrupting contact operator to reclosc said interrupting contacts upon opening of said closing contacts, means for causing said closing contact, operator to reelose said closing contacts upon reclosing of said interrupting contacts, a disconnect contact operator for effecting relative long stroke movements between said disconnect contacts, and means operative only upon repeated opening of said interrupting contacts for causing said disconnect contact operator to open said disconnect contacts.

7. In combination, an electric circuit, a circuit breaker comprising a pair of circuit interrupting contacts, a separate pair of circuit closing contaste, and a separate pair of disconnect contacts, said interrupting contacts, closing contacts and disconnect contacts being serially connected into said circuit, an operator for effecting relative movement between said interrupting contacts, an operator for effecting relative movement between said closing contacts, means responsive to an overload condition of said circuit for opening said interrupting contacts, means operative upon opening of said interrupting contacts for opening said closing contacts, means operative upon opening of said closing contact for closing of said interrupting contacts, means operative upon closing of said interrupting contacts for rcengaging said closing contacts, a source of gas under pressure, means for admitting a blast of gas from said source adjacent said interrupting contacts during separation thereof, means for admitting gas under pressure from said source adjacent said closing contacts during the sepa ration thereof, an operator for effecting relative movement between said disconnect contacts, and means operative only upon repeated opening of said interrupting contact for separating said disconnect contacts.

3. An electric circuit breaker comprising in combination, a source of gas under pressure, an insulating blast passage connected at one end thereof with said source, a main valve arranged adjacent the opposite end of said passage for con trolling a blast of gas issuing therefrom, a pair of relatively movable circuit interrupting contacts arranged adjacent the region of saidblast, an interrupting contact operator arranged at ground potential, a rotatable insulating column adapted at one end thereof to be rotated by said interrupting contact operator, and at the opposite end thereof arranged to operate one of said interrupting contacts and to initiate the operation of said main valve, a contact chamber, an auxiliary valve under the control of said insulating column for admitting gas under pressure from said passage to said chamber, a pair of relatively movable circuit closing contacts arranged in said chamber" and arranged to" be" 16 connected in series with said interrupting contacts, closing contact operating means arranged at an elevated potential and under the control of said column for effecting relative movement between said closing contacts, tripping means responsive to a circuit condition for actuating said interrupting contact operator to separate said interrupting contacts, means for actuating said closing contact operating means to open said closing contacts upon opening of said interrupting contacts, means for actuating said interrupting contact operator to close said interrupting contacts upon opening of said closing contacts, means for actuating said closing contact operating means to reengage said closing con tacts upon closing of said interruptingcontacts, a separate pair of relatively movable disconnect contacts connected in series with said interrupting contacts and said closing contacts, a disconnect contact operator for effecting relative movement between said disconnect contacts, and means for causing said disconnect contact operator to separate said disconnect contacts upon repeated opening of said interrupting contacts.

9. An electric circuit breaker comprising in combination, a source of gas under pressure, means defining a first contact chamber, a pair or relatively movable circuit interrupting contacts in said first contact chamber, means defining a. second contact chamber arranged generally transverse with respect to said first contact chamber, a pair of relatively movable circuit closing contacts in said second contact chamber arranged to be connected in series with said interrupting contacts, an operator for efiecting relative movement between said interrupting contacts, an operator for effecting relative movement between said closing contacts, fault responsive means for opening said interrupting contacts, means operative upon opening of saic interrupting contacts for opening said closing contacts, means operative upon opening of said closing contacts for closing of said interrupting contacts, means operative upon closing of said interruptingv contacts for reengaging said closing contacts, common means for admitting gas under pressure from said source to said first contact chamber and said second contact chamber, a pair of relatively movable disconnect contacts connected in series with said interrupting contacts and said closing contacts, an operator for effecting relative movement between said disconnect contacts, and means operative only upon repeated opening of said interrupting contacts for causing opening of said'disconnect contacts.

10'. An electric circuit breaker comprising in combination, a source of gas under pressure, a pair of relatively movable circuit interrupting contact comprising a nozzle shaped contact and a cooperating plug shaped contact, a pair of relatively movable circuit closing contacts comprising a plurality of finger type contact elementsarranged to engage a cooperating contact element on opposite surfaces thereof, a first operator for actuating said pair of interrupting contacts, a second operator for actuating said pair of closing contacts, fault responsive means for causing admission of gas under pressure from said source adjacent said pair of interrupting contacts and adjacent said pair of closing contacts and for opening said pair of interrupting contacts, means for actuating said second operator to open said pair of closing contacts upon opening of said pair of interruptingcontacts and extinctionot the are formed therebetweem-meaxw for actuating said first operator to reclose said pair of interrupting contacts upon opening of said pair of closing contacts, means for actuating said second operator to reclose said pair of c1osing contacts upon reclosing of said pair of interrupting contacts, a pair of relatively movable disconnect contacts, means for serially connecting said pair of interrupting contacts, said pair of closing contacts and said pair of disconnect contacts into a circuit, a. third operator for effecting relative movement between said pair of disconnect contacts, and means operative only upon 18 repeated opening of said pair 01' interrupting contacts for causing said third operator to open said pair of disconnect contacts.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,430,128 Lerstrup Nov. 4, 1947 2,464,237 Kelle Mar. 15, 1949 2,528,694 Kelle Nov. 7, 1950 2,533,559 Chipman Dec. 12, 1950