US2282348A

US2282348A - High speed circuit breaker reclosing mechanism

Info

Publication number: US2282348A
Application number: US285091A
Authority: US
Inventors: Thumim Carl
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1939-07-18
Filing date: 1939-07-18
Publication date: 1942-05-12
Anticipated expiration: 1959-05-12

Description

May 12, 1942. c. THUMIM HIGH SPEED CIRCUIT BREAKER RECLOSING MECHANISM Filed July 18, 1939 TO OPEN Ihven tor: Cafl Thumnim, by 717 :flM

-His Attorney.

Patented May 12, 1942 men sraan omcorr BREAKER. aacrosmc MECHANISM Carl Thumim, Yeadon, Pa., assignor to General Electric Company. a corporation of New York Application July 18', 1939, Serial No. 285,091

12 Claims.

My invention relates to high speed reclosing mechanisms, more particularly as applied to electric circuit breakers which are connected in high voltage networks or power transmission lines, and has for its principal object the provision of an improved high speed reclosing mechanism that is efilcient, positive and very rapid in operation, and that is effective to apply the reclosing force instantly at a predetermined point in the opening stroke.

In electric distribution systems where continuity of service is a very important factor, means have been provided for quickly reclosing an electric circuit breaker one or more times after automatic opening in response to a fault on the assumption that a very large percentage of faults, such as surges due to lightning, for example, are of a temporary nature. From the standpoint of service continuity, the ideal condition is that the breaker be reclosed instantly after the breaker has cleared the fault. Accordingly, where standard opening and closing mechanisms are employed, reclosure does not actually start until the full opening stroke has been completed.

The function of a circuit breaker is not only to open a circuit and clear faults, but also to maintain the circuit clear under adverse voltage conditions. That is, the length of stroke of the circuit breaker must be sufficient to prevent restriking of the arc in case the line voltage is several times that of normal. As contrasted with this isolating function of the breaker, it should be borne in mind that a well designed breaker can actually clear a fault within a few inches of opening stroke.

There is disclosed in my application, Serial No. 85,789, filed June 17, 1936, for High speed reclosing mechanisms, a reclosing mechanism wherein a pair of separately energized motor mechanisms are interrelated for the purpose of obtaining rapid reclosure. There is also disclosed in my application, Serial No. 192,782, filed Februray 26, 1938, for High speed reclosing mechanism, a reclosing mechanism of this character wherein spring energy is instantly available for reclosing.

In acco..dance with the present invention, a trip-free linkage operatively interconnecting the circuit breaker and a'motor, such as a solenoid or the like for closing the breaker, is controlled by a plurality of selectively operated latches or tripping devices whereby trip-free protection is provided during a high speed reclosure instantly following tripping due to a fault.

My invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawing, the single figure thereof is a partly diagrammatic layout of a high speed circuit breaker reclosing mechanism of the solenoid type embodying the present invention.

The automatic reclosing system shown comprises essentially a source of motive power M, such as a solenoid, a thrust transmitting linkage T, and circuit breaker operating means such as the rod 1. The circuit breaker operating rod l is moved to the closed circuit position shown by means of the solenoid M and the linkage '1' (which is latched in thrust-transmitting position) and is held in such position by the linkage T against the bias of the usual circuit breaker opening springs (not shown).

Referring more specifically to the operating linkage T the arrangement is fundamentally similar to that disclosed and claimed in my Patent 1,827,626, granted October 13, 1931, for Switch operating mechanism, although it is obviously not limited to this specific form of linkage. As

held stationary by a latching deveice Li so that when the plunger ll of the solenoid is raised, the roller l2 connected to the floating lever is engaged and the rocking lever l rotated clockwise to close the breaker.

As the linkage approaches the closed position a prop P is latched at La to hold the linkage in the thrust transmitting position shown upon deenergization of the solenoid. The prop P comprises a pair of toggle links I3 and H, the link l3 having a resilient resetting connection at l5 with the floating lever 6 through the pin l6, and the link it being mounted on a fixed pivot 14' and having an extension on which a roller I1 is mounted for engagement with the latching device L2. The link I3 is also provided with a slot l3 for co-acting with the pin it to permit tripping of the linkage at Ll independently of 1a.

The latching device L2 comprises a pivoted latch I8 that is biased by spring I9 to the latching position shown. This position is determined by comprises a

toggle linkage

23, 24 arranged to be held in the under-set position shown by a latch 25. The link 23 is mounted on a fixed pivot at.23 and the link 24 is connected to the pivot l as shown. The tripping latch 25 is operatively related to the tripping solenoid 26 in a well-known manner. 7

r by maintaining a tripping circuit at the latch L1.-

P resets under bias of the spring I5 behind the Accordingly, in the closed circuit position shown the linkage T is latched at both L1 and L2. It will be apparent that release of either latching device will permit upward or opening .movement of the breaker rod I. That is, if latch L2 were operated, the prop P would collapse thereby permitting the floating lever 6 to drop clockwise about the pivot I. If the latch "L1 were oper. ated, the pivot 'I' would be released so as to permit first lateral movement toward the left and then rotation of the floating lever 6 to open the breaker; The initial movement of lever 6, and hence lever 4, toward open position causes the lug I8 secured to the lever 4 to trip the latch I8, thereby permitting latch L1 to reset, since in the openposition of the breaker but one latch may be locked. I 1

Thecycle of operation of the mechanism together with the control means therefor will now indicated at s: which has sufiicient m. m. f. when I energized to hold the switch closed at S2 after a single operation of the main solenoid plunger I I. This prevents pumping or repeated operation of the solenoid if the operator holds the switch C closed since the circuit must be reestablished at $1 in order to energize the solenoid a second time. The m. m. f. of the magnet is not sufficient to attract its armature from the position shown, the magnetic circuit being closed by the plunger II Since switch contacts s2 parallel contacts 872, thetransfer relay TR remains energized, there- At the final part of the closing stroke, the prop latch 18. It will now be assumed that the breaker has been fully closed without the necessity for fault operation. The solenoid M is now de-energized as the relay SR drops out at the contacts 8T1. When this occurs, the limit switch S opens the fault relay circuit at 82 with the resultthat the tripping circuit is again transferred at contacts tr: back to latch L2. This transfer is slightly delayed by means of-the dashpot in so 1 that there can be no chance of losing trip-free protection during the'complete closing operation; In the absence of a fault or initiation of the opening operation under direction of the op--, erative, the mechanism will remain in the position shown.

The closed breaker is now ready for tripping at either latch L1 or L2. If manual tripping is selected, the opening switch 0, which parallels the be described. Assuming that the breaker rod I is in the open circuit position so that the roller I2 is resting on the solenoid plunger I I, the closing operation can be initiated by closing the'switch C, thereby energizing the winding of the solenoid from the source of control voltage E through the solenoid relay SR. The relay SR is picked up by means of the circuit established through the upper contacts 5 31'2 energizes the throw-over or transfer relay TR, thereby closing the transfer relay circuit at the contacts tri.

It will therefore be noted that thebreakermechanism is now trip-free, i e., has trip-free protection during closing, since the solenoid 26' of the latch L1 is now in readiness to trip the mechanism irrespective of its position in case the fault relay FR is closed to trip the mechanism through the latch L2. The tripping circuit is established through control switch 0, auxiliary switch a and contacts trz of the transfer relay. Since automatic reclosing is not desired when theopening switch 0 is manually operated, thisv switch also controls the auxiliary contacts or for opening'the automatic reclosing circuit. Switch 0 remains in the tripping'position with the conoverload or fault relay FR, is energized to close at in. closed as the breaker reaches closed position. This auxiliary switch may assume a variety of forms and can comprise a simple spring biased plunger 21 co-acting with a cam member 28 carried by the breaker rod I so that the switcha isclosed when the breaker is closed and is open when the breaker is open. As shown, the a" switch is in series with the relays TR and FR The breakera" switch indicated at a is so that the latch Li'can be operated only when the breaker is substantially closed.

Substantially at the completion of the closing operation the solenoid plunger II operates the overhanging extension of limitswitch S to open the contacts s1, thereby de-energizing the relay SR, and closing the contacts s2. The switch is preferably controlled by a simple holding magnet,

tacts 01 open in order to prevent automatic reclosing. The operative returns switch 0 to the non-tripping position shown as he operates switch C to close the breaker. If desired, interlocking means well-known in the art can be provided for switches O and C so that switch O'is opened automatically when C is closed. In case of manual tripping at latch L2, the lever 6 simply drops in clockwise direction until the roller I2 engages the'solenoid plunger II, the pivot I remaining fixed. In case of fault tripping, the rev lay FR also functions in the manner above described to trip the breaker at the latch L2.

The operation for automatic reclosing is as follows. Let it be assumed that the fault relay FR trips the mechanism in the manner previously described through the latch L2. As the breaker rod I moves upward in opening it causes closing of the auxiliary switch at b by means of a cam at 28'. in a manner similar to the auxiliary switch at a; The relay circuit of SR is now closed through-the auxiliary switches 01, b and .91 for energizing the solenoid M in the manner previously described. Accordingly as the floating lever 6 drops in response to tripping toward the collapsed position, the plunger II of the solenoid is already on the way up to meet the roller I2 even before thebreaker has completely opened. Therefore the movement of the'lever 6 is instantly reversed andthe breaker is reclosed from that point.

It will be apparent that the point in the opening stroke at which automatic reclosing is to be initiated can be determined by the position of the cam 28' which can readily be adjusted with respect to the rod I. As the breaker recloses, trip-free protection is provided as previously described by the latch L1. That is, if the fault in the main circuit still persists the mechanism is immediately tripped open upon reclosure since the fault relay FR will be energized. The tripping circuit includes switch a, contacts tn of the transfer relay. It will be noted that this circuit can be maintained if desired for a short time after actual closing of the breaker by reason of the time delay device at tr: for the purpose of insuring trip-free protection at the latch Ll.

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

1. A high speed automatic circuit breaker reclosing mechanism comprising a source of motive power, a trip-free linkage interconnecting said source of power and circuit breaker for closing said circuit breaker, a latch operatively related to said linkage for causing trip-free opening thereof, and a second latch for holding said breaker in closed circuit position.

2. A high speed automatic circuit breaker reclosing mechanism comprising a source of motive power, a trip-free linkage of the thrust transmitting type interconnecting said source of power and circuit breaker for closing said circuit breaker, a latch operatively related to said linkage for causing trip-free opening thereof, and a second latch for holding said breaker in closed circuit position, said second latch being operable only when said circuit breaker is in closed circuit position.

3. A high speed automatic circuit breaker reclosing mechanism comprising a source of motive power, a trip-free linkage including a floatinglever interconnecting said source of power and circuit breaker, a latch operatively related to said floating lever for causing trip-free opening of said linkage, and a second latch for holding said breaker in closed circuit position, said secbnd latch being inoperative when said circuit breaker is open.

4. A high speed automatic circuit breaker reclosing mechanism comprising a source of mo tive power, a trip-free linkage including a floating lever and a pivoted rocking lever interconnecting said source of power and circuit breaker for closing said circuit breaker, a latch operatively related to said linkage for establishing a stationarypivot for said floating lever, release of said latch causing trip-free opening of said linkage, and a second latch for holding said breaker in closed circuit position, said second latch being operable only when said circuit breaker is in closed circuit position to cause opening of said circuit breaker independently of said first latch.

5. A high speed automatic circuit breaker reclosing mechanism comprising a source of motive power, a trip-free linkage interconnecting said source of power and circuit breaker for closing said circuit breaker, a latch operatively related to said linkage for causing trip-free opening thereof, and a second latch also operatively related to said linkage for holding said circuit breaker in closed circuit position.

6. A high speed automatic circuit breaker reclosing mechanism comprising a source of motive power, a trip-free linkage including a floating lever interconnecting said source of power circuit breaker for closing said circuit breaker, a latch for establishing a stationary pivot for said floating lever whereby tripping of said latch causes trip-free opening of said linkage, and a second latch also operatively related to said floating lever for holding said circuit breaker closed and being operative to trip said linkage only when said circuit breaker is in the closed circuit position.

7. A high speed automatic circuit breaker reclosing mechanism comprising a source of motive power, a trip-free linkage interconnecting said source of motive power and circuit breaker for closing said circuit breaker, a latch operatively related to said linkage for causing tripfree opening thereof, a second latch also related to said linkage for holding the same in thrust transmitting position and for holding said breaker in closed circuit position, and means for causing tripping of said second latch in response to tripping of said first-named latch.

8. A high speed automatic circuit breaker reclosing mechanism comprising a source of motive power, a trip-free linkage interconnecting said source of motive power and circuit breaker for closing said circuit breaker, a latch operatively related to said linkage for causing trip-free opening thereof, a second latch also related to said linkage for holding the same in thrust transmitting position and for holding said breaker in closed circuit position, and means related to said circuit breaker for causing tripping of said second latch in accordance with initial opening movement of said circuit breaker in response to tripping of said first latch.

9. A high speed automatic circuit breaker reclosing mechanism comprising a source of motive power, a trip-free linkage of the thrust transmitting type interconnecting said source of power and circuit breaker for closing said circuit breaker, a latch operatively related to said linkage for causing trip-free opening thereof, a prop including a toggle connected to said linkage and a'second latch related to said toggle for holding said breaker in closed circuit position.

.10. A high speed automatic circuit breaker reclosing mechanism comprising a solenoid, a trip-free linkage interconnecting said solenoid and circuit breaker for closing said circuit breaker, a latch operatively related to said linkage for causing trip-free opening thereof, a second latch related to said linkage for holding said breaker in closed circuit position, and means for energizing said solenoid to reclose said breaker in response to tripping of said breaker at said second latch.

11. A high speed automatic circuit breaker reclosing mechanism comprising a solenoid, a trip-free linkage including a floating lever interconnecting said source of power and circuit breaker, alatch operatively related to said float ing lever for causing trip-free opening of said linkage, a second latch for holding said breaker in closed circuit position, means for rendering said second latch inoperative when said circuit breaker is open, means for energizing said solenoid to reclose said breaker after predetermined opening of said breaker and means for transferring the tripping control to said first latch during reclosing of said breaker.

12. A high speed automatic circuit breaker reclosing system comprising a solenoid, a trip-free linkage for operatively interconnecting said solenoid and circuit breaker to close said circuit breaker, a latch connected to said linkage for trip-free operation thereof, a second latch op- I 4- g r 2,282,848

eratively related to said linkage for holding said means including a relay energized in accordance circuit breaker closed, fault responsive means with the solenoid closing operation for transferfor controlling said second latch to cause opening ring the tripping control from said second latch of said circuit breaker, means for energizing said to said first-named latch during closing of said solenoid in accordance with opening of said cir- 5 circuit breaker.

cuit breaker, to cause rapid reclosure thereof be- CARL THUMIM. fore the open circuit position is reached, and