US2274350A

US2274350A - Circuit breaker operating mechanism

Info

Publication number: US2274350A
Application number: US319491A
Authority: US
Inventors: Thumim Carl
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1940-02-17
Filing date: 1940-02-17
Publication date: 1942-02-24
Anticipated expiration: 1959-02-24
Also published as: GB545482A

Description

Feb. 24, 1942.

c. THUMIM CIRCUIT BREAKER OPERATING MECHANISM 2 Sheets-Shet 1 Filed Feb. 17, 1940 lnv encorz Carl Thurni n, by F0476. JWAW His Attorney.

, Feb. 24, 1942.

C. THUMIM CIRCUIT BREAKER OPERATING MECHANISM Filed Feb. 17, 1940 2 Sheets-Sheet 2 Inventor: Carl Thum'lm, b

His Attorney.

Patented Feb. 24, 1942 UNITED STATES PATENT OFFICE CIRCUIT BREAKER OPERATING MECHANISM Carl Thumlm, Lansdowne, Pa., assignor to General Electric Company, a c poration of New York Appllcation'lebruary 17, 1940, Serial No. 319,491

8 Claims.

' breaker operating mechanism of the aforesaid type.

.Automatic reclosing circuit breaker systems have been proposed wherein the circuit opening operation in the reclosing cycle is checked prior to completion of the opening stroke and the reclosing operation is started immediately so that the reclosing cycles takes but a fraction of the time that would be required for completely opening and thenreclosing the circuit breaker. In certain of these Systems, a plurality of faultresponsive trip coils have been used for obtaining high speed normal and trip-free overload protection respectively, the tripping control being transferred as needed in accordance with the operating cycle. That is, one trip coil for example would be designated solely for trip-free protection. This arrangement although generally satisfactory in practice necessitates a more or less complicated electrical control and is therefore more expensive.

In accordance with my invention, the reclosing system and mechanism are simplified by the use of but a single trip coil without impairing the speed of the reclosing cycle, and without sacrificing adequate normal and trip-free overload protection. More particularly, a plurality of latches areselectively controlled by a single panying drawings, andthe 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 drawings, Fig. 1 is a partly diagrammatic showing by way of example a solenoid operating mechanism embodying the present invention latched in the closed circuit position, and Fig. 2 is a similar view showing another form my invention may assume. 7

The mechanism shownby Fig. 1 comprises suitable actuating means, such as the main operating solenoid I for moving the circuit breaker (or. zoo-49) operating rod 2 to cloud circuit position agains the bias of an opening spring 3. The circuit breaker per se, which may be of any suitable type, is not illustrated in the interest of simplicity of the drawing. The solenoid l and the circuit breaker operating rod 2 are operatively' interconnected by a chain'linkage 4 that is guided on a roller 5 carried by one arm of a normally latched crank 6. The crank which is pivoted at I is provided with a latching roller 8 carried by the other crank arm for engaging a rotatable latch 9 that is pivotally mounted at Ill.

The mechanism so far described is essentially of the type disclosed and claimed in my Patent No. 2,112,054, granted March 22, 1938, for Operating mechanism and further detail description thereof is believed to be unnecessary other than to point out that tripping of the crank 6 by movement of the latch 9 from beneath the roller 8 causes collapse of the chain linkage 4 under bias of the spring! and opening of the circuit breaker.

In the closed circuit position illustrated, the plunger l of the solenoid is held or latched in its retracted position within the operating coil against the bias of its resetting spring I" and breaker spring 3 by a tripping toggle I l-l 2. The toggle link II is pivoted at I! and the link I2 is pivotally connected at It to the solenoid plunger, the knee l5 of the toggle having a roller it that is arranged to be engaged by pivoted latch I1 for holding the toggle extended.

The latch II, which is pivotally mounted at I8, is arranged to coact with a co-pivotally mounted releasing member I9 through a pin 20 Ill that is secured to the latch l1. That is, when the member I! is engaged by the movable plunger 2| of the fault responsive tripping coil 22, the overhanging pin 20 of the latch I1 is struck by the member 19 so as to cause simultaneous clockwise movement of both members. As the latch ll moves from beneath the roller I6, the toggle lll2 collapses under the reacting spring and the solenoid plunger rises as the breaker opens. It will be noted that the tripping operation above described can be independent of the crank 6 since the chain linkage l is simply guided on the roller 5.

The solenoid plunger l is now in its elevated or open circuit position and either the normal closing or automatic reclosing operation can be initiated regardless of the fact that the latch H has not yet been returned to the reset position under influence of biasing spring 11'. During the above-described tripping operation, which will hereinafter be described as the normal tripping operation, the latch 9 remains 'in engagement with the roller 8 to hold the chain linkage generally in the position shown for transmitting instantly a closing force to the breaker substantially at right angles to the direction of movement of the solenoid plunger.

However, under certain predetermined conditions, namely, in case of trip-free operation when the breaker is being closed by the solenoid, actuation of the member I9 by the tripping solenoid 22 causes release of the latch 9 and immediate opening of the breaker in the manner firt described. To this end; the member I9, which is loosely mounted as indicated on the shaft I8, is connected with a selecting or latch releasing member 23 that is also loosely mounted as indicated on.the shaft I0. The member 23 is adapted to strike an offset pin 24 that is secured to the latch 9 for the purpose of moving the latch 9 away from the roller 8. The means interconnecting the members I9 and 23 in the present instance comprises a linkage 2526 connected at and 26' to said members and having an intermediate joint at 21. In the rmrmal tripping operation above described, clockwise rotation of the member I9 causes corresponding movement of the member 23, but due to the spacing between member 23 and the pin 24 in the position shown, tripping of the roller 8 does not occur as the member 28 stops before striking the pin 24.

The closing or reclosing operation of the mechanism will now be described. For the purpose of simplicity, an automatic reclosing electric control system is diagrammatically illustrated,

wherein the operating solenoid I can readily be energized for automatic reclosing through auxiliary contacts, for example, in accordance with predetermined opening movement of the breaker rod As illustrated, a switch 28 controls energizatiorx of the solenoid I from a source of control power: indicated at 29. Also connected in parallel with solenoid I is an auxiliary solenoid 39, the movable plunger 3| of which is connected through the link 32 to the pivot joint 21 of the latch controlling linkage 2528. Accordingly, when the control switch 28 is closed, the solenoids l and 30 will be simultaneously energized, the plunger I of the main solenoid being drawn downward to close the breaker, and the'auxiliary solenoid plunger 3| being raised to extend the linkage 2525 to the dotted line position iIldL'.

cated. The upward movement of the linkage is limited by a stop pin 33, and since the counterclockwise movement of the member I! is limited by a stop pin 34, it will be apparent that the latch or reclosed, and that overload or fault still exists in the main power circuit, the plunger of the fault responsive tripping solenoid 22 will again be actuated to strike and rotate the member I9 clockwise. In this case, hawever, since the auxiliary solenoid 30 is now energized the linkage 25-46 in moving to the right from the dotted line position as viewed in the fiEure rotates the member 23 so that it strikes the pin and rohates the latch 9 from beneath the roller 8 thereby tripping the mechanism. As the chain 4 collapses in response to clockwise movementof the crank G, the breaker opens under influence of the opening spring 3 in the trip-tree manner above described.

After the opening operation and deenergization of the main and auxiliary solenoid coils, the member I9 and linkage 2526 are reset by spring IS, the crank 6 is reset by its spring 6' and the latch 9 also is reset by its spring 9 beneath the roller 8. In thi position solenoids I and 3| are both deenergized and the mechanism is in readiness for another closing stroke. Assuming that no fault exists during the closing operation, the latch I1 drops behind the roller Ii of the solenoid holding toggle I I-I2 as the solenoid finally moves to its fully closed position. The mechanism is now in the normally closed circuit position illustrated and in readiness for high speed tripping in response to fault actuation of the tripping solenoid 22 and also in readiness for subsequent trip-iree operatio upon either normal or high speed reclosing.

The automatic high speed reclosing cycle takes place in the following manner. With the breaker in the closed circuit position shown, the auxiliary switches a and b, which are spring biased as indlcated and directly operated by the circuit breaker rod 2, are in the closed and open circuit positions respectively. These auxiliary switches may be actuated in any suitable manner, as by cam surfaces a and b respectively on the circuit breaker rod, the main essentials being that switch a shall be closed when the breaker is closed and open when the breaker is open, and that the automatic reclosing switch I: shall be closed only after predetermined opening of the breaker rod.

That is, the switch b should close at some predetermined intermediate point in the opening stroke at which the high speed reclosing operation should be initiated.

The manual control snap-over switch M hould also be in the position shown wherein the contacts m are open and the contacts at m: are closed for automatic performance 01 the reclosing cycle. The solenoid controlling relay SR is normally deenergized so that the relay sealing-in contacts sri are open as is the main solenoid switch 28.

Let it now be assumed that the fault relay FR i energized in response to a fault on' the main power circuit (not shown) thereby closing the contacts at In. The tripping relay 22 is accordingly energized from the control source 29 through the switch contacts at in and a, the breaker thereupon opening in the manner previously described.

As the breaker opens, the reclosing switch b is closed at a predetermined point in the opening stroke and the switch a is opened to permit resetting of the apparatus at the trip coil 22. Also the solenoid limit switch L is closed as the solenoid plunger rises in response to the tripping operation. Immediately upon closing of the switches b and L, the energizing coil at SR for the control switch 28 is energized from the source 28 through the contacts at ma, b and L. The switch 28 is thereupon closed to energize the solenoids I and 30 for reclosing the. circuit breaker, the sealing-in conact 8T1 insuring complete operation of the main solenoid independently of the'auxiliary switch I). When the solenoid plunger I again reaches the closed position, the limit switch L is opened to deenergize the coil at SR. The switch 28 is thereupon opened.

For manual tripping without automatic reclosing control, the manual switch M is moved to close the contacts at 1m, thereby opening the automatic reclosing circuit at m:. The contacts 1111 which are in shunt with the contacts of the fault relay FR control tripping of the breaker in the manner above described.

The high speed trip-free operation in case of instantaneous reclosure is possible by reason of the fact that the latch 9 is in immediate readiness for a tripping operation independently of the condition of the latch II. It will be apparent that my invention is particularly adapted for high speed reclosing mechanisms wherein the opening and reclosing operation must be performed within a fraction of a second since no time is consumed in the resetting of latches and such time might be of the order of several cycles at the best.

In the mechanism shown by Fig. 2, the actuating means illustrated by way of example also comprises a main solenoid I. It shall be clearly understood, however, that the actuating means in both Figs. 1 and 2 can be of any suitable type, either electrical or mechanical, such as, for example, a pneumatically operated piston.

The breaker operating rod 2 in the present mechanism is movable generally in the same direction as the solenoid plunger I, and for this reason the interconnecting structure can assume a different form. As illustrated, the breaker rod 2 is connected to one end of a walking beam 40 pivotally mounted at H, the other end of the beam being connected through a link 42 to one end of a floating lever 43. The floating lever 43 at its other end carries a roller 44 that is normally held stationary by a-pivoted latch 45. The lever 43 is also connected at the roller pin 44' to a guide link 46. The latch 45, which is provided with a notch defining a latching surface 45, is biased towards its latching position by the spring 41 so that in the position shown the roller 44 is held with respect to upward movement.

The floating lever 43 is also latched in the closed circuit position at an intermediate point by a pivoted latching member 48 arranged to engage a roller 49 carried by the floating lever. It will therefore be observed that if either the latch 45 orthe latch 48 are actuated to move out of restraining engagement with the rollers 44 and 49 respectively, the walking beam 48 will be free to rotate' counter-clockwise under bias of the opening spring 3 to cause opening of the circuit breaker. That is, if the latch 48 alone is actuated, the floating lever 43 drops in clockwise direction about the pivot 44', and if the latch 45 is also actuated, the roller 44 is free to moveupward, the floating lever 43 then rotating clockwise about the intermediate roller 49.

The latch 48 is controlled by a member 58 that is co-pivotally and loosely mounted with respect thereto at 5I. A resetting spring 52 biases the latch 48 toward its latching position beneath the roller 49 and into engagement with a stop pin 53. The member 58 is also provided with a pin 54 that is offset so as to strike and rotate the latch 48 when the member 58 is struck and rotated clockwise by the plunger 55 of the tripping fault responsive solenoid 56. The member 58 is also biased toward its reset position by a spring 51 against a pin stop 58.

Accordingly, when the tripping solenoid 55 is actuated upon occurrence of a fault in the main circuit, the members 58 and 48 move as a unit to unlatch the roller 49 and thereby cause opening of the circuit breaker. When this occurs, the floating lever 43 drops in a clockwise direction about 44 until the roller 49 engages the upper extension I" of the solenoid plunger I'.

If now high speed reclosing or normal closing is desired, the energizing coil of the solenoid I can be suitably controlled in the manner previously explained. As diagrammatically illustrated in Fig. 1, the control switch 28 can be closed in any suitable manner to energize the solenoid from the control source 29, thereby causing upward movement of the plunger I. The solenoid plunger extension I acting on the roller" imparts clockwise rotation to the floating lever 43 until it reaches the position shown where it is again latched as the spring 52 snaps the latch 48 beneath the roller. 49. The above operation as described is on the assumption that no fault exists on the main circuit during the closing or automatic reclosing operation.

When a circuit breakeris closed during a fault condition in the main circuit, trip-free operation is generally required in order to avoid damage to the circuit breaker. In the case of tripping during high speed reclosing, the latch releasing control must be at the latch 45 since the plunger I' is at that time acting directly on the roller 49. For the purpose of controlling the latch 45 for trip-free operation, the latch is pivotally connected at 69 to a selecting member 5| having an irregularly shaped slot 52 in which a pin '63 secured to the member 58 is operable. The slot 62 includes an offset recess 62' for permitting free movement of pin 63 when the member 58 is operated by the tripping solenoid in the normally closed position of the circuit breaker shown. When, however, the breaker is being closed, an extension 64 carried by the plunger I engages the selecting member 6| to raise it so that the pin 63 lies within the lower restricted Dart-of the slot 62. If now the tripping solenoid 55 is actuated in response to a fault, the pin 63 is driven against the slot wall 62" of the selecting member BI so as to cause counterclockwise rotation of the latch 45. The roller 44 is thereby released and the breaker opens under bias of spring 3 as the lever 43 rotates clockwise about. roller 49 on the solenoid plunger extension I.

When the breaker is in the fully open position, the solenoid I is deenergized by opening of the switch 28, or by a suitable limit switch operatively connected to the circuit breaker, and the plunger I drops to the lower position shown in the drawings. The weight of the linkage 43-46 causes it to reset, the roller 49 dropping down and resting on the extension I" of the Iii) plunger I, and the roller 44 camming counterclockwise the latch 45 until the latch spring 45 snaps the latch over the roller as illustrated.

In this position the roller'44 is held flxed and the mechanism is in readiness for another closing operation.

It will be noted that the mechanisms shown by both Figs. 1 and 2 employ but a single trip coil in combination with selecting means for controlling one or more latches for causing opening of the circuit breaker. Since different mechanical means obviously may be used for obtaining this result, applicant does not consider his invention limited to the specific structural arrangements disclosed for obtaining trip-free protection on high speed reclosing by the same fault responsive trip coil that also initiates the normal opening operation.

It should also be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated,

and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

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

1. Circuit breaker operating mechanism comprising means for closing and means for opening the circuit breaker, dual tripping control means for either tripping the circuit breaker in the circuit breaker, dual tripping control means for either tripping the circuit breaker in the normal closed circuit position or for trip-free operation of said circuit breaker when said closing means is being actuated, mechanical selecting means arranged to be inoperative when the circuit breaker mechanism is in said normal closed circuit position and operative with respect to one of said dual control means when said mechanism is being closed, and a fault responsive device for actuating the other of said dual control means and said selective means.

3. Circuit breaker operating mechanism comprising means for closing and means for open ing the circuit breaker, dual tripping control means for either tripping the circuit breaker in the normal closed circuit position or for trip-free operation during the closing operation of said circuit breaker, a fault responsive device for actuating one of said dual means, a selecting member operatively connected to one of said dual means, said member normally having a lost-motion travel with respect to the other of said dual means, and means for taking up said lost-mo tion travel when said mechanism is being closed whereby said selecting member causes actuation of said other dual means in response to fault oper'ation of said device.

4. Circuit breaker operating mechanism comprising an actuating solenoid, trip-free structure operatively connecting said solenoid to the circuit breaker for closing said circuit breaker, two latches related to said trip-free structure either. one of which may cause tripping of the circuit breaker, a fault responsive tripping coil associated with one of said latches for causing normal tripping, a selecting member also operatively related to said tripping coil and arranged to have alternate positions with respect to the other of said latches in accordance with the open and closed positions of said solenoid, said selecting member being in an inoperative-position during said normal tripping, and means for moving said selecting member to 'its operative position with respect to said other latch in accordance with the closing operation'of said solenoid so that fault operation of said trip coil is eflective to cause trip-free operation of said circuit breaker.

5. Circuit breaker operating mechanism comprising electromagnetic actuating means, tripfree structure operatively connecting said actuating means to the circuit breaker for closing and holding closed said circuit breaker including two latches either one of which may cause tripping of the circuit breaker, a tripping coil for controlling one of said latches for causing normal tripping, a selecting member arranged to be moved in response to actuation of said coil, an auxiliary electroresponsive means arranged to be energized in accordance with the energization of said main actuating means for also moving said selecting member relative to the second latch so that said second latch is actuated for trip-free operation during the circuit breaker closing operation in response to actuation of said tripping coil.

6. Circuit breaker operating mechanism comprising a main actuating solenoid, trip-free structure operatively connecting said solenoid to the circuit breaker for closing and holding closed said circuit breaker including two latches either one of which may cause tripping of the circuit breaker, a fault responsive tripping coil associated with one of said latches for causing normal tripping of the breaker in the closed circuit position, a selecting member associated with the second latch and movable in response to actuation of said fault responsive coil, an auxiliary electromagnet arranged to be automatically energized in accordance with energization of said main solenoid for also moving said selecting member relative to said second latch, said selecting member and second latch then being so positioned relative to each other that said second latch is actuated in response to actuation of said fault responsive coil for trip-free operation during -the circuit breaker closing operation.

7. Circuit breaker operating mechanism comprising an actuating solenoid, trip-free structure operatively connecting said solenoid to the circuit breaker for closing and holding closed said circuit breaker including a latch related to said structure for causing normal tripping thereof and a second latch related to said structure for also causing tripping, a fault responsive device for actuating said first latch, a selecting member interposed with respect to said device and second latch, said selecting member normally being inoperative with respect to said second latch through a lost-motion connection, and means related to said solenoid for changing said lost-motion connection to a driving connection so that during the solenoid closing stroke actuation of said fault respon ive device also causes actuation of said second 12 :ch.

8. Circuit breaker operating mechanism comprising an actuating solenoid, trip-free structure operatively connecting said solenoid to the circuit breaker for closing and holding closed said circuit breaker including a latch related to said structure for causing normal tripping thereof and a second latch related to said structure for also causing tripping during the closing operation, a fault responsive tripping coil for controlling the first latch, a selecting member opera tively connected to said first latch, said selecting member also having a lost-motion connection with respect to said tripping coil, and means movable with said solenoid for changing said lost-motion connection to a driving connection so that in the event of a fault during the solenoid closing stroke said selecting member constitutes a driving connection to actuate said econd latch thereby causing trip-tree operation of said mechanism.

CARL THUMIM.