US2295309A - High speed circuit breaker reclosing mechanism - Google Patents

Description

C. THUMIM Filed July 18, 1939 .p. .m M w 0 mM n 6 m d P IVE a 13. W N

Sept. 8, 1942.

HIGH SPEED CIRCUIT BREAKER RECLOSING MECHANISM Patented Sept. 8, 1942 HIGH SPEED CIRCUIT BREAKER CLOSING MECHANISM Cari Thumim, Yeadon, Pm, assignor to Genon! Electric Company, a corporation of New York Application July 18, 1939, Serial No. 285,092

8 Claims. (01. 175-294) My invention relates to hi h sp d r clos n mechanisms, more particularly as applied to electric circuit breakers which are connected in high voltage networks of power transmission lines, and has for its principal object the provision of an improved high speed reclosing mechanism that is efficient, positive and very rapid in operation, and that is effective to apply the reclosing force instantly at a predetermined P int in the opening stroke. v

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 strokeof 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 February 26, 1938, for "High speed reclosing mechanism," a reclosing mechanism of this character wherein spring energy is instantly available for reclosing.

In accordance with the present invention, a tripfree linkage operatively interconnects the circuit breaker and a source of stored energy, such as a charged spring for example, that is in turn controlled by a plurality of selectively operated latching devices.

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 charged spring, type embodying the present invention.

The automatic reclosing system shown comprises essentially a source of motive power M, such as a motor, a thrust transmitting linkage T, and circuit breaker operating means such as the rod l. The circuit breaker operating rod l is moved to the closed circuit position shown by means of the motor M and the linkage T (which is latched in thrust-transmitting position), and is held in such position by latching means against the bias of the usual circuit breaker opening springs I".

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 illustrated, the linkage is connected at one end to a fixed pivot 2 and at the other end at 3 to a rocking lever 43 for operating the breaker rod I. The linkage comprises an intermediate fioating lever B that is connected at 'l to a guide link 8 and at 9 to the lever 43 through a connecting link Hi. The floating lever 6 can be rotated counterclockwise by an energy storing device, such as a charged spring, about the pivot l, which is normally held stationary by a latching device L1.

In accordance with the above patent, the latching device L1 comprises a toggle linkage 23-24, the link 23 having aflxed pivot at 23 and the link 24 being connected to the pivot pin 1. The toggle in the restraining position shown is underset and held in such position by a solenoid controlled latch 25 that engages a roller 25' carried by the link 23.

In the present instance the floating lever 6 is operated by means of a pivoted lever 30 that is connected at pin 3| to a spring carriage 32. The spring carriage for the operating spring 33 comrises in addition to the upper spring seat 32', a lower spring seat 34 provided with a roller 35 for co-action with a cam 36. The upper spring seat 32" is rigidly connected to a guide rod 33 that is slidably mounted in the lower spring seat 34. Accordingly, it will be noted that when the upper spring seat 32' is held stationary, rotation of the cam 38 is effective to raise the lower seat 34 thereby to charge the spring. The cam 36 is adapted to be Operated by the motor M through a suitable gear train 31. The lower end of the spring carriage is positioned by a pivoted guide link In the closed circuit position shown the linkage T is latched at; Ll so that the floating lever B can be operated about the normally stationary pivot I. The breaker rod I is held in the closed position independently of the linkage T against the bias of an opening spring I" by a latch L2 arranged to engage a roller I carried by the rod I. The latch L2 is pivotally mounted at 38, as is also the armature 39 of a; high speed tripping magnet 40. The armature 39 is biased at 4| clockwise toward the open magnetic circuit position to facilitate high speed tripping. The latch L2 is also biased by a spring 42 co-acting with the armature 39 toward the latched position shown. For releasing the latch L2 when the coil of the tripping magnet is energized, the armature 39 is provided with a lug 39' disposed in alinement with the latch. The breaker operating rod I is connected to the linkage 'I' by means of a rocking lever 43 that is provided with a cam surface 44 arranged to engage the roller I for depressing the rod I to close the breaker. The lower end of the rod is connected to a guide link 45 as shown.

Another latching device for controlling the spring 33 will now be described. The lever 30, which is connected to the spring carriage at 3| is provided with a latching roller 30' that may be engaged by two separately actuated latches L3 and L4. The latch L3 is adapted to be electrically operated by means of a tripping solenoid 46, and the latch L4 is adapted to be mechanically actuated by means of its extension 41 and the coacting roller I. The latches L3 and L4 can be co-pivotally mounted at 48 and are both spring biased as shown toward the latching position with respect to the roller 30. It will therefore be apparent that the spring 33 cannot be released to discharge its energy unless both latches L3 and L4 are actuated.

The cycle of operation is as follows. Let it be assumed that the spring 33 is charged as shown and the breaker is open, that is, with the lower end of the rod I in the dotted line position indicated. The closing operation by spring energy now can be initiated by closing the switch C thereby to energize from the source of control voltage E the tripping solenoid 48 of the latch L3. This tripping circuit also includes auxiliary switch Contacts $1 of the cam switch S so that tripping can be accomplished only if the spring 33 is charged with the cam 36 in the position illustrated.

Since the breaker in moving to the open position necessarily releases the latch L4 by reason of engagement of latch extension 41 by the roller I, the latch L4 is already tripped and operation of the latch L3 causes release of the lever 30 and therefore the spring 33. The spring energy causes in turn counterclockwise rotation of the lever 30, floating lever B, the roller I2 being in abutting relation to'the lever 30, and clockwise rotation of lever 43 to close the breaker through the cam surface 44 and roller I. During this operation a spring 49 interconnecting the armature 39 and the lever 43 as shown is stressed for resetting said armature with respect to the magnet 40. As previously indicated the latch L2 under bias of its spring 42 snaps over the roller I to hold the breaker in the closed position independently of the operating mechanism.

At the end of the breaker closing stroke an auxiliary motor switch m1 is closed by the lever 30 thereby energizing the motor 50 that the cam 36 is rotated clockwise, first causing the roller 35 to drop to the low point of the cam to reset the linkage T as well as latches In and L4 and then recharging the spring 33. As the roller 35 drops to the low point of the cam the linkage T is stretched so as to reset all latches prior to the spring charging operation. As the cam continues to rotate clockwise from its low point the spring seat 32 is held stationary by the latches and the spring seat 34 moves upward to compress and recharge the spring.

As the mechanism resets in response to initial rotation of the cam the switch mi opens and a second auxiliary switch S2 closes after predetermined rotation of the cam. To this end an auxiliary cam 36 controls the pivoted switch arm of switch S so that switch .92 closes when the low point of the cam is reached. The motor M therefore remains energized and continues to recharge the spring until the high point of the cam is again reached. At this point the switch s2 cuts out the motor as shown, and switch 81 which is in the circuit of tripping solenoid 43 is closed.

In trip-free operation it will be noted that all latches are tripped. That is, in closing the breaker, the auxiliary switch b is momentarily closed by a cam 50 carried by the rod I to energize the transfer relay TR and thereby connect the coil 52 of the tripping latch L1 in the circuit. The tripping circuit so established is through the auxiliary switch a, which, as in the previous case is closed by cam 5! on the breaker rod when the breaker is closed and is open when the breaker is open, contacts In of the fault relay FR, contacts in of transfer relay TR and the tripping solenoid 52 of the latch Ll. It will be noted that when the fault relay FR is energized the latch L3 also is always operated by reason of contacts in which shunt the switch C. Also the circuit for maintaining trip-free protection during reclosing is held for a brief time at the contacts tn by a dashpot in to insure that the breaker is fully closed before tripping control is again transferred to latch L2.

In the automatic reclosing cycle, the fault relay FR actuates both the latches L3 and L2, the latter latch being operated through the high speed tripping magnet at 40. Energization of the tripping coil of magnet 40 is effective to release the spring 4| which rotates the armature 39 clockwise and release the latch L2 as previously described. The latch L4 can obviously be adjustable with respect to the roller I so that after predetermined opening movement of the breaker rod I the latch will be released to allow the spring 33 immediately to reclose the breaker in the manner above described.

Where the opening operation under manual control is desired an opening switch 0 is protem comprising a source of motive power, tripfree structure operatively interconnecting said source of power and circuit breaker for closing said circuit breaker, latching means for holding said circuit breaker in closed circuit position independently of said trip-free structure, fault responsive means for releasing said latching means, and means controlling said source of motive power for initiating reclosure of said circuit breaker in accordance with predetermined opening movement thereof.

2. An automatic circuit breaker reclosing system comprising a source of motive power, a trip-free linkage operatively interconnecting said source of power andvcircuit breaker for closing said circuit breaker, a latch directly controlling said trip-free linkage, and a second latch directly related to said circuit breaker for holding said circuit breaker in closed circuit position independently of said trip-free linkage.

3. An automatic circuit breaker reclosing system comprising a source of motive power, a tripfree linkage operatively interconnecting said source of power and circuit breaker for closing said circuit breaker, said linkage including a member disengageably related to said circuit breaker for closing said circuit breaker, a latch for holding said circuit breaker in closed circuit position independently of said trip-free linkage, and means responsive to tripping of said latch and opening of said circuit breaker for causing reclosure of said circuit breaker bysaid motive means. w

4. An automatic circuit breaker reclosing system comprising a closing spring, trip-free structure operatively interconnecting said spring and circuit breaker, and latching means for controlling the release of spring energy including means responsive to initial circuit opening movement of said breaker and means responsive to a fault condition in said circuit.

5. An automatic circuit breaker reclosing system comprising a closing spring, trip-free structure operatively interconnecting said spring and circuit breaker, a latch for holding said circuit breaker in closed circuit position-independently of said trip-free structure, a second latch for holding said spring in charged condition, said second latch being actuated in accordance with predetermined opening movement of said circuit breaker, and .a third latch also holding said spring "in charged condition, said third latch being responsive to a fault condition in said circuit whereby release of said first and third latches in response to a fault condition causes release of the spring energy to reclose said cirmotive power including a motor and a spring arranged to be charged by said motor, a tripfree linkage operatively interconnecting said spring and circuit breaker, latching means for holding said circuit breaker closed independently of said linkage, other latching means for holding said spring in charged condition, means responsive to manual control for releasing said firstnamed latching means to open said circuit breaker, fault responsive means for releasing said first-named latching means and also said other latching means for causing said spring to reclose said circuit breaker after predetermined opening movement of said circuit breaker, and means responsive to said reclosing operation for causing energization of said motor to reset said linkage and recharge said spring.

7. An automatic circuit breaker reclosing system comprising a circuit breaker, a source of motive power including a motor and a spring arranged to be charged by said motor, a trip-free linkage operatively interconnecting said spring and circuit breaker, latching means for holding said circuit breaker closed, other latching means including two selectively operable latches for holding said spring in charged condition, tripping of both said latches being essential to releasesaid spring, fault responsive means operable to cause tripping of said first-named latching means and also one of said spring latches, and means related to said circuit breaker for causing tripping of said second spring latch after predetermined opening movement of said circuit breaker for releasing said'spring thereby to reclose said circuit breaker.

8. An automatic circuit breaker reclosing system comprising a circuit breaker, a source of motive power including a motor and a spring arranged to be charged by said motor, a tripfree linkage operatively interconnecting said spring and circuit breaker, latching means for holding said circuit breaker closed, a latch for holding said spring in charged condition, fault responsive means operable to cause tripping of said first-named latching means to open said circuit breaker, and means mechanically related to said circuit breaker for directly causing tripping of said spring latch in accordance with predetermined opening movement or said circuit breaker.

. CARL

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