US2034146A - Circuit breaker operating and control means - Google Patents

Description

March 17, 1936. J. LINDE CIRCUIT BREAKER OPERATING AND CONTROL MEANS Original Filed Oct. 19, 1955 2 Sheets-Sheet l h'wvehtor- Leonard J. Lihde,

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March 1 7, 1936.

Original Filed Oct. 19, 1933 L. J. LINDE CIRCUIT BREAKER OPERATING AND CONTROL MEANS 2 Sheets-Sheet 2 2 Q I W Z lhvehnof- Leonard J. Linde Attorheg u Patented Mar. 17, 1936 2 UNITED STATES CIRCUIT BREAKER, OPERATING AND CONTROL MEANS Leonard J. Linde, Folcroft, Pa., assignor to General Electric Company, a. corporation of New York Original application October 19, 1933, Serial No.

Divided and this application September 22, 1934, Serial No. 745,078

6 Claims.

My invention relates to circuit breaker operating and control means; more particularly to motor actuated electric circuit breakers, and has for its principal object the provision of improved operating and control-means for circuit breakers of the aforesaid type which shall be eificient and reliable in operation, simple and compact in design while permitting ready assembly or disassembly of the component parts, and rugged in construction.

This application is a division of my copending application, Serial No.. 694,282, filed October 19, 1933, for Operating mechanism.

My invention will be more fully set forth in the following description referring to the accompanying drawings, 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 drawings, Fig. l is a perspective View, partly in section, illustrating in detail an electric air circuit breaker and its asso ciated operating mechanism embodying the present invention; Fig. 2 is a view, partly in section, of brake structure illustrated in Fig. 1 in the braking position thereof; Fig. 3 is a similar view of the brake structure in non-braking position; Fig. 4 is an elevational view of apparatus illustrated in Fig. 1 in the closed circuit position; Fig. 5 is a similar view illustrating the apparatus in open circuit position before the resetting operation is completed; Fig. 6 is a similar. view of the apparatus illustrating the same in the completely reset position; Fig. 7 is an elevational front view of the assembled circuit breaker and operating mechanism unit, Fig. 8 is an elevational side view of the unit shown in Fig. 7, and Fig. 9 is a detailed view of ,a modified form of the resetting means.

Referring more particularly to Fig. 1, there is illustrated operating mechanism i for effecting predetermined travel .of the movable element of an electric circuit breaker 2. The operating mechanism 1 generally comprises suitable motive means as an electric motor 3 and collapsible thrust transmitting means 4 which is op'eratively connected to the motor in a manner hereinafter described. The thrust transmitting structure 4 is likewise operatively connected to the movable element 5 of the circuit breaker.

The circuit breaker as shown is of the polyphase type, the circuit controlling contacts of each phase including (Figs. 1 and 5) movable arcing and main contacts 6 and 7, respectively, which are carried by the movable element 5, and

coacting stationary contacts 8 and 9. The detailed construction of the circuit breaker which forms no part of the present invention will be described later.

The power circuit through the circuit breaker 2 includes in general a terminal member ill, a flexible braided conductor ll composed of suitable conducting material as copper interconnecting terminal ll] and the movable contacts, the pairs of movable and stationary contacts 6-8 and 3-9, a magnetic blowout coil l2 and terminal 03. There are likewise included a pair of transfer or burning contacts 7' and 9' arranged in shunt with the main and arcing contacts.

Upon opening of the circuit breaker due to pivotal counterclockwise movement of the movable element 5 about a fixed shaft it, separation of the main contacts l and 9 occurs prior to separation of the transfer and arcing contacts for confining a ng and burning upon opening of the circuit to the latter contacts. The arc extinguishing means may comprise any suitable arrangement, as an arcing horn it connected to the stationary arcing contact 8 and a magnetic blowout coil l2 which is connected in series in the power circuit between the stationary arcing contact 8 and terminal it.

The operative connection between the motor 3 and the thrust transmitting structure 5 comprises a rotatable shaft l'l directly connected to the motor 3, and a rotatable shaft 98 on which is mounted an actuating cam iQ coacting with the thrust transmitting structure 5. The motor shaft l7! and the cam shaft it are interconnected by automatic brake structure 20 and suitable speed reducing gearing 2i. Energization of the motor 3 eiiects rotation of the actuating cam 39 and a circuit closing operation on the circuit breaker 2 through thethrust transmitting structure 4 in a manner hereinafter described.

In mechanism or" this character it is highly desirable that overrunning or over-travel of the actuating cam be prevented except within comparatively narrow limits so that the operating mechanism may be readily tripped, reset and reclosed, if necessary, without interference by the actuating cam. Heretofore upon deenergization of the motor the inertia of the moving parts made it very diihcult to control the final position of the actuating cam. The problem of mechanical braking is complicated by the fact that energizetion of the motor must be continued to a certain point to insure positive closing of the circuit breaker and the braking operation must commence immediately upon deenergization in order that the actuating cam shall be stopped shortly beyond the point where the circuit closing operation is completed.

For the purpose of braking the actuating cam immediately upon deenergization of the motor after the completion of the circuit closing operation, the brake structure 2|] is designed so that a brake member is moved to a non-braking position in response to predetermined motor torque ahd is moved to a braking position in response to decrease of transmitted motor torque below said value. To this end the motor shaft ll is connected to a brake member 22 by a resilient connection comprising a torsion spring 23 which is connected at one end as at 2G to the brake member 22 and at its other end as at 25. to the motor shaft H. The shaft ll likewise is provided with a limited lost motion connection with a hublike extension 22' of the brake member comprising a pin and slot connection 26-27. V

The brake member which comprises a disk or the like having an annular flange as illustrated for receiving the torsion spring 23 is provided with a centrally disposed recess 28 within which the lower end of. the motor shaft H is freely positioned. Accordingly, it will be noted that the brake member 22 may both rotate and move axially with respect to the motor shaft ll within certain prescribed limits.

The pin and slot connection 26-27 interconnecting the shaft H and brake member 22 is arranged so that the pin* 26, which is secured to the driving shaft l1, rides in a diagonal slot 27 in the hub member 22' so as to cam the brake member 22 in a direction axially of the shaft i1 depending on the direction of rotation of said shaft. For the purpose of maintaining the brake member 22 in positive driving relation at all times to the driven shaft 29 which is directly connected to the actuating cam l9 through the reducing gearing 2!, the shaft 29 is provided with a squared extension 29 slidably mounted within a corresponding aperture in the lower end of the hub member 22'. Accordingly, the brake member 22 is always positively connected to the-actuating cam notwithstanding axial movement of the brake member.

The actual braking surface of the brake member 22 may comprise any suitable brake lining material secured as at 30 to the lower side of the brake disk. A fixed brake member 3| comprising part of the brake housing surrounds the hub,

member 22' and is provided with a brake surface 32 adapted to coact with the brake lining 30.

- The operation of the above-described brake structure is as follows. When the motor 3 is deenergized or at rest as illustrated in Fig. 2 the spring 23, which is normally under torsion, tends to rotate the brake member 22 with respect to the motor shaft H in the direction indicated so that the brake member 22 is cammed down-.

wardly, through the pin and slot connection 262|, to engage the coacting fixed brake member 3|. The spring 23 is designed so that it moves the brake member 22 to braking position when the torque transmitted by motor 3 decreases below a certain value. Due to the fact that brake member 22 is positively connected to the shaft 29, it will be apparent that movement of the brake member 22 to its braking position efiects direct \braking of actuating cam 19.

Immediately upon energization of the motor tending to rotate shaft I! in the direction indi-' cated referring more particularly to Fig. 3, the torsion of spring 23 is opposed by the motor torque. When the motor torque overcomes the torsion of spring 23, the spring yields permitting rotation of shaft H with respect to brake member 22. After limited movement of the shaft H with respect to the brake member 22 the pin 26 engages the opposite end of the slot so as to constitute a direct and positive driving connection beween shaft ll, brake member 22 and shaft 29, movement of the pin to this position in the meantime causing camming of the brake member 22 upwardly to a non-braking position as clearly illustrated in Fig. 3.

While the motor transmits normal torque through shaft H the spring 23 is maintained flexed and under tension and the brake member is maintained in non-braking position. When, however, the motor is deenergized and the transmitted torque decreases to a certain value the opposing torque of the charged spring 23 causes camming of the brake member 22 downwardly to the braking position illustrated in Fig. 2. Ac-

cordingly, there is provided a direct positive drive between the motor and actuating cam when the motor is transmitting the required torque, and

I likewise an automatic and quick acting brake effective in response to decrease of the motor torque upon completion of the circuit closing opprovided with afixed pivot 38 and an extension.

39 having at its outer end a roller 40 coacting with latching and tripping means hereinafter described. The toggle member 36 comprises a triangularly shaped l'ink pivotally supported at an intermediate point, as indicated at 31, by the member 35 and having rollers 4| and 42 mounted at opposite sides of said pivotal support. The roller 4| is arranged to be in the path of the actuating cam I9 when the circuit breaker is to be closed and the roller 42 is arranged to engage an inclined actuating face 43 of a pivoted supporting member 44 of the movable circuit breaker element 5. The member 44 which is pivotally mounted on shaft I4 is resiliently biased as by a compression spring 45 towards open circuit position.

The mechanism as illustrated by Fig. 4 is in the closed circuit position wherein the toggle 3536 is overset so as to hold the.element 5 in closed circuit position, the toggle being latched ,in this position by a pivoted latch member 46 engaging the roller 40. The latch 46 is provided with an extension 46 so as properly to position the latch with respect to the roller 40.

The toggle when latched as shown by Fig. 4

dead-center position with respect to the toggle 75 thrust.

comprises an arrangement whereby a comparatively small tripping force is effected to release a charged spring or the like for causing positive and quick release of the main latch 46. In other words, the available tripping force, which may be comparatively small as in the case of alternating current trip coils, effects release of an intermediate energy-storing device as a spring charged trigger which in turn releases the main toggle controlling latch.

To this end the trip coil 56 coacts with a pivoted catch or latch 5| which is spring biased as at 52 so as normally to be engaged by a roller 53 carried by the trigger member 54. The trigger member 54, which is co-pivotally mounted at 55 with the latch 46, is resiliently biased as indicated at 56 in clockwise direction. The application of the spring tension at 56 is shown as slightly oiT-center with respect to the pivot 55 so that the spring force is available immediately to rotate the trigger member 54 clockwise upon releasing movement of catch 5|. A pin carried by the trigger 54 is arranged so that upon clockwise movement of the trigger the pin sharply strikes an extension of the latch 46 so as to rotate the same clockwise position.

It will, therefore, be apparent that a much greater releasing force than that delivered by the trip coil 56 is available for releasing the latch 45 since the force required to maintain the spring 55 charged-near its dead-center position with respect to pivot 55 is obviously comparatively small.

The resetting means for the latch and trigger arrangement above described is best illustrated by Figs. 5 and 6. The arrangement is such that immediately upon collapse of the main toggle 35-3B and circuit opening movement of the element 5, the trigger 54 is reset and the latch 46 positioned so that it is in readiness immediately to latch the main toggle when the roller thereof returns to its initial position. The trigger resetting means may comprise any suitable arrangement as a member 58 carried by the element 5 and provided with an extension 58' arranged to engage the trigger 54 and rotate the same counterclockwise as illustrated in Fig. 5. Return of the trigger 54 to its initial position causes it to be latched by the catch 5| which is resiliently biased so that it snaps over the roller 53 as the same is rotated counter-clockwise. The resetting operation by the circuit breaker element 5 likewise recharges the spring at 56 by compressing the same against a fixed stop (not shown).

The positioning of the latch 46 for relatchng the roller 46 of the main toggle is accomplished by means of a resilient connection, as a leaf spring 59, arranged between the trigger and latch 46. As illustrated, the spring 59 is secured at one end to the trigger 54 and is flexed so as to engage at its other end the latch 46 and urge the same in counter-clockwise direction. The stop pin 66 limits the counter-clockwise rotation of latch 46.

In order further to increase the sensitivity of to the toggle releasing the tripping means, the toggle member 35 in riding under the latch 46 to its latched position may flex the spring 59 suiliciently so that the trigger spring at 56 is on dead center with respect to pivot 55. In this arrangement the tension of spring 56 is sufllcient, upon releasing movement of catch 5|, to move the trigger 54 clockwise oif center so that the trigger is immediately snapped over to actuate the latch 46.

Immediately after collapse of toggle 3536 and opening movement of the element 5, the toggle member 35 is urged counterclockwise from the extension 39 engages a stop 39'. When the toggle member 35 is returned to this position the latch 46 snaps over the roller 40 as illustrated by Fig. 6.

In this position the toggle member 36 may be rotated counter-clockwise about the restrained pivot 31 by the actuating cam 6 so that the roller 42 in riding along the inclined face 43 causes circuit closing movement of the element 5. The cam l9, which rotates clockwise to engage the roller 4 I, is designed to meet the operating characteristics of the circuit breaker so that the same may always be positively closed without diflflculty. The brake mechanism above described is effective to stop rotation of cam l9 within a few degrees of rotation after circuit closing movement of the main toggle as illustrated in Fig. 4. The cam in this position is, therefore, free of the thrust transmitting structure and is likewise in a predetermined position for effecting a circuit closing operation by a single revolution thereof.

paratively small movement of the trigger 54 due to the lengthening of the lever arm with respect to the pivot of member 62. Accordingly, the trigger 54 may be reset during the main part of the opening travel of the element 5, the trigger being unaffected by slight variations in the final position of said element.

In summarizing the operation of the mechanism, it may be briefly stated that the thrust transmitting toggle 35-36 is held in a thrust transmitting position, both in the closed circuit position illustrated by Fig. 4 and also during rotation of the toggle member 36 by the actuating cam l9, by the latch 46 which is in turn controlled by the spring charged trigger 54. The trigger is nicely balanced so that a comparatively small trip force is effective to actuate the same. The tripping impulse at the trip coil 50 actuates the catch 59 causing release of trigger 54 and consequent actuation of latch 46 with the result that the toggle 35-36 is no longer restrained in thrust transmitting position and collapses under the system means above described resets the spring charged trigger 54 which in turnthrough spring 59 positions the latch 46 for resetting so that the lower edge thereof is in the path of the toggle roller 40.

After collapse of the toggle 3536 and opening of the circuit breaker, the toggle spring 6| throws the toggle from the position shown in Fig. 5 to that shown in Fig. 6 wherein the roller 40 engages the restraining face of latch 46. The mechanism is now inreadiness for a closing operation which is accomplished by a single clockwise revolution of the actuating cam l9, returning the mechanism to the position illustrated in Fig. 4.

It will be noted that the mechanism is trip-free at all stages of its operation. That is, the occurrence of a tripping impulse during the camming operation causes actuation of the latch 36 in the usual manner and collapse of the toggle 35-36, the element 5 thereupon returning to open circuit position notwithstanding continued rotation of the cam is. When the cam comes to rest the toggle spring 61! causes relatching of the toggle in the manner above described.

Where manual operation of the circuit breaker, either alone or in combination with the motor, is desired, an actuating cam 65 (Fig. 1) similar in design to cam is is mounted on a shaft 66 so as likewise to coact with the toggle roller M. In the present instance the shaft 66, which is provided with an operating handle 5? at the outer end thereof, extends longitudinally through the hollow motor operated cam shaft it so that the handle 67 may be applied to the opposite end The operation of of the shaft where necessary. shafts I8 and 66 are entirely independent of each other.

The shaft 68 is provided with a tripping and positioning member 58 arranged to engage, as by extension 68', a guided member 69 coacting with the extension lt of the main toggle latch. When tripping of the breaker by the manual means is desired the handle 67 is rotated counterclockwise (as viewed in Fig. 1) a short distance so that the member 69 is raised and the latch Alt actuated to release the toggle 35-35. A positioning spring Hi coacting with notches in the member 68 serves to maintain the shaft 66 in definite positions.

In Fig. 1 there is likewise illustrated a control for insuring proper operation of the motor. The motor as shown is energized from a suitable source of power, indicated at It, the motor control circuit including a push button control switch 72, circuit breaker limit switch 13, and manual control switch Hi. When the manual operating means is in inoperative position and the element 5 of the circuit breaker is in open circuit position the manual switch M and the limit switch 13 are both closed. An interconnecting linkage 75 serves to operate the limit switch 73 in accordance with opening and closing movements of element 5.

The control circuit which includes a solenoid l6 may be completed by closing of the push button switch 12. Energization of solenoid i6 is in turn effective to close contacts l1 thereby completing the switch 14. Shortly after closing of contacts ill and energization of the motor, the push button 12 may be released since the plunger of solenoid 16 is mechanically sealed in contacting position by a cam element 78 mounted on shaft l8. The cam 78 seals in the contacts Tl only during normaltravel of cam i9, the motor meanwhile being energized from the source it directly through contacts Ti and switch 1 5. Upon comto the sealing-in cam 18.

motor circuit through the manual pletion of the circuit closing operation the cam- 18 permits the contacts TI to be biased open thereby deenergizing the motor and stopping the actuating cam l9.

When the switch element 5 is closed the limit switch 13 is open preventing energization of solenoid 16 from source 11 through push button 12. In the case of trip-free operation the actuating cam I9 is rotated to its normal final position due When the manually operated cam 65 is rotated to 'operative position, the switch Hi is opened with the result that energization of the motor 3 from the source H is impossible.

The present invention is not limited to the specific type of circuit breaker shown, it being understood that the movable element 5 is equivalent to the movable element generally of a circuit breaker of either the air'or oil type. ,The more detailed construction of the air circuit breaker illustrated is as follows:

As previously described the movable contacts of the circuit breaker are carried by the element 5 which includes the pivoted arm id on which is mounted an insulating cross-bar 8B. Secured to the cross-bar are a plurality of contact supporting members 8|, each member being channelshaped as illustrated and forming a bearing at 232 for the pivot pin of an arcing contact support 83. Each contact support 83 is resiliently biased, as by springs 85, clockwise so as normally to urge the corresponding arcing contact point into engagement with its coacting contact. This movement is limited by a pin 85 adapted .to engage a leg 85 forming a part of the member M. The main current-carrying contacts I are mounted within the supports 8! for limited reciprocal movement, as by pin and slot connection 86-86. The contacts 1 are biased by a spring 8'! so as to provide resilient engagement of the contacts I and 9.

The transfer contacts I are connected to the corresponding contacts I by a flux conducting strip 88. Upon opening of the circuit; current through the main contacts I and 9 is first transferred to the contacts l and 9 in order to avoid burning at the main contacts. Heavy currents cannot be shunted directly to the arcing coils without some burning at the main contacts by reason of the inductance of the blowout coil.

The above described circuit breaker and operating mechanism are compactly assembled and designed so that each main component part may be assembled or disassembled as a unit with respect to the associated parts. In the present instance the motor 3 and brake structure 22 is' assembled as a unit with respect to the shaft- 29 by simply positioning the motor and brake unit above the shaft and sliding the hub 22' on the squared extension 29 of the shaft. The reducing gearing 2| and a portion of the shaft I8 are likewise removable as a unit by reason of a detachable interlocked connection dividing the shaft l8 into separate sections as indicated at 90. Upon disassembly, the reducing gearing and associated portion of shaft l8 are slidable longitudinally on the manuallyoperated shaft 66 after removal of the motor and brake unit.

In view of the fact that the thrust transmitting structure 3 has no permanent connection with the movable element 5, it will be apparent that this portion of the structure including the the mechanism.

The same likewise applies to th latch and trigger mechanism. A mechanism so designed is not only quickly and efiiciently assembled but may be produced at comparatively low'cost. That individually constructed so that considerable time is saved as compared with the usual method of having a number of workmen assemble the entire apparatus in a single frame. I

The complete circuit breaker and mechanism unit are illustrated by Figs. 7 and 8 wherein. a

- panel 9| has mounted thereon the phase units of related to said circuit the circuit breaker 2 and the operating mechanism therefor including the motor and brake unit indicated at 92, the reduction gearing unit indicated at 93 and the thrust transmitting and tripping and latching units indicated at 94 and 95,

respectively. An auxiliary switch unit including the limit switch is indicated at 96. Starting with the motor and brake unit, the mechanism may be readily disassembled by units by merely loosening and removing the clamping bolts provided for securing together the casings of said units where indicated.

It should 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 spiritv of my invention. t

What I claim as new and desireto secure by Letters Patent in the United States is: i

1. Operating and control means for an electric circuit breaker comprising a motor, a rotatable shaft operatively connected to said motor having means for actuating said circuit breaker, a relay for controlling said motor, means initially actuating said relay, and means related to said shaft for mechanically sealing said relay in motor energizing position during circuit closing operation.

2. Operating and control means for an electric circuit breaker comprising. a motor, a'rotatable shaft operatively connected to said motor having means for actuating said circuit breaker, a motor starting relay, a limit switch operatively breaker and connected in series with the energizing winding of said relay, means initially actuating said relay when said circuit breaker is in open position whereby said motor is energized, and means for mechanically is, the component units may be sealing said relay in energizing position during 1 the circuit closing operation.

3. Operating and control means for an electric motor operated circuit breaker comprising a motor, a rotatable shaft operatively connected to said motor coacting with structure for directly actuating said circuit breaker, a relay controlling energization of said motor, means for manually actuating said circuit breaker independently of said motor, and a control switch operatively connected to said manual means for deenergizing said motor when said manual means is in other than inoperative position.

4. Operating mechanism for an electric circuit breaker unit comprising a motor, a rotatable operating shaft driven by said motor, a circuit breaker actuating cam mounted on said shaft, a manually operated shaft mounted in part within andconcentrically of said motor operated shaft, said manually operated shaft extending beyond the opposite ends of said motor operating shaft so as to be operable at each end and a second cam mounted on said manually operated shaftadjacent said motor operated cam for actuating the circuit, breaker in a similar manner.

5. Operating mechanism for an electric circuit breaker, comprising a motor, a rotatable shaft having a circuit breaker actuating cam mounted thereon, said shaft operatively connected to said motor, a manually'operated shaft having acircuit breaker actuating cam, motor circuit controlling contacts carried by said manually operated shaft, a limit switch operatively connected to the movable element of the circuit breaker, a motor starting relay having an energizing coil connected in series with said limit switch and L 'means carried by said motor operated shaft for

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