DE1938929A1 - Circuit breaker - Google Patents

Description

Patent attorney

Dl-Ibjj. Wilhelm! Corpse!

FianMuii / Main-l

5979

FEDERAL PACIFIC ELECTRIC COMPANY, Newark, New Jersey, V.St.A.

Circuit breaker

The invention relates to circuit breakers, and more particularly to circuit breakers which are molded or cast Casings.

It is an object of the invention to provide an improved circuit breaker that can operate under fault conditions has a reduced opening time. The improved circuit breaker is also said to open in two ways, depending on automatically selected by the current state to be interrupted. The improved circuit breaker should continue in one mode of operation, compared to its second, normal mode of operation, have an increased contact separation. It is also intended to be a circuit breaker / device too create, which has a reduced inertial mass for the purpose of faster opening and still for their normal closing process has sufficient mass to close quickly in the event of malfunctions and during normal operation. The improved circuit breaker should also respond very quickly to high fault currents. Next, the circuit breaker should be in a predetermined spatial dimension an increased interruption performance compared to conventional circuit breakers available so far. After all, supposed to be a circuit breaker be created, which enables an improved, quickly effective high-voltage tripping.

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To solve the above problem, the invention is based on one Circuit breaker with an elongated contact arm that carries a movable contact piece at one end, which comes into contact with a mating contact piece when the circuit breaker is closed, wherein the other end of the contact arm has a pivot bearing device, further with a Knee joint which is connected by a bearing pin to the elongated contact arm between its ends and the Contact arm moved between positions in which the circuit is closed or open and with a device, which the contact arm for an opening movement around the bearing pin around the knee joint.

The invention is characterized in that an instantaneous release device the pivotably supported opposite end of the contactor in response to sudden highs Overcurrent triggers and that an additional overcurrent release device causes the knee joint to buckle and an opening of the contacts under other overcurrent conditions caused.

The invention will now be described in detail with reference to the accompanying drawings, all of which are taken from the description and the details or features emerging from the figures can contribute to the solution of the task within the meaning of the invention and were included in the application with the intention of being patented. Show it:

Pig. 1 is a side view of a multi-pole circuit breaker with certain features of the invention, namely partly in section along the line 1-1 in Pig. 2;

Pig. Figure 2 is a top plan view of the Pig's circuit breaker. 1, with some parts broken off and other ropes omitted;

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Pig * 3 is a side view of another embodiment animal Invention as a multi-pole circuit breaker illustrated showing certain other features of the invention illustrated. This view is what it is

looks around a partial section along line 3-3 '"in Pig. 4 |

Pig. 4 is a top plan view of the circuit breaker of FIG. 3, in FIG which some parts have broken off and other parts left out and '

Pig. 5 is a partial side view of a further exemplary embodiment.

It is now on Pig. 1 referred to. The circuit breaker device is enclosed in a housing made of molded insulating material which contains a cover 10 and a base 12. The circuit runs through an illustrative pole of the circuit breaker (when it is closed) from a terminal 14 via a return path conductor 15 to the stationary contact piece 16, then to the movable contact piece 18, over the contact arm 20, along the conductive, flexible stranded wire 22, via the bimetal 24 to the conductive rail 26 and finally to the opposite terminal 28, the contact arm 20, which carries the contact piece 18, is supported by a bearing pin 30 in the contact arm support 32 and biased by compression springs 34 in one direction that it generates a contact pressure when the contacts are closed. When the contact pieces are opened, the deflection of the contact arm 20, which is generated by the spring 34, is limited by the abutment of a part of the contact arm against the lower edge of the U-shaped contact arm carrier 32. The contact arm support 32 is attached to an insulated shaft or connecting rod 36, the ends of which are designed as bearing journals 38 which are supported by oppositely arranged locking devices 40. The locking devices 40 are mounted on guide parts 42 which are attached to the cast base

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part 12 fixed at both ends of the connecting rod 36 are. The bearing journals 38 move in slots 44 and are guided through them. The slots 44 are in the guide parts 42 designed for purposes that will be explained in detail later. Several contact arm supports 32 with corresponding cont clock arms 20 are coordinated on the aforementioned wave for one Cooperation of the contact pieces fixed in a multipole circuit breaker.

A spring device that can be adjusted beyond the dead center, which is indicated generally at 46, is for actuating the contact pieces between the closed and the first of

W two alternative open positions are provided, and in some exemplary embodiments also to bring about automatic tripping and opening of the contact pieces as a function of overloads. The actuating device contains a manually actuatable lever 48 and handle 50. The lever 48 is pivotably mounted at its lower end in a fixed frame 52 which is fastened to the interrupter lower part 12. The frame comprises two spaced apart metal pieces or plates which extend from a point adjacent the center point of the breaker housing towards one end of the housing. An overload release part or "fork" 54 has a bearing pin 56 which is fixed in the frame 52. A knee joint 57 contains two knee joint joints

'of 58 and 60 that are attached to a knee or joint 62 are pivotally connected to each other. These knee joints have an upper bearing pin 64 and a lower bearing pin 66 in parts 54 and 32 at the center pole of the circuit breaker of FIGS. 1 and 2, for example. Two Pairs of springs 68 extend between the hand lever and the hinge point 62 of the knee joint, albeit only one Pair can be seen in Fig. 1. The position of the contact arm, in that the circuit is open is determined by the contact between the carrier 32 and the bearing pin 56. In the embodiment the invention according to Figures 1 and 2 is only

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a single actuating device 46 is available for all contact arm carriers, which are actuated by the connecting rod 36, while in the embodiment of FIGS. and 4 multiple actuators can be used.

The breaker operating device 46 and a co-operating secondary locking device 70 are both arranged in the center pole position of the embodiment of Figures 1 and 2. The end of the fork 54 * that is remote from its trunnion 56 is normally locked by the secondary locking device .70, the. _; is pivotally mounted on the side frame 52, restrained from movement in the direction in which the knee joint collapses. Details of this secondary locking device and actuator can be found in U.S. Patent No. 3,209,098, entitled "Circuit Breakers Having Improved Tripping Mechanisms," owned by the applicant. In order to understand the present invention, it is unnecessary to go into further details and are therefore omitted from the following explanation.

It is now on Pig. 2 referred to. A switching rod 72 of insulating material extends across all pole positions and is pivotably mounted in frame 52. A spring is between the shift rod 72 and the locking device 70 clamped and pulls them into engagement with each other. The secondary locking device 70 engages a main locking device 75, which is carried by the shift rod.

All circuit breaker poles shown are in the exemplary embodiment according to Figures 1 and 2 with two overcurrent sensing devices Mistake. Since the poles are identical, only one pole will be described in detail. The two provided Overcurrent sensing devices speak to different ones Overcurrent values at »Vo a protection against permanent overload

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, 1 V

If it is desired, the overcurrent sensing device usually includes a reversed timing characteristic in order that as the overcurrent increases, the response time decreases. This mode of operation is achieved by using the known properties of the bimetal member 24 through which the current flows. when the breaker is closed. The bimetal 24 bends due to the overcurrent flowing through it and comes into engagement with an adjusting screw 76 which is carried by the switching rod 72. A further or continued deflection of Bimetalls.bewegt die.Sehaltstange 72 counterclockwise to the side locking device 70 to separate from the main locking device 75 and to open the Stromun- terbrecher W, as will be explained below.

In order to achieve "instantaneous" or "instantaneous" switching of the circuit breaker in the event of harmful overloads, an arrangement is provided which is electromagnetically responsive to the flow of current through the bimetal 24. Reference is now made to FIGS. 1 and 2. A channel-shaped or U-shaped pole piece or yoke 78 is secured around and close to the bimetal 24 at the point where the bimetal is secured to the conductive rail 26. An armature 80 that cooperates with and is magnetically attracted to the yoke is. attached to a switching rod 82 of insulating material which extends across all poles. For the sake of clarity and convenience, the first-mentioned shift rod 72 will hereinafter be referred to as the time delay shift rod, while the shift rod 82 will hereinafter be referred to as an instantaneous shift rod. The momentary shift rod 82 is carried at each end by locking devices 40, which in turn are pivotably mounted on the guide members 42. The locking device 40 contains a lever arm part 84 which has a front side 84 a which comes into engagement with the contact arm guide pin 38 and releasably supports this in cooperation with the guide slots 44. A to-r- ,

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Sion spring 86 acts between the locking part 84 and the guide part in order to generate a return force for the locking device 40.

It will, now on Pig. 1 referred to. The return path conductor 15 includes a conductive member 88 that is bent back against itself. A spacer made of insulating material 90 is sandwiched between the legs of member 88 which are secured to one another by suitable means (not shown). An insulating layer 92 is attached to the part of the conductor 15, which is located outside of the arc shield 94 to a Ensure arc interruption within the arc shield (or spark chamber).

The contact opening bias is provided in part by a hairpin spring 96 generated, which acts between the lower part 12 and the contact arm 20 · The spring 96 supports the movement of the contact arm in both alternative positions in which the circuit is open, as detailed below is explained.

The circuit breaker is shown in Figures 1 and 2 in its "normal" open position shown with the fork 54 locked so that the actuator is in a State in which it closes the contact pieces when it is actuated. The guide pins 38 are in one position supported, in which the interrupter through the locking device 40 performs the normal closing operation. the Closure of the breaker is achieved in that the hand lever 48 is moved to the right as shown in the drawing. The upper ends of the tension springs 68 are according to. shifted right, and when the spring tension is above the knee or the hinge point 62 is displaced so that it is along the line to the right of the upper bearing pin 64 in the fork 54 is effective, the knee or joint is biased to the right, and it tends to tighten the knee joint

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ORIGINAL

stretch. This takes place in a snap action, whereby the contact carrier 32 is suddenly driven in the closing direction, which in turn causes the movable contact piece 18 to counteract the stationary contact piece 16 is driven as this is done by the dashed lines in Pig. 1 is shown. An over-movement of the carrier 32 over the point of engagement of the associated Contacts out, biases the "overtake" spring 34 in each contact arm, whereby the contact pressure is generated.

When the contact pieces are closed, the lower toggle bearing pin 66 assumes the position indicated at 66a » At this point the line of upward pressure runs through the joint point of the knee joint to the right of the upper knee joint bearing pin 64 in the fork 54 over. In the embodiment shown in Figures 1 and 2 there are two possible opening types for the circuit breaker to effect the separation of the contacts. In the first or normal operation in the event of an overcurrent, is.die fork 54 by the time delay switch rod 72 for a Clockwise rotation about its bearing pin 56 is released, and the upper toggle bearing pin 64 shifts afterwards to the right and across the resulting line of action of the springs 68. When this takes place, the tensioned over-dead-center springs 68 free and cause a sudden buckling of the knee joint and, in a corresponding manner, a Pivoting movement of the various contact carriers 32 around the bearing journals 38 as a unit of their closed Standing out. The release of the fork 54 is achieved that the bimetal 24 deflects under the influence of a continuous overcurrent. When the bimetal 1 bends to the left, it finally presses against the adjusting screw 76, with the result that the time delay switch rod moves 72 pivoted, with the main locking device 75 out of engagement with the secondary locking device 70 is adjusted, which is then free to rotate and the fork 54, as mentioned above, to free-

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give. When the breaker opens in this way, it returns to the full in Pig. 1 position shown which position is considered the "normal" open position can be. The opening of the interrupter by hand by reversing the adjustment of the actuating handle 48 also causes the knee joint to buckle, with the result that the breaker opens into the normal position in which the circuit is open.

It is very important that the circuit breaker, for example, contains a new device whose puncture will now be explained will. If a harmful overload or short circuit occurs in the monitored circuit, the current increases the affected pole or poles suddenly. This current runs through the bimetal 24 and causes the yoke 78 the armature 80 strongly pulls on the momentary switch rod 82 is attached before the bimetal can deflect far enough to the time delay shift rod 72 to operate. The pivoting movement of the Moinentan switch rod causes the locking device 40 to pivot the arm 84, wherein the surface 84a is adjusted so that the contact arm guide pins 38 are released, which at the end the connecting rod 36 are formed so that they are under the influence or drive of the spring 96 along the guide move slots 44. The contact arm pivots first around its bearing pin 66 against the knee joint without waiting for the knee joint to buckle. At the start this movement is the bearing pin 66 in the position 66a, in which the circuit is closed. That Knee joint is retained during the instant opening of the interrupter. Before that, during normal operation of the interrupter, the contact arm pivoting about the pin 38 through the interaction of the guide pins 38, the slots 44 and the locking device 40 prevented. The straightening movement of the knee joint, which was transmitted via the journal 66, caused that

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the contact arm in an arc to the closed position waved. The actuation of the locking device 40 by the overcurrent releases the restrained end of the contact arm and enables the arm to rotate about the bearing journal en 66. The bearing pin moves to position 66b when the contact arm is in its upper position in dashed lines Line shown position (Pig. 1) moved. The rotation of the contact arm continues until the arm rests with the Bearing pin 56 comes. It is noted that this second position in which the circuit is open is a "wide" one. Open position is that a larger gap between the moving contact piece 18 and the stationary contact piece 16 than in the normal position of the arm. This expanded or reinforced separation causes an increase the breaking capacity of the circuit breaker.

The return current path conductor 50 accelerates the Contact arm in the wide open position due to the action of the current in the conductor 15 and in the contact arm 20 flows. Those skilled in the art will recognize that the relocation the effective bearing parts of the contact arm from the locked Luhrungszapfen 38 to the pivot bearing 66 the The pivot point of the contact arm has moved from a point adjacent one end thereof to a point closer to the center point the mass of the contact arm is located. This shift in the pivot bearing parts causes a very large change the moment of inertia of the contact arm and therefore enables faster movement to the position in which the circuit is open. The change in movement The carrying mass causes the contact arm to better respond to the relatively weak contact opening springs 96 of each Low-contact and also significantly better on the electrodynamic Repulsive effect between the contact arm and the return path in the upper part of the conductor 15 responds.

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The resetting of the circuit breaker to a condition for reclosing after tripping by a sustained moderate overload is effected by moving the operating handle 48 slightly beyond the open or off position. The handle drives the fork 54 to bring the secondary and main locking lung device back into engagement in a known manner. Resetting the circuit breaker upon the occurrence of a "momentary" overcurrent condition in which the contact arms have moved to the second open position without buckling the knee joint is effected simply by switching the circuit breaker to the off position. When the springs 68 are moved to the off position, the hinge point of the knee joint is displaced, with the result that the knee joint buckles, and the force of the springs 68 acting on the knee or the hinge point of the knee joint 62 is so great that the contact arms are raised to their normal open position. Each guide pin 38 pushes its locking arm 84 off track when it returns to the position shown in Fig. 1 while the locking device snaps into a position below the guide pin under the influence of the lock return spring 86 previously described.

In certain applications where only the momentary short-circuit response property is desirable, for example when the circuit breaker is used with a motor starter that has a built-in Has overload protection, the over current discharge device 24 can be omitted. The time delay shift rod 72 and the associated love lock device 70 are also omitted. In this construction, the magnet yoke 78 is arranged around an extension of the conductor 26, to monitor the current flowing across the pole. The fork 54 is held fixed in the position shown in FIG. 1, and the knee joint 57 is used to normally open and close the circuit breaker and the circuit breaker

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breaker after actuation of the locking device to reset depending on the current circuit. The contact arms 20 remain in the wide open Position until the handle 50 is moved to the off position, the knee joint 57 buckling. When the knee joint is buckled, raise the above dead center j-pedern the contact arms in their starting or reset position »

Referring now to Figures 3 and 4, there is shown another embodiment of the invention and parts similar to parts in Pig. 1, are identified by the same reference numerals but with a prime. For the sake of clarity and simplicity, only those parts are specially marked which are necessary for an understanding of the exemplary embodiment. In the multipole circuit breaker of Figures 3 and 4, a number of actuators 46 'are provided, one for each pole of the circuit breaker. The actuating ^{levers 48 1 of} the respective poles are connected to one another for common actuation by a handle 98 which is in engagement with the actuating levers for the common simultaneous opening and closing of all poles. Each pole contains a frame 52 'which contains two spaced apart pieces of metal or plates which extend from a point adjacent the center point of the breaker housing to one end of the housing, and an overload release part or fork 54V which is too slow ^! 52 * has fixed bearing pin 56 '. The knee joint 57 * contains two knee joint members 58 * and 60 ·, which are connected to one another at a joint point 62 * so that they can rotate *. These knee joint members have an upper bearing pin 64 'and a lower bearing pin 66' in the parts 54 'and 32'. Two pedals 100 extend between the hand lever and the articulation point 62 »of the knee joint. The contact arm 20 'of each pole contains guide pins 38 which slide in guide slots 44' which are machined in the frame parts 52 '.

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Each pole has a secondary locking device 70 'associated with the end of the corresponding fork 54 'cooperates and restrains the fork from moving in the direction that the knee joint buckles. A common shift rod 72 'made of insulating material extends across all pole positions and is in the outer frame parts 52' of the outer pole (see. Pig. 4) rotatably mounted. A spring 74 'extends between the shift rod 72 · and of each individual secondary locking device 70 * and pulls this in engagement with the shift rod. The secondary locking device 70 'engages a corresponding master locking device 75' which is in each pole position is carried by the shift rod 72 '.

As in the embodiment of Figures 1 and 2, each pole is provided with two Überstrora sensing devices, which on respond to different overcurrent values. As before speaks the bimetal 24 'in a reversed time characteristic, while the electromagnetic "instantaneous" overcurrent characteristic by the yoke 78 · is created around the bimetal 24 'is arranged around, as well as by an anchor 80', the is carried by a dedicated momentary switch rod 82 'at each pole. The common time delay switch rod 72 ' enables all poles to be opened in response to an overload of any one. The movement of the shift rod 72 ' through the bimetal 24 'of the overloaded pole, triggers each of the individual forks 54' to buckle the knee joint 57 ' and opens the circuit via the corresponding poles.

When one of the% poles is switched by a harmful short circuit which causes the latch 40 'of this pole to open the contact arm for very fast movement at low Releases moment of inertia in the "wide" open position; will the other poles opened in a similar manner. When the bearing journals 38 · of the released contact arm after release

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run along the slots 44 'they will encounter one End 102a of the angle lever 102, which is rotatable in the frame 52 ' is stored. The movement of the pin 38 'causes a pivoting movement of the angle lever 102 counterclockwise, with end 102b against the time delay switch rod 72 'is driven to trip the forks 54' of all poles. The release of the forks 54 'has the consequence that the corresponding knee joints 57' buckle together and all the poles be opened. It is noted that the contact arm of the overloaded pole initially moves to the wide open position opens and then returns to the normal open position with the buckling of his knee joint. The length of time in that the pole is in the "wide" open position can be determined in part by adjusting the end 102a of the bell crank to be determined. The buckling of the knee joint 57 'of the overloaded pole automatically brings the pole in a state in which it closes normally by the actuating springs 100 pushing the bearing pin 38 'as in the exemplary embodiment 1 and 2 above the locking surfaces 84a. If the angle lever 102 is omitted, the "forward flow" is sufficient, which flows through the bimetal 24 'of the overloaded pole during the interruption process, normally off, to deflect the bimetal 24 'towards the switching point, wherein the knee joints 57 * are buckled together and all poles are opened.

Referring now to Figure 5, a locking structure is shown in the exemplary embodiments of FIGS. 1 to 4 is applicable and is responsive to electrodynamic forces which occur between the contact arm 20 and the return current conductor 15 are generated. If large overload currents flow through the contact arm and conductor, will creates a great force tending to lift the arm off the ladder. The arm can be pivoted with the knee joint connected and connected to the contact arm via the contact pressure springs

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OA ORIGINAL

carrier. When the arm climbs up, it reaches a limit position in the support 32 due to a stop or when the coils of the spring 34 mesh so that the spring becomes stiff or "solid". The electrodynamic force generated in the arm 20 is then converted into a downward pressure of the pegs 38 ^rt against the locking surface 84a ". This locking surface does not have an arc around its location 40", but has an angle of repulsion. A force component of the pin 38 "seeks to unscrew the lock 40" from the release path of the pin. If this force component exceeds the forces which are due to the friction and to the return spring 86 ", the pins are released so that the arm can move into the" wide "open position 3 and 4, the locking arms 84 can be suitably connected to one another for a common movement or the common release of all poles can preferably be made dependent on the angle levers 102. This locking construction can also be used in the exemplary embodiment of FIGS The magnetic yoke and the associated armatures of Figures 1 to 4 can be omitted if the lock is provided with a push-off angle, or locks with a push-off angle can be used together with the anchors. to respond to the electrodynamic force of the contact arm, the below r harmful overcurrent conditions is created and it promotes faster tripping under such conditions.

Although the embodiments of the invention apply to more refer to pole circuit breakers, it is apparent to the person skilled in the art that the invention also applies to single-pole Circuit breaker is applicable.

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Claims (7)

Claims \ j Circuit breaker with an elongated contact arm which at one end carries a movable contact piece »which comes into contact with a mating contact piece when the circuit breaker is closed, the other end of the contact arm having a pivot bearing device, further with a knee joint which is supported by a Bearing pin is connected to the elongated contact arm between its ends and moves the contact arm between positions in which the circuit is closed or opened and with a device that biases the contact arm for ■ an opening movement around the bearing pin of the knee joint, da .d ,: h rc h -. ■ "indicated that an instantaneous tripping device (40, 82, 84, 78, 8o) triggers the pivotably supported opposite end (38) of the contact arm (20) in response to sudden high overcurrent conditions and that an additional overcurrent tripping device ( 24, 76, 72) causes the knee joint (57) to buckle and causes the contact pieces (16, 18) to open under other overcurrent conditions. 2. Circuit breaker according to claim 1, d ad u r c h characterized in that a return flow path (15) next to the contact arm (20) is provided, which has an electrodynamic Reaction between the current flowing in the contact arm (20) and the current in the return flow path (15) generated in order to open a supplementary contact opening force of the contact arm after the contact arm .by sudden high overcurrent conditions have been triggered • 3. Circuit breaker according to claim 2, characterized characterized in that the instantaneous trip device (40, 82, 84, 78, 80) responds exclusively to high values of electrodynamic reaction forces due to the current, which flows in the contact arm (20) and in the return current path (15) so that the instantaneous trip device is the other End (38) of the contact arm (20) in its supported position holds at all lower current values. 909886/1 4. Circuit breaker according to claims 1, 2 or 3,
characterized 'in that the movable contact piece (18) performs a much larger opening movement when the instantaneous release device (40, 82, 84, 78, ^. 80) works than in other opening processes. . 5. Circuit breaker according to one of claims 1 to 4,
characterized in that the additional overcurrent release device (24, 76, 72) has an inverse time-current characteristic. 6. Circuit breaker according to one of claims 1 to 5,, "
characterized in that it includes a plurality of contact arms (2O0 forming a plurality of poles, that each contact arm (20 ') has a corresponding knee joint (57'), and that a common handle (98) the knee joints for a common manual actuation connects and each contact arm contains separate instantaneous overload trip devices. 7. circuit breaker according to claim 6, characterized by a device with a switching rod (72 ')> the buckling of the
Knee joints (57 *) controls to keep the contact arms (20 ·) normally in their closed position, and by a coupling device (102) between the shift rod (72 ·) and each contact arm (20 '), which reacts to the triggering of one of the Contact arms through 'the instantaneous tripping device responds to move the switching rod in a knee-joint Kinkst position, whereby all other poles of the circuit breaker are opened. Pu / Gu 909886/1166