JP2719436B2 - Undervoltage trip device for breaker - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an undervoltage trip device for a circuit breaker that trips a trip device and cuts off an electric circuit when a power supply voltage is insufficient.

[Prior art] As a circuit breaker, besides an overcurrent tripping device that detects an overcurrent (overload current or short-circuit current) and trips a trip device to cut off an electric circuit, when a current voltage is insufficient, Some of them have an undervoltage trip device for tripping a trip device to cut off an electric circuit. This undervoltage trip device includes an electromagnet unit including a coil through which a current according to a power supply voltage is supplied, and a trip mechanism unit that performs a trip operation when the attraction force of the plunger of the electromagnet unit decreases. When a shortage occurs, a trip device that opens a contact by a trip mechanism is driven.

[Problems to be Solved by the Invention] However, the conventional undervoltage trip device requires a special reset mechanism for resetting the trip mechanism to an undervoltage detection state when the trip mechanism trips, which complicates the structure. In addition, when the plunger driven at the time of resetting is returned to the reset position, the reset distance of the plunger at that time is large, so that there is a problem that a large coil is required and the size becomes large.

The present invention has been made in view of the above points, and an object of the present invention is to provide an undervoltage trip device for a circuit breaker having a simple structure and a small size.

Means for Solving the Problems In order to achieve the above object, the present invention provides a coil bobbin around which a coil to which a current according to a power supply voltage is applied, a yoke containing the coil bobbin, and a A plunger inserted and retracted into the coil bobbin, a lever rotatably mounted on the support frame, a drive spring for applying a one-way rotational force to the lever, and a rotatable support frame. A link is attached to the shaft and the lever and the plunger are locked to each other at the time of setting. When the power supply voltage is normal, a one-way rotating force is applied to the link by the spring force of the drive spring via the lever locked to the link. And at the same time restricts the rotation of the link by a plunger which is locked to the link, and sets the drive spring in a set state in which the spring force is accumulated, thereby exciting the coil when the power supply voltage is insufficient. Due to the lowering of the state, the rotation inhibiting force of the plunger is made lower than the rotational power given to the link by the drive spring. At this time, the locked state of the lever and the link is released by the rotation of the link, and the lever is released. A contact device provided on the crossbar when a crossbar holding a movable contact having a movable contact rotates in a contact opening direction by tripping a trip device that opens a contact by rotation. The outer surface of the lever contacts the lever to rotate the lever to the reset state, and the lever pushes the plunger into the coil bobbin with the rotation.

In order to avoid the need to change the capacity of the coil even when the spring force of the drive spring is changed according to the capacity of the circuit breaker, the rotation preventing force applied to the link by the plunger is assisted. An auxiliary spring may be provided.

Further, in order to prevent a mistrip due to a failure in the reset state, a pushing spring for applying a force for pushing the plunger into the coil bobbin when the lever is pushed by the opening operation of the crossbar may be provided.

[Operation] As described above, according to the present invention, when the crossbar holding the movable contact provided with the movable contact rotates in the opening direction of the contact, the outside of the contact holding portion provided on the crossbar is connected to the lever. And the lever is turned to the reset state, so that a special reset mechanism is not required on the undervoltage trip device side, the configuration is simplified, and the lever pushes the plunger into the coil bobbin during this opening operation. The electromagnetic force for attracting the plunger by exciting the coil can be reduced, and the coil can be reduced in size.

In addition, an auxiliary spring that assists the rotation preventing force applied to the link by the plunger is provided, and when the spring force of the drive spring is changed according to the capacity of the circuit breaker, it is possible to simply change the spring force of the auxiliary spring. It is not necessary to change the capacity of the coil.

Further, when a pushing spring is provided to the plunger to apply a pushing force into the coil bobbin when the lever is pushed by the opening operation of the crossbar, the pushing spring pushes the plunger into the coil bobbin at the time of resetting. And the occurrence of mistrip due to a defective reset state can be prevented.

Embodiment 1 FIGS. 1 to 6 show an embodiment of the present invention. In addition,
First, the basic configuration and operation of a circuit breaker to which the present invention is applied will be described. This circuit breaker is of a three-pole type. Basically, as shown in FIG. 5, an overcurrent trip device 10 driven by overcurrent and a trip operation when the overcurrent trip device 10 is driven are performed. And a contact device 110 that is momentarily opened when the trip device 40 performs a trip operation.
And an arc extinguishing device 130 for extinguishing an arc generated when the contact device 110 is opened.
A handle 100 interlocked with the trip device 40 protrudes from the upper surface of the housing 1 so that the handle 100 can be turned upside down. The overcurrent trip device 10, the contact device 110, and the arc extinguishing device 130 are provided for each pole, and the trip device 40 is provided so as to be shared by three poles. The housing 1 includes a base 1a and a cover 1b fitted on the base 1a.
The handle 100 projects outside the housing 1 through a handle insertion hole 2 formed in the center of the housing 1. An exhaust plate 9 that connects the inside and outside of the housing 1 to each other is fitted into a side surface of the housing 1 on the side of the arc extinguishing device 130.

The overcurrent trip device 10 of the circuit breaker is an electromagnetic trip device 10a.
And a thermal trip device 10b.

The electromagnetic trip device 10a includes a coil 11, a yoke 12, a plunger 13, and a return spring 14.The coil 11 is a half-turn coil formed by bending a sheet metal, and a terminal for connecting a load wire to one end. The piece 18 is integrally extended, and is disposed in a space below the yoke 12 formed by bending a flat magnetic material into a substantially S shape. The plunger 13 has a substantially L-shaped hooking piece (not shown) formed at the upper end thereof, which is inserted into the yoke 12 so as to be vertically movable, and is returned by a return spring 14 disposed in a space above the yoke 12. It is urged to move upward when the coil 11 is not excited.

The thermodynamic trip unit 10b includes a heater plate 31, a bimetal plate 32, and a pressing screw 33.
On the 10a side, the heater plate 31 and the bimetal plate 32 are erected side by side, and the lower end is fixed integrally to the coil 11, and the heater plate
A connection wire 37 made of a braided wire is connected to the upper end of the base 31, and when the heater plate 31 is heated by a current supplied to the heater plate 31, the upper end of the bimetal plate 32 bends toward the electromagnetic trip device 10a. .

FIG. 6 is an exploded perspective view of the trip device 40. The trip device 40 includes a holding frame 41, a latch link 51, a locking lever 71, a cradle 81, first and second links 91 and 94, and an interlock bar 61. It is composed of The holding frame 41 is formed in a shape in which supporting plates 41a separated in parallel to the left and right are integrally connected, and a latch link 51 is pivotally supported by a link pin 52 at an end on the side of the overcurrent trip device 10 so as to be swingable. It is urged in a counterclockwise direction by a compression spring 54 sandwiched between the holding frame 41 and a portion closer to the overcurrent trip device 10 than the pivot portion.
In this latch link 51, a latch piece 55 extending from an end near the overcurrent trip device 10 is locked to the interlocking bar 61, and is located at an end farther from the overcurrent trip device 10 than the pivot portion. The upper end of the locking lever 71 is pressed by the formed pressing piece 56.

The interlocking bar 61 has a pressing piece 63 and a hooking piece 64 projecting in a direction substantially orthogonal to each other at substantially equal intervals from three locations in the axial direction, and is latched at a central portion in the axial direction in a direction substantially orthogonal to the pressing piece 63. Link
A locking piece 65 for locking the latch piece 55 of the projection 51 is protruded, and both ends of the interlocking bar 61 are rotatably supported between the inner surfaces of the housing 1. Here, the pressing piece 63 is disposed corresponding to the tip of the pressing screw 33 of the thermal trip device 10b, and
64 is disposed on the lower surface side of the hooking piece of the electromagnetic trip device 10a, and the plunger 13 of one of the overcurrent trip devices 10 provided for each pole is drawn downward, or the bimetal plate When the bend 32 turns away from the heater plate 31, the interlock bar 61 rotates counterclockwise in FIG.

The lower end of the locking lever 71 is pivotally attached to the holding frame 41 by a link pin 72 so as to be swingable, and the compression lever 74 is interposed between the holding frame 41 and a portion above the attachment portion in a clockwise direction. Has been energized.

The cradle 81 is bent into a substantially U-shape having legs substantially parallel to both support plates 41a of the holding frame 41, and is provided with a link pin.
The lower end is pivotally attached to the holding frame 41 by a pivot 83, and a shaft projection 84 protruding from the inner surface of the cradle 81 is provided so as to project from the overcurrent trip device 10 side of one leg. A locking projection 82 that is locked in the notch hole 75 of the locking lever 71 is provided in a protruding manner, and a pressing projection 86 is provided on both legs in a direction opposite to the overcurrent trip device 10 side.
Is formed.

The first link 91 is formed in a substantially U-shape that fits between the two leg pieces of the cradle 81, and the upper ends of the two leg pieces are connected to the shaft projections 84 of the cradle 81.
, And is rotatably mounted on the shaft.
Is rotatably connected to the upper end of the extension pin by a link pin 93, and one end of a tension spring 102 is coupled to the link pin 93. A substantially U-shaped connecting groove 95 is formed at the lower end of the second link 94, and the connecting groove 95 is connected to the contact device 110.

The handle link 101 is formed in a substantially U-shape that is opened downward, the upper end is integrally connected to the handle 100, and the shaft provided with the bearing groove 104 at the lower end protruding from the outer surface of the support plate 41a of the holding frame 41. By engaging with the protrusion 44, the handle 100 swings as the handle 100 is raised and lowered. The other end of the tension spring 102 is connected to the handle link 101.

The contact device 110 includes a movable contact 111 having a movable contact 112.
A crossbar 121 holding the movable contact 111; and a compression spring 11 interposed between the crossbar 121 and the movable contact 111.
3 and a fixed contact 131 fixed to the upper surface of the fixed contact plate 132 of the arc extinguishing device 130. The other end of the connection line 37 whose one end is connected to the heater plate 31 is connected to the movable contact 111. The crossbar 121 is formed of an insulating material such as a synthetic resin, is supported between the inner surfaces of the housing 1, and simultaneously holds the movable contacts 111 of each pole by contact holding portions 122 formed at three locations in the axial direction. When any one of the movable contacts 111 is driven, the other movable contact 111 is simultaneously driven.

The movable contact 111 has a second link 9 at a substantially central portion in the longitudinal direction.
4 is rotatably locked, a shaft pin 114 is inserted, and a spring receiving pin 1 is inserted into a portion of the shaft pin 114 from the overcurrent trip device 10.
16 is inserted.

The compression spring 113 includes a spring receiving portion 126 formed below the base portion 122 of the crossbar 121 and a spring receiving pin of the movable contact 111.
The movable contact 111 is sandwiched between the
By biasing in the direction away from the 10 side, the crossbar 61
The lower part of the second link 94 is held between the retaining projection 129 of the holding body 122b and the shaft pin 114.

The arc extinguishing device 130 is a fixed contact plate to which the fixed contact 131 is fixed.
132, an arc traveling plate 133 provided at one end of the fixed contact plate 132, a fixed plate 135 integrally formed with a fixed piece 135a for connecting a power line to one end, and an arc traveling plate of the fixed contact plate 132.
One end is connected to the end opposite to 133, and the other end comprises an arc drive coil 134 having the other end connected to a fixed plate 135, and an arc extinguisher 137 disposed above the arc traveling plate 133.
The arc extinguisher 137 includes a plurality of grid plates 138 and a holding frame 139 formed of an insulating material for holding the grid plates 138.

In this circuit breaker, the terminal strip 18, the coil 11, the heater plate 31, the connection line 37, the movable contact 111, the movable contact 112, the fixed contact 131, the fixed contact plate 132, the arc driving coil 134, and the fixed plate 135 A passing main electric path is formed.

Hereinafter, the electric circuit cutoff operation of the present embodiment will be described. First, when the handle 100 is tilted toward the overcurrent trip device 10 (right side in FIG. 5), the movable contact 112 and the fixed contact 131 are separated. In this state, the locking piece 65 of the interlock bar 61
Is engaged with the latch piece 55 of the latch link 51, and the latch link 51 is urged counterclockwise around the link pin 52 by the compression spring 54. At this time, the latch link 51
The lower surface of the holding piece 56 is in contact with the upper edge of the locking lever 71, and the locking lever 71 is urged clockwise around the link pin 72 by the compression spring 74. Here, the rotation of the latch link 51 is stopped by the contact between the latch link 51 and the locking lever 71. The locking projection 82 of the cradle 81 is inserted into the cutout hole 75 of the locking lever 71, and the rotation of the cradle 81 is stopped. On the other hand, the straight line connecting both ends of the tension spring 102 passes on the right side of the shaft projection 84, and
Since an upward spring force acts on the link pin 93 connecting the link 91 and the second link 94, the first link 91 is
Is biased counterclockwise around. Accordingly, the second link 94 is pulled up to the upper right along with the movable contact 111 connected to the second link 94, and the movable contact 112 and the fixed contact 131
Are separated, and the crossbar 121 is urged clockwise. Here, a straight line connecting both ends of the compression spring 113 passes rightward of the shaft pin 114 and the spring force of the compression spring 113 acts upward, so that the movable contact 111 is urged counterclockwise.

Next, as shown in FIG.
When tilted to the 30 side (left side in the figure), the straight line connecting both ends of the tension spring 102 passes through the left side of the shaft projection 44 and the spring force acts downward, so that the handle link 101 is urged counterclockwise. The state in which the handle 100 is tilted to the left is maintained. Further, in this state, a straight line connecting both ends of the tension spring 102 passes on the right side of the link pin 83 which supports the cradle 81, and the spring force acts upward.
Will be biased counterclockwise. Here cradle
81, the locking lever 71, the latch link 51, and the interlocking bar 61 are maintained in the same state as the above-described contact opening state. Meanwhile, the first
Since the link pin 93 connecting the link 91 and the second link 94 is pulled to the left by the spring force of the tension spring 102, the first link 91 and the second link 94 are substantially aligned, and The movable contact 111 connected to the lower end of the second link 94 is pressed downward, and the movable contact 112 and the fixed contact 131 are closed. Further, since a straight line connecting both ends of the compression spring 113 passes rightward of the shaft pin 114 and the spring force acts upward, a sufficient contact pressure can be obtained. Thus, when the handle 100 is tilted to the left, the set state is reached in which the spring force of the tension spring 102 is accumulated.

When an extremely large current such as a short-circuit current flows in the main circuit while the contacts are closed as described above, the movable contact 112 and the fixed contact 131 are instantaneously separated by the electromagnetic repulsion. At this time, since the straight line connecting both ends of the compression spring 113 passes below the shaft pin 114 and the spring force acts to the left, the movable contact 112 is attached in a direction away from the fixed contact 131 by the spring force of the compression spring 113. Will be inspired. As described above, the compression spring 113 acts as a reversing spring so as to apply a contact pressure when the contacts are closed and to accelerate the opening of the contacts when the contacts are separated. Here, an arc is generated with the opening of the contact, but the arc is strongly applied to the arc extinguisher 137 due to the Lorentz force acting between the magnetic field generated around the arc driving coil 134 and the arc. And the arc length is rapidly extended.

Following the separation of the contacts by the electromagnetic repulsion, the trip device 40 is driven by the electromagnetic trip device 10a. The electromagnetic trip device 10a operates when not only short-circuit current but also a large current of several times or more of the rated current flows. That is, the electromagnetic trip device
When a large current flows through the coil 11a of 10a, the plunger 13 is pulled downward against the spring force of the return spring 14, and the hook piece 64 of the interlock bar 61 is lowered by the hook piece formed at the upper end of the plunger 13. Is drawn to. As a result, the interlock bar 61 rotates counterclockwise, and the latch piece 55 of the latch link 51 is pressed downward by the locking piece 65. That is, the latch link
51 rotates clockwise against the spring force of the compression spring 54, and the pressing force on the locking lever 71 is released.
Is rotated clockwise by the spring force of the compression spring 74, and the cradle 81
Is released from the notch hole 75 of the locking lever 71. As described above, since the cradle 81 is urged counterclockwise by the spring force of the tension spring 102, the cradle 81 rotates counterclockwise when the engagement with the locking lever 71 is released, and the first link 91
To the upper left. When the first link 91 is pulled up, the second link 94 is pulled up to the upper right along with the contraction of the tension spring 102, and the movable contact 111 is pulled up so as to separate the movable contact 112 from the fixed contact 131. At this time, the cross bar 122 is moved by the movable bar 112
Rotates in a direction away from the fixed contact 131. These series of operations are performed instantaneously, and perform a so-called trip operation. In this way, the movable contact 112 becomes the fixed contact 131
Away from the arc, the arc length is extended, the arc is divided by the grid plate 138 of the arc extinguisher 137, and the arc is rapidly extinguished. The high-pressure arc gas generated by the arc is discharged out of the housing 1 through the exhaust plate 9. At the contact open position, a straight line connecting both ends of the compression spring 113 passes through the right side of the shaft pin 114, and the spring force acts upward to urge the movable contact 111 counterclockwise. .

As described above, when a large current that is several times or more of the rated value passes, the electromagnetic trip device 10a operates and the trip device 4a is activated.
0 is driven, but when an overcurrent slightly larger than the rating is supplied for a long time, the bimetal plate 32 is bent by the heater plate 31 heating the bimetal plate 32,
When the pressing screw 33 presses the pressing piece 63 of the interlocking bar 61, the interlocking bar 61 is rotated in the counterclockwise direction, and the trip device 40 is operated to open the contact as in the case described above.

Thus, when the trip device 40 operates, the cradle
Since 81 is disengaged from the locking lever 71, it is necessary to reset the contact in order to close the contact again. The reset is performed by tilting the handle 100 to the right as far as possible. That is, when the handle 100 is tilted to the right as much as possible, the pressing protruding piece 86 of the cradle 81 is pressed rightward by the pressing pin 105 provided on the handle link 101, and the cradle 81
Rotates clockwise. By this operation, the locking projection 82 of the cradle 81 is inserted into the notch hole 75 of the locking lever 71, and the locking lever 71 rotates counterclockwise by the pressing force from the cradle 81. Therefore, the upper end of the locking lever 71 is
It comes into contact with the lower surface of the pressing piece 56 of 51, and if the force of tilting the handle 100 to the right side is removed here, it will return.

Hereinafter, the undervoltage trip device 200 which is a feature of the present embodiment will be described. The undervoltage trip device 200 of the present embodiment includes:
Over-current trip device when the power supply voltage falls below the specified voltage
By turning the interlocking bar 61 counterclockwise in the same manner as in 10, the trip device 40 is tripped and the contact is opened. More specifically, as shown in FIGS. 1 and 2, a coil through which a current corresponding to a power supply voltage is supplied.
201 and a coil bobbin 202 around which the coil 201 is wound
And a substantially U-shaped yoke 203 opening upward to accommodate the coil bobbin 202, and an insertion hole 205 formed in the yoke 203.
And the plunger 206 inserted into the through-hole 204 of the coil bobbin 202 through the sensor to detect an insufficient power supply voltage. That is,
When the coil 201 is excited when the power supply voltage is normal, the plunger 206 is attracted. When the power supply voltage is insufficient, the attraction force of the plunger 206 is weakened, so that the power supply voltage shortage state is detected. Due to the decrease in the attraction force of the plunger 206 due to the shortage of the power supply voltage, the trip mechanism including the support frame 207, the link 209, the lever 212, and the drive spring 213 is operated. Here, the support frame 207
Is a substantially U-shaped opening on the side of the overcurrent trip device 10 and has a yoke.
A link 209 is rotatably attached to the support frame 207 by a link shaft 208, and a lever 212 is rotatably attached to the support frame 207 by a lever pin 210. The link 209 has a side piece 209a protruding toward the overcurrent trip device 10, and a bridge pin 211 for locking to the lever 212 is bridged between the distal ends of the side pieces 209a to form a central piece 209b.
The plunger 206 is inserted through the insertion window 214 protruding from the inside.
Is inserted, and a locking claw 206a formed at the lower end of the tip of the plunger 206 is locked to the inner peripheral surface of the insertion window 214. Here, the latch pin 211 is rotatable in the circumferential direction.
It is attached between a. The lever 212 includes pieces that protrude in three directions with a substantially passing angle. One piece is a locking piece 212a that is locked to the latch pin 211 of the link 209, and the other is a pressing piece that presses the hooking piece 64 of the interlocking lever 61. One piece 212b and another piece are release pieces 212c, one end of which is the support frame 20c.
7, and the other end is urged clockwise by a drive spring 213 which is locked to a surface of the locking piece 212a facing the plunger 206 side. Note that a stopper pin 215 is bridged on the opening side of both side pieces of the support frame 207, and this stopper pin 215
The rotation of the lever 212 is regulated by the contact of the locking piece 212a with the locking piece 212a.

Hereinafter, the operation of the undervoltage trip device 200 will be described.
When the power supply voltage is normal, the plunger 2 is driven by an electromagnetic force generated by a current flowing through the coil 201, as shown in FIG.
06 is separated from the overcurrent trip device 10 (second
At the same time, the central piece 209 of the link 209 is sucked.
The locking pawl 206a of the plunger 206 inserted into the link 209 through the insertion window 214 formed in b locks on the inner peripheral surface of the insertion window 214, thereby applying a force to pull the link 209 to the left in the drawing. ing. In the state of the link 209, the latching piece 212a of the lever 212 is locked to the latch pin 211 of the link 209, and the link 209 receives a clockwise turning force by the spring force of the drive spring 213 via the lever 212. Has been granted,
The rotation of the link 209 at this time is prevented by the plunger 206. That is, when the power supply voltage is normal, the clockwise force applied to the link 209 by the attraction force of the plunger 206 is:
Since the spring force of the drive spring 213 is set to be larger than the counterclockwise direction which is received via the lever 212, the link 209
And the lever 212 does not rotate. Therefore, at this time, the driving spring 213 is in the set state in which the spring force is accumulated.

Now, assuming that the power supply voltage is insufficient, the current flowing through the coil 201 at this time decreases, thereby causing the plunger 206
The electromagnetic force for sucking is reduced. Therefore, the link mentioned above
209 and the relationship between the clockwise and counterclockwise forces is reversed,
That is, the counterclockwise force applied to the link 209 by the lever 212 increases, so that the link 209 rotates counterclockwise. When the link 209 rotates in this way, the third
As shown in the figure, the locking piece 212a of the lever 212 and the latch pin 2
When the lever 212 is released from the locked state, the lever 212 rotates clockwise by the spring force of the drive spring 213. When the lever 212 rotates in this manner, the pressing piece 212b of the lever 212
4, the trip device 40 trips in the same manner as the operation of the electromagnetic trip device 10a described above, and the contacts are opened.

At this time, as shown in FIG. 4, the crossbar 121 rotates clockwise, and the outer surface of the contact holding portion 122 formed on the crossbar 121 is moved to the release piece 212 c formed on the lever 212. Upon contact, the lever 212 is rotated counterclockwise. That is, the contact holding portion 122 of the cross bar 121 operates as a cam.
a is rotated to a position slightly rotated counterclockwise from the normal position of the power supply voltage. In this case, lever 212
The surface opposite to the locking surface of the locking piece 212a contacts the tip of the plunger 206, so that the plunger 206
At this time, the locking portion 206a of the plunger 206 further pushes the inner peripheral surface of the insertion window 214 of the central piece 209b of the link 209, and rotates the link 209 clockwise. For this reason,
When the pressing force of the release piece 212c of the lever 212 by the contact holder 122 is released, the locking piece 212a of the lever 212
A state in which the latch pin 210 can be latched. That is,
In the case of this embodiment, since the undervoltage trip device 200 is reset using the crossbar 121, the undervoltage trip device 200 does not need to have a special reset structure. In addition, since the plunger 206 is pushed back by the lever 212 to a position where the gap with the yoke 203 is close to zero by the lever 212, it is necessary to provide a spring or the like for returning the plunger 206 to the electromagnet portion including the coil 201, the yoke 203, and the plunger 206. However, since the plunger 206 is pushed to some extent at the time of resetting, the magnetomotive force of the electromagnet portion can be reduced, so that the structure of the electromagnet portion can be simplified and the electromagnet portion can be reduced in size.

When the circuit breaker is turned on by operating the handle 100, the crossbar 121 rotates counterclockwise, so that the pressing force of the contact holding portion 122 applied to the release piece 212c of the lever 212 is released. The lever 212 is driven by the drive spring 21
3 rotates clockwise by the spring force of
212a is locked to the latch pin 210 of the link 209. At this time, a current flows through the coil 201 at the same time, and a force for pulling the plunger 206 acts on the plunger 206. Therefore, a counterclockwise force by the lever 212 and a clockwise force by the plunger 206 are applied to the link 209. At this time, if the power supply voltage is normal, the force by the plunger 206 is strong, so that the latch state shown in FIG. 2 is maintained. When the power supply voltage is insufficient, the undervoltage trip device 200 performs a trip operation by the same operation as described above.

Embodiment 2 FIGS. 7 to 9 show another embodiment of the present invention. The present embodiment relates to a case where the undervoltage trip device 200 of the first embodiment is applied to a large-capacity circuit breaker. When the undervoltage trip device 200 described above is applied to a large-capacity circuit breaker, it is necessary to increase the tripping force of the trip device 40, and therefore it is necessary to increase the spring force of the drive spring 213. Along with this, the force for sucking the plunger 206 must be increased.
In this case, it is necessary to individually form the undervoltage trip devices 200 according to the capacity of the circuit breaker. Therefore, the present embodiment provides an undervoltage trip device 200 that can be applied to circuit breakers having different capacities with only slight changes.

Hereinafter, a specific configuration of the present embodiment will be described. The undervoltage trip device 200 according to the present embodiment includes a drive spring 213 having a spring force commensurate with tripping the trip device 40 of the circuit breaker. Auxiliary spring 217 for applying a counterclockwise force to link 209 minus the suction force of plunger 206
Is characterized by the fact that is newly provided. That is, the increase in the spring force of the drive spring 213 is supplemented by the auxiliary spring 217, so that the capacity of the circuit breaker can be handled without changing the suction force of the plunger 206. Here, the auxiliary spring 217 is attached to a stopper pin 215 that regulates rotation of the locking piece 212a of the lever 212, both ends are locked to the opening edge of the support frame 207, and free ends are connected to the latch pins 211 of the link 209. It is engaged.

In this embodiment, when the power supply voltage is normal,
The force that rotates the link 209 in the counterclockwise direction, which combines the suction force of the plunger 206 and the spring force of the auxiliary spring 217, is less than the clockwise rotation force on the link 209 via the lever 212 of the drive spring 213. growing. Therefore, the undervoltage trip device 20
0 is maintained in a set state in which the spring force of the drive spring 213 is accumulated.

If the power supply voltage is insufficient, the plunger 20
As the suction force of the link 209 is weakened, the clockwise rotation of the link 209 overcomes the turning force, whereby the latching state of the latch pin 211 of the link 209 and the locking piece 212a of the lever 212 is released, and the pressing piece 212b of the lever 212 is released. As a result, the hooking piece 64 of the interlocking bar 61 is rotated counterclockwise, and the trip device 40 trips. Note that the auxiliary spring 217 has no effect on the rotation of the lever 212 once the locked state of the locking piece 212a of the lever 212 and the latch pin 211 of the link 209 is released.

Further, even when the lever 212 is reset by the operation of the handle 100, the auxiliary spring 217 does not affect the operation of the lever 212, so that the contact holding of the trip device 40 is performed in the same manner as in the above-described embodiment. The reset is performed by the unit 122. In addition, when the above-described auxiliary spring 217 is provided, the link 209 can be prevented from rotating when vibration or impact is applied, so that there is an advantage that the link 209 is resistant to vibration or impact.

Embodiment 3 FIG. 10 shows another embodiment of the present invention. In the present embodiment, an insufficient voltage trip device 200 is prevented from causing a mistrip when the breaker is set due to an insufficient pushing amount of the plunger 206 by the locking piece 212a of the lever 212 at the time of reset. For this purpose, as shown in FIG. 10, a compression spring 218 is disposed between the locking piece 212a of the lever 212 and the plunger 206. In other words, the plunger 206 is pushed to a predetermined position in the through hole 205 of the coil bobbin 202 at the time of reset by the spring force of the compression spring 218, whereby the pushing amount is stabilized, so that the suction force of the plunger 206 when the breaker is set is set. Of the undervoltage trip device 2 due to poor suction of the plunger 206.
No. 00 prevents the occurrence of a mistrip so that the circuit breaker cannot be turned on. Note that the spring load of the compression spring 218 is set to be much smaller than the spring load of the drive spring 213 so as not to hinder the operation of the undervoltage trip device 200.

Incidentally, in addition to the compression spring 218, FIGS.
A leaf spring 219 shown in the figure may be used. Here, in FIG. 11, the leaf spring 219 is fixed to the locking piece 212a similarly to the compression spring 218 in FIG.
FIG. 12 shows a case where a leaf spring 219 is fixed to the plunger 206 side by welding or the like.

[Effects of the Invention] As described above, the present invention is provided on the crossbar when the crossbar holding the movable contact having the movable contact rotates in the contact opening direction by the reset operation of the trip device. The outer surface of the contact holder is in contact with the lever to rotate the lever to the reset state. Regardless of the presence or absence of the undervoltage trip device, the crossbar provided on the circuit breaker is used to pull the undervoltage. Since the external device is reset, there is no need for a special reset mechanism on the undervoltage trip device side.
The configuration is simplified, and the plunger is pushed into the coil bobbin by the lever at the time of this reset operation, so that the electromagnetic force for attracting the plunger by exciting the coil can be reduced, and the coil can be reduced in size.

Moreover, since various springs of the trip device mechanism intervene between the handle and the crossbar, the operating force of the reset operation is assisted by the spring force, so that a large force is not required for the handle when resetting the undervoltage trip device. There is an advantage.

In addition, if an auxiliary spring is provided to assist the rotation inhibiting force applied to the link by the plunger, even when the spring force of the drive spring is changed according to the capacity of the circuit breaker, only the spring force of the auxiliary spring is changed. It is possible to cope with this, and it is not necessary to change the capacity of the coil.

Further, when a pushing spring is provided to the plunger to apply a pushing force into the coil bobbin when the lever is pushed by the opening operation of the crossbar, the pushing spring pushes the plunger into the coil bobbin at the time of resetting. And the occurrence of mistrip due to a defective reset state can be prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view of one embodiment of the present invention, FIG. 2 is a cross-sectional view showing an operation state at the time of setting the same, FIG. 3 is a cross-sectional view showing an operation state at the same time of a trip, and FIG. FIG. 5 is a cross-sectional view showing an operation state at the time of reset, FIG. 5 is a cross-sectional view of a circuit breaker provided with the same, FIG.
FIG. 8 is a perspective view of another embodiment of the present invention, FIG. 8 is a cross-sectional view showing an operating state when the above is set, FIG. 9 is a cross-sectional view showing an operating state when the same is a trip, and FIG. FIGS. 11 and 12 are cross-sectional views of still another embodiment of the present invention, in which the compression spring is replaced with a leaf spring. 200 is an undervoltage trip device, 201 is a coil, 202 is a coil bobbin, 203 is a yoke, 206 is a plunger, 207 is a support frame, 209 is a link, and 212 is a lever.

Continuation of the front page (72) Inventor Masaru Omuro 1048 Odakadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works, Ltd. (56) References JP-A-2-21530 (JP, A) JP-A-60-151924 (JP) , A) Japanese Utility Model Showa 62-70340 (JP, U) Japanese Utility Model Showa 55-45192 (JP, U)

Claims (3)

(57) [Claims] A coil bobbin wound with a coil through which a current according to a power supply voltage is applied, a yoke accommodating the coil bobbin, a plunger penetrating through the yoke and freely inserted into and retracted from the coil bobbin; A lever pivotally mounted on the support frame, a drive spring for applying a one-way rotational force to the lever, and a lever and a plunger which are rotatably mounted on the support frame and are locked to each other at the time of setting When the power supply voltage is normal, a one-way turning force is applied to the link by the spring force of the drive spring via a lever locked to the link, and the link is rotated by a plunger locked to the link. To a set state in which the spring force of the drive spring is accumulated, and the rotation preventing force of the plunger is applied to the drive spring by lowering the excitation state of the coil when the power supply voltage is insufficient. In this case, the locking state between the lever and the link is released by turning the link, and the trip device that opens the contact point by turning the lever is tripped. When the crossbar holding the movable contact provided with the movable contact rotates in the contact opening direction, the outer surface of the contact holding portion provided on the crossbar comes into contact with the lever and turns the lever to the reset state. An undervoltage trip device for a circuit breaker, wherein the plunger is pushed into the coil bobbin as the lever is rotated. 2. The undervoltage trip device for a circuit breaker according to claim 1, further comprising an auxiliary spring for assisting a rotation preventing force applied to the link by the plunger. 3. The undervoltage trip device for a circuit breaker according to claim 1, further comprising a pushing spring for applying a force for pushing the plunger into the coil bobbin when the lever is pushed by the opening operation of the crossbar.