JPH0728675Y2 - Circuit breaker trip device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an electromagnet used in a trip device for a circuit breaker for wiring, which is made of a non-magnetic material and has a cylindrical shape having at least one bottom surface. A rod-shaped plunger made of a ferromagnetic material and formed in the same direction and inserted in the same axial direction,
A tubular body that accommodates a return spring that presses the plunger against the bottom surface, is filled with a buffer solution that controls the axial movement speed of the plunger, and has an armature at the other end; A magnet yoke that forms the magnetic path in the radial direction of the plunger that contacts the cylindrical body on the outside and supports the armature that is attracted to the armature; and a magnetic path in the radial direction of the plunger of the magnet yoke and the armature. And a coil which surrounds the tubular body and generates a magnetic flux in the axial direction of the tubular body.

[Conventional technology]

FIG. 6 shows a structural example of an electromagnet used in a conventional trip device for a circuit breaker. In the figure, 4 is a cylindrical body made of a non-magnetic material and having a bottom surface 4a at one end, and a rod-shaped plunger 3 made of a ferromagnetic material which is inserted inward in the same axial direction. A return spring 7 that presses against the bottom surface 4a is accommodated, and silicon oil 8 is filled as a buffer solution for controlling the moving speed of the plunger 3 when it moves in the axial direction. The other end of this cylindrical body has an armature. 6 is provided. Further, the tubular body 4 is
A radial magnetic path of the plunger 3 is formed by vertically penetrating one side of a magnet yoke 1 made of a steel plate bent in an L shape so as to be integrated with the magnet yoke 1 and contacting the cylindrical body on the outer side of the cylindrical body. Is formed, and this magnetic path regulates the position of one end in the axial direction of the coil 5 surrounding the tubular body 4.

An armature 2 is supported on the other one side of the L-shaped magnet yoke 1 via a Z-shaped supporting member 1a, and this armature is constantly pressed by the spring 9 to one side of the Z-shape to form an armature 6. The intervals are kept constant.

In such an electromagnet configuration, when the current flowing through the coil is less than or equal to the rated current, the amount of magnetic flux passing through the magnetic path formed by the plunger 3, the armature 6, the armature 2, the magnet yoke 1 and the plunger 3 is small, and the plunger 3 is restored. It is impossible to overcome the spring 7 and move it toward the armature 6. However, when the current flowing through the coil exceeds the rated current, the magnetic flux passing through the magnetic path increases, and the plunger 3 overcomes the return spring 7 and is attracted and moved toward the armature 6. With this movement, the magnetic resistance of the magnetic path decreases and the magnetic flux increases, and the armature 2 overcomes the spring 9 and is attracted to the armature 6 to pull the circuit breaker of the wiring near the end of the moving stroke of the plunger 3. Remove and operate. The state of the electromagnet at this time is shown in FIG. Also,
The speed at which the plunger 3 is sucked and moved in the direction of the armature 6 is almost dependent on the size of the gap formed between the maximum outer diameter of the plunger 3 and the inner diameter of the tubular body 4 through which the silicone oil 8 passes. By appropriately setting this gap, a desired relationship can be established between the magnitude of the overcurrent flowing through the coil and the time from the beginning of this overcurrent to the start or end of the operation of the armature 2. Obtainable. Generally, in such an electromagnet configuration, the relationship between the operating time and the coil current has an anti-time limit characteristic as shown in FIG. 9 because of the viscosity of silicon oil as a buffer solution.

When a short-circuit accident occurs in the circuit where the circuit breaker for wiring is arranged, this short-circuit current causes the magnetic path of the electromagnet (see 3-
The magnetic flux generated in 6-2-1-3) is generated by the armature 2 with the plunger 3 hardly moving as shown in FIG.
Is large enough to quickly attract the magnet to the armature 6 and the circuit breaker is instantly removed. The tripping of the circuit breaker is carried out in the direction of the armature 6 provided on the tubular body 4 by the overcurrent flowing through the coil 5 of the electromagnet in FIGS. 4 and 5 showing the configuration of the circuit breaker for wiring. This is performed by sucking the armature 2, disengaging the engaging portion 2a with the operating mechanism, and breaking the toggle link 11 that has held the circuit breaker in the closed state. Reference numeral 12 is a movable contactor which is opened by a blocking spring when the toggle link 11 is opened.

[Problems to be solved by the invention]

The problems with the electromagnet configured as described above are as follows. That is, for minimum coil current, that is the minimum coil current so-called minimum operating current I _t to exerting a force capable tripping the fitting part 2a of the armature 2 and the operating mechanism to the armature in FIG. 5 may caused to operate the electromagnet, the plunger 3 Momentary tripping operation current value I that allows the armature 2 to be instantly attracted while the
Conventionally, _st has been manufactured to be about 8 times, but at this magnification, when using this type of circuit breaker in a circuit with a large inrush current, such as the transformer primary side, it is closed. At times, there is a risk that the shut-off operation will be performed unnecessarily, and even if an attempt is made to adjust this magnification in order to avoid such an operation, it has been difficult for the reasons described below.

That is, in the configuration of the electromagnet shown in FIG. 6, the coil current required to move the plunger 3 against the return spring 7 to the armature position is small because the force of the return spring is weak, but the armature 2 In order to release the engagement between the armature and the circuit breaker operating mechanism, it is necessary to generate a predetermined magnetic flux density between the armature and the armature.Therefore, the current that should flow in the coil with the plunger in contact with the armature. That is, the minimum operating current is equal to, but greater than, the current required to bring the plunger to the armature.

On the other hand, the instantaneous tripping operating current value must generate a magnetic flux density required for tripping the armature from the operating mechanism between the armature 2 and the armature 6 while the plunger 3 hardly moves. When the current value is increased to increase the multiplication factor with respect to the minimum operating current, the air gap between the plunger 3 and the armature 6 is increased, and the magnetic path: the plunger 3-the armature 6-the armature 2-the magnet yoke 1-. It is necessary to increase the magnetic resistance of the plunger 3, which lengthens the electromagnet in the axial direction, resulting in an increase in the size of the circuit breaker incorporating the electromagnet.

An object of the present invention is to provide a structure of an electromagnet which can increase the ratio of the instantaneous tripping operating current to the minimum operating current without lengthening the electromagnet in the axial direction, thereby avoiding upsizing of the circuit breaker.

[Means for Solving the Problems] In order to achieve the above object, according to the present invention, a cylindrical shape is made of a non-magnetic material and has a bottom surface at least at one end, and is inserted inward in the same axial direction. A rod-shaped plunger made of a ferromagnetic material and a return spring that presses the plunger against the bottom surface, is filled with a buffer solution that controls the moving speed of the plunger in the axial direction, and has an armature at the other end. And a magnet yoke that forms a magnetic path in the radial direction of the plunger that is in contact with the cylindrical body outside the cylindrical body and that supports an armature attracted to the armature; A coil that surrounds the tubular body between the magnetic path in the radial direction of the plunger and the armature and that generates a magnetic flux in the axial direction of the tubular body. In the trip device for a circuit breaker for wiring, the electromagnet is set to a height such that a coil surrounding the tubular body substantially leaves a gap between the armature and the plunger on the magnetic path side of the magnet yoke in the plunger radial direction. It shall be rolled up.

[Action]

By constructing the electromagnet in this way, the conventional three
As shown in the figure, the magnetic flux φ passing through the magnetic path in the plunger radial direction of the magnet yoke by passing a current through the coil.
A large proportion of _c passes through the air gap between the armature and the armature, so that even if the instantaneous tripping operation current is not so large, the armature can be pulled out from the operating mechanism of the circuit breaker and attracted to the armature. On the other hand, as shown in FIG. 2, in the magnetic flux φ _c , a leakage magnetic flux φ _L directly flowing from the coil to the magnet yoke is generated between the coil and the armature, so that the magnetic flux passes through the armature. As a result, the magnetic flux φ _a toward the armature is reduced, and with the same instantaneous tripping operation current as in the conventional case, it is no longer possible to obtain an attractive force sufficient to detach the armature from the operating mechanism. For this reason, it is necessary to flow a larger current through the coil, which results in a larger instantaneous trip operating current than in the conventional case. On the other hand, the minimum operating current is
The force of the return spring is weak, and even if the coil current is small, the plunger can be easily moved to the armature position.
Also, when the plunger is in contact with the armature, the inside of the coil is a magnetic path made only of ferromagnetic material, and the magnetic flux generated between the armature and armature is independent of the coil height and is only due to the magnetomotive force of the coil. Therefore, if the number of coil turns is equal, the minimum operating current does not change. Therefore, as in the present invention, by winding the coil on the magnetic path side of the magnet yoke in the radial direction of the plunger to a height that substantially leaves a gap between the armature and the plunger, the electromagnet is minimized in operation in the axial direction. It is possible to increase the ratio of the instantaneous trip operation current to the current. In this case, since the height of the coil is lower than that of the conventional one, the coil can be increased in the radial direction.
The circuit breaker fits in the space around the coil and does not increase the size of the circuit breaker.

[Embodiment] FIG. 1 shows the structure of an electromagnet according to an embodiment of the present invention.
The coil 15 that surrounds the tubular body 4 is wound from the surface of the magnetic path in the radial direction of the plunger of the magnet yoke 1 to a height h, and the axial direction between the left end surface of this coil and the right end surface of the armature 6 is increased. The distance between the left end surface of the plunger 3 and the armature 6
Is approximately equal to the distance from the right end face of the. Except for the coil 15, the construction and components of the electromagnet are exactly the same as the conventional one (FIG. 6).

In this way, by winding the coil surrounding the tubular body at a height which leaves a gap between the armature and the plunger on the plunger radial direction magnetic path side of the magnet yoke, when a current is applied to the coil. Of the magnetic flux in the axial direction generated inside the cylindrical body, a leakage magnetic flux that directly goes between the armature and the coil end face in the direction of the magnet yoke is generated. Insufficient force to remove from the operating mechanism. For this reason, it is necessary to flow a larger current through the coil, and the instantaneous tripping operating current becomes large and the multiplication factor with respect to the minimum operating current becomes large.

[Effect of device]

As described above, according to the present invention, a rod-shaped plunger made of a non-magnetic material and formed of a ferromagnetic material, which is formed into a cylindrical shape having a bottom surface at at least one end and is inserted inward in the same axial direction, A tubular body that accommodates a return spring that presses the plunger against the bottom surface, is filled with a buffer solution that controls the moving speed of the plunger in the axial direction, and has an armature at the other end; A magnet yoke that forms a magnetic path in the radial direction of the plunger that contacts the cylindrical body outside the magnet and supports an armature attracted to the armature; a magnetic path in the radial direction of the plunger of the magnet yoke and the armature. A tripping device for a circuit breaker having an electromagnet, the coil surrounding the tubular body and generating a magnetic flux in the axial direction of the tubular body; Since the electromagnet is configured such that the coil surrounding the tubular body is wound on the plunger radial direction magnetic path side of the magnet yoke at a height that substantially leaves a gap between the armature and the plunger, the electromagnet is It is possible to increase the ratio of the instantaneous trip operating current to the minimum operating current without increasing the size, and it is possible to provide a circuit breaker of the same size as the conventional one that can be installed on the primary side of the transformer. It was

[Brief description of drawings]

FIG. 1 is a partial sectional view showing the structure of an electromagnet according to an embodiment of the present invention, FIG. 2 is an explanatory view showing the state of magnetic flux in the electromagnet of the present invention, and FIG. 3 is showing the state of magnetic flux in a conventional electromagnet. Explanatory drawing, FIG. 4 and FIG. 5 show the mounting condition of the electromagnet in the circuit breaker for wiring, FIG. 4 is a partial sectional plan view of the circuit breaker for wiring, and FIG.
FIG. 6 is a partial sectional view showing a configuration example of a conventional electromagnet,
FIG. 8 is an explanatory view showing the position of the plunger when operating with the minimum operating current of the electromagnet shown in FIG. 6, and FIG. 8 is an explanatory view showing the position of the plunger when operating with the instantaneous trip operating current of the electromagnet shown in FIG. FIG. 9 is a diagram showing the relationship between the current flowing through the coil and the operating time of the electromagnet. 1: Magnet yoke, 2: Armature, 3: Plunger,
4: Cylindrical body, 4a: Bottom surface, 5,15: Coil, 6: Armature, 7: Return spring, 8: Silicon oil (buffer solution).

Claims (1)

[Scope of utility model registration request] 1. A rod-shaped plunger made of a non-magnetic material and made of a ferromagnetic material which is formed in a cylindrical shape having a bottom surface at least at one end and is inserted inward in the same axial direction, and the plunger is pressed against the bottom surface. And a return spring that accommodates a return spring, which is filled with a buffer solution for controlling the moving speed of the plunger in the axial direction and has an armature at the other end; and a tubular body outside the tubular body. A magnet yoke that forms a magnetic path in the radial direction of the plunger that is in contact with and supports an armature that is attracted to the armature; and the tubular body between the magnetic path in the radial direction of the plunger of the magnet yoke and the armature. In a tripping device for a circuit breaker for wiring, which has an electromagnet having a coil for generating a magnetic flux in the axial direction of the tubular body, a coil surrounding the tubular body. Le almost leave tripping of circuit breaker, characterized by being wound in height while supplying air gap between the armature and the plunger to the plunger radially path side of the magnet yoke.