JP5325015B2 - Circuit breaker electromagnetic trip device - Google Patents

Description

  The present invention relates to an electromagnetic trip device for a circuit breaker for operating a breaker mechanism when a short-circuit current is detected and breaking a circuit.

  The circuit breaker is equipped with an electromagnetic trip device that instantly detects when a short-circuit current, etc. flows in the circuit, and the circuit breaker operates in response to the short-circuit current detection operation of the electromagnetic trip device. Is opened (see, for example, Patent Document 1).

Conventional electromagnetic tripping devices used for such purposes include a fixed electromagnetic piece that is fixedly installed and a movable electromagnetic piece that is closed by electromagnetic force to this fixed piece. It was made of a metal made of a magnetic material.
The fixed electromagnetic piece and the movable electromagnetic piece are made of, for example, iron. However, since such a magnetic body has difficulty in processing accuracy, it has been a cause of variation in operating characteristics and generation of roaring noise. Therefore, the configuration as shown in FIG. 4 has been adopted.

In FIG. 4, 101 is a fixed electromagnetic piece, 102 is a movable electromagnetic piece, and 103 is an electric circuit. The fixed electromagnetic piece 101 is formed so as to be bent in a substantially U shape and surround the electric circuit 103. It arrange | positioned so that the U-shaped open part of the fixed electromagnetic piece 101 may be obstruct | occluded.
The movable electromagnetic piece 102 was formed of a magnetic plate 102a having magnetism that covers the entire open portion of the fixed electromagnetic piece 101, and a hinge member 102b formed of a nonmagnetic member such as a nickel steel plate. Thus, by forming the rotating shaft portion 102c from a metal that is easy to process with high accuracy, the processing accuracy can be increased, and variations in operation and the like can be eliminated. In FIG. 4, S2 is the minimum distance in the open state of the fixed electromagnetic piece 101 and the movable electromagnetic piece 102, T2 is the maximum distance, and S2 = 0.15 mm and T2 = 3.0 mm.

JP-A-8-315704

However, even when the movable electromagnetic piece 102 is composed of two members as shown in FIG. This roaring sound is generated when a large current near the rated current flows through the electric circuit 103, and is generated when the movable electromagnetic piece 102 is attracted to the fixed electromagnetic piece 101 by the magnetic force generated at this time.
For this reason, it can be easily estimated that if the distance between the fixed electromagnetic piece 101 and the movable electromagnetic piece 102 is sufficiently large, it can be easily suppressed. However, if the distance is simply increased, the characteristic itself for detecting the short-circuit current changes. The standard will not be satisfied, and the electromagnetic tripping device will be enlarged. In addition, a large design change is required from the conventional configuration as shown in FIG. 4, which is not a problem that can be simply solved.

  Accordingly, in view of such problems, the present invention provides an electromagnetic trip device for a circuit breaker capable of preventing the occurrence of a roaring sound without greatly changing the conditions such as the dimensions of an electromagnetic trip device having a conventional configuration. The purpose is to do.

In order to solve the above-mentioned problem, the invention according to claim 1 includes a fixed electromagnetic piece that is bent in a substantially U-shape and includes a back plate and left and right side plates, and a U-shaped opening portion of the fixed electromagnetic piece. A movable electromagnetic piece disposed on the left and right side plates so as to open and close the U-shaped opening, and an electric circuit is inserted between the fixed electromagnetic piece and the movable electromagnetic piece. In the electromagnetic tripping device of the circuit breaker in which the movable electromagnetic piece in the open state is closed by the magnetic field generated by a short-circuit current flowing in the electric circuit and is in contact with the side plate, the movable electromagnetic piece is A magnetic plate covering at least a part of the U-shaped open portion of the fixed electromagnetic piece, and a hinge member having a hinge piece made of a non-magnetic material that holds the magnetic plate and is hinged to the left and right side plates. is configured, the magnetic plate has a width across the left and right side plates and, Has a height 50% to 70% of the height of the serial side plates, the U-shaped is open portion a portion covering disposed at a site distant from the hinged piece, the said magnetic plate in the open state The minimum distance from the fixed electromagnetic piece is 0.8 mm or more, and the maximum distance is about 3 mm.
According to this configuration, since the minimum distance between the magnetic plate in the open state and the fixed electromagnetic piece, that is, the minimum distance between the movable electromagnetic piece in the steady state and the fixed electromagnetic piece is not less than 0.8 mm, a large current near the rated current is obtained. Even if a squeezes flow, no humming noise is generated by the generated magnetic force. Moreover, the maximum value of the distance between the magnetic plate of the movable electromagnetic piece and the fixed electromagnetic piece is about 3 mm, which is the same as the conventional numerical value, and the short circuit current is detected well without increasing the overall size of the electromagnetic trip device. Can be done.
And since the magnetic plate is not arranged in the vicinity of the hinge piece closest to the fixed electromagnetic piece, the distance between the fixed electromagnetic piece and the movable electromagnetic piece can be set to 0.8 mm or more without increasing the entire distance between the fixed electromagnetic piece and the movable electromagnetic piece. It becomes possible. In addition, since the rotational force of the magnetic plate due to the magnetic force generated by the short-circuit current is so small that it reaches the vicinity of the hinge piece, even if no magnetic member is disposed in this portion, the short-circuit current detection operation is not greatly affected. Therefore, it is possible to prevent a roaring sound with a minimum design change.

  In the case of an electromagnetic tripping device having a configuration in which a movable electromagnetic piece is arranged so as to cover the U-shaped open portion of the fixed electromagnetic piece and both are hinged, the fixed electromagnetic piece and the movable electromagnetic piece (magnetic body thereof) It has been experimentally confirmed that no roaring sound is generated if the distance is more than a specific value of 0.8 mm. The maximum distance between the fixed electromagnetic piece and the movable electromagnetic piece in the open state is usually about 3.0 mm.

According to the present invention, the distance between the magnetic plate in the opened state and the fixed electromagnetic piece, that is, the distance between the magnetic member and the fixed electromagnetic piece in the steady state movable magnetic piece is 0.8 mm or more, so it is close to the rated current. Even if a large current flows through the squeal, no squealing noise is generated by the generated magnetic force. Further, since the maximum value of the distance between the magnetic plate of the movable electromagnetic piece and the fixed electromagnetic piece is about 3 mm, the overall size of the electromagnetic tripping device does not increase.
In addition, since there is no need for a magnetic plate in the vicinity of the hinge piece, the magnetic plate can be made shorter than the height of the side plate, and the distance from the fixed electromagnetic piece can be made 0.8 mm or more with a minimum design change. .

It is side explanatory drawing which shows an example of the electromagnetic trip apparatus of the circuit breaker which concerns on this invention. FIG. 2 is an explanatory plan view of FIG. 1. It is side surface explanatory drawing of the electromagnetic trip apparatus which shows the other form of this invention. It is side surface explanatory drawing of the conventional electromagnetic trip device.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described in detail with reference to the drawings. 1 and 2 show an example of an electromagnetic trip device for a circuit breaker according to the present invention. FIG. 1 is a side view and FIG. 2 is a plan view. In the figure, 1 is a fixed electromagnetic piece, 2 is a movable electromagnetic piece, 3 is an electric path made of a strip-shaped copper piece, and 4 is an engaging piece that makes a non-illustrated shut-off mechanism section cut off by rotating the movable electromagnetic piece 2. For convenience of explanation, the following description will be made with the left direction in the drawing as the front and the right direction as the rear.

The fixed electromagnetic piece 1 is formed by bending a metal plate having magnetism, such as iron, into a U shape as shown in FIG. 2, and has a back plate 1a and left and right side plates 1b and 1b. The left end of the side plate 1b, which is the tip of the side plate 1b, has end faces 1c and 1c arranged in parallel as shown in FIG. 2, and the pair of end faces 1c and 1c are slightly inclined as shown in FIG. And is a contact surface of the movable electromagnetic piece 2. And the axial part 10 which hinges the movable electromagnetic piece 2 is provided in the lower part of the side plate 1b.
The fixed electromagnetic piece 1 is disposed so as to accommodate the electric circuit 3 inside the space surrounded by the back plate 1a and the side plate 1b, and is fixed in a circuit breaker housing (not shown).

The movable electromagnetic piece 2 includes a magnetic plate 2a having magnetism with a quadrangular plate, and a hinge member 2b connected to the fixed electromagnetic piece 1 and made of a nonmagnetic material. The magnetic plate 2a is connected to the hinge member 2b by caulking.
The magnetic plate 2a has a width extending to the left and right side plates 1b, and the height L2 is formed to be about 60% of the height L1 of the fixed electromagnetic piece 1 so as to face the upper portion of the end surface 1c of the fixed electromagnetic piece 1. Be placed.

The hinge member 2 b includes a holding piece 11 that holds the magnetic plate 2 a, a hinge piece 12 that extends backward from the left and right ends of the holding piece 11 to be hinged to the fixed electromagnetic piece 1, and a movable electromagnetic piece 2. Is engaged with the coil spring 14 by projecting forward from the center of the lower end of the holding piece 11 in order to bias it in a predetermined direction (a direction in which the front of the fixed electromagnetic piece 1 is opened away from the fixed electromagnetic piece 1). It consists of a piece 13. The left and right butterfly pieces 12, 12 are arranged outside the left and right side plates 1b and are respectively attached to the shaft portion 10. Thus, the movable electromagnetic piece 2 is hinged to the fixed electromagnetic piece 1.
Compared with the conventional configuration of FIG. 4, the magnetic plate 2a has a size of about 60%. At the time of opening in a steady state, the minimum distance S1 formed at the lowermost portion between the magnetic plate 2a and the fixed electromagnetic piece 1 is 1.0 mm, and the maximum distance T1 formed at the uppermost portion is 3.0 mm. is there.

It has been confirmed by experiments that this minimum distance S1 can be eliminated if the minimum distance S1 is 0.8 mm or more, and can be reduced to a specific value of 0.8 mm. On the other hand, the maximum distance T1 is the same as the conventional value of 3.0 mm in FIG. This distance should not be changed in terms of operating characteristics, and is preferably the same. However, if it exceeds 3.5 mm, the overcurrent detection characteristic is deteriorated, which is not preferable.
Further, when the height of the magnetic plate 2a is 50% or less of the height L1 of the fixed electromagnetic piece 1, the short-circuit current detection operation is affected. When the height exceeds 70%, the shortest distance T1 is set to a specific value. In order to secure the above, design change matters such as lengthening the hinge piece 12 increase, and therefore the height of the magnetic plate 2a is preferably 50 to 70% of the height T1 of the fixed electromagnetic piece 1.

The electromagnetic tripping device configured in this way generates a magnetic field B as shown in FIG. Due to this magnetic field B, an electromagnetic force that attracts the magnetic plate 2 a is generated in the fixed electromagnetic piece 1, and the movable electromagnetic piece 2 rotates in the direction of arrow A 1 against the bias of the coil spring 14, and the fixed electromagnetic piece 1 abuts against the end face 1c. This moment (rotational force) is smaller than the case shown in FIG. 4 in which the magnetic plate 2a is formed long so as to cover the entire length of the end face 1c, but the magnetic plate in the vicinity of the hinge piece 12 having a originally small moment. Is simply deleted, the moment is reduced slightly, and no significant change occurs in the breaking operation characteristics.
Thus, the movable electromagnetic piece 2 rotates, and the upper end of the movable piece 2 comes into contact with the engaging piece 4 so that the engaging piece 4 moves rearward as indicated by an arrow A2 in FIG. As a result, a not-shown shut-off mechanism is shut off, and a contact (not shown) provided in the middle of the electric circuit 3 is opened.

Thus, since the distance between the open magnetic plate 2a and the fixed electromagnetic piece 1, that is, the distance between the stationary movable electromagnetic piece 2 and the fixed electromagnetic piece 1 is not less than a specific value of 0.8 mm, it is close to the rated current. Even if a large current flows through the squeal, no squealing noise is generated by the generated magnetic force. Moreover, since the maximum value of the distance between the magnetic plate 2a of the movable electromagnetic piece 2 and the fixed electromagnetic piece 1 is 3.0 mm, the overall size of the electromagnetic trip device does not increase.
And since the magnetic plate 2a is not disposed near the hinge piece closest to the fixed electromagnetic piece 1, the distance between the fixed electromagnetic piece 1 and the movable electromagnetic piece 2 is 0.8 mm or more without increasing the entire distance between the fixed electromagnetic piece 1 and the movable electromagnetic piece 2. It becomes possible. Moreover, since the rotational force of the magnetic plate 2a due to the magnetic force generated by the short-circuit current is so small that it reaches the vicinity of the hinge piece 12, it does not significantly affect the short-circuit current detection operation even if the magnetic plate 2a is not disposed in this portion. . Therefore, it is possible to prevent a roaring sound with a minimum design change.

FIG. 3 is an explanatory side view showing another example of the electromagnetic tripping device of the present invention, and will be specifically described below. However, the same components as those in the above embodiment are given the same reference numerals and the description thereof is omitted. In FIG. 3, 21 is a fixed electromagnetic piece, 22 is a movable electromagnetic piece, and the fixed electromagnetic piece 21 is formed by bending a metal plate having magnetism such as iron into a U-shape as in the above embodiment. The back plate 21a and the left and right side plates 21b and 21b are formed.
On the front surface of the side plate 21b, a flat end surface 21c with which the movable electromagnetic piece 22 abuts is formed at the upper part with a slight inclination, and the lower part is provided with an inclination in the opposite direction to ensure a distance from the movable electromagnetic piece 22. It has been. In addition, a shaft portion 30 that hinges the movable electromagnetic piece 22 is provided below the side plate 21b.

  The movable electromagnetic piece 22 includes a magnetic plate 22a having a rectangular plate shape and magnetism, and a hinge member 22b connected to the fixed electromagnetic piece 21 and made of a nonmagnetic material. The magnetic plate 22a has the same size as the magnetic plate 102a of FIG. That is, it has a width across the left and right side plates 21b, 21b, and the height L2 is formed to be substantially the same as the height L1 of the fixed electromagnetic piece 1 and is disposed so as to face the upper portion of the end surface 21c of the fixed electromagnetic piece 21. The

The hinge member 22 b includes a holding piece 31 that holds the magnetic plate 22 a, a hinge piece 32 that extends backward from the lower left and right ends of the holding piece 31 to be hinged to the fixed electromagnetic piece 21, and the coil spring 14. It is comprised from the engaging piece 13 to engage. The left and right butterfly pieces 32, 32 are disposed outside the left and right side plates 21b, 21b, and are pivotally attached to the shaft portion 30, respectively. Thus, the movable electromagnetic piece 22 is hinged to the fixed electromagnetic piece 21.
The hinge piece 32 is formed slightly longer than the hinge piece 12 of the above-described embodiment, and the position of the shaft portion 30 formed on the side plate 21b is slightly moved backward. Thus, the minimum distance S1 formed at the lowermost portion between the magnetic plate 22a and the fixed electromagnetic piece 21 at the time of opening in a steady state is 1.0 mm, and the maximum distance T1 formed at the uppermost portion is 3.0 mm. .

The electromagnetic tripping device configured in this way is the same as in the above embodiment, and when a short-circuit current flows through the electric circuit 3, the movable electromagnetic piece 22 rotates against the bias of the coil spring 14, and the fixed electromagnetic It abuts on the end face 21c of the piece 21. As a result, a not-shown shut-off mechanism is shut off, and a contact (not shown) provided in the middle of the electric circuit 3 is opened.
The moment (rotational force) at this time is the same as the magnetic plate 102 in FIG. 4 because the size of the magnetic plate 22a is the same as the shape of the tip of the side plate 21b, the position of the shaft portion 30, and the length of the hinge piece 32. Although there is a difference, the moment does not change greatly, and the breaking operation characteristics do not change.

  As described above, since the distance between the open magnetic plate 22a and the fixed electromagnetic piece 21, that is, the distance between the stationary movable electromagnetic piece 22 and the fixed electromagnetic piece 21 is not less than 0.8 mm, a large current is close to the rated current. Even if a squeezes flow, no humming noise is generated by the generated magnetic force. Moreover, since the maximum value of the distance between the magnetic plate 22a of the movable electromagnetic piece 22 and the fixed electromagnetic piece 21 is 3.0 mm, the overall size of the electromagnetic tripping device does not increase.

  In the above embodiment, the magnetic plates 2a and 22a are held from the front by the hinge members 2b and 22b, but may be held from the side. Moreover, although the electric circuit 3 inserted through the fixed electromagnetic pieces 1 and 21 is a strip-like copper piece, it may be a bimetal piece for detecting an overcurrent.

  1 .... Fixed electromagnetic piece, 1a ... Back plate, 1b ... Side plate, 1c ... End face, 2. Moving electromagnetic piece, 2a ... Magnetic plate, 2b ... Hinge member, ... Electric circuit, 10 ... Shaft part, 21 .. Fixed electromagnetic piece, 21a ... Back plate, 21b ... Side plate, 21c ... End face, 22 ... Movable electromagnetic piece, 22a ... Magnetic plate, 22b ... Hinge member, 30 ... Shaft part .

Claims (1)

A fixed electromagnetic piece that is bent in a substantially U-shape and includes a back plate and left and right side plates, and a U-shaped open portion of the fixed electromagnetic piece is disposed so as to open and close the U-shaped open portion. A movable electromagnetic piece hinged to the left and right side plates, an electric path is inserted between the fixed electromagnetic piece and the movable electromagnetic piece, and a magnetic field generated by a short-circuit current flowing through the electric path is opened. In the electromagnetic tripping device of the circuit breaker in which the movable electromagnetic piece in the closed operation is brought into contact with the side plate,
The movable electromagnetic piece includes a magnetic plate that covers at least a part of the U-shaped open portion of the fixed electromagnetic piece, and a hinge piece made of a non-magnetic material that holds the magnetic plate and is attached to the left and right side plates. A hinge member having
The magnetic plate has a width ranging from the left and right side plates and a height of 50 to 70% of the height of the side plates, and is a part that covers the U-shaped opening and is separated from the butterfly piece. Placed in the site,
An electromagnetic trip device for a circuit breaker, wherein a minimum distance between the magnetic plate in the open state and the fixed electromagnetic piece is 0.8 mm or more and a maximum distance is about 3 mm.

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