JP2013126262A - Closed type switchboard - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a closed type switchboard capable of easily performing opening operation of a single swinging door disposed at an opening part of a board case, being hardly affected by magnetic attraction force of passage magnetic flux even during a period in which a main circuit conductor is being energized only by changing housing position of the door.SOLUTION: The closed type switchboard is equipped with a single swinging door 2 at an opening part of a board case 1 made from a steel plate in which a main circuit conductor 4 is installed. The door 2 is arranged so that, at a door closing position, a door end part 2b on the side opposite to a hanging part is accommodated inside the opening part of the board case 1. With this configuration, the direction of a magnetic flux which passes the board case 1 and the door 2 due to electrified magnetic field of the main circuit conductor 4 and the direction of a magnetic attraction force generated between the door and the board case following the magnetic flux passage are almost orthogonal to the direction of opening the door. As a result, the effect of the magnetic attraction force acting as a resistive force at the time of opening operation of the door is reduced, allowing easy opening of the door even during electrification of the main circuit.

Description

  The present invention relates to a closed type switchboard applied to a DC power supply facility or the like, and more particularly to an arrangement structure of doors arranged in a casing opening of the switchboard.

  First, the configuration of a conventional switchboard is shown in FIGS. 3 (a) and 3 (b), taking as an example a closed type switchboard applied to the DC power supply equipment described above. In the figure, reference numeral 1 is a box-shaped panel housing surrounded by a steel plate panel, 2 is a single door provided at an opening (maintenance / inspection port) of the panel housing 1, 2a is a handle of the door 2, Reference numeral 3 denotes a hinge shaft that pivotally supports the suspending source of the door 2 on the frame of the panel housing 1, and 4 denotes a main circuit conductor (bus bar) installed in the panel. A hinge may be used instead of the hinge shaft 3.

  Here, the door 2 is a steel plate (plate thickness: about 2 to 3 mm) that is bent inward on the four sides around the door plate, and the door 2 is closed when the door 2 is closed. As shown in the figure, the end 2 on the opposite side (grip side) to the suspension base is abutted against the front end surface of the frame 1a to close the opening of the panel housing 1 Like to do.

  By the way, in the energized state in which a current is passed through the main circuit conductor 4 by the closed type switchboard in which the main circuit conductor 4 is laid inside the board casing 1 assembled with the steel plate (magnetic material) as described above, the main circuit conductor 4 As shown in FIG. 4, a magnetic flux φ flows through the steel plate casing 1 and the door 2 due to the magnetic field generated around, and the passage of the magnetic flux φ causes an arrow between the casing 1 and the door 2 to pass through. The magnetic attraction force F as shown is applied, so that the end 2b of the door 2 opposite to the suspension side is attracted to the closed position.

  Here, when the horizontal coordinate axis of the switchboard is X and the longitudinal coordinate axis is Y, the magnetic attractive force F acting between the end 2b opposite to the door 2 and the panel housing 1 is Y axis. The direction is opposite to the direction of opening the door 2. For this reason, when the user pulls the handle 2a of the door 2 from the closed position shown in FIG. 1 and tries to open the door, the magnetic attractive force F acts as a drag and makes it difficult to open the door. Note that a magnetic attraction force is generated between the door 2 and the suspension side of the door 2 as the magnetic flux φ passes, but the end of the door 2 on the suspension side rotates around the hinge shaft 3. The influence of the magnetic attractive force acting on the suspension side when the door 2 is opened is extremely small.

  If the main circuit current is alternating current (for example, three-phase alternating current), the main circuit conductors of each phase installed in the panel are wired close to each other, so that the magnetic field is canceled between the phase conductors. Therefore, the magnetic flux φ passing through the panel casing 1 and the door 2 is reduced, but in the case of direct current, the forward path and the return path of the main circuit conductor 4 are often separated separately and installed in the panel. Accordingly, the amount of magnetic flux passing through the panel casing 1 and the door 2 also increases.

  For this reason, in a closed type switchboard having a large current capacity applied to a DC power supply facility, when the rated current of the main circuit reaches several thousand A, when the door 2 is closed, It has been experienced that a large magnetic attractive force F (see FIG. 4) acts between the front end of the opening of the panel housing 1 and it is extremely difficult to open the door 2 by the force of one maintenance person.

  In order to avoid unforeseen electric shock accidents, the closed type switchboard is normally locked to the closed position while the main circuit is energized so that it cannot be opened. In some cases, there is a middle door equipped with measurement and control devices, and the door 2 may be opened to perform measurement, control operation, and inspection even when the main circuit is energized.

  Therefore, as a countermeasure for allowing maintenance personnel to easily open the switchboard door 2 even when the main circuit is energized, as disclosed in Patent Document 1, there is a non-contact between the panel casing 1 and the door 2. There has been known one in which a magnetic attractive force acting between both members is reduced by interposing a spacing member of a magnetic material.

Japanese Patent Laid-Open No. 11-8914

  By adopting the panel structure disclosed in Patent Document 1, it can be expected that the door opening operation performed while the main circuit is energized can be easily performed. In addition to the complexity of the assembly structure at the front, manufacturing costs increase, and when rubber or the like is used for the nonmagnetic spacing material, it becomes difficult to ensure the strength of the switchboard.

  Therefore, an object of the present invention is to provide a simple circuit modification of the main circuit conductor by simply changing the position of the door, without additionally installing a nonmagnetic spacing material between the opening of the panel housing and the door. An object of the present invention is to provide a closed type switchboard in which door opening operation can be easily performed without being affected by magnetic attractive force due to passing magnetic flux even during energization.

In order to achieve the above object, according to the present invention, in a closed type switchboard equipped with a single door at the opening of a board casing made of a steel plate laid with a main circuit conductor in the board,
The door is arranged so that the door end on the side opposite to the suspension base is accommodated inside the panel housing opening at the door closed position.

  According to the above configuration, the magnetic flux passing between the opening of the board casing made of steel plate (magnetic material) and the opposite end of the single door by energization of the main circuit conductor installed in the board, and The direction of the magnetic attractive force generated between the door and the panel housing as the magnetic flux passes is in a direction substantially perpendicular to the direction of opening the door toward you. Thereby, the influence of the magnetic attractive force acting as a drag force during the door opening operation is reduced, and the door can be opened easily even when the main circuit is energized.

  Moreover, there is no need to add a nonmagnetic spacing material to the opening of the panel housing as in the above-mentioned Patent Document 1 in terms of structure, and the door end on the side opposite to the door suspending source is in the closed position. This can be done simply by making a simple modification to fit inside the opening.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic block diagram of the closed type switchboard by the Example of this invention, Comprising: (a) is an external appearance perspective view of the whole board, (b) is a cross-sectional plan view of the switchboard front part in (a). It is explanatory drawing of the magnetic attraction force which acts between a board | substrate housing | casing and a door by the structure of FIG. It is the schematic structure figure of the conventional closed type switchboard, Comprising: (a) is an external appearance perspective view of the whole panel, (b) is a cross-sectional top view of the switchboard front part in (a). It is explanatory drawing of the magnetic attraction force which acts between a panel housing | casing and a door by the structure of FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on the examples shown in FIGS.
In the drawings of the illustrated embodiment, members corresponding to those in FIGS. 3 and 4 are denoted by the same reference numerals and description thereof is omitted.

  The closed type switchboard of the illustrated embodiment has basically the same structure as the conventional switchboard shown in FIG. 3, but the single door 2 disposed in the opening of the panel housing 1 is in the door closed position. The arrangement position is changed and arranged as follows.

  That is, as shown in FIG. 1B, when the door 2 is closed, the peripheral edge of the door 2 is arranged so as to be inside the frame 1 a (inner peripheral side) disposed in the opening of the panel housing 1. . Although not shown, the frame 1a is provided with a receiving seat (stopper) made of, for example, non-magnetic metal or resin along the inner periphery thereof. The plate is received in the closed position.

  With the above configuration, when the door 2 is closed, the magnetic flux φ passing through the panel housing 1 and the door 2 crosses the end 2b of the door 2 on the side opposite to the suspension side as shown in FIG. As shown in the drawing, the magnetic attraction force F acting on the door 2 also flows along the Y-axis direction between 1a and 1a. The direction is substantially orthogonal to the opening / closing direction of the.

  Therefore, the magnetic attraction force F does not prevent the door 2 from being opened unlike the conventional structure (see FIG. 4), and the door 2 can be opened easily even when the main circuit conductor 4 is energized and with the power of one maintenance person. Moreover, it is not necessary to provide a nonmagnetic spacing material at the opening of the panel housing 1 as in the above-mentioned Patent Document 1, and the door end 2b on the side opposite to the suspension side at the closed position of the door 2 is This can be easily handled by making a slight change so as to fit inside the frame 1a arranged in the opening.

DESCRIPTION OF SYMBOLS 1 Panel housing 1a Frame 2 Single door 2a Door handle 2b Anti-hanging side edge of door 3 Hinge shaft of lifting side 4 Main circuit conductor φ Magnetic flux F Magnetic attraction force

Claims (1)

In a closed type distribution board equipped with a single door at the opening of the board casing made of steel plate with the main circuit conductor laid in the board,
The closed type switchboard, wherein the door is arranged so that a door end opposite to a suspension base is accommodated inside a panel housing opening at the door closed position.