JP4916212B2 - Heater using eddy current due to load current - Google Patents

Description

  The present invention relates to a heater installed in a distribution box such as a substation.

  Conventionally, in a substation or the like, a distribution box is installed, and a switch or a controller as an accessory is provided therein. In such a distribution box, when dew condensation occurs in a low temperature period such as winter, it causes rust in terminal portions of various devices such as a switch, a controller, or a relay. In order to prevent condensation, a space heater and a dehumidifier are installed in the distribution box.

  Since the operation of such a space heater or dehumidifier consumes electric power, there is a problem of increasing the electric power consumption in the station. In addition, since the space heater is disconnected due to its life, it is necessary to temporarily interrupt the power for replacing the disconnected space heater.

Patent Document 1 below discloses a ventilation structure in which a ventilation plate is provided on the upper part of the distribution box in order to prevent condensation on the inner wall of the distribution box. In this ventilation structure, a ventilation plate that forms a step portion having an opening is provided on the upper part of the distribution box to prevent rain from entering and condensing.
Japanese Utility Model Publication No. 5-41317

  However, such a ventilation structure with only a ventilation plate is not sufficient for preventing condensation on various devices installed in the distribution box.

  In view of these problems, an object of the present invention is to provide a heater that can prevent dew condensation in a distribution box and can reduce power consumption without using a space heater or a dehumidifier.

The present invention has a hole through which a connection conductor such as a power cable in a distribution box is electrically insulated, and is made of a material that generates heat using an eddy current generated by a current flowing through the connection conductor. A heater having a heater member , wherein a slit communicating with the hole is provided in a side portion of the heater member, and a bimetal switch is disposed in the slit .

In a preferred embodiment, the heater member has a notch portion extending from the hole to one side and an adjustment member movably disposed in the notch portion. In another form, you, wherein no heat is generated to prevent the occurrence of eddy currents in the heater member to release the notch moves in the direction to draw the adjusting member from the notch.

According to the present invention, the current flowing through the connection conductors such as power cables through the holes of the heater member, since the heat generation by eddy current is generated in the heater member, not separately require power, current flowing through the connection conductor Can be used. Moreover, since there is no disconnection, there is no need for replacement.
Furthermore, the generation of eddy currents can be automatically stopped at a predetermined temperature or higher by a bimetal switch disposed in a slit provided on the side of the heater member.

  FIG. 1 is a perspective view of a distribution box in which a heater using eddy current due to load current is installed.

The distribution box 1 is formed in a box shape by a metal plate. In the distribution box 1, three-phase power cables 2 and 3 are provided as connection conductors, and a switch 4 connected to the power cable 2. And another switch 5 connected to the power cable 3 is provided. These switches 4 and 5 act so as to open and close circuits to various external devices.

  The power cable 2 is provided, for example, on the front side in the distribution box 1, and the power cable 3 is provided behind the power cable 2. The heaters 10 that use eddy currents are respectively disposed on the three-phase power cables 2 and 3 in the distribution box 1. In addition, the distribution box 1 is provided with a temperature sensor 6 or a temperature sensor that also serves as a humidity sensor at an appropriate position.

  The distribution box 1 has a large size of width × width × height, for example, 2200 × 700 × 2400 (mm), and a large current of 200 to 400 mm flows through the three-phase power cables 2 and 3 respectively. Yes. As described above, since a large amount of current flows through the power cables 2 and 3, when the heater 10 is attached to the power cables 2 and 3, an eddy current is generated in the heater 10 and the heater 10 itself generates heat. It can be used as a heater for heating means. Such use of the heater 10 is used in a cold season so as to prevent condensation, and is not used in a season when there is no concern about condensation.

  The heaters 10 are respectively attached to the power cables 2 and 3 in the distribution box 1 at height positions spaced apart from each other in the vertical direction. By arranging the heaters 10 in such a state, the heaters 10 are provided so as not to interfere with each other, and can be arranged so that the distance between the power cables 2 and 3 can be sufficiently maintained. The interval between them can be narrowed, and the size of the distribution box 1 can be reduced.

  For example, the power cable 2 has a thickness of about 40 mm, a height in the distribution box 1 of about 1200 mm, a distance between the cables of the power cable 2 of 200 mm, and a vertical distance of the heater 10 of about 300 mm. Further, the thickness of the power cable 3 is about 40 mm, the height in the distribution box 1 is about 1000 mm, the distance between the cables of the power cable 3 is 200 mm, and the vertical distance of the heater 10 is about 300 mm.

  2 and 3 show the heater member 12 constituting the heater 10, which is formed in a rectangular shape from a metal plate of a magnetic material such as an iron plate, for example, and has three holes 20 for the power cables 2 and 3. It has been. The shape of the heater member 12 is not limited to a rectangle, and can be formed in any other appropriate shape, and can be formed into an arbitrary shape such as a rectangle or a square according to the shape and size of the distribution box 1 as a container to be installed. Is possible.

  The heater member 12 is provided with a notch 21 along one side of the metal plate. A U-shaped notch 22 as a guide groove is formed on a side surface of the notch 21. The adjusting member 14 is inserted and slidably provided, and is slidably attached so that the adjusting member 14 can be inserted or pulled out in the front-rear direction by an eyebolt 18 provided on the front side of the adjusting member 14. Yes.

  Furthermore, the heater member 12 is provided with slits 23 narrower than the notches 21 with respect to the respective holes 20 on the opposite side portion, and the bimetal switch 16 is disposed in each slit 23. Such a heater member 12 has a sufficient thickness and is made of an iron plate thicker than the thickness of the adjusting member 14, and bolts or screws are attached to the mounting hardware 7 (FIG. 4) provided in the distribution box 1. Alternatively, both ends are fixedly attached by welding or the like. The mounting hardware 7 is made of mold steel such as an angle member, and is attached to the inner wall of the distribution box 1. Both ends of the heater member 12 are fixed, and the heater member 12 is attached to the distribution box 1 in a shelf shape. It has been.

  4 and 5 show a state in which the heater 10 is attached to the power cable 2, and passes through substantially the center of the three holes 20 for the power cables 2 and 3 provided in the heater member 12. The power cables 2 and 3 extend in a substantially vertical direction.

  Therefore, the heater member 12 is attached to the fitting 7 of the distribution box 1 by an appropriate fixing means such as a screw, a bolt, or welding, and the power cable 2 is approximately at the center of the hole 20 of the heater member 12. Moreover, it is disposed in an electrically insulated state so as not to touch the edge of the hole 20, and extends vertically through the hole 20.

  Further, the heater member 12 can adjust the generation of eddy current in the heater member 12 by sliding the adjustment member 14 slidably attached to the notch 22 with respect to the heater member 12. The adjustment member 14 can be slid by engaging and operating a hook 30 (FIG. 11) at the tip of the insulating rod 26 to an eyebolt 18 provided on the front surface side of the adjustment member 14.

6 to 8 show a use state for adjusting the generation of the eddy current by the adjusting member 14 as described above. FIG. 6 shows the maximum use, and FIG. 7 shows the intermediate use inserted to the middle. FIG. 8 shows a non-use state in which the minimum insertion is almost zero. The adjustment member 14 can be adjusted steplessly from the maximum use state of FIG. 6 to the minimum non-use state of FIG. 8. The adjustment member 14 is formed in the notch 22 of the notch 21 of the heater member 12. In order to prevent the adjustment member 14 from being pulled out, a stopper 24 is attached to the inner side of the cut 22, that is, the rear side, and a stopper 25 is attached to the outer front side, for example, welding. And is fixed. Further, instead of providing the stoppers 24 and 25, it is also possible to prevent the adjustment member 14 from being inserted and withdrawn by caulking a part of the cut 22 or the like.

  Such an adjustment member 14 is made of a plate-like member such as an iron plate, for example, and is provided with a locking portion 15 protruding left and right on the rear surface side. The locking portion 15 engages with the stopper 24 of the notch 22 so as to prevent the adjustment member 14 from protruding into the hole 20 when the adjustment member 14 is fully inserted, and in the direction in which the adjustment member 14 is pulled out. It is formed to engage with a stopper 25 on the front side of the notch 22 so as to prevent the adjustment member 14 from coming out of the notch 22 of the heater member 12 and falling off when being pulled out.

  Therefore, the adjusting member 14 is slidable along the notch 22 and can be slid so that the position can be freely moved so that it can be inserted and extracted, thereby suitably adjusting the generation of eddy current in the adjusting member 14. be able to.

  That is, at the time of use, the adjusting member 14 is moved along the notch 22 and is, for example, at the maximum use (FIG. 6) inserted to the innermost position, at the intermediate use (FIG. 7) inserted to the middle, and at a minimum It is possible to adjust to three states when the plug is not used (FIG. 8). The eddy current is often generated at the maximum use when the adjustment member 14 is inserted to the end, and the eddy current is less generated at the intermediate use when the adjustment member 14 is inserted to the middle. In the state, eddy current is hardly generated. Therefore, it is possible to adjust the generation of eddy current substantially steplessly according to the amount of insertion of the adjusting member 14 from the maximum use state of FIG. 6 to the non-use state of FIG.

  Further, the notch 22 is not limited to the U-shaped cross section, but can be formed in any other cross sectional shape that can act as a guide groove or a guide path, and the adjustment member 14 can be slid during use. Therefore, it is important in which state the adjustment member 14 can be arranged and positioned.

  The eyebolt 18 is attached to the front surface of the adjusting member 14 to move the adjusting member 14. The eyebolt 18 includes a ring portion 18 a and a bolt portion 18 b, and the threaded bolt portion 18 b is attached to the adjusting member 14. The screw can be screwed into the screw hole or attached to the upper or lower surface of the adjusting member 14 by welding. In the case of screwing with screws, the adjustment member 14 needs to have a sufficient thickness in order to provide a screw hole for mounting the screw. Alternatively, the thickness of the adjustment member 14 may be small for welding to the lower surface, and it is not necessary to make the adjustment member 14 as thick as when screwing. Further, the eyebolt 18 can be welded to the front portion of the adjusting member 14 only as the ring portion of the head.

The bimetal switch 16 is provided in the slit 23 formed on the other side of the hole 20 of the heater member 12 as described above, and includes the contact member 16a and the bimetal member 17 formed by bonding different metals. At all times, the bimetal member 17 is in contact with the fixed contact member 16a as shown in FIG. 9, and the bimetal member 17 is deformed and separated from the fixed contact member 16a during an operation at a predetermined temperature or higher . As a result , the bimetal switch 16 acts as a switch that automatically stops the generation of eddy currents at a predetermined temperature or higher (FIG. 10).

  FIG. 11 shows a state where the adjustment member 14 is operated by the insulating rod 26. In order to slide the adjusting member 14 to which the eyebolt 18 is attached, the insulating rod 26 has a grip portion 27, a collar 28, an operating rod portion 29, and a hook 30 at the tip of the operating rod portion 29. Made of an insulating material.

  The insulating rod 26 is formed so that the gripping portion 27 is gripped and the hook 30 at the tip is locked in the hole 19 of the eyebolt 18 of the adjustment member 14 so that the adjustment member 14 can be slid. The collar 28 acts to protect the operator's hand holding the grip portion 27. Further, it is preferable that the tip of the operation rod portion 29 is chamfered so that it can be operated so as not to hit other portions.

  Therefore, the adjustment member 14 can be pulled out by the insulating rod 26 to adjust the generation of the eddy current in the heater member 12. If the amount of the adjustment member 14 is small, the generation of the eddy current is large and the amount of the extraction is small. If the number is large, the generation of eddy current is reduced, and the heat generation amount of the heater member 12 can be adjusted according to the generation amount of the eddy current.

Although the present invention has been described with reference to one embodiment, the present invention is not limited to this embodiment, and various changes and modifications can be made. For example, the above embodiment is a case where the power cable is arranged in the distribution box, but the present invention is similarly applied not only to the power cable but also to the case where the connection conductor generating eddy current is arranged. .

It is a perspective view of the distribution box which has a heater using an eddy current. It is a top view of a heater member. It is a front view of the heater member of FIG. It is a top view of the heater member installed with respect to the power cable in a distribution box. It is a longitudinal cross-sectional view of the power cable and heater member of FIG. It is a top view at the time of maximum use of an adjustment member. It is a top view at the time of intermediate use of the adjustment member of FIG. It is a top view at the time of non-use of the adjustment member of FIG. It is sectional drawing at the time of the contact of the bimetal in a heater member. FIG. 10 is a cross-sectional view of the bimetal of FIG. 9 during operation. It is a figure which shows the state which operates an adjustment member with an insulation stick.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Distribution box, 2, 3 ... Electric power cable, 4, 5 ... Switch, 10 ... Eddy current heater, 12 ... Heater member, 14 ... Adjustment member, 15 ... Locking part, 16 ... Bimetal switch, 16a ... Contact member , 17 ... Bimetal member, 18 ... Eye bolt, 20 ... Hole, 21 ... Notch, 22 ... Notch, 23 ... Slit, 24, 25 ... Stopper, 26 ... Insulating rod, 27 ... Grip part, 28 ... Gutter, 29 ... Operation Stick part, 30 ... hook.

Claims (3)

A heater member made of a material that has a hole through which a connection conductor such as a power cable in the distribution box is electrically insulated and that generates heat using an eddy current generated by a current flowing through the connection conductor. A heater comprising :
A heater characterized in that a slit communicating with the hole is provided in a side portion of the heater member, and a bimetal switch is disposed in the slit . 2. The heater according to claim 1, wherein the heater member includes a notch portion extending from the hole to one side opposite to the side portion, and an adjustment member disposed movably in the notch portion. A heater characterized by that.   3. The heater according to claim 2, wherein generation of eddy current in the heater member is prevented when the adjusting member is moved in a direction to be pulled out from the notch and the notch is opened.

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