JPS5855834Y2 - Air-cooled electrical equipment - Google Patents

Description

[Detailed description of the invention] This invention increases the size of the structure by covering the entire circumference of a part of the circumferential surface of the heat radiating element that is connected to the mounting surface of the heating element with an insulator with a space interposed therebetween. The present invention relates to an air-cooled electric device which has a large insulation creepage distance and prevents insulation breakdown when dust adheres to an insulating plate to which a heat radiator is attached.

Generally, electrical equipment such as rectifiers, inverters, and AC voltage control power supplies use heating elements such as semiconductor elements as components, so a means to cool the heating elements is required. There are two types: an oil-cooled type that is cooled with cooling oil, and an air-cooled type that is cooled with air.

However, oil-cooled electrical equipment requires large amounts of cooling oil.
As the capacity of the device increases, the area of the heatsink must also increase, making the device larger in size, which leads to various disadvantages such as a large space required for installation and increased manufacturing costs. have.

A cooling method that eliminates this drawback and does not increase in size even when the capacity of the equipment increases is the air cooling type.Explaining a conventional air cooling type electric equipment, for example, a rectifier for plating processing, the rectifier The device supplies a low voltage and large current to a load, and as shown in Figure 1, it is a thyristor made by connecting a three-phase AC power source 1, an input switch 2 and two thyristors 3 in antiparallel. 3 phase 200 through stack 4
V or 400μ to the primary side of the transformer 5, and the low voltage and large current on the secondary side of the transformer 5 is controlled by the inexpensive thyrisk stack 4. , are output from an output terminal 7 via a diode stack 6.

As shown in FIG. 2, the assembly of each component shown in FIG. In this case, a cooling air inlet 10 is formed in the upper part of one side, and an outlet 11 is formed in the lower face, and a cooling fan 12 for sucking air is formed in the upper part of the casing 9, facing the inlet 10. Decorated.

Since the thyristor 3 of the thyristor stack 4 generates heat as described above, installation requires some effort. Mounting surface 14' of mounting part 14''
Then, as shown in FIGS. 3 to 5, the thyristor 3 is led out from the through hole 16 of the insulating plate 15, and the mounting surface 14' of the heat sink 14 is attached to the insulating plate 1 with screws or the like.
5, and an insulating plate 15 is installed between the two mounting arms 17 so that the heat radiator 14 is located in the flow path of cooling air by the cooling fan 12.

Therefore, by driving the cooling fan 12, cooling air is blown against the fins 13 of the heat radiator 14, and the thyristor 3 is cooled via the heat radiator 14.

Note that 18 is a shielding plate attached to the mounting arm 17 in close proximity to the upper and lower ends of the insulating plate 15, and a 3-phase AC voltage of 200 V or 400 mm is applied to the thyristor 3 as described above. Therefore, the cooling air flows through thyristor 3.
It is shielded from being hit.

By the way, inside factories such as plating or electrolytic factories where the above-mentioned plating processing rectifier is installed, or chemical factories and steel factories where other air-cooled electrical equipment is installed, there is moisture, corrosive gas, dust, etc. Therefore, the cooling fan 12 sucks in dust etc. from the suction port 10, and this dust etc. adheres to the insulating plate 15 and stains the insulating plate 15. between the heat sink 14 and the mounting arm 1
Insulation deterioration occurs during the 7-day period, impeding the operation of the equipment and shortening the life of the equipment.

In addition, since the heat sink 14 to which the thyristor 3 is mounted is usually formed by cutting an extruded aluminum profile into a predetermined length, if acid or alkali dust adheres to the insulating plate 15, the heat sink 14 will be damaged. Arc discharge tends to occur from the sharp corners of the ends of the fins 13, further reducing the insulation properties and eventually causing dielectric breakdown.

Therefore, it is possible to prevent dielectric breakdown by increasing the insulation creepage distance from the heat dissipation body 14 to the mounting arm 17 in the insulating plate 15, but this increases the size of the insulating plate 15 and increases the size of the equipment. This eliminates the advantages of the air-cooled system, and it also becomes expensive.

This invention takes into account the various shortcomings of the conventional methods and uses a simple structure to increase the insulation creepage distance and prevent dielectric breakdown without increasing the size of the insulator.
Next, this invention will be explained in detail with reference to the drawings of FIGS. 7 to 9 showing embodiments thereof.

First, in FIGS. 7 and 8 showing one embodiment,
Components that are the same as those in FIGS. 1 to 6 are given the same symbols, and the difference is that an insulator 19 is provided.
This insulator 19 has a heating element 20 such as a semiconductor element in the center.
．． An insertion hole 21 is provided through the mounting surface 14' of the heat sink 14.
a rectangular substrate 19a with slightly larger vertical and horizontal dimensions;
Peripheral portions 19b extending perpendicularly from each of the four sides of the substrate 19a are integrally formed.

Then, the heating element 20 is attached to the mounting portion 14'' of the heat radiating element 14, and the heating element 20 is inserted into the insertion hole 21 of the insulator 19 to connect the substrate 19a of the insulator 19 and the mounting surface 14' of the heat radiating element 14. After joining, the heating element 20 is inserted into the through hole 16 of the insulating plate 15 from the cooling air flow path side, and the heating element 20 is inserted into the through hole 16 of the insulating plate 15.
The heat radiator 14 is fixed to the insulating plate 16 via the insulator 19 with screws or adhesive.

Therefore, the mounting surface 14 of the heat radiator 14, which has descended from the mounting portion 14'', is attached to the insulating plate 15 with the insulator 190 substrate 19a interposed therebetween.
At the same time, the entire circumference of a part of the circumferential surface of the heat sink 14 connected to the mounting surface 14' is connected to the insulator 1 through the space 22.
9, the insulation creepage distance from the corner of the heat sink 14 to the mounting arm 17 is
As shown by the broken line in the figure, compared to the insulation creepage distance of conventional air-cooled electrical equipment shown by the dashed line in the figure, the insulation plate 1
5 without increasing its shape, and even if dust adheres to the insulating plate 15, arc discharge does not occur because the insulation creepage distance is long, and insulation deterioration is unlikely to occur.

Note that since the cooling air hits the peripheral surface of the heat radiator 14 that is not covered with the insulator 15, there is no problem with the cooling effect of the heat generator 20.

Alternatively, a configuration as shown in FIG. 9 may be used.

That is, the insulator 23 is formed of insulating paper such as Mylar, the heating element 20 attached to the heat sink 14 is inserted into the insertion hole 24 of the insulator 23, and the heating element 20 is inserted into the through hole 16 of the insulating plate 15. When the heat radiator 14 is fixed to the insulating plate 15, the center path of the insulator 23 is pressed by the heat radiator 14, and the peripheral edge 23' of the insulator 23 rises. The entire circumference of a part of the circumferential surface continuous with the mounting surface 14' is covered with the space 22', and the same effect as in the previous embodiment is obtained.

As described above, according to the air-cooled electrical equipment of this invention, on one mounting surface of the block-structured heat radiator having fins,
Attach the heating element of the semiconductor element, attach the heating element such as the heating element through the through hole of the insulating plate, lead out the heating element through the through hole of the insulating plate, and remove the mounting surface excluding the mounting part of the heating element. , is attached to an insulating plate via an insulator, the periphery of the insulator is raised up, and between the periphery of the insulator and the entire circumference of a part of the circumferential surface of the heat sink that extends to the mounting surface, By forming a space, the insulation creepage distance can be increased without increasing the size of the equipment, and when dust adheres to the heat sink and insulation plate, arc discharge from the corners of the heat sink can be prevented. This can be prevented, and dielectric breakdown can be prevented.

Furthermore, since it has a simple configuration that only requires an insulator, it is inexpensive.

In particular, the air-cooled electrical equipment of this invention exhibits remarkable effects when installed in plating factories, chemical factories, steel factories, etc., where there is a lot of dust and corrosive gas.

[Brief explanation of the drawings] Figures 1 to 6 show conventional air-cooled electrical equipment, with Figure 1 being a wiring diagram, Figure 2 being a cutaway right side view, and Figure 3 being a view from the front. FIG. 4 is a plan view of FIG. 3, FIG. 5 is a right side view of FIG. 3, FIG. 6 is a perspective view of the heat sink, and FIGS. One embodiment of the refrigerated electrical equipment is shown, FIG. 7 is an exploded perspective view of the main parts, FIG. 8 is a cutaway plan view of the main parts, and FIG. 9 is a cutaway plane of the main parts of another embodiment of this invention. It is a diagram. 13... Fin, 14... Heat sink, 1
4'...Mounting surface, 14''...Mounting part,
15...Insulating plate, 16...Through hole, 19
゜23...Insulator, 19 b, 23'...
... Peripheral part, 20 ... Heating element, 22.22'.
...Space department.

Claims (1)

[Scope of utility model registration request] Mounting a heating element such as a semiconductor element on one mounting surface of a heat radiator having a block structure having fins, leading out the heating element through a through hole in an insulating plate, and mounting the heating element excluding the mounting part of the heating element. The surface is attached to the insulating plate via an insulator, the peripheral edge of the insulator is raised up, and the peripheral edge of the insulator and a part of the peripheral surface of the heat sink that continues to the mounting surface are Air-cooled electrical equipment with a space formed between the entire circumference.