JP3245220B2 - Capacitor - Google Patents

Abstract

PURPOSE:To provide a reliable capacitor having simple and easily applicable means for quickly measuring the temperature distribution over the whole capacitor. CONSTITUTION:A capacitor case 1 is coated in part or overall with reversible temperature-sensitive paints 11-13 or irreversible temperature-sensitive paints 14 and 15; the individual paints change colors at different temperatures. Preferably, both reversible and irreversible paints are applied in regular bands 11-13 and 14-15, and the temperature range, in which they change colors, extends both sides of the maximum operating temperature of the capacitor. Although not limited, stripes of paints are typically applied on the capacitor case vertically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large industrial capacitor, and more particularly to a technique for controlling the surface temperature of a capacitor for a high-frequency AC filter or a commutation capacitor.

[0002]

2. Description of the Related Art Generally, an industrial capacitor is provided with a predetermined capacitor.
Connect multiple elements in series and parallel to satisfy the ratings.
CapacitorElement groupForming this capacitorElement group
In a case filled with electrical insulating oildo itComposed
ing.

Among such industrial capacitors, NH capacitors and SH capacitors are used as high-frequency AC filter capacitors and commutation capacitors used in inverter circuits and the like. In this case, the NH capacitor is formed by combining a thin film of a capacitor and an organic film, or an element in which a dielectric film made of only an organic film and a metal electrode foil such as an aluminum foil are wound in a case and housed in a case. The SH capacitor is configured by combining vapor-deposited metallized paper and an organic film, or by storing an element wound by only a vapor-deposited metallized film in a case.

Incidentally, these NH capacitors and SH
If a capacitor is used in a high-frequency power supply as a high-frequency AC filter or commutation capacitor,
The temperature of the main body rises due to the internal loss of the element . This
As a countermeasure for reducing the temperature rise of, but the dielectric low loss can be reduce internal losses of the element by using, if the temperature rises by eddy current loss due to the high frequency large current and conductor resistance loss is there. Also, the capacitor body
It may occur even temperature rise when caused abnormalities such as a short circuit
Was .

[0005] Such a rise in the temperature of the capacitor is a major factor that significantly affects the life of the capacitor, and also serves as a criterion for determining the presence or absence of an abnormality such as a short circuit. Therefore, it is required that the state of the capacitor is determined by grasping the temperature of the entire capacitor, and if there is an abnormality, this can be easily and promptly detected to prevent a serious accident from occurring.

[0006] Then,like thisTemperature of entire capacitor
There are several conventional methods for measuring temperature
Is considered. For example, Temperature around the capacitor
Place a measuring instrument to measure the temperature around the capacitor.
How to Attach a thermocouple to the case surface to
How to measure the degree, Put a thermo label on the case surface
There is a method for measuring the case surface temperature
You.

FIG. 2 shows such a method. Thermo
The method of attaching the label is based on the AC
Shows an example applied to capacitors used in filter circuits
It is a figure, (a) is a top view and (b) is a front view. You
That is, it is used for AC filter circuit of inverter circuit.
Capacitor returns the harmonic current to the inverter side.
Heat generation is relatively problematic.
As such a capacitor, 230VAC-200μ
F, f = 420Hz (for 7th harmonic)
Considering that, the effective current is about 124 A and the apparent power is about 28
kVA.

In this case, typically, as shown in FIG. 2, the size of the case 1 of the capacitor body is 240 × 9.
It becomes 0 × 300 (mm). A pair of electrode terminals 2 and 3 are arranged side by side at the center in the front-rear direction on the upper surface of the case 1, and a distance of 120 m is provided between the electrode terminals 2 and 3.
m intervals are provided. Further, a ground terminal 4 is arranged at a right rear corner near the right electrode terminal 3 on the upper surface of the case 1.

Then, in order to measure the temperature of the capacitor body having such a structure, the upper surface of the case 1
Thermolabels 5 and 6 are attached to the end near the left electrode terminal 2 and the rear of the center between the electrode terminals 2 and 3, respectively. Further, thermolabels 7 and 8 are attached to the front and center of the front surface of the case 1 at the center in the width direction, respectively.

In the method shown in FIG. 2, the temperature distribution of the entire capacitor can be grasped visually, though roughly, by sticking thermo labels 5 to 8 on each part of the surface of the case 1. Since it has an advantage that it can be grasped in a general manner, it has been conventionally generally employed.

[0011]

However, the conventional capacitor temperature measuring method as described above has the following problems.

That is, How to measure ambient temperaturePlace
CombinationIf there is another heating element around the capacitor,
Because it is affected by the heat, another source
It can be used only when there is no heat. Besides, this
The method measures the temperature of the space around the capacitor and
By comparing with the temperature, the surrounding
It can only measure the temperature rise of the space,
Depending on the situation, there may be considerable errors.
It can only be expected to know the degree of heat generation of the densa.

Next, How to attach a thermocoupleIn the case of,
Work of wiring thermocouples is required, and temperature measurement is continued
Equipment needs to be continuously installed
Yes, but this is practically difficult. Therefore, this one
The law is only used in formal tests.

On the other hand, as shown in FIG. Sir
How to attach a morabellein the case ofIs, as mentioned above,
By attaching a thermo label to each part of the case surface
The temperature distribution of the entire capacitor is not
However, it can be grasped visually and
It has the advantage that it can be done. On the other hand, this one
According to the law, multiple thermo labels are attached to each part of the case surface.
Work, especially for more detailed temperature distribution
If you are trying to measure
Must be individually applied all over the case surface
No workability. In addition, thermo label dimensions
Is small, and even if you look
Display cannot be checked all at once.
To grasp the temperature distribution of the entire sensor,
Each morelle must be checked visually
No. Therefore, the temperature distribution of the whole capacitor can be easily done in a short time.
There is a disadvantage that it cannot be grasped.

The present invention has been proposed to solve the above-mentioned problems of the prior art, and its object is to easily and accurately grasp the temperature distribution of the entire capacitor in a short time.
Can, to provide a capacitor having high reliability with a temperature measuring means simple structure excellent in workability. Another purpose is to detect the abnormality of the capacitor easily and promptly by such a temperature measuring means and to prevent a serious accident before it occurs.

[0016]

A capacitor according to the present invention comprises an element in which a dielectric film consisting of a combination of a thin film of a capacitor and an organic film or a dielectric film consisting of only an organic film and a metal electrode foil such as an aluminum foil are wound. In the case of an NH capacitor housed in an SH or an SH capacitor in which a device obtained by combining vapor-deposited metallized paper and an organic film or wound by only a vapor-deposited metallized film is housed in a case, a part of or the entire surface of the case has a discoloration temperature. Characterized in that a plurality of different types of reversible thermosensitive paints and irreversible thermosensitive paints different from each other are applied.

The reversible thermosetting paint and the irreversible
In general, reversible and irreversible thermal paints having several discoloration temperatures centered on the upper limit of the operating temperature range of the capacitor are applied to the application area which is regularly divided. it is intended to be applied, respectively. in this case,
Although the division of the application region of the temperature indicating paint can be appropriately selected, typically, the application is made to a plurality of rows of band-like application regions extending in the vertical direction of the case.

[0018]

According to the capacitor of the present invention having the above-described configuration, a plurality of types of reversible thermosensitive paints and irreversible thermosensitive paints having different discoloration temperatures are applied to a part or the entire surface of the case. The temperature distribution of the capacitor body is
Since it is reflected in the colors of multiple types of paint, the temperature distribution of the entire capacitor can be grasped by visually checking the discoloration state of these multiple types of paint, and whether the operating temperature has reached the discoloration temperature. It can be easily grasped.

That is, in both the reversible thermoreactive paint and the irreversible thermoreactive paint, when the case surface temperature rises above its discoloration temperature, the paint discolors and the case surface temperature reaches the discoloration temperature or more. To show that In this case, since the reversible temperature-indicating paint returns to the primary color when the temperature becomes lower than the discoloration temperature, it has a function of immediately displaying the case surface temperature. On the other hand, the irreversible temperature-indicating paint has a function of displaying the history of the case surface temperature being equal to or higher than the discoloration temperature in order to maintain the discolored state without changing the color even when the temperature is lower than the discoloration temperature. . And since the temperature distribution of the whole capacitor can be confirmed by the color of the paint,
Unlike the conventional case where a plurality of thermolabels are attached, it is not necessary to visually confirm the individual labels, and it is possible to easily visually confirm them collectively.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of an embodiment of a capacitor according to the present invention will be described below with reference to FIG. This figure 1
Is the same as the conventional capacitor shown in FIG.
A capacitor of the same rating and dimensions for the C filter, ie, 230 VAC-200 μF, f = 420 Hz (7th
The case size is 240 × 90 × 300
It is a figure which shows one Example which applied this invention to the capacitor of (mm), (a) is a top view, (b) is a front view. In this case, the basic configuration of the capacitor body in the present embodiment is the same as that of the prior art in FIG. That is,
A pair of electrode terminals 2 and 3 are arranged side by side at the center in the front-rear direction on the upper surface of the case 1, and a distance of 120 mm is provided between the electrode terminals 2 and 3. A ground terminal 4 is disposed at the right rear corner near the electrode terminal 3. The maximum allowable temperature of this capacitor is 60 ° C., and the capacitor is designed to allow a temperature rise of 15 ° C. or less.

In this embodiment, in order to display the temperature of the capacitor body having such a configuration,
Approximately 20 mm extending from the upper surface to the front surface of case 1
Strip-shaped application regions 11 to 15 having five rows in width were provided. That is, these band-shaped application regions 11 to 15 extend linearly from the rear end of the upper surface of the case 1 to the front end,
The case 1 was provided so as to extend linearly from the upper end to the lower end so as to be continuous with the front surface of the case 1. Of these, 50 ° C., 60 ° C., and 70 ° C.
Each of the three types of reversible temperature-indicating paints having a color change temperature of 0 ° C. is applied, and the remaining two rows of application areas 14 and 15 on the right side are applied.
Two irreversible thermostatic paints having discoloration temperatures of 70 ° C and 80 ° C, respectively, were applied. In this case, as the reversible temperature-indicating paint, a paint mainly containing a complex salt of mercury iodide was used, and as the irreversible temperature-indicating paint, a paint mainly containing a double salt of nickel and cobalt was used. .

Next, the operation of the capacitor of the present embodiment configured as described above will be described. That is, five rows of the temperature-indicating paint application areas 11 to 1 in the capacitor of the present embodiment.
In order to specifically examine the action of No. 5, the capacitor body of FIG. 1 was left in a constant temperature bath set at 50 ° C., 60 ° C., 70 ° C., and 80 ° C., and the results shown in the following Table 1 were obtained. was gotten.

[0023]

[Table 1]

As can be seen from Table 1, clear discoloration was confirmed in a short time in the three rows of the reversible thermosensitive paint application areas 11 to 13 and the two rows of the irreversible thermosensitive paint application areas 14 and 15. . Subsequently, after discoloration at each temperature, the capacitor body was left at room temperature, and the two rows of irreversible thermosensitive paint application areas 14 and 15 maintained the discolored state.
The reversible thermosensitive paint application areas 11 to 13 in the row all returned to the primary colors in a short time.

These results indicate that the discoloration of the reversible temperature-indicating coating areas 11 to 13 and the return to the primary colors can be achieved immediately in a temperature range from about 50 ° C. to about 70 ° C. around the maximum allowable temperature (60 ° C.). The temperature can be easily, accurately and continuously grasped, and at the same time, a temperature of 70 ° C. or more, which exceeds the maximum allowable temperature, is reached by the discoloration of the irreversible thermosensitive paint application areas 14 and 15 and the maintenance of this discolored state. It shows that you can easily and accurately grasp your background.

Therefore, in the capacitor according to the present embodiment, it is continuously determined whether or not the operation state of the capacitor is immediately appropriate based on the instantaneous temperature display by the reversible thermosensitive paint application areas 11 to 13. While being able to
The life of the capacitor can be determined based on the high-temperature history display by the irreversible temperature-indicating paint application areas 14 and 15. As a result, the reliability of the entire device can be improved. In addition, the use of the temperature indicating paint as the temperature measuring means can contribute to the simplification of the configuration, and the application of the temperature indicating paint is extremely easy and can be automated by a machine. There is an advantage that it can contribute to improvement.

It should be noted that the present invention is not limited to the capacitor designed in the above embodiment, but can be similarly applied to capacitors of various ratings. The type and number can be appropriately selected, and the application area can be freely selected.

[0028]

As described above, in the present invention, a plurality of types of reversible thermosensitive paints having different discoloration temperatures and irreversible thermosensitive paints are applied to a part or the entire surface of the case, thereby obtaining the entire capacitor. The temperature distribution can be easily and accurately grasped in a short time, and a highly reliable capacitor having a temperature measuring means having a simple configuration excellent in workability can be provided. Then, by displaying the temperature using the temperature indicating paint, it is possible to easily and quickly find an abnormality in the capacitor and prevent a serious accident from occurring.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a capacitor according to the present invention, wherein (a) is a plan view and (b) is a front view.

FIG. 2 is a diagram showing an example of a conventional capacitor;
(A) is a plan view, (b) is a front view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Case 2, 3 ... Electrode terminal 4 ... Earth terminal 5-8 ... Thermo label 11-13 ... Reversible thermosensitive paint application area 14, 15 ... Non-reversible thermosensitive paint application area

Claims (1)

(57) [Claims] 1. An element in which a capacitor thin paper and an organic film are combined or a dielectric film composed of only an organic film and a metal electrode foil are stacked and wound, or a combination of a vapor-deposited metallized paper and an organic film or a vapor-deposited metallization In a capacitor in which an element wound by a film alone is housed in a case, a plurality of types of reversible thermosensitive paints and irreversible thermosensitive paints having different discoloration temperatures are applied to part or the entire surface of the case. Capacitor.