JPH0528015U - Oil immersion condenser - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an oil-immersed capacitor that reliably maintains the pressure contact state of the packing rubber, which greatly affects the dielectric strength between grounds, and long-term stability, and that is highly reliable even in harsh environments. With the goal. [Structure] In a terminal lead-out structure of an oil-immersed capacitor, a reinforcing plate is sandwiched between insulating plates 6 so as to face 80 to 100% of the area of the part where the packing rubber 5 comes into pressure contact with the insulating plates 6 to face each other. Place the portion 12.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an oil-immersed capacitor having a terminal extraction structure and having improved dielectric strength between a terminal and a closed outer case (hereinafter referred to as a ground) when a closed outer case made of metal is used.

[0002]

[Prior Art]

 Conventionally, as shown in FIG. 5, the structure of taking out the lid terminal of the oil-immersed capacitor includes an insulating cup 3, an upper lid metal plate 4, a packing rubber 5, and an insulating plate 6 between the terminal fitting 1 and the seat portion A of the terminal rod 2. A method of scissors, press-contacting and welding fitting is adopted. In the figure, 7 is a metal case, 8 is an insulating case, 9 is a capacitor element, 10 is impregnated oil, and 11 is a lead plate.

FIG. 6 is an enlarged cross-sectional view of the terminal lead portion, and it can be seen that the dielectric strength between the grounds is maintained by the packing rubber 5 entering between the terminal rod 2 and the upper lid metal plate 4.

[0004]

[Problems to be solved by the device]

 However, as can be seen from FIG. 6, the portion B is the weakest point in terms of proof stress because the insulation distance between the grounds is the shortest, and most of the faults between the grounds occur at this portion. As mentioned above, the dielectric strength between grounds depends largely on the packing rubber condition.

[0007] Therefore, if the packing rubber is initially in a badly inserted state or the state is deteriorated during actual use, there is a high possibility that a problem will occur, which is dangerous.

[0006] The cause is that, as described above, under a heat cycle environment due to long-term use due to high temperature or intermittent use thereof, the force exerted on the packing rubber which is always in pressure contact is weakened, and as a result, As shown in FIG. 7, a minute gap is generated in the D portion, and the dielectric strength is reduced. The reason why the pressure contact force is weakened is that the insulating plate 6, which is the base for pressure contacting the packing rubber, is gradually distorted under the above-mentioned environment to become permanent strain and weaken the pressure contact force.

When the inside of the oil-immersed capacitor is heated to a high temperature due to heat generation and ambient temperature, the hermetically sealed outer casing slightly expands due to expansion of the impregnated oil. However, when the temperature is returned to room temperature again, the sealed outer casing made of metal does not completely return and some permanent strain occurs, resulting in a negative pressure state where the internal pressure is lower than normal pressure. It is known that in this negative pressure state, the aforementioned decrease in dielectric strength is further accelerated.

However, in recent years, the demand for the environment in which the oil-immersed capacitor is used has become strict, and there is a demand for a highly reliable one that can withstand higher temperature use and has a longer life. Therefore, it is necessary to reduce the dielectric strength of the conventional structure.

Therefore, the present invention solves the above problems and provides a highly reliable oil-immersed capacitor that can be used at higher temperatures for a longer period of time.

[0010]

[Means for Solving the Problems]

 As mentioned above, it was found that the dielectric strength between grounds largely depends on the pressure contact state of the packing rubber. Therefore, in the present invention, as a method of improving this point, insulation is performed so that 80 to 100% of the area of the packing rubber 5 pressed against the insulating plate 6, that is, the area C shown in FIG. A reinforcing plate made of metal or resin was placed on the opposite side of the plate.

[0011]

[Action]

 By providing the reinforcing plate part, the pressure contact force of the packing rubber can be made even and strong, so that it is possible to maintain a more stable pressure contact state against negative pressure due to long-term use or high temperature use.

[0012]

【Example】

 Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

1A and 1B are an enlarged sectional view and an enlarged front view of a terminal lead-out portion of an oil-immersed capacitor according to a first embodiment of the present invention. The embodiment shown in FIG. 1 (a) is an example in which a metal plate or a resin plate is sandwiched between the reinforcing plates 12 and assembled, and the positional relationship is shown in FIG. 1 (b). E is the packing rubber 5 after pressure welding, F is the reinforcing plate 12, and G is the outer circumference of the seat of the terminal rod 2. The reinforcing plate 12 covers 80-100% of the area of the bottom surface of the packing rubber 5. It is provided in.

2 (a) and 2 (b) show a second embodiment of the present invention. The embodiment of FIG. 2 (a) is a discharge resistor 13 in which the metal reinforcing plate 12 shown in FIG. This is an example in which it is also used as a mounting leg of, and the work and process are simplified and a great effect is obtained. FIG. 2B is a front layout view thereof.

FIG. 6 shows a third embodiment of the present invention in which the seat portion A of the terminal rod 2 is also used as a reinforcing plate.

Here, the effect is greatest when the shape of the reinforcing plate is circular, but as described above, the area of the reinforcing plate is arranged so as to cover 80 to 100% of the bottom area of the packing rubber. There is an effect by being present, and there is no particular focus on the shape.

FIG. 4 shows data of a reliability test conducted to prove the effect of the present invention. As the test method, a dielectric breakdown test between earths was performed with a capacitor rated at 2000 V and 1 μF, and after conducting a continuous current of 85 V at 2500 V for 2000 hours at room temperature, in oil.

As a result, it was confirmed that the capacitor according to the present invention was slightly superior even in the initial stage, and the characteristic deterioration was small even in the negative pressure state after continuous energization, which was very effective.

[0019]

[Effect of the device]

 As described above, the present invention provides a highly reliable oil-immersed capacitor that is stable for a long period of time in terms of ensuring dielectric strength between earths and can withstand high temperature use.

[Brief description of drawings]

FIG. 1A is an enlarged sectional view of a terminal lead portion of an oil-immersed capacitor according to a first embodiment of the present invention. FIG. 1B is an enlarged front view showing the arrangement of a reinforcing plate of the same embodiment.

FIG. 2 (a) is an enlarged sectional view of a terminal lead portion in a second embodiment of the present invention. FIG. 2 (b) is an overall layout view of a discharge resistor constructed in the same embodiment.

FIG. 3 is an enlarged cross-sectional view of a terminal lead portion in the third embodiment of the present invention.

FIG. 4 is a graph showing reliability test data of an oil-immersed capacitor according to an embodiment of the present invention.

FIG. 5 is a sectional view of a conventional oil-immersed capacitor.

FIG. 6 is an enlarged sectional view of the terminal lead-out portion.

FIG. 7 is an enlarged cross-sectional view of the terminal lead-out portion.

[Explanation of symbols]

 1 Terminal Metal Fitting 2 Terminal Rod 3 Terminal Cup 4 Top Lid Metal Plate 5 Packing Rubber 6 Insulation Plate 12 Reinforcement Plate 13 Discharge Resistance

Claims (3)

[Scope of utility model registration request] 1. A lid terminal lead-out structure for an oil-immersed capacitor formed by using a pair of metal foils with a plastic film and insulating paper as a dielectric and winding them together to join a terminal fitting and a lead plate from a capacitor element. When the insulation cup, metal top plate, sealing packing rubber, paper or resin insulating plate, discharge resistance mounting leg, etc. are sandwiched between the terminal rod and the terminal bar, and the parts are welded together by pressure welding, the packing rubber after pressure welding The oil-immersed capacitor is characterized in that a reinforcing plate is arranged on the opposite side of the insulating plate so that 80% to 100% of the area of the part in contact with the insulating plate faces each other. 2. The oil-immersed capacitor according to claim 1, wherein the metal plate used as the reinforcing plate is a mounting leg of the discharge resistor. 3. The oil-immersed capacitor according to claim 1, wherein the seat of the terminal rod is used as a reinforcing plate.