JPS5819784Y2 - Arc extinguishing chamber for oil-filled breaker - Google Patents

Description

[Detailed explanation of the idea] This invention relates to an arc extinguishing chamber of an oil breaker.

In the arc extinguishing chamber of an oil breaker, a suppression resistance wire such as nichrome wire is connected between the fixed contact and the intermediate contact, and when the movable contact is in contact with the fixed contact, the intermediate contact is The suppressing resistance wire is short-circuited through the movable contact in contact with the movable contact, and when the suppressing resistance wire is opened, a resistance circuit is formed between the movable contact and the fixed contact by the suppressing resistance wire, thereby suppressing the re-electromotive voltage. Such a resistance shielding system is well known.

Generally, the suppression resistance wire is placed around the outer periphery of the insulating tube that makes up the arc extinguishing chamber.
It is common practice to install a resistance wire by winding it into a coil.

Experiments have shown that when inspecting an oil breaker, when the tank is lowered, insulating oil adheres to the resistance wire wrapped around the arc extinguishing chamber, and due to surface tension, it becomes covered with an oil film, causing the coil to be tightly wound. If it is, the spiral resistance wire will look like a cylindrical pipe.

Even after the tank is returned to its original position and the arc extinguishing chamber is immersed in insulating oil, it is recognized that air is trapped inside this pipe-shaped coil and cannot be easily released.

By the way, when the movable contactor opens while the breaker is in use, a high voltage is applied to both ends of the suppressing resistance wire, current flows through the resistance wire, and the temperature becomes high.

At this time, if air remained inside the resistance wire coil as mentioned above, it would heat up and expand, filling the inside and outside surfaces of the resistance wire, and the creeping dielectric strength of the resistance wire would rapidly decrease. The resistance decreases, develops into an open circuit between the terminals, and becomes useless as a resistor.

In order to avoid this, conventionally the pitch between the coils of the resistance wire was increased so that the surface tension of the oil would not act, but this had the disadvantage that the coil length became too large and the insulating tube had to be larger. was.

The purpose of this invention is to release the air inside the coil and obtain a predetermined dielectric strength even if the coil pitch of the suppression resistance wire is dense and the surface tension of oil acts.

This invention is characterized in that a plurality of portions of the coiled suppression resistance wire are provided with a particularly sparse coil pitch.

To explain the embodiment of this invention with the drawings, 1 is an insulating cylinder constituting an arc extinguishing chamber, and as is well known, this is an insulating cylinder with an arc extinguishing plate installed inside and a bushing surrounding a fixed contact. Fixed downward.

A semicircular groove 3 is formed in a spiral shape on the outer periphery of the insulating cylinder 1, avoiding the oil injection hole 2, and a coiled suppressing resistance wire (for example, nichrome wire) 4 is fitted into this groove 3 to insulate it. Wrap it around the outer circumference of tube 1.

These configurations are no different from known configurations, but according to this invention, particularly sparse coil pitch portions 5 (hereinafter referred to as splits) are provided in a part of the circular coil-shaped suppressing resistance wire 4 at regular intervals. .

This split 5 is provided at a plurality of locations on the outer periphery of the insulating cylinder 1.

The work is easy because the cut 5 is simply provided in the suppression resistance wire 4 wound around the outer periphery of the insulating cylinder 1.

In the above configuration, when the oil tank is lowered and installed after inspection, even if the coil pitch is close and an oil film is formed due to the surface tension of the oil, the air in the coiled resistance wire 4 will not flow through the insulating cylinder 1. Groove 3 having a spiral shape and therefore a public distribution
Since it is attached to the wall, it is emitted from the split 5.

Therefore, since the inside of the coiled resistance wire 4 is completely immersed in insulating oil, it is possible to avoid a decrease in dielectric strength between the coils and the coil surface due to residual air.

Note that in the embodiment shown in the figure, the suppressing resistance wire is wound around the outer periphery of the insulating tube 1, but it goes without saying that this idea is also applicable even if the suppressing resistance wire is wound around a dedicated insulating tube instead. As detailed above, according to this invention, the reduction in dielectric strength can be prevented by winding the suppression resistance wire in a dense manner, instead of winding it with a uniform sparse coil pitch as in the past. This has the effect of reducing the length of the winding of the suppressing resistance wire and making the arc extinguishing chamber more compact.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the invention, Fig. 2 is a back view showing an embodiment of the invention, Fig. 3 is a plan view of the suppression resistance wire, and Fig. 4 is a plan view of the suppression resistance wire.
The figure is an enlarged sectional view of an insulating tube and a partially suppressed resistance wire. 1...Insulating tube, 4...Suppressing resistance wire, 5
・・・・・・Sparse pitch part.

Claims (1)

[Scope of utility model registration request] A tightly coiled suppressing resistance wire is wound tightly so that the wires of the coil are covered with an oil film, and is wound spirally around the outer periphery of an insulating cylinder, and the pitch of the coil is made particularly sparse by pressing buttons at regular intervals. An arc extinguishing chamber for an oil-immersed circuit breaker, in which an insulating cylinder provided with the suppressing resistance wire is placed in oil, and a plurality of parts are provided with the suppressing resistance wire.