JPH05274950A - Structure of disconnecting switch contact portion - Google Patents

Abstract

PURPOSE:To omit the process of polishing and cleaning a contact surface at a disconnecting switch contact portion while stopping electricity if switching is not carried out for a long period of time, the process being required to prevent failure in the transmission of electricity which may be caused by compounds forming on the contact surface, or to prevent losses due to melting. CONSTITUTION:Metal fittings 9 are placed between a shape memory alloy coil 3 attached to an anchoring bolt 7 and a bias spring 4 and a fixed contact piece 1 is fixed to a fixing portion base 6 by the anchoring bolt 7. In an electric circuit provided between the fixing portion base 6 and the fixed contact piece 1, the shape memory alloy coil 3 and a flexible conductor 5 form a parallel circuit, and when electricity is transmitted a current to be passed from the fixing portion base 6 to the fixed contact piece 1 flows through the shape memory alloy coil 3 and the flexible conductor 5. Then an increase or decrease in the amount of the transmitted electricity causes the temperature of the shape memory alloy coil 3 to fluctuate about its shape memory temperature and the coil 3 is thereby deformed, resulting in rotation of the fixed contact piece to the right and left sides alternately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an opening / closing contact portion (hereinafter referred to as a contact portion) of a disconnector.

[0002]

2. Description of the Related Art A conventional contact portion has a structure in which a blade and a finger are in contact with each other and a contact surface does not move in a closed state.

[0003]

Since the conventional contact portion is in a closed state for a long period of time and the contact surface does not move for a long period of time, over time, chlorine or a compound thereof in the air or sulfur or a compound thereof is present in the atmosphere. Then, the metal on the contact surface reacts with each other to form a compound (hereinafter referred to as a compound) of the metal on the contact surface and chlorine or sulfur. Since the compound has a high electric resistance, it is electrically closed at the contact surface of the contact portion. Alternatively, the metal on the contact surface is melted by heat generated by energization. To prevent this, the contact surface is regularly polished to remove the compound. For this reason, there is a drawback that it takes time and labor for stopping the energization and for polishing.

The present invention was devised in order to eliminate the above-mentioned drawbacks of the prior art.
The purpose is to remove the compound on the contact surface by moving the contact surface by a change in the energizing current during the daytime and at night (hereinafter described in this example).

[0005]

In order to achieve the above object, a fixed contact piece of a contact portion is fixed to a fixed portion base via a shape memory alloy, and a current is supplied to the shape memory alloy in whole or in part. The circuit is a flowing circuit, and the contact surface is moved by the change in the memory state and the non-memory state of the shape with the temperature change of the shape memory alloy due to the increase and decrease of the energization current in the daytime and the nighttime.

[0006]

[Function] At night when the amount of electricity is small, the shape memory alloy forming a part of the electricity supply circuit is lower than the shape memory temperature and the shape is in a non-memory state. When the temperature becomes equal to or higher than the temperature, the memorized shape is brought into an expanded state, the force of the bias spring is overcome, the fixed contact piece is rotated in one direction, and the contact surface slides on the edge of the movable contact piece. At night when the energization amount is low, the shape memory alloy falls below the shape memory temperature, loses the force of the bias spring and becomes a non-shape memory compressed shape, and the fixed contact piece rotates in the opposite direction. At this time as well, the contact surface slides. In this way, when the change in the applied current is day or night as described above, the contact surface is slid and polished once a day to remove the compound.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIG. 1, a fixed contact piece 1 comprises a finger 1a and a fixed contact piece base 1b. The fixed contact piece base 1b has a fixed contact piece bolt hole 11 which is sized to move through the fixed bolt 7. The fixing fitting 9 has a fixing fitting bolt hole 10 through which the fixing bolt 7 can pass. The fixing metal fitting 9 is fixed to the fixing portion base 6 by sandwiching the flexible conductor 5. The fixed contact piece base 1b is fixed to a fixing fitting 9 with a fixing bolt 7 via a shape memory alloy coil 3 and a bias spring 4. The fixed bolt 7 is the center O of the movable contact.
It has an arc with a radius R that is the distance to the fixed contact piece bolt hole 11. The movable contact piece edge portion 12 forms an arc centered on the movable contact piece center O. The memory alloy coil 3 and the flexible conductor 5 form a parallel circuit between the fixed contact piece 1 and the fixed portion base 6 in the energization path.

FIG. 1 (a) shows the shape memory alloy coil 3 in a non-shape memory shape, that is, in a compressed state at a shape memory temperature or lower. When the amount of energization increases and the current flowing through the shape memory alloy coil 3 also increases and the shape memory alloy coil becomes the shape memory temperature or higher, the shape memory alloy coil 3 has its memorized shape, that is, an expanded shape, as shown in FIG. Then, the fixed contact piece 1 is rotated to the left by overcoming the force of the bias spring 4.

When the amount of energization is reduced and the shape memory alloy coil 3 falls below the shape memory temperature, the shape memory alloy coil 3 loses the force of the bias spring 4 and becomes in a compressed state, and the fixed contact piece 1 rotates to the right, as shown in FIG. The state shown in a) is obtained. The contact surface 8 slides on the edge 12 of the movable contact piece 12 when the fixed contact piece 1 is rotated to the left or right based on the increase or decrease in the amount of energization, and the portions forming the contact surface 8 of the finger 1a and the movable contact piece 2 are polished. Remove the compound.

[0010]

According to the present invention, the compound generated on the contact surface of the disconnector can be removed by changing the amount of electric current to prevent the generation of a closed circuit at the contact portion due to the compound or the heat generation and melting loss.

[Brief description of drawings]

FIG. 1 (a) is a state in which the energization amount is small, the shape memory alloy coil is lower than the shape memory temperature, the shape memory alloy coil is in a non-shape memory shape compressed state, and the fixed contact portion is rotated to the right. Indicates. (B) has a large amount of electricity, and the shape memory alloy coil has a temperature higher than the shape memory temperature and is deformed into an expanded shape which is the memorized shape and overcomes the force of the bias spring to compress it. Shows the state of rotating.

[Explanation of symbols]

 1 Fixed Contact Piece 1a Finger 1b Fixed Contact Piece Base 2 Movable Contact Piece 3 Shape Memory Alloy Coil 4 Bias Spring 5 Flexible Conductor 6 Fixed Part Base 7 Fixing Bolt 8 Contact Surface 9 Fixing Bracket 10 Fixing Bracket Bolt 11 Fixed Contact Piece Bolt Hole 12 Movable contact edge

Claims (1)

[Claims] 1. A fixed contact piece is fixed to a fixed portion base via a shape memory alloy at a disconnecting switch opening / closing contact portion, and the fixed contact deformation is rotated in one direction by deformation of the shape memory alloy into a memorized shape. The fixed contact piece rotates in the opposite direction due to the return to the non-shape memory shape, and the contact surface (hereinafter referred to as the contact surface) between the contact portion of the finger and the movable contact piece in the closed state of the disconnector opening / closing contact portion, The structure of the disconnecting switch opening / closing contact part that slides and polishes the contact surface by reciprocating the movable contact edge.