JPS645341Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Technical field of invention] This invention relates to circuits and disconnectors.

[Prior Art] FIGS. 1 to 3 are cross-sectional views of conventional circuits and disconnectors, each showing different operating states.

1 is a cover, 2 is a base, and the cover 1 and the base 2 constitute a container 3. 4 is a fixed contact, which has a fixed contact 6 at one end of its fixed conductor 5;
The other end is a terminal portion to be connected to an external conductor (not shown). A movable contact 7 has a movable contact 9 at one end of a movable conductor 8 facing the fixed contact 6. 10 is a movable contact device, 11 is a movable arm, and the movable arm 11 is limited to a crossbar 12, and each pole is configured to open and close at the same time. 13 is an arc extinguishing chamber, and an arc extinguishing plate 14 is held by a side plate 15. 16 is a toggle link mechanism,
It is composed of an upper link 17 and a lower link 18. One end of the upper link 17 is connected to the cradle 19, and the other end is connected to one end of the lower link 18, respectively.
1. The other end of the lower link 18 is connected to the movable arm 11 of the movable contact device 10. 22 is a tilting operation handle, 23
is an operating spring, and the operating spring 23 is stretched between the shaft 21 of the toggle link mechanism 16 and the operating handle 22. Reference numerals 24 and 25 designate thermal and electromagnetic tripping mechanisms, respectively, which rotate the trip bar 28 counterclockwise by means of a bimetal 26 and a movable iron core 27, respectively, when activated. Reference numeral 29 is a latch whose one end is locked to the trip bar 28 and the other end is locked to the cradle 19.

When the operating handle 22 is tilted to the closing position with the cradle 19 locked to the latch 29, the toggle link mechanism 16 is extended, the shaft 21 is locked to the cradle 19, and the movable contact 9 is joined to the fixed contact 6. .
This state is shown in FIG.

Then, by tilting the operating handle 22 to the open position,
The toggle link mechanism 16 is bent to separate the movable contact 9 from the fixed contact 6, and the movable arm 11 is locked to the cradle shaft 30. This state is shown in FIG.
Furthermore, when an overcurrent flows through the circuit in the closed circuit state shown in FIG. The cradle 19 rotates clockwise around the center and is locked to the stopper shaft 31. In this case, since the connection point between the cradle 19 and the upper link 17 exceeds the line of action of the operating spring 23, the toggle link mechanism 16 is bent by the spring force of the operating spring 23, and each pole is interlocked by the cross bar 12. Performs automatic cutting. This state is shown in FIG.

Next, the behavior of the arc that occurs when the circuit or breaker interrupts the current flow will be explained.

Now, when the movable contact 9 and the fixed contact 6 are in contact, the power is transferred from the power source to the fixed conductor 5, the fixed contact 6, the movable contact 9, and the movable conductor 8.
It is supplied to the load side via sequentially. In this state, when a large current such as a short circuit current flows through this circuit, the movable contact 9 is separated from the fixed contact 6 as described above. At this time, an arc 32 is generated between the fixed and movable contacts 6 and 9, and an arc voltage is generated between the fixed and movable contacts 6 and 9. This arc voltage increases as the separation distance of the movable contact 9 from the fixed contact 6 increases, and at the same time, the arc 32 is attracted and expanded in the direction of the arc extinguishing plate 14 by magnetic force. , further rises.

In this way, the arc current reaches a current zero point and the arc 32 is extinguished, completing the shearing. During such disconnection and disconnection operations, the arc 32 causes a short period of time between the movable contact 9 and the fixed contact 6.
In other words, a large amount of energy is generated within a few milliseconds. Therefore, the temperature of the gas inside the container 3 rises and the pressure also rises rapidly, but this high temperature and high pressure gas is released into the atmosphere from the outlet 33 formed in the side wall of the container 3 on the power supply side. be done.

In the operation of a circuit or disconnector as described above, arc resistance R is generally given by the following formula.

That is, R=ρl/S where R: arc resistance (Ω) ρ: arc resistivity (Ω・cm) l: arc length (cm) S: arc cross-sectional area (cm ² ) However, in general, In a short arc 32 with a large current and an arc length l of 50 mm or less, the arc space is occupied by metal particles. Moreover, this release of metal particles occurs in a direction perpendicular to the contact surface. Further, the ejected metal particles have a temperature near the boiling point of the metal at the contact point at the time of ejection, and furthermore, as soon as they are injected into the arc space, they are heated to high temperature and high pressure by being injected with electrical energy.

If the contacts 6 and 9 are exposed to such conditions for a long period of time, the contacts 6 and 9 may melt. For this reason, as shown in FIGS. 4A and 4B, an arc runner 34 is arranged on the rear side of the contact fixing position on the fixed conductor 5. This is due to the arc 32 generated between the contacts 6 and 9.
The main purpose is to protect the contacts 6 and 9 by quickly moving the leg on the fixed contact 6 side to the arc runner 34.

However, in the above method, even if the arc 32 is dislocated to the arc runner 34, it is difficult to completely separate from the fixed contact 6, and the arc current at the time of this dislocation is
As shown by the arrow in FIG. 4B, the current flows from the base end of the fixed conductor 5 to the arc runner 34 by bypassing the fixed contact 6 side, so that the fixed contact 6 is overheated by the passage of the current, and therefore the contact 6 It has the disadvantage that it becomes easy to wear out.

[Summary of the idea]

This invention was made in order to eliminate the drawbacks of the above-mentioned conventional ones, and the conductor tip side of one of the electric contacts of a pair is shaped to have a substantially U-shaped part and a contact fixing piece part. By installing an arc runner on the conductor that transfers the arc at the time of opening to the power supply side, and setting the non-contact side end of the arc runner closer to the contact side than the non-contact side end of the arc extinguishing plate, the wear of the contact is reduced. The purpose of this invention is to provide a circuit breaker that can prevent arcs from occurring behind the arc-extinguishing plate, and also has good breaker performance.

[Example of idea]

Embodiments of this invention will be described below with reference to the drawings.

Figures 5 and 6 show the configuration of essential parts in an embodiment of the circuit shield and breaker according to this invention, and the same parts as in Figures 1 to 4 are given the same reference numerals. The explanation will be omitted.

In the figure, 51 is a fixed contact, which is composed of a fixed conductor 52 and a fixed contact 6. The tip side 520 of the fixed conductor 52 is bent into a substantially U-shape with the conductor main surface side open, and the tip of the vertical piece 520a on the load side of the U-shaped tip 520 is used as a contact fixing piece 521. It extends horizontally toward the power supply side.

53 is a stud 5 on the base end side 522 of the fixed conductor 52.
The arc runner is a plate-shaped arc runner that is fixed by a wire such as 4, and is used to transfer the arc 32 generated between the contacts 6 and 9 to the power source side. 530 is the above arc runner 53
At the end of the non-contact side, the end portion is bent toward the arc extinguishing plate 14 side. This terminal end 530 is set to be located closer to the contacts 6 and 9 than the non-contact side terminal end 140 of the arc-extinguishing plate 14.

A pressure reflector 57 is made of a high resistance material having a resistivity higher than that of the fixed conductor 52, and is fixed to the fixed conductor 52 so as to cover the area around the contact point of the fixed conductor 52. Examples of the high-resistance materials include organic or inorganic insulators, or high-resistance metals such as nickel, iron, copper-nickel, copper-manganese, iron-nickel, and iron-chromium, which can be coated by thermal spraying or fixed to molded products. It is set up in this way. Also on the movable conductor 8 side, as shown in FIG. 7, a pressure reflector 58 having the same structure as above is provided.

Next, the operation of the above configuration will be explained.

The opening/closing operations by the fixed and movable contacts 51 and 7 are the same as those of the conventional one, and therefore their explanation will be omitted.

With the opening operation of the movable contactor 7, an arc 32 is generated between the contacts 6 and 9 as shown in FIG. and begins to expand. When the arc runner 53 is now set at the position shown in FIG. 6A, the tip 531 of the arc runner 53 is heated by the arc 32. For this reason, arc 32
The foot of the arc 32 tends to move toward the tip 531 of the arc runner 53, and in the middle of the opening period, the arc 32 quickly moves to the arc runner 53, and is further extended, and the arc voltage rises at the current zero point and is extinguished. arced.

In the state where the arc 32 is transferred to the arc runner 53, the arc current does not flow to the fixed contact 6 due to the fixed conductor shape, and the arc 32 can quickly move to the arc runner 53 side, so that the wear of the contact 6 etc. is reduced. It will be suppressed as much as possible. Moreover, since the arc 32 is easily transferred to the arc runner 53 and expanded greatly, the shearing performance is also improved.

Further, the arc 32 drawn into the arc extinguishing plate 14 has its power supply side leg reaching the terminal end 530 of the arc runner 53, but its position is inside the non-contact side terminal end 140 of the arc extinguishing plate 14, that is, the contact point 6 .

On the other hand, at the beginning of contact opening, the vertical piece 5 on the power supply side of the substantially U-shaped tip 520 of the fixed conductor 52
20b in the direction of the arrow i in FIG. 6, an initial current limit is obtained, especially when the pressure reflector 5
Together with the arc narrowing action of Nos. 7 and 58, the above-mentioned current limiting property is ensured.

[Effect of idea]

As described above, in this invention, the tip side of the conductor of one of the pair of electric contacts is approximately U.
It has a special shape with a letter-shaped part and a contact fixing piece part, and the non-contact side end of the arc runner installed on this is set closer to the contact side than the non-contact side end of the arc extinguishing plate, so it is possible to prevent contact wear. Moreover, it is possible to provide a circuit breaker that can improve the insulation performance.

[Brief explanation of the drawing]

Figures 1 to 3 are cross-sectional views of conventional circuit breakers and breakers in different operating states, and Figures 4A and B are perspective views of fixed contacts with arc runners in conventional circuit breakers and breakers, respectively. FIG. 5 is a perspective view showing a fixed contact incorporated in an embodiment of the circuit breaker according to this invention; FIG.
B and C are explanatory diagrams of the operation of the circuit breaker. 3... Container, 6, 9... Contact, 7, 51... Electric contact, 8, 52... Conductor, 14... Arc-extinguishing plate,
140... Non-contact side end of arc extinguishing plate, 32... Arc, 53... Arc runner, 530... Non-contact side end of arc runner, 520a... Load side vertical piece part, 521... Contact fixing piece part. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] At least one pair of electrical contacts consisting of a conductor and a contact fixed thereto and operating to open and close within the container; a plurality of arc-extinguishing plates disposed in a substantially U-shape with the tip side of the conductor of one of the pair of electric contacts opening toward the main surface side of the conductor; At the same time, the tip of the load-side vertical piece of this substantially U-shaped tip extends toward the power source side as a contact fixing piece, and the contact fixing piece faces the contact side and extends toward the tip side. An arc runner is fixed to the conductor of one of the electrical contacts, and the non-contact end of the arc runner is positioned closer to the contact side than the non-contact end of the arc extinguishing plate. Or disconnection.