JPH04184829A - Vacuum circuit breaker - Google Patents

Abstract

PURPOSE:To reduce heating amount so as to restrain the temperature increase in a movable shaft of a vacuum valve and increase current capacity by integrating the movable shaft with a clamp part. CONSTITUTION:A movable shaft 5b is integrated with a clamp 6 both being made of the same material. A flexible conductor 7 is fastened by a plurality of bolts to the clamp 6, and a lower conductor 4b therebelow is fastened by a plurality of bolts to the conductor 7. With the constitution, there is no screw and thread parts respectively at both movable shaft 5b and the clamp 6, and thereby no contact heat resistance is interposed, which causes a good heat conduction. Furthermore, fins and the like are set on the circumference of the clamp 6 to increase heat radiation area to thereby increase a cooling effect still more.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a vacuum circuit breaker.

(Prior Art) In FIG. 3 showing a vertical cross-sectional side view of a conventional drawer-type vacuum circuit breaker and FIG. 4 showing an enlarged Y-Y cross-sectional view, the frame 2
A partition 2a is vertically provided in the middle or on the front side to partition the vacuum circuit breaker into front and rear parts.

On the other hand, a bottom plate 12 is provided at the lower end of the frame 2, and wheels 12a are provided on both sides of the bottom plate 12 (front and rear), so that the frame 2 can be freely drawn out.

Furthermore, an electromagnet 1a is provided at the upper end of the front side of the partition 2a, and below this electromagnet 1a is a link mechanism 1b (wipe spring 1b) which is operated by the operation of this electromagnet 1a.
The upper end of the rond penetrating through the inside of the wipe spring 1b is connected, the lower end of this wipe spring 1b is engaged with the upper end of the connecting member, and the lower end of this connecting member is attached to the upper part of the bottom plate 12 with the middle part as a fulcrum.
It is connected via a pin to the front end of an operating lever 8 provided so as to be freely operable.

On the other hand, a strip-shaped mounting plate 2a3 bent into a substantially trapezoidal shape is vertically fixed to the upper rear surface of the partition 2a.
Above a3, the support insulator 3A is on the subassembly surface, and the mounting plate 2
Support insulators 3B are fixed to the slopes at the lower ends of a3.

Among these, a strip-shaped upper conductor 4 is provided on the rear surface of the support insulator 3A.
The front end of A and the front end of a band-shaped lower conductor 4B are respectively fixed to the rear surface of the support insulator 3B. and,
The upper end of the vacuum valve 5 is fixed to the lower surface of the upper conductor 4A via a fixed shaft 5a, and a plurality of contacts are arranged on the outer periphery of the rear end of the upper conductor 4A via a coil spring (not shown). A main circuit disconnection section 13A that is pressed toward the center is provided at the front end.

Similarly, the above-mentioned main circuit disconnection section 1 is also connected to the rear end of the lower conductor 4B.
It is provided at the front end of the main circuit disconnection section 13B, which is symmetrical to the main circuit disconnection section 3A. The lower ends of a pair of flexible conductors 7 are fixed to the upper surface of the lower conductor 4B, and the upper ends of the flexible conductors 7 are fixed to the upper surface of the lower conductor 4B.
is fixed to the bottom edge of the

The middle part of the movable shaft 5b vertically passes through the middle part of the pair of clamps 6, and the upper end of the movable shaft 5b is connected to the vacuum valve 5.
A movable electrode (not shown) is penetrated through the end plate at the lower end via a guide and a bellows (not shown), and is brazed to the upper end.

Furthermore, the lower end of the first movable shaft 5b vertically passes through the middle part of the lower conductor 4B, and is connected to the upper end of the vertically provided insulating rod 9, and the lower end of the insulating rod 9 is at the front). It is connected to the rear end of the lever 8 via a pin.

Further, a barrier 11 is provided between each phase of the vacuum valve 5 and the insulating rod 9.

Now, in the vacuum circuit breaker configured in this way, when the electromagnet 1a is excited, the operating lever 8 is rotated about the intermediate fulcrum by the link mechanism 1b via the wipe spring 1b1 and the connecting member below it. Operated clockwise.

Then, the insulating rod 9 whose lower end is connected to the rear end of the operating lever 8 moves upward, and the movable shaft 5b is moved together with the clamp 6.
The movable shaft 5b also moves upward, and the movable electrode (not shown) at the upper end of the movable shaft 5b is thrown into the fixed electrode.

On the other hand, when shutting off the vacuum circuit breaker in the closed state, by cutting off the excitation of the electromagnet 1a, the link mechanism 1b and the operating lever 8 operate in the opposite direction to the above operation, and the insulating rod 9 and the movable shaft 5b move. Move down.

By the way, when the electricity is turned on after being turned on, the portion of the vacuum bulb 5 where the fixed electrode (not shown) and the movable electrode are in contact generates the largest amount of heat, and the temperature also becomes high.

Since there is no convection inside the vacuum valve 5, most of the heat is radiated by conduction from the fixed shaft 5a to the upper conductor 4A, from the movable shaft 5b to the clamp 6, the flexible conductor 7, the lower conductor 4B, etc.

(Problem to be solved by the invention) In the vacuum circuit breaker configured in this way, the movable shaft 5
b has a male thread formed thereon, and is clamped between a female threaded portion formed on the clamp 6 and a bolt to conduct electricity and heat conduction.

As electricity and heat conduction occur in the kS male and female threads, the contact area is small, and the temperature rises due to heat generation due to electrical contact resistance.Also, the contact thermal resistance is large and sufficient heat conduction is not performed. There wasn't.

Therefore, in the conventional vacuum circuit breaker, when the current is increased, the temperature rise of the movable shaft 5b becomes high, and the current carrying capacity of the vacuum circuit breaker is determined by the temperature rise limit, making it unsuitable for increasing the capacity.

An object of the present invention is to provide a vacuum circuit breaker that can increase current carrying capacity.

[Structure of the Invention] (Means and Effects for Solving the Problems) In order to achieve the above object, the present invention provides a vacuum valve that has an opening at the bottom of the partition wall that partitions the frame into front and rear parts and is housed in the rear part of the partition wall. In a vacuum circuit breaker where the movable shaft is connected to an insulating rod via a clamp, the movable shaft of the vacuum valve and the clamp part are integrated, eliminating electrical contact resistance between the movable shaft and the clamp part and reducing heat generation. At the same time, it is possible to increase current carrying capacity by eliminating contact thermal resistance and improving heat conduction to suppress the temperature rise of the movable shaft, which is the highest temperature part.

(Example) Hereinafter, one example of the vacuum circuit breaker of the present invention will be described with reference to the drawings. However, parts that overlap with those in FIG. 3 are given the same reference numerals and their explanation will be omitted.

FIG. 1 is a vertical cross-sectional side view showing one phase of the vacuum circuit breaker of the present invention, and FIG. 2 is an enlarged cross-sectional view taken along line XX in FIG. 1.

In FIGS. 1 and 2, the movable shaft 5b and the clamp pro are integrated and made of the same material. Further, a flexible conductor 7 is fastened to the clamp 6 with a plurality of bolts, and a lower conductor 4B below the clamp 6 is fastened to the flexible conductor 7 with a plurality of bolts.

In the vacuum circuit breaker configured in this manner, since there is no threaded portion between the movable shaft 5b and the clamp 6, there is no intervening contact thermal resistance V and good heat conduction is achieved.

Note that the size of the clamp 6 may be increased to the same extent as the size of the flexible conductor 7.

Furthermore, by attaching fins or the like to the outer periphery of the clamp 6, the area can be purposely increased to further increase the cooling effect.

[Effects of the Invention] As described above, the present invention provides a vacuum system in which an opening is provided at the bottom of a partition wall that partitions a frame into front and back parts, and the movable shaft of a vacuum valve stored in the rear part of the partition wall is connected to an insulating rod via a clamp. In circuit breakers, by integrating the movable shaft of the vacuum valve and the clamp part, we eliminate electrical contact resistance between the movable shaft and the clamp part, reducing heat generation, and also eliminate contact thermal resistance to improve heat conduction. It is possible to obtain a vacuum circuit breaker with increased current carrying capacity by suppressing the temperature rise of the movable shaft, which is the highest temperature part.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional side view showing an embodiment of the vacuum circuit breaker of the present invention, Fig. 2 is an enlarged cross-sectional view taken along line X-X in Fig. 1, and Fig. 3 is a longitudinal cross-sectional view showing an example of a conventional vacuum circuit breaker. FIG. 4 is an enlarged cross-sectional view taken along the Y-Y line in FIG. 3. 5 ...... Vacuum valve 5b ...... Movable shaft 6 ...... Clamp agent Patent attorney Noriyuki Chika No. 1 Figure 2 Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] A vacuum circuit breaker in which an opening is provided in the lower part of a partition wall that partitions the frame into front and rear parts, and a movable shaft of a vacuum valve housed in the rear part of the partition wall is connected to an insulating rod via a clamp, A vacuum circuit breaker characterized in that a movable shaft and the clamp are integrated.