JPS62172615A - Vacuum switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a vacuum switch, and particularly relates to a vacuum switch for switching and closing a three-phase AC power supply.

B1 Overview of the Invention The present invention provides a first aspect of the invention that corresponds to three-phase AC power. In a vacuum switch having 9 true switch switches for the second and third phases, one of the vacuum switches is placed near the operating shaft, the other two are placed further away from the operating shaft, and the one vacuum By setting the wipe length of the switch to be shorter than the wipe lengths of other vacuum switches, induced cutting surges are suppressed.

C1 Prior Art Figure 7 is a front view showing the structure of a conventional three-phase electromagnetic stirrer, and Figure 8 is a side view. As shown in these figures, each of the vacuum switches IA to IC has an insulating frame 14 on the fixed side.
The upper terminals 2a to 2c+ attached to the
It is electrically connected to a to 5C. Further, each of the movable leads 3a to 3C is connected to an operating lever 8 via insulating rods 6a to 6Ci. The base of the movable core 10 is the operating shaft 9
It is sprayed to the operating lever 8 via. In FIG. 8, reference numeral 11 indicates an operating electromagnet fixedly attached to a mounting frame 12 having a rectangular cross-section, and reference numeral 13 indicates a cutoff spring provided between the frame 12 and the movable core 10. In Figures 7 and 9, 30
3 is an operating arm attached to the operating shaft 9, 31 is a roller provided at the tip of the operating arm 30, 32 is a hook that is pivoted on the shaft 33 and engages with and disengages from the roller 31, 34 is a tripping electromagnet, and 35 is this This is the movable core of the tripping 11 magnet 34.

When the operating electromagnet 11 is energized, the movable iron core 10 is attracted to the operating electromagnet 11 against the interruption spring 13. As a result, the operating lever 8 is pulled upward and placed in the closed state.

When charging, the operating shaft 9 rotates, and the roller 31 sprayed onto the operating arm reaches onto the hook 32 to mechanically maintain the inserted state. Also at this time, the wipe spring 7a (7b
, 7c), the contact is in a pressurized state and the rewipe length a
(am)yal-keep. When shutting off, the tripping electromagnet 34 is energized and the hook 3 is placed at the tip of the movable iron core 35.
After the second strike, the hook 32 and the roller 31 are disengaged, the movable core 10 is pushed by the cutoff spring 13, and the operating lever 8 is pulled down to enter the cutoff state. The above operations are performed centering around the operating shaft 9 attached to all three phases, so the three phases operate simultaneously.

While the D0 invention is trying to solve the problem, it is said that the abrasion contactor is equipped with a vacuum pulp arc extinguishing chamber, so it has excellent arc extinguishing ability and insulation recovery properties, but it generates opening and closing surges. There are drawbacks. Therefore, the e! There is the problem of threatening people. Therefore, it is necessary to keep the switching surge voltage low, and expensive A is used as a contact material for vacuum breakers.
A material with a low melting point, such as G-based material or Bi, with a low electrical strength and cutting value (IA or less) is used to suppress cutting surges.

However, there is a problem with the re-ignition surge and the cutting surge induced by the re-ignition, which is the largest of the generated surges. Therefore, an expensive surge absorber is required.

The mechanism of induced cutting surge occurs when a small current contactor with a lagging power factor is used to cut off the power supply and load sides of the contactor under circuit conditions such as cables with appropriate capacitance and capacitance. Out.

That is, FIG. 10 shows an equivalent circuit, and FIG. 11 shows voltage and current waveforms when three phases are cut off at once. 1st theta
In the figure, L is the load inductance.

R is the load resistance, Lo is the line leakage inductance, co is the stray capacitance of ik'21, 1u
.

lv and 1w are the peak points in the U, V, and W phases, respectively. In other words, the three phases are opened at once, so Figure 11 (5)~
If the contact is opened at point P as shown in ■, the current in the U phase reaches zero and the current iu is cut off, but the vacuum switch IA~
Since the gap between the contacts of the IC is known, the withstand voltage between electrodes is lower than the restart voltage, causing a flashover. Then, in the equivalent circuit of Fig. 10, the firing current is c, LOlu LOc
However, due to the high arc extinguishing ability of the vacuum breaker, the arcing flow is also cut off and the pressure rises again. At this time, the voltage between the electrodes of the V and W phases is also lower than the re-electromotive voltage, so that a flash short circuit occurs in the V and W phases. This repeated firing causes a firing surge in the U phase. On the other hand, since the first arc flow also flows through the v and W phases with Co and Lo flowing out, the first flow
As shown in diagram O, the 'II flow forcefully reaches the zero point and is cut off. This means that the cutting current is several times the current value of 1 ampere or less, and a large cutting (induced cutting) surge voltage and voltage are generated.

Means for solving the E1 problem: 1. Turning on/off the first, second, and third phase power. Snoring 2. It consists of an opening/closing part equipped with a vacuum switch of Hawk 3, and an opening/closing operation part that moves the movable leads of each vacuum switch of the opening/closing part by a predetermined stroke, and is arranged near the operating shaft of any one of the vacuum switches. The other two vacuum switches are arranged further away from the operating shaft, and the wipe length of one of the vacuum switches is set shorter than the other wipe lengths.

In a vacuum switch equipped with vacuum switches for three phases of F0 action, the wipe length of one of the vacuum switches is set shorter than the wipe length of the other vacuum switches, so the one vacuum switch is connected to the other vacuum switch. The electrode opens faster than the previous one, and induced cutting surges are suppressed.

G. EXAMPLES The present invention will be specifically explained below using examples shown in FIGS. 1 to 6.

In this embodiment, as shown in FIG. 1 and FIG. V which is the second phase
Phase and @3 phase W phase $2 A empty switch IB and 3rd
The vacuum switch IC is placed on the rotating end side of the operating lever 8 at a predetermined distance from the person looking at the vacuum switch 1. In addition, as shown in Figure 1, the wipe length a, which corresponds to the distance between the tip of the insulating rod 6a of the vacuum switch 1 and the stopper 15a, is set to the second. Third vacuum switch IB
, the tips of the IC insulations 5b, 5c and the stoppers 15b, 1
5 (! It is shorter than the wipe length between.

Since the wipe length a of the first vacuum switch IA is shorter than the wipe lengths of the second and third vacuum switches IB and tC, when a cutoff command is issued and the operation lever 8 is pulled down, the first vacuum Valve IA opens, and after a predetermined period of time, the second valve IA opens. The third vacuum switches IB and IC are opened.

In other words, Figure 3 shows the operation stroke characteristics, and the straight line 4
1 is the stroke characteristic of the vacuum switch IA of Hawk 1, straight line 4
2 is the second. This is the stroke characteristic of the third vacuum switch IB and IC. In Figure I@3, (is at the time of injection, tl is the first
At the start of a new vacuum switch for one person, tl is the second vacuum switch. The time point at which the third vacuum switch 1B and IC start to shut off, and to, is the time point at which the first to third vacuum switches IA to IC complete shutoff.

In other words, as shown in Figure 4 (6), when the insulating rod 6a of the first vacuum switch IA hits the stopper 15a, it opens against the spring force of the wipe spring 7a and the self-closing force of the contact. The poles are formed and the distance between them is C. At this point, Sen's second. The contacts of the vacuum switch IB and IC of @3 are in the process of opening, but the insulating rod 6a is the stopper 15a l: The darkness of the opening distance a until the roar is the spring force and self-closing force of the wipe spring 7b (7c) It does not open due to

After that, when the insulating rod 6b (6C) of the 1<empty switch IB and IC of the 2nd degree WJ3 moves by a stroke of b-a, the 2nd degree WJ3 moves as shown in FIG. 40. The e-edge rod 6b (5c) of the third vacuum switch IB and IC is the stopper 15b.
(15c), these @2. The contacts of the third vacuum switches IB and IC are opened against the spring force of the pressure spring 7b (7C) and the self-closing force of the contacts, and the opening distance becomes d. Operation lever 8 is the vacuum switch IA for river 1.
When the wipe length reaches a, the vacuum switch IA at @1 starts to shut off (h) L, and then the vacuum switch IB at @2.3.

Lower the vacuum switch IB until the wipe length of the IC is reached.

IC shutoff starts (tl). For this reason, tr t
1 only 2nd. @3 Vacuum switch IB, IC cut-off is delayed, 1. ), the shutoff operation is completed.

By arranging the first vacuum switch IA'Y near the operating shaft 9, the stroke lengths of the first vacuum switch IA and the second and third vacuum switches IB and IC can be adjusted to tl, respectively.
tt (A1<12), and even if the wipe length a (b), the cap length d of the first phase and the second and third phases can be made the same. By delaying the opening of the second and third phases against the phase, even if the first phase starts to open and flows, the second and third phases are closed during that time, so induced cutting does not occur.

In order to prevent the occurrence of induced cutting surges, it is desirable that the distance be at least the first cycle. Induced cutting surge is triggered by 71. This occurs when the current multiplies other phases, and its origin lies in the firing of one of the three phases.

That is, if the opening of the first phase is the U phase as shown in Fig. 6, a lightning strikes in the V and W phases at point A with I14 flow,
While the flow is multiplied, the V and W phases are naturally closed, so no induced cutting surge occurs. In this case, the cutoff point of the V and W phases is at point B2.

Next J: Phase 0 to P where no firing surge occurs in U phase
If the U phase is rarely opened at, for example, 22 points among the points, the V phase is opened at, for example, F'2 point. At this time, in the V phase, the arcing time is short, so an arcing trench occurs, and the U and W phases are multiplied by the firing current, and a forced current zero point occurs. After 1/3 cycle, the opening drops, and the opening of the U phase becomes 0. No matter which point between points ~P1 is opened, the opening of the V and W phases will be after the 0' and P'1 points, and the zero current point of the V and W phases will be after the current zero point of the U phase. Therefore, the cutoff point of the U phase is point A, and the cutoff point of the V and W phases is B! .

It will be 82 points.

H0 Effect of the invention According to the invention, instead of opening the three phases all at once,
First, the negative phase is opened, and the other two phases are opened after that, and at least one phase of the AC cold current is opened after the first phase is opened.
Since the other two phases are controlled to open after the /3 cycle, no matter what the opening phase of the first phase is, C: or even if the firing m1R is multiplied by the other phase, a! Cutting and cutting
There is no chance of any damage occurring. Therefore, it is possible to use a vacuum switch with a small capacity without the need for expensive insulation materials, and to achieve high performance and reliability without the need for a surge absorber and the insulation on the load side. You can obtain a vacuum switch of this type.

[Brief explanation of drawings]

Fig. 1 is a side view showing essential parts of a vacuum switch according to an embodiment of the present invention, Fig. 2 is a plan view, Fig. 3 is an operation stroke characteristic diagram, and Figs. Figures 5 and 6 are side views showing the state, Figures 5 and 6 are characteristic diagrams when #I is activated, Figure 7 is the front view of a conventional vacuum switch, Figure 8 is a side view, and Figure @9 is the structure of the latch part. Figure 10 is an equivalent circuit diagram, and Figure @11 is the conventional one?
! FIG. 3 is a diagram showing the operating characteristics of the switch. IA, IB, IC... true 2 switch,
3a, 3b. 3C...Movable lead, 7a, 7b, 7
c...wipe spring, 8...operation lever, 9...operation shaft, lO...movable iron core, 15a, tsb,
tsc-...x totsupa, a, b--fibe length, c, d
...opening distance. Fig. 1 Fig. 2 Fig. 3 Fig. 5 Fig. 7 Fig. 9 L: 3-carrying inductance R1 Grading stance Lo・Line leakage So inductance Co' Line stray 1,000 watts Fig. 11 Blood P development

Claims (1)

[Claims] an opening/closing unit equipped with first, second, and third vacuum switches that turn on and cut off power of the first phase, second phase, and third phase;
A vacuum opening/closing device comprising an opening/closing operation section for opening and closing the opening/closing section, and the opening/closing operation section moves each movable lead of a first, second, and third vacuum switch of the switch by a predetermined wipe length. In the device, any one of the first, second, and third vacuum switches is arranged near the operating shaft of the opening/closing operation section, and the other two vacuum switches are connected from the one vacuum switch to the operating shaft. A vacuum switch characterized in that the vacuum switch is arranged a predetermined distance away from the vacuum switch, and the wipe length of one vacuum switch is set shorter than the wipe length of the other vacuum switches.