JPS596590Y2 - vacuum switchgear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum switchgear with a large current carrying capacity that can be used by being directly connected to an electric circuit of a generator, for example.

For example, if a short circuit occurs in the electrical circuit of a large-capacity generator,
A current zero point may appear after several cycles to several tens of cycles.

In such a case, the circuit breaker normally extinguishes the arc at the zero current point, so a short circuit current flows through the equipment for a long time, posing the risk of damage.

On the other hand, it is effective to insert a DC resistance into the circuit in order to make the current zero point appear quickly, and this effect can be achieved by the arc resistance generated between the contacts of the breaker when the circuit is cut off.

However, the vacuum breaker is characterized by a low arc resistance between the contacts, and cannot be expected to have the effect of causing the above-mentioned current zero point to appear quickly.

For this reason, it is considered inappropriate to use a vacuum breaker in the electrical circuit of a generator.

Further, in the electrical circuit of a generator, the normal current flowing is several thousand amperes to tens of thousands of amperes, and it is necessary to use an extremely large vacuum breaker, which is extremely difficult in terms of manufacturing technology.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a vacuum switching device that uses a small-sized vacuum valve, has a large current capacity, and can also be used to interrupt short circuits in generator circuits. It is something to do.

An embodiment of the present invention will be described in detail below with reference to the drawings.

In the figure, 1 is a vacuum valve with a fixed contact 1a and a movable contact 1b.
A piston 1C is provided on the drive shaft of the movable contact 1b.

The vacuum valve 1 is disposed at the center of a movable contact table 2 made of a conductive material and has a cylindrical shape with a bottom, and is held at the bottom thereof.A first cylinder 2a that drives the piston 1C forward and backward is provided outside the bottom. It takes shape.

A fixed contact base 3 made of a conductive material and having a through hole 3a in the center is disposed at a predetermined distance on the fixed contact 1a side of the vacuum valve 1.

An arc contact 4 held on the fixed contact 1a side of the vacuum valve 1 so as to be movable forward and backward is provided on the fixed side contact base 3 so as to be movable towards and away from the fixed contact base 3.

The arc contact 4 is biased in the direction of contacting the fixed contact base 3 by the force of the spring 4a.

A second cylinder 2b is formed on the outer periphery of the movable contact table 2, and a piston 5a formed at one end of the cylindrical movable contact 5 is held in the second cylinder 2b so as to be movable forward and backward.

Note that the movable contact 5 and the arc contact 4 are connected via an insulating spacer 6 so that they are driven forward and backward as a unit.

In addition, when the arc contact is in contact with the fixed contact base 3, the arc contact 4 closes the through hole 3a at the center of the fixed contact base 3, and the other end of the movable contact 5 is provided on the fixed contact base 3 side. It comes in contact with the sliding contact 3b and is electrically conductive.

In addition, there are third and fourth contacts in the axial direction at the center of the outside of the fixed side contact table 3.
The cylinders 7 and 8 are provided with pistons 7a and 8a disposed in the cylinders 7 and 8, and a valve 3C that closes the outside of the through hole 3a, which are integrally connected by a shaft 3d.

The outer periphery of the vacuum valve 1 is insulated by an insulating cylinder 1d, and the movable contact table 2 and the fixed contact table 3 are airtightly connected by an insulating cylinder 9 provided on the outer periphery of the movable contact 5.

Sliding contacts 2 C , 2 d , and 2 C are provided between the drive shaft of the movable contact 1b and the movable contact base 2, between the movable contact base 2 and the movable contact 5, and between the fixed contact 1a and the arc contact 4, respectively.
4b is provided to ensure reliable conduction.

Further, an arc guide 10 is provided in the through hole 3a of the fixed side contact table 3.

and 11a is the first insulating tube that supplies the input operation air.
, each input air chamber A of each second cylinder 2a, 2b,
It is connected to H.

Also, an insulating tube 11 that supplies the cutoff operation air to each of the cutoff air chambers C and D of the first and second cylinders 2a and 2b.
I am trying to communicate with b.

11C is also an insulated pipe that supplies cutoff operation air, and communicates with the cutoff air chamber E of the third cylinder 7 via the check valve 12a in the forward direction, so that both sides of the piston of the third cylinder 7 are It communicates with the air chamber F on the other side through the hole.
is communicated with the insulating pipe 11C through the check valve 12b in the forward direction.

11 d is an insulating tube that supplies high-pressure air to blow out the arc that occurs when the arc is cut off. The through hole 3a of the fixed side contact table 3 is filled with high pressure air.

Further, this high-pressure air acts on the air chamber F on one side of the fourth cylinder 8, and biases the valve 3C to the left in the figure, that is, in the direction of closing the opening of the through hole 3C.

Further, the movable side contact table 2 and the fixed side contact table 3 are respectively provided with terminals 13a and 13b for connection to an external electric circuit.

With such a structure, in the closed state shown in the drawings, the following energization path is established.

In the closed state, the insulating cylinder 11a is filled with air, filling the charging air chambers A and B of the first and second cylinders 2a and 2b, respectively.

Also, insulating cylinders 11 b, 11 that supply cutoff operation air
C is in the exhaust state, and each of the first and second cylinders 2
The cutoff air chambers C and D of a and 2b and the air chambers E and F of the third cylinder 7 are at atmospheric pressure.

When a shutoff command is given here, a control valve (not shown) exhausts the operation air supplied through the insulating tube 11a and supplies shutoff operation air through the insulated tubes 1lb and 11c.

This high-pressure air fills the air chamber E of the third cylinder 7 through the see-through valve 12a, drives the piston 7a to the right in the figure, opens the valve 3C, and releases the high-pressure air in the through-hole 3a, that is, the arc extinguishing chamber. Exhaust.

On the other hand, the cut-off operation air supplied through the insulating tube 11b enters the air chamber D of the second cylinder 2b and reaches the movable contact 5.
is driven to the right in the figure to separate it from the sliding contact 3b.

In this state, the current path is terminal 13a → movable contact base 2 →
The order is as follows: movable contact 1b→fixed contact 1a→sliding contact 4b→arc contact 4→fixed contact base 3→terminal 13b.

When the movable contact 5 moves further to the right, the integrally attached insulating spacer 6 comes into contact with the collar of the arc contact 4 and is driven to the right in the figure, separating the arc contact 4 from the fixed contact base 3.

At this time, since the pressure behind the nozzle portion of the opening 3a is decreasing, high-pressure air is blown onto the arc generated between the contacts to narrow the arc and connect the arc guide 10 and the arc contact 4 by the arc.

When this state is reached, the air chamber D of the second cylinder 2b
The operating air that has passed through enters the air chamber C of the first cylinder 2a, drives the piston 1C to the right in the figure, opens the contacts 1a and 1b of the vacuum valve 1, and cuts off the current.

Further, the high-pressure air supplied to the air chamber E of the third cylinder 7 gradually enters the air chamber F on the opposite side through the small hole of the piston 7a, and after the arc is extinguished, the pressure is equalized and the pressing force against the piston 7a is eliminated.

The high-pressure air supplied to the air chamber G of the fourth piston 8 drives the valve 3C to the left in the figure to close the opening 3a and stop the high-pressure air from being exhausted.

Then, the fixed side contact table 3, the movable side contact table 2, and the arc contact 4 are brought into a discontinuous state in the high pressure air, and the disconnection is completed.

Therefore, when the arc is cut off, the arc is connected between the arc contact 4 and the arc guide 10, and the arc is constricted by high-pressure air at the nozzle portion of the through hole 3a, and a DC resistance is generated by the arc.

For this reason, a sufficient effect can be obtained to attenuate the DC component of the short circuit, and the current zero point appears quickly, making it possible to interrupt the current.

In addition, during the closing operation, the closing operation air is exhausted by a control valve (not shown) in response to the closing command, but the high pressure air in the air chamber E is not exhausted due to the check valve 12a of the third cylinder 7, and the air in the air chamber F is not exhausted. only is exhausted.

For this purpose, the piston 7a is driven to the right to open the valve 3C and the high pressure air in the through hole 3a, that is, the arc extinguishing chamber, is exhausted.

On the other hand, the first and second cylinders 2a,
The high pressure air in the air chambers C and D of 2b is also exhausted.

Also, the first and second cylinders 2a are connected via the insulating tube 11a.
, 2b are supplied with input operation air to close the vacuum valve 1 and drive the movable contactor 5 to the left in the figure.

Then, the arc contact 4 is joined to the fixed side contact base 3 by the spring force of the spring 4a to make the closed state, and the movable contact 5 is further joined to the sliding contact 3b to reliably maintain the closed state.

The piston 7a of the third cylinder 7 equalizes the pressure in the air chambers E and F on both sides by the small hole, and the piston 7a of the third cylinder 7
The piston 8a is moved to the left in the figure by the pressure of high-pressure air acting on the piston 8a, and the through hole 3a is closed by the valve 3C, completing the injection.

Further, in this closed state, almost no current flows through the vacuum valve 1 due to the skin effect of the tributary current, and most of the current flows through the movable contact 5 disposed around the outer periphery of the vacuum valve 1.

For this reason, the current carrying capacity of the vacuum valve 1 only needs to be small, and it is sufficient that the breaking capacity and short-time current carrying capacity satisfy the rating that can withstand use, so it is possible to carry a large current using a relatively small vacuum valve. can do.

As detailed above, the present invention has a contact section consisting of a fixed contact stand and an arc contact in series with the vacuum valve, and a movable contact on the outer periphery of the contact section. Since the valve is opened and closed in the reverse order when it is turned on, it is possible to provide a vacuum switching device that can obtain a large current capacity using a small vacuum valve and can also be used to interrupt short circuits in generator circuits. .

[Brief explanation of the drawing]

The figure is a sectional view showing an embodiment of the present invention. 1... Vacuum valve, 2... Movable side contact table, 2a... First cylinder, 2b...
・Second cylinder, 3...Fixed side contact base, 3a
...Through hole, 3C...Valve, 4...
・Arc contact, 5...Movable contact, 6...
...Insulating spacer, 9...Insulating tube, 13 a
, 13 b...Terminal.

Claims (1)

[Scope of utility model registration request] A bottomed cylindrical movable contact base provided with a terminal for connecting to an external electric circuit, a vacuum valve placed within the movable contact base with the movable contact side attached to the bottom, and the movable contact base. A first cylinder and a piston are provided at the bottom and drive the movable contacts of the vacuum valve to open and close by the pressure of the operating fluid from the outside; A fixed side contact table has a through hole defining the arc extinguishing chamber and has a terminal for connection to an external electric circuit, and a second cylinder shaped around the movable side contact table holds the movable side contact table and is operated from the outside. a movable contact that is driven by fluid pressure to move toward and away from the fixed contact base; and a movable contact that is held movably on the fixed contact side of the vacuum valve and is elastically connected to the center of the fixed contact base by a spring force. an insulating spacer that connects the movable contact and the arc contact with a predetermined play, and a high voltage that airtightly connects the movable contact base and the fixed contact base and fills the interior thereof. It is equipped with an insulating tube for sealing air, a valve that communicates the through hole of the fixed side contact table with the outside during a shutoff operation to exhaust the high pressure air and extinguish the arc, and a vacuum valve during a closing operation. A movable switching device characterized in that an arc contact and a movable contact are closed in this order, and when a cutoff operation is performed, a movable contact, an arc contact and a vacuum valve are opened and separated in that order.