JPH0777107B2 - Vacuum breaker operating mechanism - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to an operating mechanism for opening and closing a vacuum circuit breaker.

[Prior art]

Some vacuum breaker operating mechanisms are provided with a mechanical free tripping mechanism that disables closing even if a tripping operation is performed even during closing operation. 4 to 6 are sectional views of an operating mechanism of a conventional vacuum circuit breaker having such a tripping free mechanism. FIG. 4 is a cut-off state, FIG. 5 is a closed state, and FIG.
The figures show the free trip states. Well then
This will be described below. When the closing coil 2 of the operating electromagnet 1 is excited in the shut-off state of FIG. 4, the plunger 3 is attracted toward the yoke 4, and the closing latch 6 is moved clockwise in the figure through the roller 5 at the tip of the rod 3a. Rotate. This rotation is transmitted to the lever 10 fixed to the opening / closing shaft 9 via the link 7 and the link 8. As a result, the lever 10 rotates in the clockwise direction in the drawing while compressing the blocking spring 12 acting on the opening / closing shaft 9 via the lever 11, and the lever 10, the rod 13, the contact spring 14, and the lever 10 are rotated.
The movable electrode 16 connected via 15 is closed to the fixed electrode 17. When the closing of the circuit is completed, the contact of the auxiliary switch (not shown) is closed and the operation circuit is opened, so that the excitation of the closing coil 2 is released and the plunger 3 returns to the state shown in FIG. On the other hand, when the closing latch 6 rotates, the claw 18 rotates clockwise in the figure by the action of the spring 19 and enters below the closing latch 6 with a slight gap. Then, when the closing coil 2 is de-excited and the plunger 3 begins to fall, the closing latch 6 is returned in the counterclockwise direction by the action of the breaking spring 12. However, when the gap is eliminated, the tip is engaged with the pawl 18. The closed state of the movable electrode 16 is maintained. FIG. 5 shows such a closed state. In the course of the above operation, the links 7 and 8 tend to collapse into an inverted V shape, but are held in the illustrated state by being supported by the plate 22 that engages with the semicircular cross section 21a of the trip shaft 21. Therefore, when the trip lever (not shown) strikes the operating lever 21b of the trip shaft 21 against the return spring (not shown) in the closed state of FIG. Slips into the slit 22a of the plate 22 and the links 7 and 8 collapse. As a result, the lever 10 rotates counterclockwise and the movable electrode 16 opens. At the same time, the pawl 18 is pushed counterclockwise by the lever 23 and is disengaged from the closing latch 6. When the closing latch 6 is disengaged from the claw 18, the closing spring 6 is rotated counterclockwise by the action of the reset spring 20, pulling back the plate 22 to the right in the drawing, and re-engaging the trip shaft 21 and the plate 22. FIG. 4 shows the blocking state as a result of this. On the other hand, if there is an accident in the circuit at the time of making, the making-immediate-interruption is performed. FIG. 6 shows the state at that moment (free tripping state). That is, when a trip command is issued immediately after turning on, the trip shaft 21 and the plate 22 are disengaged, and the link 7,
8 collapses and becomes the state shown. However, the operating electromagnet 1 does not move immediately after the operating circuit of the closing coil 2 is opened.
Since it has not descended yet, the closing latch 6 remains pushed up. However, since the links 7 and 8 are broken, the lever 10 can rotate, and there is no problem in opening the movable electrode 16 (tripping freely).

[Problems to be Solved by the Invention]

As described above, in the operation mechanism having the tripping free mechanism, even if the trip command is issued immediately after the closing operation, the plunger 3 in the suction position is disconnected without any interruption, and due to the characteristic of the link mechanism, the plate 22 and Since the engagement force with the trip shaft 21 is also small, the tripping force can be reduced. However, since the above-mentioned trip free mechanism has a complicated mechanism and a large number of parts, it is disadvantageous in terms of reliability. Further, since the structure is such that it can be tripped by a small force, on the other hand, malfunctions easily occur due to solidification of grease due to the influence of dust, temperature, and humidity. Therefore, there is a problem in maintaining the operational reliability of the operating mechanism for many years. Therefore, an object of the present invention is to provide an operating mechanism of a vacuum circuit breaker having a simplified structure and improved operation reliability.

[Means for Solving the Problems]

In order to achieve the above object, an operating mechanism of a vacuum circuit breaker according to the present invention includes an opening / closing shaft on which a breaking spring acts, a lever fixed to the opening / closing shaft and connected to a movable electrode via a contact spring, and a closing coil. A plunger having a hollow structure which moves up and down in the inside is provided, and the plunger faces the lever via a roller, and rises when the closing coil is excited to rotate the lever against the breaking spring. The movable electrode is closed, and when the closing of the movable electrode is released, the operating electromagnet which descends while receiving the spring force of the return spring when the closing coil is released, and the spring force of the lever when the movable electrode is closed. After entering the downward direction and releasing the excitation of the closing coil, a pawl that engages with the lever via a roller to hold the movable electrode in the closed state, and a pawl by a trip command To release the engagement between the serial lever shall be composed of a tripping device which is to be opened the movable electrode.

[Action]

In the present invention, the tripping free mechanism is abolished, and the lever fixed to the opening / closing shaft is directly rotated by the plunger to engage the lever with the claw. However, in order to prevent the open circuit from being obstructed even when the plunger is in the suction position during closing-immediate-cutoff, the plunger has a hollow structure and is made lighter. It is easy to remove the plunger by. Further, in order to reduce the tripping force to a small force, the engagement between the lever and the claw is performed via the roller. With such a structure, even if the trip free mechanism is abolished, substantial trip free movement is possible.

【Example】

An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view of an operating mechanism for one pole of a three-pole vacuum circuit breaker. FIG. 1 is a cut-off state, FIG.
The figures respectively show closed states. The substantially same parts as those in the conventional example are designated by the same reference numerals. In FIG. 1, the cylindrical plunger 31 that moves up and down in the closing coil 2 of the operating electromagnet 1 is formed in a hollow structure to reduce the weight. Also, the plunger 31 and the yoke 4
A return spring 32, which is a coil spring, is inserted between and, and the plunger 31 is constantly urged in the descending direction. A rod 31a is connected to the tip end side of the plunger 31. The tip of the lever 33 fixed to the opening / closing shaft 9 is the shaft 34 and the rod 13
Further, a roller 35 is attached to the shaft 34 via a full complement roller bearing (not shown). The tip of the rod 31a of the plunger 31 faces the roller 35 with a slight gap. A lever 11 is fixed to the opening / closing shaft 9 in a direction substantially opposite to the lever 33, and one end of a guide rod 36 for guiding the blocking spring 12 is coupled to the lever 11 by a shaft 37. The other end of the guide rod 36 is slidably supported by a fixed portion 38 of the breaker body. The blocking spring 12 acts to rotate the opening / closing shaft 9 in the counterclockwise direction in the figure, but the rotation is blocked by the lever 11 hitting the stopper 39. A roller 40 is attached to the tip of the lever 33 by a shaft 41 via a full complement roller bearing (not shown), and a claw 42 that engages with the lever 33 via the roller 40 is arranged in front of the roller 40. There is. The pawl 42 is supported by a shaft 43 and is constantly urged clockwise by a spring 44. 45 is a trip lever fixed to the claw 42, the tip of which is opposed to a trip device (not shown),
When a trip command is given, it is driven counterclockwise. In such a configuration, the closing coil 2 of the operating electromagnet 1
Is excited, the plunger 31 is attracted to the yoke 4 side against the return spring 32 and rises. The plunger 31 contacts the roller 35 and rotates the lever 33 clockwise against the blocking spring 12. The movement of the lever 33 is transmitted to the movable electrode 16 through the rod 13, the contact spring 14 and the lever 15 to close the fixed electrode 17. Meanwhile, when the roller 40 comes out of the upper surface of the pawl 42, the pawl 40 which receives the force of the spring 44 rotates clockwise until the trip lever 45 hits the roller 40, and enters below the lever 33. FIG. 2 shows such a closed circuit instantaneous state. After that, when the closed contact of the auxiliary switch (not shown) is opened and the operation circuit of the closing coil 2 is opened, the excitation of the closing coil 2 is released and the plunger 31 descends, but the lever 33 moves through the roller 40. The closed state is continued by engaging with the pawl 42, and the closing operation is completed. FIG. 3 shows such a closed state. When a fault current occurs in the main circuit in the closed state of Fig. 3, the overcurrent relay (OCR) detects this via the current transformer (CT),
Close the contact and issue a trip command to the trip device. As a result, the tripping device strikes the trip lever 45 in the direction of the arrow Q in the figure to disengage the closing latch 42 and the lever 33.
As a result, the lever 33 is rotated counterclockwise by the action of the blocking spring 12 to open the movable electrode 16. If such a shutoff operation is executed at the same time as closing (closing-immediately-breaking), the plunger 31 is placed at the same position as the closed circuit instantaneous state in FIG. 2 when the overcurrent signal from CT is generated. is there. That is, the operating circuit of the closing coil 2 is opened at the same time when the closing circuit is closed, but the overcurrent signal is only output at that moment, so that the plunger 31 is still in the raised position. By the way, it usually takes 20 to 50 ms until the CT detects the fault current and closes the contact of the OCR, thereby issuing a trip command, but this causes the coil of the trip device to be excited and the plunger to operate. Is further delayed by 100 ms or more. After all, it generally takes about 200 ms from the detection of the overcurrent to the actual operation of the trip device. On the other hand, the auxiliary switch whose contacts are opened simultaneously with the closing of the main circuit instantly opens the operating circuit of the closing coil 2. Therefore, after the circuit breaker is closed, that is, 200 ms after the excitation of the closing coil 2 is released, the trip device releases the engagement between the lever 33 and the pawl 42, and the roller 35 begins to descend. The plunger 31, which has been reduced in weight by the above, receives the force of the return spring 32 and starts moving in the descending direction. After that, the roller 35 rapidly descends under the rapid opening of the movable electrode 16 by the breaking spring 12, but the closing coil 2 is demagnetized at this time, and the plunger 31 is lightweight and has a small inertia and the return spring. Biased to 32, so roller
The movement of 35 is hardly hindered by the plunger 31. That is, the freedom of trip can be executed without any trouble. In other words, although the tripping free mechanism is not specially provided in the illustrated configuration, the tripping device (not shown) delays the operation time, the hollow structure of the plunger 31 reduces the weight, and the return spring 32 mounted on the plunger 31 causes the closing operation. -Immediately-It prevents the operating mechanism from lowering its operating speed when shutting off, and enables free tripping while simplifying the structure. Further, by engaging the lever 33 also serving as a closing latch and the claw 42 via the roller 40 using a full-roller type bearing, the tripping force is reduced and the tripping device similar to the conventional trip device is used. It is possible to operate. In the operating mechanism of the present invention, a roller bearing is used for the rotation support portion such as a roller and a lever, and the contact surface between the roller and the bearing component is subjected to surface treatment to eliminate the need for a lubricant, so that grease etc. It is possible to guarantee stable operation for a long period of time by eliminating the effects of solidification and deterioration over time of the lubricant, and to further improve operational reliability. As the surface treatment, titanium nitride (TiN) ceramic coating, soft nitriding (soft nitriding) treatment, and molybdenum disulfide (MoS ₂ ) baking coating can be used.

【The invention's effect】

According to the present invention, the plunger of the operating electromagnet is made hollow so as to reduce the weight, the return spring is inserted, and the lever and the claw are engaged with each other through the roller, thereby allowing the tripping free mechanism. It is possible to make closing-immediately-breaking with a simple structure not particularly provided, and to improve the operation reliability of the vacuum circuit breaker.

[Brief description of drawings]

1 to 3 are sectional views of an embodiment of the present invention. FIG. 1 shows a shutoff state, FIG. 2 shows a closed circuit instantaneous state, and FIG. 3 shows a closed circuit state. 4 to 6 are cross-sectional views of a conventional example, FIG. 4 shows a shut-off state, FIG. 5 shows a closed state, and FIG. 6 shows a free tripping state. 1 ... operating electromagnet, 2 ... closing coil, 9 ... opening / closing axis,
12 …… breaking spring, 14 …… contact spring, 16 …… movable electrode, 17
...... Fixed electrode, 31 ...... Plunger, 32 ...... Return spring, 33
...... Lever, 35 …… roller, 40 …… roller, 42 …… claw.

Front page continuation (72) Inventor Shunichi Hatakeyama 1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. Fuji Electric Co., Ltd. (72) Inventor Mitsuo Nakamura 1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. (56) Reference JP-A-52-6971 (JP, A) JP-A-SHO 54-39877 (JP, A) Actual development Sho-55-173834 (JP, U) Japanese patent Sho-50-40226 (JP, B1)

Claims (1)

[Claims] 1. A plunger having an opening / closing shaft acted by a breaking spring, a lever fixed to the opening / closing shaft and connected to a movable electrode via a contact spring, and a plunger having a hollow structure for moving up and down in a closing coil. Is opposed to the lever via a roller, and rises when the closing coil is excited to rotate the lever against the breaking spring to close the movable electrode, and with the closing of the movable electrode. When the energization of the closing coil is released, the operating electromagnet descends while receiving the spring force of the return spring, and when the movable electrode is closed, the spring force causes the spring to enter below the lever to release the excitation of the closing coil. Is engaged with the lever via a roller to hold the movable electrode in a closed state, and the trip command releases the engagement between the nail and the lever to open the movable electrode. That trip vacuum circuit breaker operating mechanism, characterized in that it consists of a device.