JPH1125817A - Electromagnetic repulsion mechanism for switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain larger repulsion with a smaller, lighter repulsive plate without making a power supply larger by composing this electromagnetic repulsion mechanism out of a repulsive coil and a thin repulsive plate fixed on a movable rod opposite to the coil surface and by setting the resonance frequency of a resonant circuit which is composed of an inductance of the coil and the capacitance of a capacitor with in a specific range. SOLUTION: This electromagnetic repulsion mechanism 48 is produced so as to comprise a switch frame 50, a switch movable rod 1A and a repulsive coil 22 fixed on the frame 50, and the repulsive coil 22 is so formed as to have an inductance having a resonance frequency set by the aid of a capacitor in a power supply in the range of 500 Hz or gher to 2000 Hz or lower. A thin repulsive plate 23 made of a thin copper plate is fixed on the movable rod 1A opposite to the coil surface of the repulsive coil 22 and has a thickness ranging from 2 to 6 mm, so as to have the same thickness as the effective depth of eddy current corresponding to frequencies from 500 to 2000 Hz. A reinforcing plate 13 is made of a light non-magnetic material and reinforces the thin repulsive plate 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for driving a contact of a switch, and more particularly to an improvement in an opening speed.

[0002]

2. Description of the Related Art Here, a description will be given using a vacuum circuit breaker as a switch. In general, a switch is required to open its contacts as quickly as possible. This is because doing so reduces the wear of the contacts due to the arc and leads to an improvement in the performance as a switch. As a driving source for quickly opening the contact, a spring has been used for a long time. Recently, however, a so-called electromagnetic repulsion mechanism has been used in addition to the spring. Figure 12 shows Tokuhei 7-6
FIG. 1 is an overall schematic view of a switch equipped with an electromagnetic repulsion mechanism similar to that shown in Japanese Patent No. 0624.

In FIG. 12, reference numeral 50 denotes a frame of the switch. Reference numeral 1 denotes a vacuum valve having a detachable main contact (movable contact), 1A denotes a movable rod for driving a main contact (not shown) of the vacuum valve 1, 2 denotes a repulsion coil fixed to a frame 50, and 3 denotes a movable rod. A repulsion plate fixed to 1A and provided close to the repulsion coil 2 is a closing (contact pressure) spring for applying a contact pressure to the main contact, and a driving mechanism 5 for driving the movable rod 1A. The drive mechanism 5 includes an opening holding mechanism, a closing mechanism, and the like (not shown). However, detailed description is not necessary for the description of the present invention, and thus detailed description is omitted.

FIG. 13 is a circuit diagram of a power supply 49 for electromagnetic repulsion connected to the repulsion coil 2. The power supply 49 for electromagnetic repulsion may be housed in the frame 50 or may be installed outside, but in any case, the housing position is irrelevant for the description of the present invention. The repulsion coil 2, the repulsion plate 3, and the power supply 49 for electromagnetic repulsion constitute an electromagnetic repulsion mechanism 6.
The power supply 49 for electromagnetic repulsion includes an AC power supply 7 for charging, a charging resistor 8 connected in series to the AC power supply 7, a diode 9 connected in series, and a capacitor connected in parallel to the power supply 7 on the output side of the diode 9. 10, a switch 11 connected in series with a diode 9. The DC power is supplied to the capacitor 10 by the charging AC power supply 7, and the switch 1
When 1 is turned on, current is discharged from the capacitor 10 to the repulsion coil 2.

Next, the opening / closing operation of the switch equipped with the electromagnetic repulsion mechanism 49 will be described. In the power supply circuit diagram of FIG. 13, the capacitor 10 is charged to a constant voltage by the charging AC power supply 7. In the case of the opening operation, the switch 11 is turned on by an opening signal instructed from the outside, and a pulse-like coil current flows from the capacitor 10 to the repulsion coil 2. FIG. 14 shows an example of the coil current waveform at this time.
When the switch 11 is closed, the capacitor 10 and the repulsion coil 2
, The current becomes oscillating as shown in the figure, but its frequency f is determined by the capacitance C of the capacitor 10, the inductance L of the repulsion coil 2 and its DC resistance R, f = 1 / [2π ｛(R / 2L) ^2- (1 / LC)｝ ^1/2 ].

A high-frequency magnetic field is generated by the oscillating current, and an eddy current is induced in the repulsion plate 3 by the high-frequency magnetic field. Due to the interaction between the high-frequency magnetic field and the eddy current, an electromagnetic repulsion is generated between the repulsion coil 2 and the repulsion plate 3.
The repulsion plate 3 is pushed down in FIG. 12 by this electromagnetic repulsion, and the contacts are instantaneously opened. When the contact position is reached, the contact 11 is opened and the contact of the vacuum valve 1 is kept in the open state by an opening holding mechanism (not shown).

In the closing operation, the opening is not held by an opening mechanism (not shown), and the opening (contact pressure) is compressed during opening.
The movable rod 1A moves together with the repulsion plate 3 in the closing direction (upward in FIG. 12) by the spring 4, and the vacuum valve 1 connected to the movable rod 1A is closed.

[0008]

In order to increase the speed at which the contacts of the vacuum valve open, it is desirable to increase the repulsive force acting between the repulsion coil and the repulsion plate as much as possible. The generated electromagnetic repulsion greatly depends on the power supply voltage. The electromagnetic repulsion can be increased by increasing the power supply voltage. However, in order to increase the power supply voltage, the size of the capacitor 10 is increased, and the size of the entire power supply device is also increased. It is also effective to increase the shape of the repulsion coil and the repulsion plate to some extent, but the size is limited by the shape of the device. In fact, what is really needed is not the force but the acceleration of the contacts.Therefore, without increasing the power supply voltage or the size of the repulsion plate, it is desirable to increase the acceleration by using a smaller repulsion plate to obtain a larger repulsion force. It is an issue. In addition, the coil current flowing through the repulsion coil oscillates, and the electromagnetic repulsion also oscillates, and peaks and valleys appear repeatedly. Therefore, when the valley of the electromagnetic repulsion just hits the length of the opening time, Electromagnetic repulsion cannot be used efficiently.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an electromagnetic repulsion mechanism capable of obtaining a larger repulsion force with a smaller and lighter repulsion plate without increasing the size of a power supply. It is to try. Another object of the present invention is to provide an electromagnetic repulsion mechanism that suppresses the vibration of the coil current, that is, the vibration of the electromagnetic repulsion, and can efficiently use the electromagnetic repulsion.

[0010]

An electromagnetic repulsion mechanism according to the present invention is used in a switch having a vacuum valve having a movable contact fixed to and detachable from a frame and a movable rod connected to the movable contact. An electromagnetic repulsion mechanism for driving the movable rod, a repulsion coil fixed to the frame around the movable rod, and a thin plate repulsion plate fixed to the movable rod corresponding to a coil surface of the repulsion coil And a power supply having a capacitor for holding a DC voltage, wherein the resonance frequency of the resonance circuit formed by the inductance of the coil and the capacitance of the capacitor is 500H.
It is Z or more and 2 KHZ or less. Increasing the resonance frequency produces an effect that the eddy current is concentrated on the surface near the repulsion coil due to the skin effect, so that the distance between the repulsion coil and the eddy current is short and the repulsion force is increased.

The electromagnetic repulsion mechanism according to the present invention is such that the thin plate repulsion plate is composed of a copper plate having a thickness of 2 to 6 mm and a reinforcing plate made of a plastic or non-magnetic metal for supporting the copper plate. According to the skin effect caused by the higher frequency, the eddy current flows intensively on the surface.As a result, the value of the eddy current does not decrease even if the rebound plate is thinned, and the weight is reduced accordingly, so the acceleration increases. Produce action.

Further, in the electromagnetic repulsion mechanism according to the present invention, the reinforcing plate has a tapered structure in which the thickness of the portion near the outer periphery is smaller than the thickness of the portion near the inner periphery. The tapered reinforcing plate has the effect of reducing weight and increasing acceleration.

The repulsion coil has a diode connected in anti-parallel. The diode produces an effect of converting the oscillating current of the parallel resonance circuit into a direct current, so that the electromagnetic repulsion is used efficiently.

The frame on which the repulsion coil is mounted is
It has a slit orthogonal to the winding of the repulsion coil. The slit on the frame side produces an effect that wasteful eddy current on the frame side is reduced, the eddy current generated in the repulsion plate is increased, and the repulsion force is increased.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 shows an electromagnetic repulsion mechanism 48 according to Embodiment 1 of the present invention. Since the configuration of the portion of the switch equipped with the electromagnetic repulsion mechanism 48 of the present invention other than the electromagnetic repulsion mechanism 48 is the same as that of the conventional one, detailed description will be omitted. In FIG. 1, reference numeral 50 denotes a frame of a switch, 1A denotes a movable rod of the switch, 22 denotes a repulsion coil fixed to the frame 50, and has a resonance frequency with a capacitor 20 of a power source (shown in FIG. It is manufactured to have the following inductance. Reference numeral 23 denotes a thin sheet repulsion plate made of a thin copper plate, which is fixed to the movable rod 1A corresponding to the coil surface of the repulsion coil 22 so as to have a thickness of the effective depth of the eddy current of 500 to 2000 HZ, for example. The thickness is 6 to 2 mm. Reference numeral 13 denotes a reinforcing plate for transmitting a repulsive force applied to the thin plate repulsion plate 23 to the movable rod, and is made of a non-magnetic material.
In addition, the shape is as light as possible. The electromagnetic repulsion mechanism 48 includes a repulsion coil 22, a thin plate repulsion plate 23, and a power supply 47 for electromagnetic repulsion described below (hereinafter, also referred to as a power supply).
It is composed of

FIG. 2 shows the relationship between the frequency of the oscillating current and the generated repulsive force in the electromagnetic repulsion mechanism 48 having the same structural dimensions. In this figure, the peak value of the coil current at each frequency is set to be the same as the peak value of the coil current when the frequency is 60 Hz, and the electromagnetic repulsion generated by the coil current is set to 1 when the frequency is 60 Hz. The vertical axis is proportionally shown. As the frequency is increased, the eddy current induced in the thin plate repulsion plate 23 due to the skin effect is distributed near the surface of the thin plate repulsion plate 23 facing the repulsion coil 22, and the eddy current between the repulsion coil 22 and the eddy current is relatively increased. Since the distance is reduced, the electromagnetic repulsion becomes larger than when the frequency is 60 Hz.

This is shown in FIG. In FIG. 3, the vertical axis indicates the distance in the thickness direction of the thin plate repulsion plate 23, the upper side is the side closer to the coil 22, and the lower side of the figure is the opposite side to the coil 22. The horizontal axis indicates the density of the current flowing inside the thin plate repulsion plate 23 in proportion. The thickness of the thin repulsion plate 23 is sufficient if the thickness of the current concentrated near the surface due to the skin effect is sufficient, so that it can be made relatively thinner at higher frequencies than at lower frequencies.

As shown by the dotted line in FIG. 2, the effect becomes saturated when the frequency of the coil current is around 500 Hz or higher, and there is no merit in manufacturing even if the thin plate repulsion plate 23 becomes thinner to some extent. On the other hand, if it is too high, apparently the resistance of the portion where the eddy current flows increases and the eddy current decreases, so that a frequency of 500 to 2000 Hz is preferably selected. Even at 500 Hz, the thickness of the thin plate repulsion plate 23 can be made 6 mm or less, the eddy current induced by the coil current can be sufficiently utilized, and the contact opening time can be made 1 ms or less, for example. Thin rebound board 2
Since 3 is thin and has low mechanical strength, the repulsive force due to the eddy current cannot be transmitted to the movable rod 1A as it is.
Therefore, the reinforcing plate 13 attached thereunder has strength against electromagnetic repulsion. FIG. 4 shows a back perspective view of the reinforcing plate 13. The reinforcing plate 13 is made of a plastic or non-magnetic material so as not to affect the magnetic field, and is provided with a suitable stiffener (beam) as shown in the figure to reduce the weight.

FIG. 5 shows a configuration diagram of a switch using the electromagnetic repulsion mechanism 48 of FIG. 1 in comparison with a conventional switch. In FIG. 5, the switch includes a frame 50, a vacuum valve 1, a driving rod 1A, a repulsion coil 22 having an inductance L1 and a resistance R1, a thin repulsion plate 23 made of a thin copper plate, and a non-reinforcing plate for reinforcing the thin repulsion plate 23. Reinforcing plate 13 made of magnetic material,
It comprises a closing (contact pressure) spring 4 and a drive mechanism 5. FIG. 6 shows an electromagnetic repulsion power supply 47 designed to have a resonance frequency of 500 HZ or more, and includes a charging AC power supply 7, a charging resistor 8, a diode 9, a capacitor 20 having a capacitance C1, and a switch 11. I have. The frequency of the oscillating current flowing through the repulsion coil 22 when the switch 11 is closed is f = 1 / [｛2π (R1 / 2L1) ² − (1 / L1C
1)｝ ^1/2 ].

The electromagnetic repulsion required as an electromagnetic repulsion mechanism is:
When the power supply voltage is constant, the repulsion coil 22 and the capacitor 20
Depends on. The external dimensions of the repulsion coil 22 are limited to some extent by the size of the switch, but within that limit, an inductance within a certain range is selected by selecting a combination of the wire thickness and the number of turns used for the coil. You can do it. Further, the capacity of the capacitor 22 can also be selected within the range of the external restrictions. That is, when the frequency is high, the capacitance is small, and when the frequency is low, the capacitance is large.

When the frequency of the coil current is set to 500 Hz or more by the combination of the repulsion coil 22 and the capacitor 20, the capacitance of the capacitor can be reduced, and the eddy current induced in the thin repulsion plate 23 is applied to the repulsion coil 22 by the skin effect. Since it is distributed near the surface of the opposing repulsion plate 23 and the distance between the repulsion coil 22 and the repulsion plate 23 becomes relatively small, it is possible to obtain an electromagnetic repulsion force larger than the electromagnetic repulsion force at the frequency of 60 Hz. it can. Further, since the thin plate repulsion plate 23 can be made thin (light), the mass of the entire movable part becomes small, and the acceleration (the speed at which the contacts open) increases.

Embodiment 2 FIG. FIG. 7 shows another embodiment of the present invention. In the drawing, Ra indicates an average radius of the center of the coil winding of the repulsion coil 22 (hereinafter referred to as radius). F indicates a repulsive force generated at a distance r from the axis center. FIG. 8 shows the relationship between the distance r from the axis and the electromagnetic repulsion F. In this figure, the electromagnetic repulsion force F is proportionally represented with the maximum value as 1, and the horizontal axis is the distance r from the axis.
And the average radius of the coil. The maximum value of the electromagnetic repulsive force F occurs at the position of the coil radius, and the electromagnetic repulsive force decreases as the distance from the coil radius increases or decreases. Since all the force applied to the thin plate repulsion plate 23 is applied to the portion connected to the movable rod 1A, the largest bending stress is generated at the center of the thin plate repulsion plate 23. Therefore, reinforcement is required at the center of the repulsion plate. On the other hand, outside the coil radius, since the electromagnetic repulsion is small, the strength of the reinforcing plate 13 can be reduced, that is, the thickness can be reduced. Therefore, the weight of the movable portion can be reduced by forming a structure in which the outer portion close to the outer periphery is tapered and thin like the reinforcing plate 13a with respect to the electromagnetic repulsive force. Can be increased.

Embodiment 3 FIG. FIG. 9 is a circuit diagram of a power supply for electromagnetic repulsion according to another embodiment of the present invention, in which a diode 12 is connected in antiparallel with a repulsion coil 22. FIG.
In the power supply for electromagnetic repulsion, a coil current that attenuates while vibrating flows (broken line in FIG. 10). In this case, the coil current oscillates and the electromagnetic repulsion also oscillates, making it impossible to obtain the energy required for high-speed opening. In FIG. 9, by connecting the diode 12 in antiparallel with the repulsion coil 22, a coil current flows as shown by the solid line in FIG. By supplying such a coil current, the energy required for high-speed opening can be used more quickly for the same charging voltage and the same capacitor capacity. Even in the case of such a current waveform, the frequency component at the first rise of the current becomes the high frequency shown in the above-mentioned equation, and it can be said that the eddy current is concentrated near the surface of the thin repulsion plate 23 by the skin effect. There is no.

Embodiment 4 In FIG. 1, the repulsion coil 2
Since the electromagnetic force of No. 2 extends to the upper part of the drawing, an eddy current is generated in a portion of the frame 50 on which the repulsion coil 22 is mounted, in contact with the repulsion coil 22. Since this acts as a one-turn short-circuit coil, it acts to weaken the electromagnetic force of the repulsion coil 22. Therefore, the plate of the frame 50 to which the repulsion coil 22 is attached may be made of a high-resistance stainless steel plate, or an insulating spacer (not shown) may be inserted between the repulsion coil 22 and the frame 50 to make the repulsion coil 22
A method such as increasing the distance between the frame and the frame 50 may be used, but since none of them is economical, the method shown in FIG. 11 is preferably used.

FIG. 11 is a plan view of FIG. 1 as viewed from above, in which 24 is a hole through which the movable rod 1A penetrates, and 25 is provided around the through hole 24 so as to be orthogonal to the coil winding of the repulsion coil 22. It is a slit. The eddy current generated in the portion of the frame 50 in contact with the repulsion coil 22 by the slit 25 becomes small, and the frame 50 does not function as a single-turn short-circuit coil. As a result, the repulsion coil 2
2, the repulsive force generated on the repulsion plate 23 also increases. Although four slits 25 are shown around the hole 24 in FIG. 11, an effect is obtained if at least one slit 25 is provided.

[0026]

According to the electromagnetic repulsion mechanism of the present invention, the peak value of the current flowing through the coil is kept constant, the capacitance of the capacitor is changed, and the frequency of the coil current is increased from 500 to 200.
By setting the frequency to 0HZ, it is possible to use an electromagnetic repulsive force larger than the electromagnetic repulsive force generated when the frequency is low,
The weight of the movable part can be reduced, and the power source for electromagnetic repulsion can be optimized.

In the electromagnetic repulsion mechanism according to the present invention, the thin repulsion plate is composed of a copper plate having a thickness of 2 to 6 mm and a reinforcing plate made of a plastic or a non-magnetic metal for supporting the copper plate. Therefore, the effect of increasing the acceleration can be obtained.

In the electromagnetic repulsion mechanism according to the present invention, the reinforcing plate has a tapered structure in which the thickness of the portion near the outer periphery is thinner than the thickness of the portion near the inner periphery. To increase the effect.

Further, since the repulsion coil has a diode connected in anti-parallel, the oscillation current of the parallel resonance circuit is converted into a DC current, and the effect that the electromagnetic repulsion is used efficiently can be obtained.

The frame on which the repulsion coil is mounted is
Since it has a slit orthogonal to the winding of the coil,
The effect of reducing unnecessary eddy current on the frame side, increasing the eddy current generated in the repulsion plate, and increasing the repulsion force can be obtained.

[Brief description of the drawings]

FIG. 1 shows an electromagnetic repulsion mechanism according to Embodiment 1 of the present invention.

FIG. 2 is a relationship diagram between a frequency and a repulsive force of the electromagnetic repulsion mechanism of FIG.

FIG. 3 is a diagram showing a current density characteristic in a thickness direction of a repulsion plate of the electromagnetic repulsion mechanism of FIG. 1;

FIG. 4 is an external view of a reinforcing plate of the electromagnetic repulsion mechanism of FIG. 1;

FIG. 5 is a view of a switch equipped with the electromagnetic repulsion mechanism of FIG. 1;

FIG. 6 is a circuit diagram of the power supply for the electromagnetic repulsion mechanism of FIG. 1;

FIG. 7 is a diagram illustrating a mechanism of an electromagnetic repulsion mechanism according to a second embodiment.

FIG. 8 is a diagram illustrating a relationship between a distance from an axis and an electromagnetic repulsion.

FIG. 9 is a circuit diagram of a power supply for electromagnetic repulsion used in the third embodiment.

FIG. 10 is an explanatory diagram of a current flowing in the circuit of FIG. 9;

FIG. 11 is a diagram showing a structure of a frame according to a fourth embodiment.

FIG. 12 is a diagram of a switch equipped with a conventional electromagnetic repulsion mechanism.

FIG. 13 is a circuit diagram of a conventional power supply for electromagnetic repulsion.

FIG. 14 is a diagram showing a coil current flowing in the circuit of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Vacuum valve 1A Movable rod 2, 22 Repulsion coil 3 Repulsion plate 5 Driving mechanism 6 Electromagnetic repulsion mechanism 7 AC power supply for charging 9 Diode 10 Capacitor 11 Switch 12 Diode 13, 13a
Reinforcement plate 22 Repulsion coil 23 Thin repulsion plate 20 Capacitor 24 Movable rod through hole 25 Slit 47 Electromagnetic repulsion power supply 48 Electromagnetic repulsion mechanism 49 Electromagnetic repulsion power supply 50 Frame r Distance from axis Ra Radius of coil of repulsion coil

Claims (5)

[Claims] An electromagnetic repulsion of a switch used for a switch having a movable valve fixed to a frame and having a movable contact that can be separated from and moved and a movable rod connected to the movable contact, the switch driving the movable rod. A repulsion coil fixed to the frame around the movable rod, a thin plate repulsion plate fixed to the movable rod corresponding to a coil surface of the repulsion coil, and a capacitor for holding a DC voltage. An electromagnetic repulsion mechanism for a switch, comprising: a power supply having a resonance frequency of 500 Hz or more and 2 KHZ or less, the resonance circuit including a coil inductance and a capacitance of the capacitor. 2. The switch according to claim 1, wherein the thin plate repulsion plate comprises a copper plate having a thickness of 2 to 6 mm and a reinforcing plate made of a plastic or a non-magnetic metal for supporting the copper plate. Electromagnetic repulsion mechanism. 3. The electromagnetic repulsion mechanism of a switch according to claim 2, wherein the reinforcing plate has a tapered structure in which a thickness of a portion near an outer periphery is thinner than a thickness of a portion near an inner periphery. 4. The electromagnetic repulsion mechanism of a switch according to claim 2, wherein the repulsion coil has a diode connected in anti-parallel. 5. The electromagnetic repulsion mechanism for a switch according to claim 1, wherein the frame on which the repulsion coil is mounted has a slit orthogonal to the winding of the repulsion coil.