JPH0582008A - Breaker with leakage alarm - Google Patents

Abstract

PURPOSE:To use a breaker in a wide range of the input voltage without using a pressure reduction transformer by providing an electricity quantity control circuit in a power source circuit, and providing a circuit for reducing the current to a holding current in a driving circuit of an alarm means. CONSTITUTION:A limit circuit of a power source circuit 10 limits a quantity of electricity to be supplied from contact points A, B of a main circuit to set the voltage of the rectifying circuit, which includes a rectifier 14, at a predetermined voltage. An alarm coil driving circuit 50 of a control circuit of an alarm means, which includes an alarm output relay coil 70, reduces the current flowing to the coil 70 after passing of the predetermined time from turn-on of a thyristor 21 to a predetermined value to be set on the basis of a value of a resister 51. Current is thereby reduced to the minimum holding current of the coil 70 to reduce the power loss of the power source circuit 10. The circuit 10 is made compact by the limit circuit, and the range of the applying voltage is enlarged without using a transformer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker, and more particularly to a circuit breaker suitable for obtaining a leakage warning function without using a step-down transformer as a power source for detecting leakage.

[0002]

2. Description of the Related Art A conventional circuit breaker with an earth leakage alarm uses a step-down transformer to supply the coil energizing current of an alarm output relay. Further, the voltage trip device also uses an AC direct drive coil.

[0003]

The above-mentioned prior art uses a step-down transformer, and the voltage trip device also uses an AC direct drive coil. Therefore, an alarm output relay is provided in the breaker case. It is not applicable to a circuit breaker having a specification such that there is no space for accommodating the current, and the current for maintaining the operation is limited. Furthermore, for the voltage trip device, it is desirable to use the same product as the trip device of the earth leakage breaker from the viewpoint of standardization of parts.
Since the trip device of the earth leakage breaker is a direct current drive device having a drive coil rated for a short time, there is a problem in application in the prior art.

An object of the present invention is to provide a leakage alarm capable of supporting a wide range of voltage inputs without using a step-down transformer by keeping a holding current of an alarm output relay low and providing a power amount limiting circuit in a power supply circuit. To provide a circuit breaker.

[0005]

The above object is to provide a detection circuit of a circuit breaker with an earth leakage alarm, an alarm means, and a power supply circuit for supplying power to a control circuit with a limiting circuit for limiting the amount of electricity supplied from a main circuit conductor. , A rectifier circuit having an AC side connected to the limiting circuit and a constant voltage circuit connected to the DC side of the rectifier circuit, and the control circuit of the alarm means becomes an alarm means after a lapse of a predetermined time from the start of operation of the alarm means. This is achieved by configuring the flowing current to decrease to a predetermined value.

[0006]

The limiting circuit of the power supply circuit limits the amount of electricity supplied from the main circuit, and sets the voltage of the rectifying circuit to a desired voltage. The control circuit of the alarm means reduces the current flowing through the alarm means to a predetermined value after a predetermined time has elapsed since the switching means was turned on. As a result, the current is reduced to the minimum holding current of the alarm output relay coil, so that the power loss of the power supply circuit can be reduced. Moreover, the power supply circuit can be downsized by the limiting circuit, and the applicable voltage range can be expanded without using a transformer.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
It will be described with reference to the drawings.

FIG. 1 shows a circuit configuration of an earth leakage breaker according to an embodiment of the present invention.

First, the block configuration will be described. A power supply circuit 10 is connected to connection points A and B on the load side of the main circuit. The power supply circuit 10 has an alarm coil drive circuit 50 as a control circuit and a detection circuit. 20 are connected.

On the other hand, the external trip coil drive circuit 60, which is connected to the external trip device drive coil 3 and has the input terminal 68, includes the power supply circuit 10 and the alarm coil drive circuit 50.
It is provided independently from.

The power supply circuit 10 includes a resistor 8 connected to a load side main circuit connection point A, a parallel circuit of a constant current diode 4 and a constant voltage diode 6 connected to the resistor 8, and a load side main circuit. The resistor 9 connected to the connection point B, the parallel circuit of the constant current diode 5 and the constant voltage diode 7 connected to the resistor 9, and one AC input terminal of the constant current diode 4 and the constant voltage diode 6 A rectifier 14 that is connected to a parallel circuit and is assembled into a bridge circuit in which a parallel circuit of a constant current diode 5 and a constant voltage diode 7 is connected to the other AC input terminal, and a positive electrode and a negative electrode on the DC output side of the rectifier 14. Power supply capacitor 1 connected between
6, a constant voltage diode 18 having an anode connected to the positive electrode of the rectifier 14, and a power supply capacitor 1 connected between the cathode of the constant voltage diode 18 and the negative electrode of the rectifier 14.
7 and a constant voltage diode 19 connected in parallel with the power supply capacitor 17.

The positive electrode of the power supply capacitor 17 is connected to the power supply terminal of the earth leakage detection circuit 20 via the light emitting portion of the reset photocoupler 30. On the other hand, the detection circuit 20 is connected to the secondary output of the zero-phase current transformer 1, and the output terminal of the detection circuit 20 is connected to the control terminal of the thyristor 21.

The cathode of the thyristor 21 is connected to the negative side of the rectifier 14, and the anode of the thyristor 21 is connected to the light receiving portion of the reset photocoupling element 30, the alarm operation display LED 72, and the coil 70 of the alarm output contact 71 so as to drive the alarm coil drive circuit. Fifty
It is connected to the.

The alarm coil driving circuit 50 includes a PNP transistor 52, a diode 54 connected in antiparallel between the emitter and the base of the PNP transistor 52, and a capacitor 53 connected between the collector and the base of the transistor 52. The transistor 52 has a resistor 51 connected in parallel between the emitter and the collector.

On the other hand, the external trip device drive coil 3 is connected to the input terminal 68 via the trip coil drive circuit 60.

The trip coil drive circuit 60 includes a power supply capacitor 62 connected to a DC output of a rectifying bridge 61.
A two-terminal trigger element 63 connected to the positive side of the capacitor 62, a parallel circuit of a constant current diode 65 and a constant voltage diode 64 connected in series with the two-terminal trigger element 63, and the constant current diode 65. And a parallel circuit of a resistor 66 and a capacitor 67 connected in series to a parallel circuit of the constant voltage diode 64. The external trip device drive coil 3 has a parallel circuit of the resistor 66 and the capacitor 67 and a negative electrode of the rectifying bridge 61. Connected to the side.

Next, the operation of each circuit will be described with reference to FIGS.
Will be explained.

First, the operation of the power supply circuit 10 will be described with reference to FIG. Now, when the switching pole 2 is closed, the voltage shown in FIG. 2A is input from the connection points A and B of the main circuit from a higher AC power supply (not shown). The change in the input current due to this is shown in FIG. In the region A, since the input current is less than the rated current of the constant current diode 4, the input current gradually increases with the value limited by the resistors 8 and 9 as the input voltage increases. Area B
Then, the input current reaches the rated current of the constant current diode 4, and thus becomes the constant current. At this time, the inter-electrode voltage of the diode 4 gradually increases as shown in FIG. Area C
In, the input voltage becomes a voltage exceeding the Zener voltage of the constant voltage diode 6, and therefore the input current is the sum of the current of the constant current diode 4 and the current of the constant voltage diode 6. In the region D, the input voltage becomes a voltage lower than the Zener voltage of the constant voltage diode 6, and the input current becomes the constant current determined by the rated current of the constant current diode 4 again. In the region E, the input current has a value lower than the rated current of the constant current diode 4, and gradually decreases at a value limited by the resistors 8 and 9 as the input voltage decreases. In the negative half cycle, the constant current diode 5 and the constant voltage diode 7 cause the input current to have a waveform symmetrical to the positive half cycle with respect to the zero level. FIG. 4D shows the current waveform of the constant current diode 5.

The voltage of the capacitor 16 is stabilized by the constant voltage diodes 18 and 19, and the voltage of the capacitor 17 is stabilized by the constant voltage diode 19 and supplied to the detection circuit.

According to this embodiment, since the reverse voltage of the rectifying bridge can be suppressed to a low level, a general-purpose small package bridge can be used, and the creepage distance can be reduced, so that the size can be reduced. Become.

Further, since only a half cycle forward current flows through the constant current diode and the constant voltage diode, individual power consumption can be reduced.

Next, the operation of the alarm coil drive circuit 50 will be described with reference to FIG. Now, when the thyristor 21 is turned on, the light receiving portion of the optical coupling element 30 is in a conducting state, so that the current of the coil 70 flows as shown in FIG. That is, in the initial stage of driving, the current of the coil 70 flows from the emitter of the transistor 52, through the base, and through the capacitor 53, but when the collector-emitter saturation voltage of the transistor 52 gradually increases, the transistor 52 eventually cuts off. Therefore, the current of the coil 70 has a value limited by the sum of the resistance of the resistor 51 and the resistance of the coil 70 itself. The value of the resistor 51 at this time is set so that the current of the coil 70 becomes the minimum holding current.

According to this embodiment, the current of the alarm output relay coil is attenuated to the holding current, so that the power consumption of the power supply circuit can be suppressed low.

Further, the photo interrupter 30 as the optical coupling element 30 is provided inside the cover, and a push button 80 provided so as to penetrate the cover shields between the light emitting portion and the light receiving portion of the photo interrupter 30. , The light receiving part of the photo interrupter 30 is turned off,
The alarm output is reset.

As a resetting method, it is also possible to insert a microswitch b contact in series at positions A to C in FIG. 1, or connect in parallel between the main electrodes of the thyristor 21.

Since the light emission current of the photo interrupter 30 is also used as the current of the detection circuit 20, the power supply circuit 10
Power consumption can be reduced.

Further, since the applied voltage when the contact of the microswitch b is opened can be suppressed to a value as low as the urging voltage of the alarm device coil 70, a small product can be used and the miniaturization of the circuit breaker is not hindered.

Next, the drive circuit 60 for the external trip coil 3
The operation will be described with reference to FIG. When an AC voltage is applied to the input terminal 68 as shown in FIG. 7A, it is full-wave rectified by the rectifier 61 and smoothed by the power supply capacitor 62 as shown in FIG. When the voltage of the capacitor 62 becomes higher than the trigger voltage of the trigger element 63, FIG.
As shown in, a current flows through the coil 3 to open the open / close electrode 2. The peak value of the current of the coil 3 is limited in the parallel circuit of the constant current diode 65 and the constant voltage diode 64,
Further, after the opening operation, it is gradually reduced by the parallel circuit of the capacitor 67 and the resistor 66.

As a result, the external trip device 60 can be driven by alternating current. The external trip device drive circuit 60 does not malfunction because the smoothing capacitor 62 stores sufficient electric charge for driving and then energizes the coil 3. After the operation, the current of the coil 3 is suppressed to the minimum value, so that the coil is not burned.

Further, all the circuits of the above-mentioned embodiments can be made into a hybrid IC or a monolithic IC, which enables further miniaturization.

5 to 7 are sectional views showing an example of mounting centering on the reset button. FIG. 5 is a sectional view of the reset button portion of the present invention, and FIG. 6 is a standby state and reset of the reset button. FIG. FIG. 7 is a sectional view of an earth leakage breaker, which is symmetrical with respect to standardization of parts. The configuration of FIG. 5 has a reset button 8
0 is arranged in the cover, and the photo interrupter 30 is mounted on the detection circuit mounting printed circuit board 85. Next, the operation will be described with reference to FIG. 6. Since light is not shielded between the light emitting portion and the light receiving portion during standby, the light receiving portion is in a conductive state. When the button 80 is pressed to reset, the light emitting portion and the light receiving portion of the interrupter 30 are shielded from each other, so that the light receiving portion is turned off and the alarm output 71 is reset. Although the present embodiment uses the optical coupling element 30,
The same operation can be expected by disposing the above-mentioned micro switch on the printed board or on the stroke of the button 80.

According to the present embodiment, the reset button is arranged in the window frame at the time of cutting the panel simply by adding the reset button, the interrupter and the micro switch without changing the structure of the earth leakage breaker, which is symmetrical to the standardization of parts. Therefore, it is possible to share parts, have compatible dimensions, and achieve the same usability.

8 to 10 are an external view showing an embodiment of the present invention and an internal structure diagram of an additional circuit. The configuration is such that an alarm coil drive circuit 50 and a trip coil drive circuit 60 as additional circuits are mounted on a printed circuit board as shown in FIG. 10, and the printed circuit board is arranged in cases 91 and 90 each having a terminal. This is attached to the left side surface of the circuit breaker body. The trip coil drive circuit 60 in the case 90 is connected to the detection circuit board 85 and the coil 3 by the wiring 92. Further, the alarm coil drive circuit 50 is housed in the case 91 together with the alarm output contact 71 and its coil 70, and the alarm coil drive circuit 50 and the coil 70 are connected to the detection circuit board 85 by wiring 93. Further, the mounting portions of the cases 90 and 91 and the circuit breaker case are compatible with the terminal block mounting portion of an internal accessory device (not shown) such as a commonly used auxiliary contact output, which is compatible with them. I have.

Electrical connectors (not shown) are provided on the cases 90 and 91, wirings 92 and 93 are connected to these connectors, respectively, and a conductive portion is attached to the mounting portions of the cases 90 and 91 on the main body case side. May be provided, and the connector and the conductive portion may be conductively connected.

If there is a storage space for the circuits 50 and 60 inside the circuit breaker, it may be arranged there.

According to the present embodiment, the additional circuit can be housed in the case that can be easily installed or the circuit breaker case can be housed without changing the structure of the earth leakage breaker, which is symmetrical to the standardization of parts. Can be manufactured.

[0037]

According to the present invention, the holding current of the alarm output relay is kept low and the amount of electricity supplied to the power supply circuit is limited, so that a wide range of voltage inputs can be supported without using a step-down transformer. A circuit breaker with an earth leakage alarm can be obtained.

[Brief description of drawings]

FIG. 1 is a circuit connection diagram of an earth leakage breaker according to an embodiment of the present invention.

FIG. 2 is a waveform diagram showing waveforms of various parts of the power supply circuit of this embodiment.

FIG. 3 is a waveform diagram showing an alarm output coil current according to the present embodiment.

FIG. 4 is a waveform diagram showing waveforms of respective parts of the external trip device drive circuit of the present embodiment.

FIG. 5 is a cross-sectional view showing the internal structure of the circuit breaker according to the embodiment of the present invention.

6A and 6B are cross-sectional views of a reset button portion of the present embodiment, in which FIG. 6A is a standby state and FIG.

FIG. 7 is a cross-sectional view of an earth leakage breaker, which is symmetrical to the standardization of parts according to the present embodiment.

FIG. 8 is a plan view showing the external appearance of the earth leakage circuit breaker of this embodiment.

FIG. 9 is a front view showing the appearance of the earth leakage breaker of this embodiment.

FIG. 10 is a perspective view showing the internal structure of the additional circuit of this embodiment.

[Explanation of symbols]

10: Power supply circuit, 20: Leakage detection circuit, 30: Optical coupling element, 50: Alarm output coil drive circuit, 60: External trip device drive circuit, 70: Alarm output relay coil, 71:
Leakage alarm output contact, 80: reset button, 90, 91: storage case

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomiyoshi Kiryu 4-3, Surugadai Kanda, Chiyoda-ku, Tokyo Inside Hitachi Techno Engineering Co., Ltd.

Claims (2)

[Claims] 1. An opening / closing means for opening and closing an electric circuit, a main circuit conductor connected to a load side of the opening / closing means, and an electric quantity connected to the main circuit conductor and supplied from the main circuit conductor is limited. A power supply circuit having a limiting circuit that outputs a direct current, a zero-phase current transformer that detects an imbalance in the current flowing through the main circuit conductor, a detection circuit that detects the output of the zero-phase current transformer, and this detection circuit Switching means operating by the output of the switching means, alarm means driven based on the operation of the switching means, and a control circuit for controlling the drive current supplied from the power supply circuit to the alarm means. A circuit breaker with an earth leakage alarm configured to reduce the drive current of the alarm means to a predetermined value after a predetermined time has elapsed from the start of driving the alarm circuit. 2. A means for accommodating said alarm means and said control circuit, said accommodating means having means for detachably connecting said alarm means and its control circuit to said detection circuit and said power supply circuit, The circuit breaker with an earth leakage alarm according to claim 1, wherein the circuit breaker is detachably mounted on a side surface of the case of the circuit breaker.