JPH09213196A - Earth leakage breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an earth leakage breaker which opens an opening/closing mechanism in leakage even if a power supply side of a main circuit is in an open phase by energizing a trip coil in ordinary and stopping the energization in leakage. SOLUTION: The secondary current is not output from a zero-phase current transformer 1 in ordinary and a signal is not output from the leakage detection part 2 so that a transistor(Tr) 12 is turned off. On the other hand, the output voltage of a rectifier 6 is entered in a gate so that a Tr 13 is turned on and a trip coil 3 is energized at the output voltage of the rectifier 6. When the leakage occurs, the secondary current is output from the zero-phase transformer 1, the signal from the leakage detection part 2 is entered in the gate of the Tr 12, the Tr 12 is tuned on, the resistance 14B is short-circuited, the Tr 13 is turned off, and the energization to the trip coil 3 is made to stop. Therefore, when the power supply side of the main circuit is in an open phase, the electromagnetic force of the trip coil 3 is disappeared, the engagement of the opening/ closing mechanism of the earth leakage breaker is disengaged, and the opening/ closing contact can be opened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth leakage circuit breaker which can operate even when a power source side is out of phase.

[0002]

2. Description of the Related Art FIG. 4 is a side view showing the structure of an earth leakage breaker. It is the figure which looked at the inside by removing the side wall of this side. In the case of such an earth leakage breaker, the electromagnet device 1
A base 20 on which the 9 is mounted and a component such as a slider 17 slidably attached to the base 20 are stored in Japanese Utility Model Laid-Open No. 3-74451 and are well known. The terminals 21A and 21B are respectively connected to the power source side and the load side of a main circuit (not shown). Inside the earth leakage breaker, the main circuit conductor 41 is connected to the terminal 2 on the power supply side.
1A passes through the zero-phase current transformer 1 via the switching contact 40 and is passed to the load-side terminal 21B. The electromagnet device 19 is supported by the base 20 fixed to the case 42, and the push rod 23 (see FIG. 5) is projected from the electromagnet device 19.
The contact portion of the slider 17 is in contact with the top end of the push rod 23. A tension type trip spring 18 is hung between a spring hook of the slider 17 and a spring hook of the base 20. The slider 17 is slidable in the vertical direction and has a convex portion 35. The trip crossbar 16 is arranged so as to face the convex portion 35.

FIG. 4 is a diagram showing a state in which the opening / closing contact 40 is closed, and the trip spring 18 is in a pulled and stored state. As will be described later, since the electromagnet device 19 pushes the push rod 23 upward by the magnetic force generated by itself, the slider 17 is also pushed upward, and the trip spring 18 stores energy. When leakage occurs on the load side of the main circuit, a secondary current flows through the zero-phase current transformer 1. When this secondary current flows, the electromagnet device 19 pushes the push rod 23 downward, so that the trip spring 18 pulls the slider 17 downward. As a result, the convex portion 35 of the slider 17 is moved to the trip crossbar 1
6, the trip crossbar 16 is rotated counterclockwise. The opening / closing contact 40 is maintained in the closed state by engagement of an opening / closing mechanism (not shown). The counterclockwise rotation of the trip crossbar 16 disengages the engagement of the opening / closing mechanism to open the opening / closing contact 40.

FIG. 5 is a sectional view showing the structure of a conventional electromagnet device for an earth leakage breaker. The electromagnet device 19 includes the trip coil 3 wound around the coil bobbin 25 on the outer circumference of the cylinder 31. A permanent magnet 28 is wound around the lower outer circumference of the cylinder 31 via a magnetic plate 29. A yoke 24 is fitted outside the trip coil 3 and the permanent magnet 28. On the other hand, the magnetic plate 32 is also fitted to the lower surface side of the permanent magnet 28 via the spacer 30. Inside the cylinder 31, a plunger 27 and a fixed iron core 26 are arranged in the axial direction, and a push rod 23 penetrating the upper fixed iron core 26 is provided on the plunger 27 so as to project. A compressible spring 22 is interposed between the yoke 24 and the push rod 23, and the plunger 27 is biased upward via the spring 22. A contact portion of the slider 17 (not shown) is in contact with the upper end of the push rod 23.

In FIG. 5, the trip coil 3 is not normally energized, but since the magnetic flux 33 of the permanent magnet 28 is generated, the plunger 27 is attracted to the fixed iron core 26 and urges the push rod 23 upward. doing. By this biasing force,
The trip spring 18 of FIG. 4 is stored. When the main circuit is leaked, the trip coil 3 is energized, so that the magnetic flux 38 of the trip coil 3 is generated in the direction in which the magnetic flux 33 of the permanent magnet 28 is weakened. by this,
As the plunger 27 moves downward, the push rod 23 is also driven downward, and the trip spring 18 in FIG. 4 moves the slider 17 downward. Along with that, trip crossbar 16
Rotates counterclockwise, the engagement of the opening / closing mechanism is pulled off, and the opening / closing contact 40 is opened.

Here, the pulling force F of the trip spring 18
And the magnitude of the magnetic force M of the permanent magnet 28 and the electromagnetic force E of the trip coil 3 are as follows.

[0007]

[Equation 1] F <M

[0008]

## EQU00002 ## F> M-E That is, there is always the relationship of the formula 1 and the trip spring 1
8 is waiting for tripping. On the other hand, at the time of leakage,
Since the relationship of the equation 2 is established, the trip spring 18 works and the engagement of the opening / closing mechanism is tripped.

FIG. 6 is a connection diagram of a drive circuit of a conventional earth leakage breaker. The secondary winding 1A of the zero-phase current transformer 1 is input to the leakage detection unit 2. The leakage detector 2 is the zero-phase current transformer 1
It outputs a signal when it receives the secondary current.
The drive circuit referred to here is the zero-phase current transformer 1 and the leakage detection unit 2.
And the trip coil 3 are excluded. That is, the drive circuit is supplied with power from the R-phase and T-phase on the load side of the main circuit, and is input to the rectifying device 6 including the rectifying diode 6A via the resistor 7. The output voltage of the rectifier 6 is
It is applied to the series circuit of the trip coil 3 and the thyristor 4 via the constant voltage diode 5. The output signal of the leakage detection unit 2 is input to the gate of the thyristor 4. In addition, 8 is a resistance and 9, 10, 11 are capacitors. The output voltage of the rectifying device 6 also serves as the power source of the leakage detection unit 2.

In FIG. 6, since the secondary current from the zero-phase current transformer 1 is not normally output, no signal is output from the leakage detection unit 2. Therefore, the thyristor 4 becomes O
In the FF state, the trip coil 3 is not energized. On the other hand, when a leakage occurs, a secondary current is output from the zero-phase current transformer 1, a signal is output from the leakage detector 2, and a signal is input to the gate of the thyristor 4. Accordingly, the thyristor 4 is turned on and the trip coil 3 is energized. As a result, as described above, the trip spring is pulled and the open / close contact is opened.

[0011]

However, in the conventional device as described above, when the power supply side of the main circuit is out of phase,
There was a problem that the open / close contact did not open even if leakage occurred on the load side. In other words, if the power supply side of the main circuit has an open phase, the voltage for energizing the trip coil will not be supplied even if leakage occurs on the load side. Therefore, the trip spring does not operate and the open / close contact does not open. Even if the main circuit is in the open phase state, the voltage of the remaining phase is applied to the ground, so that there is a possibility of leakage. Even if the main circuit is in the open phase state, it is preferable from the viewpoint of safety to detect leakage and shut off all phases of the main circuit.

An object of the present invention is to open / close the contact when the power source side of the main circuit is out of phase.

[0013]

In order to achieve the above object, according to the present invention, an opening / closing contact provided in a main circuit, an opening / closing mechanism for maintaining the opening / closing contact in a closed state, and a load of the main circuit. A zero-phase current transformer that outputs a secondary current when the side leaks, a leakage detector that outputs a signal by receiving this secondary current, and a main circuit that drives the leakage detector and the trip coil. Energize the power supply and the trip coil at all times,
A drive circuit that stops energizing the trip coil when receiving the output signal of the leakage detection unit, and energy is stored by the electromagnetic force of the trip coil, and when the electromagnetic force disappears, the stored energy is released to open and close the opening / closing mechanism. And a trip spring that trips the engagement of the trip circuit, and when the power supply side of the main circuit is open-phase, the electromagnetic force of the trip coil disappears and the stored energy of the trip spring is released to engage the opening / closing mechanism. Should be tripped. Thereby, the trip coil is normally energized, and when the main circuit is leaked, the trip coil is deenergized. Even if the power supply side of the main circuit is out of phase, the switching contacts will open.

In such a structure, it is preferable that the electromagnetic force of the trip coil is superposed with the magnetic force of the permanent magnet. As a result, the electromagnetic force of the trip coil is smaller than that in the case of using the trip coil alone. Therefore, the energy constantly required by the trip coil is reduced and the energy consumption is reduced. Further, in such a configuration, the drive circuit may stop energizing the trip coil when the main circuit voltage becomes equal to or lower than the set voltage. As a result, even when the main circuit voltage drops, the opening / closing contact opens. Therefore, it can also serve as an undervoltage trip device.

In this structure, an auxiliary case is attached to the side surface of the main body of the earth leakage breaker, a drive circuit is housed in the auxiliary case, and a power supply terminal is attached. May be Accordingly, when it is required to add an undervoltage trip device to a small-capacity earth leakage breaker, it is possible to deal with it even if the case on the main body side is small.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. FIG. 1 is a connection diagram of a drive circuit for an earth leakage breaker according to an embodiment of the present invention. The transistor 13 is connected in series with the trip coil 3, and the transistor 1
The output voltage of the rectifier 6 divided by the resistors 14A and 14B is applied to the gate of the transistor 3, and the collector of another transistor 12 is connected to the gate of the transistor 3. The output signal of the leakage detection unit 2 divided by the resistors 15A and 15B is input to the gate of the transistor 12, and the emitter of the transistor 12 is connected to one side of the output end of the rectifier 6. Others are the same as the conventional configuration of FIG. The same parts as those of the related art are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, since the secondary current is not normally output from the zero-phase current transformer 1, no signal is output from the leakage detector 2. Therefore, the transistor 12
Is off because no signal is input to the gate. On the other hand, the transistor 13 is turned on because the output voltage from the rectifier 6 enters the gate. Therefore, the trip coil 3 is always energized by the output voltage from the rectifier 6. When leakage occurs, a secondary current is output from the zero-phase current transformer 1 and a signal from the leakage detector 2 enters the gate of the transistor 12, so that the transistor 12
Turn on. Since the resistor 14B is short-circuited accordingly,
The gate voltage of the transistor 13 disappears, and the transistor 13 is turned off. As a result, the power supply to the trip coil 3 is stopped.

FIG. 2 is a sectional view showing the structure of an electromagnet device used in the device of FIG. The electromagnet device 43 is shown in FIG.
However, the magnetic flux 34 generated by the trip coil 3 is in the opposite direction to that in the conventional case of FIG. That is, the trip coil 3 is wound around the coil bobbin 25 so that the direction of the electromagnetic force generated by the trip coil 3 is the same as that of the magnetic force of the permanent magnet 28.

In the electromagnet device shown in FIG. 2, as described with reference to FIG. 1, the trip coil 3 is always energized and the plunger 27 is biased upward by its electromagnetic force. When leakage occurs, the trip coil 3 is de-energized, the plunger 27 moves downward, and the trip spring 1 shown in FIG.
8, the slider 17 moves, the engagement of the opening / closing mechanism is tripped via the trip crossbar, and the opening / closing contact 40 is opened.

The magnitude relationship among the pulling force F of the trip spring 18, the magnetic force M of the permanent magnet 28, and the electromagnetic force E of the trip coil 3 in this device is as follows.

[0021]

[Equation 3] F <M + E

[0022]

## EQU00004 ## F> M That is, there is always a relation of the equation 3 and the trip spring 1
8 is waiting for tripping. On the other hand, at the time of electric leakage, since the relation of the equation 4 is satisfied, the trip spring 18 works,
The engagement of the opening and closing mechanism is pulled out.

Here, the permanent magnet 28 is not always necessary. That is, normally, the trip spring 18 is placed in a waiting state for tripping only by the electromagnetic force E of the trip coil 3, and at the time of electric leakage, the engagement of the opening / closing mechanism is tripped by the force of the trip spring 18 alone. You can also do it. Since the permanent magnet 28 is provided, the magnetic force M is the electromagnetic force E of the trip coil 3.
In addition, the electromagnetic force generated by the trip coil 3 can be reduced as compared with the case where the trip coil 3 is used alone. Therefore, the energy required for the trip coil 3 at all times is reduced, and the energy consumption is reduced.

Returning to FIG. 1, this drive circuit can also stop the energization of the trip coil when the main circuit voltage becomes equal to or lower than the set voltage. Resistors 14A and 1
Adjust the voltage division ratio with 4B or the value of resistor 7,
When the main circuit voltage becomes insufficient, the voltage applied to the gate of the transistor 13 decreases, causing the transistor 13 to turn off.
F can be set. As a result, the power supply to the trip coil 3 is stopped. That is, the drive circuit can also serve as an undervoltage trip device, and the voltage drop between the R and T phases of the main circuit is detected to shut off the main circuit. When an undervoltage trip device is required to be added to the earth leakage breaker, conventionally, another set of devices similar to the earth leakage breaker such as an electromagnet device, a slider, a trip spring, and a drive circuit is required. Therefore, in the case of a small-capacity earth leakage circuit breaker, there is a problem that the case 42 (FIG. 4) of the body of the earth leakage circuit breaker has a space limitation and cannot be applied. The drive circuit of FIG. 1 eliminates the need for an electromagnet device, a slider, and a tripping spring, and can reduce the size of an earth leakage breaker with an undervoltage tripping device.

FIG. 3 is a perspective view showing the structure of an earth leakage breaker according to another embodiment of the present invention. An auxiliary case 36 is attached to the side surface of the case 42 on the main body of the earth leakage breaker, and a drive circuit is housed in the auxiliary case 36 and a power supply terminal 37 is attached. This earth leakage breaker is provided with an undervoltage trip device, and of the three-phase main circuit, the phase for monitoring the undervoltage is connected to the power supply terminal 37. This power supply terminal 37 is an auxiliary cable.
It becomes the power source of the drive circuit in the space 36. The drive circuit of FIG. 1 can reduce the size of the earth leakage breaker with the undervoltage trip device, but since the trip coil 3 is always energized, a large capacity resistor 7 is used. . Therefore, in the case of an earth leakage breaker having an extremely small capacity, the drive circuit of FIG. 1 may not be entirely accommodated in the case 42 of the main body. By providing the auxiliary case 36, an undervoltage trip device can be added to the earth leakage breaker of any size. In addition to the drive circuit, the auxiliary case 36 may contain a leakage detection unit.

[0026]

As described above, the present invention is provided with the drive circuit which normally energizes the trip coil and which stops energization to the trip coil when receiving the output signal of the leakage detector.
The trip spring is configured to store energy by the electromagnetic force of the trip coil, and release the stored energy to release the engagement of the opening / closing mechanism when the electromagnetic force disappears. With this, it is possible to provide a highly safe earth leakage breaker in which the open / close contacts are opened if the power supply side of the main circuit is out of phase.

In such a structure, the magnetic force of the permanent magnet is superimposed on the electromagnetic force of the trip coil. Thereby,
The electromagnetic force of the trip coil is less than that of the trip coil alone, and an energy saving type earth leakage circuit breaker can be provided. Further, in such a configuration, the drive circuit may stop energizing the trip coil when the main circuit voltage becomes equal to or lower than the set voltage. As a result, even when the main circuit voltage drops, the opening / closing contact opens. Therefore, it is possible to reduce the size of the earth leakage breaker with the undervoltage trip device. Furthermore, it has become possible to add an undervoltage trip device to a small-capacity earth leakage breaker.

Further, in this structure, an auxiliary case is attached to the side surface of the case of the main body of the earth leakage breaker, the drive circuit is housed in the auxiliary case, and the power supply terminal is attached. Good. Thereby,
When it is required to add an undervoltage trip device to the earth leakage breaker, it can be handled even if the case of the main body side is small, and no matter how small the earth leakage breaker is, an undervoltage trip device must be added. Is now possible.

[Brief description of drawings]

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

2 is a cross-sectional view showing the configuration of an electromagnet device used in the device of FIG.

FIG. 3 is a perspective view showing the configuration of an earth leakage breaker according to another embodiment of the present invention.

FIG. 4 is a side view showing a configuration of an earth leakage breaker.

FIG. 5 is a cross-sectional view showing the configuration of an electromagnet device of a conventional earth leakage breaker.

FIG. 6 is a connection diagram of a drive circuit of a conventional earth leakage breaker.

[Explanation of symbols]

1: Zero-phase current transformer, 2: Leakage detector, 3: Trip coil, 18: Tripping spring, 28: Permanent magnet, 36: Auxiliary case, 37: Power supply terminal, 40: Open / close contact, 42:
Case 43: Electromagnet device

Claims (4)

[Claims] 1. A switching contact interposed in a main circuit, a switching mechanism that maintains the switching contact in a closed state, and a zero-phase current transformer that outputs a secondary current when the load side of the main circuit leaks. A leakage detection unit that receives this secondary current and outputs a signal, a power supply that is taken from the main circuit and that drives the leakage detection unit and the trip coil, and normally supplies electricity to the trip coil, and outputs the output signal of the leakage detection unit. The drive circuit that stops energizing the trip coil when receiving it, and the electromagnetic force of the trip coil stores energy. When the electromagnetic force disappears, the stored energy is released and the engagement of the opening / closing mechanism is released. When the power supply side of the main circuit is out of phase, the electromagnetic force of the trip coil disappears, the stored energy of the trip spring is released, and the engagement of the opening / closing mechanism is tripped. Characteristic leakage interruption Vessel. 2. The earth leakage breaker according to claim 1, wherein the electromagnetic force of the trip coil is superposed with the magnetic force of a permanent magnet. 3. The method according to claim 1, wherein
An earth leakage circuit breaker characterized in that the drive circuit stops energizing the trip coil when the main circuit voltage becomes equal to or lower than a set voltage. 4. The apparatus according to claim 3, wherein an auxiliary case is attached to a side surface of the main body of the earth leakage breaker, a drive circuit is housed in the auxiliary case, and a power supply terminal is attached. An earth leakage circuit breaker characterized by being formed.