JPH0620583A - Molded case circuit breaker - Google Patents

Abstract

PURPOSE:To enhance the leak follow-up property and safety of a molded case circuit breaker and to save required power by means of automatic switching of a leak alarm and a command to shut by using transistors as elements for driving leak-alarm generation means so as to provide the circuit breaker as a self-reset type, and shutting a distribution line only when a leak alarm is continued beyond a predetermined period of time. CONSTITUTION:A molded case circuit breaker 4A has the following constitution: a ground detector 40 provided across a distribution 3 to detect ground current; a first transistor which is turned on in response to a signal indicating detection of ground from the ground detector 40; a switching element which is made when the output level of the first transistor exceeds gate potential by a predetermined amount; and a second transistor which is turned on in response to the output of the switching element. The circuit breaker is also provided with leak alarm generation means 45, 46 for giving a leak alarm according to the output of the second transistor; and shutting means (42, 43, 47, 48, etc.) for shutting the distribution line 3 when the leak alarm is continued for a preset period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker for wiring, and more particularly to a self-resetting type circuit breaker having a leakage warning function.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing a conventional self-holding type circuit breaker having a leakage warning function. In the figure, 1 indicates a high AC voltage of 6600 V, for example, 40
A power transformer for converting to a low AC voltage of 0 V, 2 is, for example, an electric motor as a load to which AC power is supplied from the power transformer 1 through the wiring path 3, and 4 is on the wiring path 3 between the power transformer 1 and the electric motor 2. It is a self-holding type circuit breaker having a leakage warning function provided in the.

The circuit breaker 4 for wiring is provided on the wiring path 3 and is a zero-phase current transformer (ZCT) 40 as a ground fault detector for detecting a ground fault (leakage), and a zero-phase current transformer 40. And wiring path 3
And an electric power supply from the wiring line 3 and an amplifier 41 for amplifying the ground fault detection signal from the zero-phase current transformer 40.
And an earth leakage trip device 42 connected to one output side of the amplifier 41 via a normally open type timer relay contact described later.
A main circuit contact 43 which is inserted into the wiring path 3 and whose opening and closing is controlled by the trip device 42; and an overcurrent trip device 44 which is also inserted into the wiring path 3 and shuts off the wiring path 3 at the time of overcurrent. , A leakage warning relay 45 which is connected to the other output side of the amplifier 41 and is activated by the output of the amplifier 41 when a ground fault occurs, and a normally open leakage warning whose opening and closing is controlled by the relay 45. Relay contact 46 for.

Reference numeral 5 is an AC power source, and 6 is a leakage warning lamp. The leakage warning lamp 6 is connected to both ends of the AC power source 5 via a timer relay 7, a normally closed push button switch 10 and a relay contact 46. , When the relay contact 46 is closed,
That is, for example, when a ground fault occurs on the load side, the light is turned on to notify the leakage warning to the outside. Further, the timer relay 7, like the earth leakage alarm lamp 6, is excited when the relay contact 46 is closed, and is a normally open type timer relay connected to the earth leakage trip device 42 at a time set by the preset time knob 9. Contact 8
To close the main circuit to activate the earth leakage trip device 42,
It serves to open 3 and to interrupt the wiring path 3. here,
AC power supply 5 to pushbutton switch 10 is circuit breaker 4 for wiring
It is a circuit portion that is more spaced apart and is used by the user.

FIG. 5 is a block diagram showing an example of a concrete circuit of the amplifier 41 of FIG. In the figure, 11 is an integrated circuit (IC) having a plurality of, for example, eight external pins P1 to P8, and the external pins P1 and P2 of this IC1 are provided with a zero-phase current transformer 40 provided in the wiring path 3. A voltage corresponding to the ground fault current detected by is supplied, and an output corresponding to this voltage is supplied to each gate of the thyristors 14 and 15 from the external pin P7. The external pin P3 of the IC 11 is grounded and the external pin P8 is connected to the power supply terminal 12. An AC voltage of 400V from the wiring path 3 (not shown) is stepped down to the power supply terminal 12, and a voltage of about 16V, for example, which is rectified and converted into a DC voltage, is the power supply voltage V.
Supplied as _S.

Reference numeral 13 is a power supply terminal which is formed in the same manner as the power supply voltage V _S and to which a voltage of, for example, about 24 V is supplied as the power supply voltage Vcc. The cathodes of the thyristors 14 and 15 are both grounded, and the anode of the thyristor 14 is connected to the power supply terminal 13 via the leak alarm relay 45, and the anode of the thyristor 15 is the relay contact 8 and the leak alarm trip device 42. Is connected to the power supply terminal 13 via.

Next, the operation will be described. Now, when the handle (not shown) of the wiring breaker 4 is turned on, the amplifier 4
Within 1, the power supply voltage V _S is applied to the external pin P8 of the IC 11, and the power supply voltage V _CC is applied to the thyristor 14 via the leakage warning relay 45. In this state, the wiring line 3 and the load of the electric motor 2 connected to the wiring line 3 are grounded (leakage).
Occurs, the ground fault detection signal (sine wave) from the zero-phase current transformer 40 that has detected the ground fault is supplied to the external pins P1 and P2 of the IC 11 of the amplifier 41.

When the input ground fault detection signal exceeds a certain level and width, the IC 11 produces an output at its external pin P7, and this output is supplied to the gates of the thyristors 14 and 15 so that only the thyristor 14 is provided. Turns on. When the thyristor 14 is turned on, the thyristor 1 is connected from the power supply terminal 3
Since a current flows to the anode side of No. 4, the leakage warning relay 45 is energized, the relay contact 46 is closed, the leakage warning lamp 6 on the user side is turned on, and the leakage warning is notified to the outside.

When the relay contact 46 is closed, the timer relay 7 is energized by the current from the AC power source 5, so that the time preset by the set time knob 9, for example, 1
After 0 seconds, the relay contact 8 is closed. Then, when the relay contact 8 is closed, a current flows from the power supply terminal 3 to the anode side of the thyristor 15, so that the earth leakage trip device 42 is energized to operate, thereby opening the main circuit contact 43 and wiring. Shut off road 3.

On the other hand, when the ground fault detection signal from the zero-phase current transformer 40 falls below a certain level and width, the output from the external pin P7 of the IC 11 in the amplifier 41 is stopped, but the thyristors 14 and 15 are Once turned on, it stays on unless the power is turned off, so the leakage warning relay 45 remains energized even if the ground fault is removed.
The relay contact 46 also keeps closing and the earth leakage warning lamp 6 continues to light. Therefore, without constant monitoring
If there is a ground fault even once in the past, the existence of the fault can be confirmed, but on the other hand, just because an earth leakage warning is issued does not necessarily mean that a ground fault has occurred at that time. Further, in order to reset the earth leakage alarm, it is necessary to push the push button switch 10 or turn off the handle to set the power supply voltages V _S and V _CC to zero.

[0011]

Since the conventional self-holding type circuit breaker having an earth leakage warning function is constructed as described above, it has the following problems. That is, in the case of a conventional self-holding type circuit breaker having an earth leakage warning function, since it is a so-called self-holding type that continues to generate an earth leakage alarm once a ground fault occurs, for example, as shown in FIG. If 7 is set to 10 seconds from the occurrence of the earth-leakage alarm until the relay contact 8 is closed, the earth-leakage alarm continues for 10 seconds even if the ground fault is substantially removed after 3 seconds. Even if a ground fault occurs that cuts off, that is, even if a ground fault occurs for a time shorter than the set time of the timer relay 7, the circuit is always cut off during the set time of the timer relay 7 and the followability to an electric leakage accident is poor, and an extra mistake is made. There was a problem that a trip occurred.

In order to prevent this, when the time when the leakage alarm is generated is shorter than the set time of the timer relay 7, the user opens the reset push button switch 10, and then the timer relay 7 is set. It may be closed after a lapse of time, but if this occurs, the user will judge the time each time an earth leakage warning occurs, and push button switch 10
Has to be turned on and off manually, which is very time-consuming and
There was also a problem in terms of safety.

Further, the timer relay 7 and its relay contact 8
Since it is on the user side, the area required for it increases,
Further, there is a problem that the number of wiring members is increased by connecting the relay contact 8 to the user side, and moreover, the push button switch 10 must be provided exclusively, and accordingly the number of components is increased.

The present invention has been made in order to solve such a problem, and can improve the followability and safety against an electric leakage accident, and at the same time, save labor by the automatic switching of an electric leakage alarm and a cutoff command. An object of the present invention is to obtain a self-resetting type circuit breaker having a leakage warning function that can be simplified.

[0015]

SUMMARY OF THE INVENTION A wiring breaker according to the present invention is provided in a wiring path and detects a ground fault current, and a ground fault detector which responds to a ground fault detection signal from the ground fault detector. A first transistor that turns on, a switching element that conducts when the output level of the first transistor exceeds a gate potential by a predetermined amount, and a second transistor that turns on in response to the output of the switching element, A leakage warning generating means for generating a leakage warning based on the output of the second transistor, and a cutoff which is provided in association with the leakage warning generating means and shuts off the wiring path when the leakage warning lasts for a predetermined set time. And means.

[0016]

According to the present invention, a transistor is used as an element for driving the earth leakage alarm generating means to be a self-reset type, and if the earth leakage alarm continues beyond a predetermined set time, the wiring path is interrupted for the first time. To do. This allows
It is possible to prevent the wiring path from being interrupted by an electric leakage warning within a predetermined set time.

[0017]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention.
In the figure, the parts corresponding to those in FIG.
Detailed description thereof will be omitted. In the figure, 4A is a self-reset type circuit breaker having a leakage warning function provided on the wiring path 3 between the power transformer 1 and the electric motor 2, and 41A is used in place of the amplifier 41, and is zero. Phase current transformer 4
It is an amplifier that is connected to 0 and the wiring path 3, is supplied with power from the wiring path 3, and amplifies the ground fault detection signal from the zero-phase current transformer 40.

Reference numeral 47 is a timer relay housed in the circuit breaker 4A for wiring and provided between the earth leakage warning lamp 6 and the relay contact 46. The timer relay 47 is similar to the timer relay 7 in the relay contact 46. It is excited at the time of closing, and when the time set by the preset time knob 49 is reached in advance, the normally open type timer relay contact 48 connected to the earth leakage trip device 42 is closed to operate the earth trip device 42. It serves to open the circuit contact 43 and to interrupt the wiring path 3.

In the present embodiment, the relay contact 48 is also housed in the wiring breaker 4A like the timer relay 47.
Further, the set time knob 49 is provided on the parel surface of the wiring breaker 4A. Other configurations are the same as those in FIG. Here, the AC power supply 5 and the earth leakage warning lamp 6 are circuit parts which are separated from the wiring breaker 4A and used by the user. Further, the leakage warning relay 45 and its relay contact 46 constitute a leakage warning generating means, and the transistor 2
4, the earth leakage trip device 42, the main circuit contact 43, the timer relay 47, the relay contact 48 and the set time knob 9 constitute a breaking means.

FIG. 2 is a block diagram showing an example of a concrete circuit of the amplifier 41A shown in FIG. In the figure, parts corresponding to those in FIG. 5 are designated by the same reference numerals, and detailed description thereof will be omitted. Two
0 is a transistor driven by an output corresponding to the ground fault detection signal from the IC 11, for example, a transistor having a current amplification factor of about 100,
Reference numeral 21 is a transistor driven by the output of the transistor 20 and having a current amplification factor of about 100, for example. Reference numeral 22 denotes a programmable unijunction transistor (PUT) as a switching element provided between the transistor 21 and transistors 23 and 24 having a current amplification factor of, for example, about 100. The PUT 22 has an output level of the transistor 21. When the voltage V _GK between the cathode and the gate exceeds a predetermined amount, for example, about 0.7 V, the transistor 2 is turned on and is turned on.
Works to turn on 3, 24.

The base of the transistor 20 is connected to the external pin P7 of the IC 21 and is grounded via the malfunction preventing capacitor 25. The collector of the transistor 20 is connected to the power supply terminal 12 via the resistor 26,
The emitter is grounded via a resistor 27 and the transistor 2 is connected via a diode 28 for blocking a leakage current.
1 is connected to the base. The collector of the transistor 21 is connected to the power supply terminal 12 via the resistor 29, and the emitter of the transistor 21 is the anode / cathode of the PUT 22 and the resistor 3.
It is connected to the base of the transistor 23 through 0, and is also connected to the base of the transistor 24 through the anode-cathode of the PUT 22 and the resistor 31.

Resistors 32 and 33 for setting the cathode-gate voltage V _GK of the PUT 22 are connected between the power supply terminal 12 and the ground, and the connection midpoint is connected to the gate of the PUT 22. The collector of the transistor 23 is connected to the power supply terminal 13 via the leakage warning relay 45, and the emitter thereof is grounded. The collector of the transistor 24 is connected to the power supply terminal 13 via the relay contact 48 and the earth leakage trip device 42, and the emitter thereof is grounded.

Next, the operation will be described. Now, when the handle (not shown) of the circuit breaker for wiring is turned on, the power supply voltage V _S changes to the external pin P8 of the IC 11, the transistors 20, 2
1 and the PUT 22, and the power supply voltage V _CC is applied to the transistor 23 via the leakage warning relay 45 and to the transistor 24 via the relay contact 48 and the leakage trip device 42. In this state, when a ground fault (leakage) occurs in the wiring path 3 or the electric motor 2 as a load connected thereto, a ground fault detection signal (sine wave) from the zero-phase current transformer 40 that detects this ground fault. ) Is supplied to the external pins P1 and P2 of the IC 11 in the amplifier 41A. IC11
When the input ground fault detection signal exceeds a certain level and width, an output is generated at its external pin P7, and this output is supplied to the base of the transistor 20 and
Is turned on, and the transistor 21 is turned on accordingly.

The output level of the transistor 21,
That is, when the anode-cathode voltage V _{AK of the} PUT 22 exceeds the cathode-gate voltage V _GK by about 0.7 V, P
The UT 22 becomes conductive and the transistor 23 is turned on accordingly. When the transistor 23 turns on, the power supply terminal 13
Since a current flows through the collector side of the transistor 23, the leakage warning relay 45 is energized and the relay contact 46
Is closed and the leakage warning lamp 6 on the user side is turned on to notify the leakage warning to the outside.

When the relay contact 46 is closed, the timer relay 47 is energized by the current from the AC power source 5, so that the relay contact 48 is closed after a time preset by the set time knob 49, for example, 10 seconds. To achieve. When the relay contact 48 is closed, a current flows from the power supply terminal 13 to the collector side of the transistor 24, so that the earth leakage trip device 42 is energized to operate, whereby the main circuit contact 4
3 opens and interrupts the wiring path 3. Therefore, even if a leakage alarm is issued, the relay contact 48 is not closed unless the setting time set by the setting time knob 49 continues, so that the wiring path 3 is not cut off even if there is a leakage alarm within the setting time.

When the ground fault detection signal from the zero-phase current transformer 40 decreases, the output from the external pin P7 of the IC11 also decreases. At that time, the current I _A flowing between the anode and cathode of the PUT 22 has a certain value. When it becomes below, PU immediately
T22 becomes non-conductive. As a result, the transistor 23
Since it also turns off, the leakage warning relay 45 is also demagnetized.
As a result, the relay contact 46 is opened, and the leakage warning lamp 6
Goes out and the leak alarm once generated is immediately reset.

As described above, in this embodiment, the transistors 20 and 2 are used as elements for driving the leakage warning relay 45 and the like.
If the leakage alarm continues for a preset time set in the timer relay 47, the leakage trip device 42 is energized for the first time to start the wiring path. Since the wiring line 3 is cut off, the wiring path 3 is not cut off even if an electric leakage warning shorter than the predetermined set time is generated. In addition, the user does not have to manually turn on and off the push-button switch each time the earth leakage alarm occurs each time, as before, and the length of the earth leakage time is determined and the earth leakage alarm and cutoff command are automatically detected. Since it is switched to each other, labor saving and safety are improved.

Further, since the timer relay 47 and its relay contact 48 are housed in the circuit breaker, the area occupied by the user can be reduced by that much, and
No wiring member is required to connect the relay contact 48 to the user side, and there is no need to provide the push button switch 10 exclusively, so that the number of components is reduced.

Example 2. In the above embodiment, the transistor 2 as the second transistor for driving the relay or the like is used.
Although the case where two transistors 20 and 21 are used as the first transistor in addition to No. 3 has been described, the number of transistors is not limited to this number, and the current amplification factor of the transistor 23 can be divided to a desired value if it is low to some extent. Other numbers may be used. Further, although the case where the PUT is used as the switching element that instantly turns off the transistor 23 has been described, the present invention is not limited to this, and any other switching element that can immediately turn off the transistor 23 when the ground fault disappears is used. It may be a switching element.

[0030]

As described above, according to the present invention, the ground fault detector provided in the wiring path for detecting the ground fault current, and turned on in response to the ground fault detection signal from the ground fault detector. A first transistor; a switching element that is turned on when the output level of the first transistor exceeds a gate potential by a predetermined amount; a second transistor that turns on in response to an output of the switching element; A leakage warning generating means for generating a leakage warning based on the output of the transistor,
Since the earth leakage alarm is provided in association with the earth leakage alarm, and the earth leakage warning is provided for a predetermined period of time, the disconnection means is provided to shut off the wiring path. As a result, the wiring path is not cut off, the followability to a leakage accident and the safety can be improved, and at the same time, labor saving and simplification of the structure can be achieved by automatic switching of the leakage alarm and the interruption command. is there.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a main part of an embodiment of the present invention.

FIG. 3 is a diagram for explaining the operation of one embodiment of the present invention.

FIG. 4 is a configuration diagram showing a conventional self-holding type circuit breaker having a leakage warning function.

FIG. 5 is a configuration diagram showing an example of an amplifier used in a conventional self-holding type circuit breaker having a leakage warning function.

FIG. 6 is a diagram for explaining the operation of a conventional example.

[Explanation of symbols]

3 Wiring path 4A Wiring circuit breaker 40 Zero-phase current transformer 41A Amplifier 42 Leakage trip device 43 Main circuit contact 45 Leakage alarm relay 46 Leakage alarm relay contact 47 Timer relay 48 Timer relay contact 49 Setting time knob 20, 21 , 23, 24 Transistor 22 Programmable Unijunction Transistor (PUT)

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[Procedure amendment]

[Submission date] April 1, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title of the invention Circuit breaker for wiring

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker for wiring, and more particularly to a circuit breaker for wiring having a self-reset type earth leakage warning function.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing a conventional self-holding type circuit breaker having a leakage warning function. In the figure, 1 indicates a high AC voltage of 6600 V, for example, 40
A power transformer for converting to a low AC voltage of 0 V, 2 is, for example, an electric motor as a load to which AC power is supplied from the power transformer 1 through the wiring path 3, and 4 is on the wiring path 3 between the power transformer 1 and the electric motor 2. A circuit breaker for wiring having a self-holding type earth leakage warning function provided in.

The circuit breaker 4 for wiring is provided on the wiring path 3 and is a zero-phase current transformer (ZCT) 40 as a ground fault detector for detecting a ground fault (leakage), and a zero-phase current transformer 40. And wiring path 3
And an electric power supply from the wiring line 3 and an amplifier 41 for amplifying the ground fault detection signal from the zero-phase current transformer 40.
And an earth leakage trip device 42 connected to one output side of the amplifier 41 via a normally open type timer relay contact described later.
A main circuit contact 43 which is inserted into the wiring path 3 and whose opening and closing is controlled by the trip device 42; and an overcurrent trip device 44 which is also inserted into the wiring path 3 and shuts off the wiring path 3 at the time of overcurrent. , A leakage warning relay 45 which is connected to the other output side of the amplifier 41 and is activated by the output of the amplifier 41 when a ground fault occurs, and a normally open leakage warning whose opening and closing is controlled by the relay 45. Relay contact 46 for.

Reference numeral 5 is an AC power source, and 6 is a leakage warning lamp. The leakage warning lamp 6 is connected to both ends of the AC power source 5 via a timer relay 7, a normally closed push button switch 10 and a relay contact 46. , When the relay contact 46 is closed,
That is, for example, when a ground fault occurs on the load side, the light is turned on to notify the leakage warning to the outside. Further, the timer relay 7, like the earth leakage alarm lamp 6, is excited when the relay contact 46 is closed, and is a normally open type timer relay connected to the earth leakage trip device 42 at a time set by the preset time knob 9. Contact 8
To close the main circuit to activate the earth leakage trip device 42,
It serves to open 3 and to interrupt the wiring path 3. here,
AC power supply 5 to pushbutton switch 10 is circuit breaker 4 for wiring
It is a circuit portion that is more spaced apart and is used by the user.

FIG. 5 is a block diagram showing an example of a concrete circuit of the amplifier 41 of FIG. In the figure, 11 is an integrated circuit (IC) having a plurality of, for example, eight external pins P1 to P8, and the external pins P1 and P2 of this IC1 are provided with a zero-phase current transformer 40 provided in the wiring path 3. A voltage corresponding to the ground fault current detected by is supplied, and an output corresponding to this voltage is supplied to each gate of the thyristors 14 and 15 from the external pin P7. The external pin P3 of the IC 11 is grounded and the external pin P8 is connected to the power supply terminal 12. An AC voltage of 400V from the wiring path 3 (not shown) is stepped down to the power supply terminal 12, and a voltage of about 16V, for example, which is rectified and converted into a DC voltage, is the power supply voltage V.
Supplied as _S.

Reference numeral 13 is a power supply terminal which is formed in the same manner as the power supply voltage V _S and to which a voltage of, for example, about 24 V is supplied as the power supply voltage Vcc. The cathodes of the thyristors 14 and 15 are both grounded, and the anode of the thyristor 14 is connected to the power supply terminal 13 via the leakage warning relay 45, and the anode of the thyristor 15 is connected to the relay contact 8 and the leakage trip device 42. It is connected to the power supply terminal 13 via.

Next, the operation will be described. Now, when the handle (not shown) of the wiring breaker 4 is turned on, the amplifier 4
Within 1, the power supply voltage V _S is applied to the external pin P8 of the IC 11, and the power supply voltage V _CC is applied to the thyristor 14 via the leakage warning relay 45. In this state, if a ground fault (leakage) occurs in the wiring path 3 on the load side of the wiring breaker 4 or the load of the electric motor 2 connected thereto, the zero-phase current transformer 40 that has detected the ground fault Ground fault detection signal (sine wave)
Are supplied to the external pins P1 and P2 of the IC 11 of the amplifier 41.

When the input ground fault detection signal exceeds a certain level and width, the IC 11 produces an output at its external pin P7, and this output is supplied to the gates of the thyristors 14 and 15 so that only the thyristor 14 is provided. Turns on. When the thyristor 14 is turned on, a current flows from the power supply terminal 13 to the anode side of the thyristor 14, so that the leakage warning relay 45 is energized, the relay contact 46 is closed, and the leakage warning lamp 6 on the user side is turned on. The electric leakage warning is notified to the outside.

When the relay contact 46 is closed, the timer relay 7 is energized by the current from the AC power source 5, so that the time preset by the set time knob 9, for example, 1
After 0 seconds, the relay contact 8 is closed. When this relay contact 8 is closed, the power supply terminal 13 causes the thyristor 15
Since a current flows to the anode side of the
Is activated to actuate, whereby the main circuit contact 43 is opened and the wiring path 3 is cut off.

On the other hand, when the ground fault detection signal from the zero-phase current transformer 40 falls below a certain level and width, the output from the external pin P7 of the IC 11 in the amplifier 41 is stopped, but the thyristors 14 and 15 are Once turned on, it stays on unless the power is turned off, so the leakage warning relay 45 remains energized even if the ground fault is removed.
The relay contact 46 also keeps closing and the earth leakage warning lamp 6 continues to light. Therefore, without constant monitoring
If there is a ground fault even once in the past, the existence of the fault can be confirmed, but on the other hand, just because an earth leakage warning is issued does not necessarily mean that a ground fault has occurred at that time. To reset the earth leakage alarm, turn the handle off and set the power supply voltage V
_It is necessary to make _S and V _CC zero.

[0011]

Since the conventional circuit breaker for wiring having a self-holding type earth leakage warning function is constructed as described above, it has the following problems. That is, in the case of a conventional wiring breaker having a self-holding type earth leakage warning function, since it is a so-called self-holding type that continues to generate an earth leakage warning once a ground fault occurs, for example, as shown in FIG. If 7 is set to 10 seconds from the occurrence of the earth-leakage alarm until the relay contact 8 is closed, the earth-leakage alarm continues for 10 seconds even if the ground fault is substantially removed after 3 seconds. Even if a ground fault occurs that cuts off, that is, even if a ground fault occurs for a time shorter than the set time of the timer relay 7, the circuit is always cut off during the set time of the timer relay 7 and the followability to an electric leakage accident is poor, and an extra mistake is made. There was a problem that a trip occurred.

In order to prevent this, when the time during which the earth leakage alarm is generated is shorter than the set time of the timer relay 7, the user may open the push button switch 10 for resetting. If so, the user judges the time each time the earth leakage warning occurs, and push button switch 1
It is necessary to open 0 manually, which is very time-consuming and there is a problem in safety.

Further, the timer relay 7 and its relay contact 8
Since it is on the user side, the area required for it increases,
Further, there is a problem that the number of wiring members is increased by connecting the relay contact 8 to the user side, and moreover, the push button switch 10 must be provided exclusively, and accordingly the number of components is increased.

The present invention has been made in order to solve such a problem, and can improve the followability and safety against an electric leakage accident, and at the same time, save labor by the automatic switching of an electric leakage alarm and a cutoff command. An object of the present invention is to obtain a circuit breaker for wiring having a self-reset type earth leakage warning function that can be simplified.

[0015]

SUMMARY OF THE INVENTION A wiring breaker according to the present invention is provided in a wiring path and detects a ground fault current, and a ground fault detector which responds to a ground fault detection signal from the ground fault detector. A first transistor that turns on, a switching element that conducts when the output level of the first transistor exceeds a gate potential by a predetermined amount, and a second transistor that turns on in response to the output of the switching element, A leakage warning generating means for generating a leakage warning based on the output of the second transistor, and a cutoff which is provided in association with the leakage warning generating means and shuts off the wiring path when the leakage warning lasts for a predetermined set time. And means.

[0016]

According to the present invention, a transistor is used as an element for driving the earth leakage alarm generating means to be a self-reset type, and if the earth leakage alarm continues beyond a predetermined set time, the wiring path is interrupted for the first time. To do. This allows
It is possible to prevent the wiring path from being interrupted by an electric leakage warning within a predetermined set time.

[0017]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention.
In the figure, the parts corresponding to those in FIG.
Detailed description thereof will be omitted. In the figure, 4A is a wiring breaker provided on the wiring path 3 between the power transformer 1 and the electric motor 2 and having a self-recovery type earth leakage warning function, and 41A is used in place of the amplifier 41 and is zero. Phase current transformer 4
It is an amplifier that is connected to 0 and the wiring path 3, is supplied with power from the wiring path 3, and amplifies the ground fault detection signal from the zero-phase current transformer 40.

Reference numeral 47 is a timer relay housed in the circuit breaker 4A for wiring and provided between the earth leakage warning lamp 6 and the relay contact 46. The timer relay 47 is similar to the timer relay 7 in the relay contact 46. It is excited at the time of closing, and when the time set by the preset time knob 49 is reached in advance, the normally open type timer relay contact 48 connected to the earth leakage trip device 42 is closed to operate the earth trip device 42. It serves to open the circuit contact 43 and to interrupt the wiring path 3.

In the present embodiment, the relay contact 48 is also housed in the wiring breaker 4A like the timer relay 47.
The set time knob 49 is provided on the panel surface of the wiring breaker 4A. Other configurations are the same as those in FIG. Here, the AC power supply 5 and the earth leakage warning lamp 6 are circuit parts which are separated from the wiring breaker 4A and used by the user. Further, the leakage warning relay 45 and its relay contact 46 constitute a leakage warning generating means, and the transistor 2
4, the earth leakage trip device 42, the main circuit contact 43, the timer relay 47, the relay contact 48 and the set time knob 9 constitute a breaking means.

FIG. 2 is a block diagram showing an example of a concrete circuit of the amplifier 41A shown in FIG. In the figure, parts corresponding to those in FIG. 5 are designated by the same reference numerals, and detailed description thereof will be omitted. Two
0 is a transistor driven by an output corresponding to the ground fault detection signal from the IC 11, for example, a transistor having a current amplification factor of about 100,
Reference numeral 21 is a transistor driven by the output of the transistor 20 and having a current amplification factor of about 100, for example. Reference numeral 22 is a programmable unijunction transistor (PUT) as a switching element provided between the transistor 21 and transistors 23 and 24 having a current amplification factor of, for example, about 100. When the gate-to-gate voltage V _GK exceeds a predetermined amount, for example, about 0.7 V, the transistor is turned on and the transistor
Works to turn on 3, 24.

The base of the transistor 20 is connected to the external pin P7 of the IC 21 and is grounded via the malfunction preventing capacitor 25. The collector of the transistor 20 is connected to the power supply terminal 12 via the resistor 26,
The emitter is grounded via a resistor 27 and the transistor 2 is connected via a diode 28 for blocking a leakage current.
1 is connected to the base. The collector of the transistor 21 is connected to the power supply terminal 12 via the resistor 29, and the emitter of the transistor 21 is the anode / cathode of the PUT 22 and the resistor 3.
It is connected to the base of the transistor 23 through 0, and is also connected to the base of the transistor 24 through the anode-cathode of the PUT 22 and the resistor 31.

Resistors 32 and 33 for setting the cathode-gate voltage V _GK of the PUT 22 are connected between the power supply terminal 12 and the ground, and the connection midpoint is connected to the gate of the PUT 22. The collector of the transistor 23 is connected to the power supply terminal 13 via the leakage warning relay 45, and the emitter thereof is grounded. The collector of the transistor 24 is connected to the power supply terminal 13 via the relay contact 48 and the earth leakage trip device 42, and the emitter thereof is grounded.

Next, the operation will be described. Now, when the handle (not shown) of the circuit breaker for wiring is turned on, the power supply voltage V _S changes to the external pin P8 of the IC 11, the transistors 20, 2
1 and the PUT 22, and the power supply voltage V _CC is applied to the transistor 23 via the leakage warning relay 45 and to the transistor 24 via the relay contact 48 and the leakage trip device 42. In this state, when a ground fault (leakage) occurs in the wiring path 3 on the load side of the wiring breaker 4A or the electric motor 2 as a load connected to the circuit breaker 4A, the zero-phase current transformer 40 that detects this ground fault. The ground fault detection signal (sine wave) from the external pin P of the IC 11 in the amplifier 41A.
1 and P2. When the input ground fault detection signal exceeds a certain level and width, the IC 11 outputs its external pin P
An output is generated at 7, and this output is supplied to the base of the transistor 20 to turn on the transistor 20, and accordingly, the transistor 21 is turned on.

The output level of the transistor 21,
That is, when the anode-cathode voltage V _{AK of the} PUT 22 exceeds the cathode-gate voltage V _GK by about 0.7 V, P
The UT 22 becomes conductive and the transistor 23 is turned on accordingly. When the transistor 23 turns on, the power supply terminal 13
Since a current flows through the collector side of the transistor 23, the leakage warning relay 45 is energized and the relay contact 46
Is closed and the leakage warning lamp 6 on the user side is turned on to notify the leakage warning to the outside.

When the relay contact 46 is closed, the timer relay 47 is energized by the current from the AC power source 5, so that the relay contact 48 is closed after a time preset by the set time knob 49, for example, 10 seconds. To achieve. When the relay contact 48 is closed, a current flows from the power supply terminal 13 to the collector side of the transistor 24, so that the earth leakage trip device 42 is energized to operate, whereby the main circuit contact 4
3 opens and interrupts the wiring path 3. Therefore, even if a leakage alarm is issued, the relay contact 48 is not closed unless the setting time set by the setting time knob 49 continues, so that the wiring path 3 is not cut off even if there is a leakage alarm within the setting time.

When the ground fault detection signal from the zero-phase current transformer 40 decreases, the output from the external pin P7 of the IC11 also decreases. At that time, the current I _A flowing between the anode and cathode of the PUT 22 has a certain value. When it becomes below, PU immediately
T22 becomes non-conductive. As a result, the transistor 23
Since it also turns off, the leakage warning relay 45 is also demagnetized.
As a result, the relay contact 46 is opened, and the leakage warning lamp 6
Goes out and the leak alarm once generated is immediately reset.

As described above, in this embodiment, the transistors 20 and 2 are used as elements for driving the leakage warning relay 45 and the like.
If the leakage alarm continues for a preset time set in the timer relay 47, the leakage trip device 42 is energized for the first time to start the wiring path. Since the wiring line 3 is cut off, the wiring path 3 is not cut off even if an electric leakage warning shorter than the predetermined set time is generated. In addition, the user does not have to manually open the push button switch each time the earth leakage alarm occurs each time as in the conventional system, and the length of the earth leakage time is determined and the earth leakage alarm and cutoff command are automatically determined. Since it is switched to, labor saving and safety are improved.

Further, since the timer relay 47 and its relay contact 48 are housed in the circuit breaker, the area occupied by the user can be reduced by that much, and
No wiring member is required to connect the relay contact 48 to the user side, and there is no need to provide the push button switch 10 exclusively, so that the number of components is reduced.

Example 2. In the above embodiment, the transistor 2 as the second transistor for driving the relay or the like is used.
Although the case where two transistors 20 and 21 are used as the first transistor in addition to No. 3 has been described, the number of transistors is not limited to this number, and the current amplification factor of the transistor 23 can be divided to a desired value if it is low to some extent. Other numbers may be used. Further, although the case where the PUT is used as the switching element that instantly turns off the transistor 23 has been described, the present invention is not limited to this, and any other switching element that can immediately turn off the transistor 23 when the ground fault disappears is used. It may be a switching element.

[0030]

As described above, according to the present invention, the ground fault detector provided in the wiring path for detecting the ground fault current, and turned on in response to the ground fault detection signal from the ground fault detector. A first transistor; a switching element that is turned on when the output level of the first transistor exceeds a gate potential by a predetermined amount; a second transistor that turns on in response to an output of the switching element; A leakage warning generating means for generating a leakage warning based on the output of the transistor,
Since the earth leakage alarm is provided in association with the earth leakage alarm, and the earth leakage warning is provided for a predetermined period of time, the disconnection means is provided to shut off the wiring path. As a result, the wiring path is not cut off, the followability to a leakage accident and the safety can be improved, and at the same time, labor saving and simplification of the structure can be achieved by automatic switching of the leakage alarm and the interruption command. is there.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a main part of an embodiment of the present invention.

FIG. 3 is a diagram for explaining the operation of one embodiment of the present invention.

FIG. 4 is a configuration diagram showing a conventional self-holding type circuit breaker having a leakage warning function.

FIG. 5 is a configuration diagram showing an example of an amplifier used in a conventional circuit breaker for wiring having a self-holding type earth leakage warning function.

FIG. 6 is a diagram for explaining the operation of a conventional example.

[Explanation of symbols] 3 Wiring path 4A Wiring circuit breaker 40 Zero-phase current transformer 41A Amplifier 42 Leakage trip device 43 Main circuit contact 45 Leakage alarm relay 46 Leakage alarm relay contact 47 Timer relay 48 Timer relay contact 49 Setting Time knob 20, 21, 23, 24 Transistor 22 Programmable unijunction transistor (PUT)

Claims (1)

[Claims] 1. A ground fault detector provided in a wiring path for detecting a ground fault current; a first transistor which is turned on in response to a ground fault detection signal from the ground fault detector; A switching element that conducts when the output level of the transistor exceeds a gate potential by a predetermined amount, a second transistor that turns on in response to the output of the switching element, and a leakage alarm is generated based on the output of the second transistor. And a circuit breaker provided in association with the circuit leakage alarm generating means, and circuit breaker for disconnecting the wiring path when the circuit leakage alarm continues for a predetermined set time. .