JPH05347120A - Circuit breaker with leak alarm - Google Patents

Abstract

PURPOSE:To allow a leak indicating button as well as a leak indicating lamp to indicate leak even when the leak disappears of itself, and allow enough time delay before cutting off when immediate cutoff is not desirable even on the occurrence of the leak, by providing a zero phase current transformer, a leak detector, a leak indicating lamp, and a leak indicating button. CONSTITUTION:A leak indicating button is driven to a indicating position by releasing the energy of a spring in normally energy storing state through a solenoid 57 which current is allowed to flow in, when leak is detected, and a timer circuit 55 is built in a breaker so as to delay cutoff. When both leak indicating button and timer circuit 55 are provided, transfer to delayed cutoff by the timer circuit 55 after the indication is performed via the operation of a change-over switch 13 so as to maintain safety.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a circuit breaker having a function of detecting a leakage of a main circuit and alarming the occurrence of the leakage.

[0002]

2. Description of the Related Art FIG. 3 shows an example of the external appearance of this type of circuit breaker with a leakage alarm. This type of circuit breaker is normally equipped with an earth leakage indicator lamp 7 as an electric leakage indicator and a leakage indicator button 5 as a mechanical indicator, and when the changeover switch 13 is set to the alarm position. When a leak occurs, the leak indicator flashes to alert the occurrence of a leak. FIG. 4 shows the circuit configuration in the circuit breaker for this leak occurrence warning.

Zero-phase current transformer 9 inserted in the main circuit of the circuit breaker
A leakage current flows through the primary conductor of the above, and when the magnitude of the leakage current exceeds a set value, a signal is output from the output terminal C of the leakage detection circuit 3 . One of these signals is sent to the gate of the thyristor 51 for operating the blinking circuit 29 of the earth leakage indicator light, and the other is applied with a trip current to the trip coil 17 of the circuit breaker indicated by AV in the figure. Contact 15a for making
Is sent to the gate of the thyristor 52 in series with the AV relay 15 that operates the. The flashing circuit 29 of the earth leakage indicator lamp is already disclosed in Japanese Patent Application No. 3-23844 filed by the present applicant, and the DC voltage for its operation is a transformer connected to the AC power supply terminals R and T. rectifying the secondary voltage of the vessel 1 by the rectifier 2 via the leakage detection circuit 3 outputs signal P,
Output from N, changeover switch 13, thyristor 51
Is input to the blinking circuit 29 via. The blinking circuit 29 is
Leakage indicator lamp 7 and flicker mode as main circuit elements
A circuit for outputting a signal (a mode in which ON and OFF operations are continuously repeated according to a predetermined order and time after a power supply voltage is applied) is provided, for example, and a leak detection circuit is provided. When a signal is output from the output terminal C of 3 and this signal is input to the gate of the thyristor 51 through the resistor 16, the timer circuit 26 is connected to the base of the transistor 21 in series with the earth leakage indicator lamp 7 through the resistor 24. The leakage indicator light 7 blinks in synchronization with the signal sent. At the same time, the output relay 4 operates to warn the central monitoring panel (not shown) of the occurrence of electric leakage. By this alarm, the worker goes to the switchboard, confirms the status of the electric leakage accident and takes necessary measures, and then switches the changeover switch 13 to operate the AV relay 15 so that a tripping current is supplied to the tripping coil (AV) 17.

FIG. 5 shows a conventional structure of an earth leakage display device for alarming the occurrence of earth leakage by a mechanical operation. The leakage display device 30 is
An earth leakage display button 31, an earth leakage display piece 32 integrated with the earth leakage display button 31, an electromagnet 34 having a display solenoid connected in parallel with the trip coil (reference numeral 17 in FIG. 4) of the circuit breaker, The armature 3 rotatably supported by the electromagnet 34 and constantly engaged with the engaging portion of the earth leakage display piece 32.
5 and a compression spring 33 which is always held in a stored state by the earth leakage display piece 32, and a current flows through the display solenoid to release the engagement between the armature 35 and the earth leakage display piece 32, and to disconnect the armature 35. When the movable holder 37 holding the main movable contact 36 of the container rotates counterclockwise, the leakage indicator piece 32
Is driven upward by the extension force of the compression spring 33, and the leakage display button 31 at the tip portion projects from the breaker cover 38 to display the leakage.

[0005]

In a circuit breaker in which a leakage warning device as a mechanical leakage warning means is constructed in this way, a leakage occurs in the main circuit and the leakage spontaneously disappears before the operation of the circuit breaker. In such a case, the operation of the earth leakage alarm device is restricted by the main circuit contact of the circuit breaker or a member interlocking with the main circuit contact, so if the earth leakage current exceeds the set value, the current flows through the earth leakage indicating solenoid, Even if the engagement between the armature 34 and the leakage display piece 32 is released, the leakage display button remains stationary and does not indicate the leakage. Even if the leakage is such that it disappears naturally, if this is repeated,
It is conceivable that the conductor and insulation of the main electric circuit will be damaged, the frequency of occurrence will increase as the number of times is repeated, and the damage of the conductor and insulation will expand, eventually leading to an accident such as a short circuit. For this,
It is important to grasp the occurrence of leakage each time without missing it. If the leakage current exceeds the set value, the leakage indicator light electrically grasps the occurrence of leakage regardless of whether or not the circuit breaker operates.However, in case the leakage indicator lamp does not blink for some reason, It is desirable to understand the occurrence of leakage. On the other hand, in an important circuit where it is necessary to accurately know the history of leakage by grasping the occurrence of leakage without letting it escape, even if a leakage occurs, it will not be immediately shut off, but the operator will be required to take necessary measures after the leakage occurrence alarm. Often breaks the circuit.

The object of the present invention is to provide an alarm for the occurrence of leakage by mechanical means regardless of the duration of leakage current exceeding a set value, and when the leakage continues for a certain time or longer. Another object of the present invention is to provide a structure of a circuit breaker capable of breaking the main circuit.

[0007]

In order to solve the above problems, according to the present invention, a zero-phase current transformer inserted in the main circuit and a main circuit connected to the secondary side of the zero-phase current transformer. Leakage detection circuit that outputs a signal when the leakage current exceeds the set value, a leakage indicator that lights up by receiving the output signal from the leakage detection circuit, and a leakage display that warns the occurrence of leakage by moving from a stationary position. In a circuit breaker with an earth leakage alarm including a button, the earth leakage display button is always held in a stored state and is released when the signal is output to drive the earth leakage display member to a display position, and this spring. And a solenoid device provided with a holding means for holding the holding means in the always stored state and a solenoid for releasing the spring by releasing the holding of the holding means by the current flowing at the time of outputting the signal, and the earth leakage warning means are configured. The breaker. In addition, a timer circuit is built in, and the circuit breaker operates to shut off when leakage continues in the main circuit for a certain period of time after the occurrence of leakage. Further, the circuit breaker is provided with the above-mentioned electric leakage warning means and a timer circuit, and the electric leakage display by the electric leakage warning means and the delayed interruption operation by the timer circuit are switched by a changeover switch.

Here, in the solenoid device of the earth leakage warning means, it is preferable to use a permanent magnet as a holding means for holding the spring in a constantly charged state. Alternatively, this holding means may be a claw.

[0009]

As described above, the mechanical leakage warning means includes the leakage indication button, the spring, the holding means for holding the spring in a constantly stored state, and the holding means released by the current flowing when the leakage is detected. When configured with a solenoid device having a solenoid for activating, the alarm operation of this earth leakage warning means, that is, the movement of the earth leakage display button to the display position, does not depend on the main movable contact or the member interlocked with this. Regardless, it is started only by the current flowing into the solenoid by the signal output from the leakage detection circuit, and
Since this movement is performed by the spring force, even if the leakage naturally disappears before the operation of the circuit breaker, the occurrence of the leakage can be continuously displayed. Further, since the operation of returning the leakage display button moved to the display position to the display standby position is performed manually, the history of occurrence of leakage can be confirmed again by this returning operation.

In the case of a circuit breaker that does not immediately shut off even if a leakage occurs, a timer circuit is built into the circuit breaker so that the leakage can be confirmed by the leakage indicator lamp and then a predetermined time can be set. After that, the circuit breaker can be activated. If the circuit breaker incorporates the earth leakage warning means and the timer circuit and the earth leakage display by the earth leakage warning means and the delayed interruption operation by the timer circuit are switched by the changeover switch, the earth leakage alarm is generated. Since it is performed electrically and mechanically, it is possible to grasp the occurrence of leakage substantially without leakage, and to ensure the maintenance of important circuits more reliably, and to perform the breaking operation of the circuit breaker after switching the changeover switch. Therefore, the operational safety of the circuit breaker is improved.

Further, if the holding means for holding the spring in the energy storage state in the solenoid device of the earth leakage warning means is a permanent magnet, the construction of the electromagnet incorporating the permanent magnet is simplified, and the earth leakage warning means is inexpensive. Can be configured to. Further, if the holding means in the solenoid device of the electric leakage warning means for holding the spring in the constantly stored state is a claw, the structure of a conventional ordinary electromagnet provided with an armature can be applied, which is highly reliable in practice. It can be used as a leakage warning means.

[0012]

FIG. 1 shows an embodiment of the present invention. In the figure, the same circuit elements as those in FIG. A mechanical leakage display circuit 54 including a solenoid of a leakage warning means whose structure will be described in detail below is added to the blinking circuit 29 of the leakage indicator light. When the leakage of the main circuit is detected on the secondary side of the zero-phase current transformer 9 and a signal is output from the leakage detection circuit 3 , this signal is sent to the gate of the thyristor 51, the thyristor 51 is turned on, and the blinking circuit. 29 operates to start blinking of the leakage indicator lamp 7, and at the same time, a voltage is applied to the base of the transistor 43 of the mechanical leakage indicator circuit 54 , the transistor 43 is turned on, and the thyristor 48 is turned on. Since the solenoid 57 of the earth leakage warning means is connected in series to the thyristor 48, a current flows through the solenoid 57 to release the spring of the earth leakage warning means which has been stored in advance, and drive the earth leakage display button (not shown) to the display position. To do. As a result, the occurrence of the electric leakage is displayed by two display means, that is, the electric leakage display lamp and the electric leakage display button.

On the other hand, the timer circuit 55 is built in the circuit breaker, and after the necessary measures after the occurrence of the leakage is confirmed, the changeover switch 13 is changed over to the timer circuit side and the switch 14 is turned on. Since the signal is sent from the leakage detection circuit 3 to the gate of the AV relay 1 after the time set in the timer circuit 55.
A current flows through the switch 5, and its contact 15a is turned on to cause a current to flow through the trip coil 17 of the circuit breaker, causing the circuit breaker to perform a breaking operation.

The solenoid 57 is a mechanical leakage display circuit 54.
FIG. 2 shows an example of the structure of the leakage warning means inserted in the. In this embodiment, the leakage warning means 60 is the solenoid 5
7, a fixed iron core 61a, a movable iron core 61b, a U-shaped yoke 62 made of a steel plate, two rectangular rod-shaped permanent magnets 58 fixed to the inside of the yoke 62, and the magnetic flux of the permanent magnets 58 is transferred to the movable iron core 61b. It is configured by using an iron piece 63 for guiding to, a spacer 64 made of a non-magnetic metal, a compression spring 59 which is always kept in a stored state as shown in the figure, and an electric leakage display button 65. When an electric current flows through the solenoid 57 at the time of detecting an electric leakage, the magnetic flux generated by the solenoid 57 cancels the magnetic flux of the permanent magnet 58 passing through the movable iron core 61b and the fixed iron core 61a, so that both iron cores lose their attractive force and the spring 59 expands. The leakage drive button 65 is driven upward by the force.

[0015]

According to the present invention, since the circuit breaker for the wiring with the electric leakage alarm is constructed as described above, the following effects can be obtained. In the circuit breaker according to claim 1, the operation of the earth leakage display button, which mechanically displays the occurrence of earth leakage by moving from the stationary position, is not restricted by the main movable contact of the circuit breaker or a member interlocking with the main movable contact, and the earth leakage occurs. The operation is started only by the signal output from the leakage detection circuit at the time of detection,
Since it is brought to the leakage display position by the spring, it is possible to leave a history of occurrence of leakage even if the leakage spontaneously disappears before the operation of the circuit breaker. Thereby, the occurrence of leakage is grasped by the electrical means by the leakage indicator light and the mechanical means by the leakage indication button, and the occurrence of leakage can be grasped substantially completely, and by the grasped history of the occurrence of leakage, The main electric circuit to which the circuit breaker is applied can be more completely maintained.

In the circuit breaker of claim 2, since the timer circuit is built in the circuit breaker, after confirming the occurrence of the leakage by the leakage indicator lamp,
The necessary treatment can be given a grace period, and the main electric circuit to which the circuit breaker is applied can be better operated. In the circuit breaker according to claim 3, the occurrence of the leakage is surely grasped by the dual display means including the leakage indicator lamp and the leakage indicator button, and the main electric circuit to which the circuit breaker is applied can be more completely maintained. At the same time, the main circuit is cut off after the changeover switch is operated after the necessary measures have been taken due to the occurrence of leakage.Therefore, a breaker is necessary even if it takes more time than planned to carry out the necessary measures. Since the operation is performed after the treatment is completed, the safety in operating the circuit breaker is improved.

The circuit breaker of claim 4 has an advantage that the mechanical leakage warning means is inexpensively constructed. The circuit breaker of claim 5 has an advantage that a highly reliable mechanical leakage warning means can be configured.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing one embodiment of a circuit breaker with a leakage alarm according to the present invention.

FIG. 2 is a front view showing an embodiment of an earth leakage warning means according to the present invention.

FIG. 3 is an external front view of a circuit breaker showing a main part of a circuit breaker for wiring with an earth leakage alarm.

FIG. 4 is a circuit diagram showing an example of a conventional circuit breaker with an earth leakage alarm.

FIG. 5 is a front view showing an example of conventional earth leakage warning means.

[Explanation of Codes] 3 Leakage Detection Circuit 5 Leakage Indicator Button 7 Leakage Indicator Light 9 Zero-Phase Current Transformer 13 Changeover Switch 29 Flashing Circuit 31 Leakage Indicator Button 54 Leakage Indicator Circuit 57 Solenoid 58 Permanent Magnet (Holding Means) 59 Spring 60 Leakage Alarm means 65 Electric leakage display button

Claims (5)

[Claims] 1. A zero-phase current transformer inserted in the main circuit, and a leakage detection circuit connected to the secondary side of the zero-phase current transformer and outputting a signal when the leakage current of the main circuit exceeds a set value. , A leakage indicator lamp that operates by receiving an output signal from the leakage detection circuit,
In a circuit breaker for a wiring with an earth leakage alarm, which has an earth leakage display button for alarming the occurrence of earth leakage by moving from a stationary position, the earth leakage display button is always kept in a stored state and is released when the signal is output. A spring for driving the earth leakage display member to a display position, a holding means for holding the spring in a normally stored state, and a solenoid for releasing the holding of the holding means by the current flowing at the time of outputting the signal to release the spring A circuit breaker with an earth leakage alarm, characterized in that an earth leakage alarm means is configured together with a solenoid device. 2. A zero-phase current transformer inserted in the main circuit, and a leakage detection circuit which is connected to the secondary side of the zero-phase current transformer and outputs a signal when the leakage current of the main circuit exceeds a set value. , A leakage indicator lamp that operates by receiving an output signal from the leakage detection circuit,
In a circuit breaker with an earth leakage alarm that has an earth leakage display button that warns of the occurrence of earth leakage by moving from a stationary position, a timer circuit is built in, and the main circuit is interrupted when the earth leakage continues for a certain period after the earth leakage occurs. A circuit breaker with a leak alarm that operates. 3. A zero-phase current transformer inserted in the main circuit, and a leakage detection circuit which is connected to the secondary side of the zero-phase current transformer and outputs a signal when the leakage current of the main circuit exceeds a set value. , A leakage indicator lamp that operates by receiving an output signal from the leakage detection circuit,
A circuit breaker for a wiring with an earth leakage alarm, which comprises an earth leakage display button for alarming the occurrence of earth leakage by moving from a stationary position, comprising the earth leakage warning means according to claim 1 and the timer circuit according to claim 2. Further, a circuit breaker with a leakage alarm, characterized in that the leakage display by the leakage alarm means and the delayed breaking operation by the timer circuit are switched by a changeover switch. 4. The circuit breaker for wiring according to claim 1 or 3, wherein the holding means for holding the spring in the solenoid device of the earth leakage warning means at all times is a permanent magnet. Wiring circuit breaker with an earth leakage alarm. 5. The circuit breaker for wiring according to claim 1 or 3, characterized in that in the solenoid device of the earth leakage warning means, the holding means for holding the spring in a constantly stored state is a claw. Wiring circuit breaker with earth leakage alarm.