JPH06133473A - Circuit breaker - Google Patents

Abstract

(57) [Abstract] [Purpose] By increasing the charging voltage of the capacitor that supplies the excitation voltage to the alarm signal output relay, the contact holding time of the alarm signal output relay can be increased by the charging voltage of the capacitor even after the output of the power supply circuit is cut off. Prolong. [Configuration] warning signal output a plurality of capacitors C _1, C ₂ the power supply circuit 7 from the electronic switch 8 is connected in parallel with the series circuit with the series circuit composed of an on state by the coil 10A and the trip signal of the relay 10 Of the plurality of capacitors C ₁ and C _{2 that} are adjacent to each other are connected by a thyristor SW1 that is turned on when the electronic switch 8 is turned on.

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 designed to prolong the output time of an alarm signal output by the input of a trip signal.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing the overall construction of a conventional circuit breaker, and FIG. 7 shows an alarm (hereinafter referred to as AL) signal output circuit 9 shown in FIG. 6 and its peripheral circuits. 3 is a circuit diagram showing the configuration of FIG. In FIG. 6, U,
V, W, and N are each phase of an AC power supply (not shown), 1 is a main circuit made of a phase conductor connecting each phase and a load, 3 is a trip coil as a tripping electromagnetic device, and is a breaking mechanism when excited. The breaking contact 2 is opened via 3A and closed when demagnetized. 4 is a current transformer having each phase conductor of the main circuit 1 as a primary winding, 5 is a circuit breaker connected to the secondary windings of these current transformers 4, and 6 is a secondary winding of the current transformer 5. A rectifier circuit connected to the line for converting alternating current in the main circuit 1 into direct current, 7 is a power supply circuit connected to the rectifier circuit 6 to supply required voltages to various circuits described later, and 8 is between both ends of the power supply circuit 7. It is an electronic switch connected in series with the trip coil 3.

9 is connected between both ends of the power supply circuit 7 and connected to AL
An AL output circuit for outputting a signal, 10 is an AL output relay connected to the AL output circuit 9 and excited by an AL signal, 10
A is a coil of the AL output relay 10, 10B is a contact (AL output contact) of the AL output relay 10, 11 is an air-core coil coupled to each phase conductor of the main circuit 1, 12 is an air-core coil 11
Is connected to the ground fault signal regeneration circuit for regenerating a ground fault signal proportional to the ground fault current of the main circuit 1, and 13 is a ground fault signal regeneration circuit 1
This is a ground fault trip circuit that outputs a trip signal to the electronic switch 8 when the ground fault signal reproduced by 1 exceeds a predetermined ground fault trip characteristic.

Next, the configurations of the conventional electronic switch 8 and the AL output circuit 9 will be described. The electronic switch 8 has a semiconductor switching element such as a thyristor 81, the anode of which is connected to the positive terminal of the power supply circuit 7 via the trip coil 3, and the cathode of which is, for example, the ground fault trip circuit 13 shown in FIG. It is connected to the output side. AL
The output circuit 9 is operated by a first semiconductor switching element such as a thyristor 91, a second semiconductor switching element such as a transistor 92, a reverse current blocking diode 93, a capacitor 94, a current limiting element such as a constant current diode 95, and an AL output relay 10. Second contact 1
With 0C.

The thyristor 91 has its anode through the coil 10A of the AL output relay 10, the collector / emitter of the transistor 92 and the diode 93, and the power supply circuit 7
Of the thyristor 81, the cathode of which is connected to the negative terminal of the power supply circuit 7 and the gate of which is connected to the gate of the thyristor 81. In the transistor 92, a constant current diode 95 is connected between its collector and base, and a second contact 10C is connected between its base and emitter. The capacitor 94 is connected between the collector of the transistor 92 and the negative terminal of the power supply circuit 7. still,
Since the other circuits are not directly related to the operation of the circuit breaker, the description thereof will be omitted here.

In the conventional circuit breaker 5 configured as described above, for example, when the ground fault current is detected according to the output of the ground fault signal reproducing circuit 12, the ground fault trip circuit 13 causes the ground fault trip characteristic of FIG. Generate a trip signal according to. This trip signal is applied to the gate of the thyristor 81 in the electronic switch 8 shown in FIG. 7 to turn on the thyristor 81, which in turn excites the trip coil 3, so that the breaker contact 2 is opened and the circuit breaker 5 is closed. To trip. The trip signal described above is also applied to the gate of the thyristor 91 in the AL output circuit 9 and
Turn on.

Then, the current flowing from one end of the capacitor 94 through the constant current diode 95, the base / emitter of the transistor 92, the coil 10A in the AL output relay 10 and the turned-on thyristor 91 to the other terminal of the capacitor 94 causes the transistor 92 to flow. Is turned on. As a result, the charge previously stored in the capacitor 94 is discharged through the collector / emitter circuit of the transistor 92, and the coil 10 of the AL output relay 10 is discharged.
A large current flows through A as shown by the waveform A in FIG.

When the coil 10A is excited by this large current, the second contact 10C is attracted and closed, and the base and emitter of the transistor 92 are short-circuited, so that the transistor 92 is turned off. After that, the current flowing through the AL output relay 10 flows from the capacitor 94 through the constant current diode 95 and the closed second contact 10C to the coil 10A and as a small constant current as shown by the waveform B in FIG.

Further, the coil 10A is driven by the above-mentioned large current.
Is excited, the first contact 10B which is interlocked with the second contact 10C is also closed, so as shown by the waveform C in FIG.
The output of the output circuit 9 is turned on. When the coil 10A is demagnetized after the capacitor 94 is completely discharged, the first contact 10
B and the second contact 10C are opened again, and the AL output circuit 9
Output is turned off. Furthermore, as shown in FIG. 10, while the output of the AL output circuit 9 is on, another relay circuit is activated,
It is also possible to operate the circuit in a self-holding manner.

[0010]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Since the L output circuit is configured as described above, when exciting the coil 10A of the AL output relay 10, the electric charge of the capacitor 94 which has charged the output of the power supply circuit 7 to the peak value is applied to the coil 10A as the exciting voltage. . Therefore, the charging voltage is low and the voltage level is 70% of the relay operating voltage.
If the time until it falls below is short, the AL output period also becomes short, and there is a problem that other circuits cannot be sufficiently operated using the AL output.

The present invention has been made to solve the above-mentioned problems, and by increasing the charging voltage of the capacitor for supplying the exciting voltage to the AL output relay, the capacitor can be operated even after the output of the power supply circuit is cut off. An object of the present invention is to obtain a circuit breaker that can prolong the contact holding time of the AL output relay by the charging voltage.

[0012]

A circuit breaker according to the present invention includes a series circuit composed of a coil of an alarm signal output relay and a first switching means which is turned on by a trip signal and a parallel connection to the series circuit. A plurality of capacitors to be connected between both ends of a power supply circuit, and between the opposite polarity terminals of the capacitors adjacent to each other in the plurality of capacitors,
The second switching means, which is turned on when the switching means is turned on, is connected, and the capacitors are connected in series.

[0013]

The circuit breaker according to the present invention normally charges each of the capacitors by the output of the power supply circuit,
When the second switching means is turned on along with the ON operation of the first switching means, the capacitors are connected in series by the second switching means and are connected in parallel to the series circuit including the coil and the first switching means. .
Therefore, an exciting voltage that is a multiple of the output of the power supply circuit is applied to the coil by a capacitor connected in series, and the excited state of the coil can be prolonged even after the power supply circuit is cut off.

[0014]

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 the overall configuration of the circuit breaker according to this embodiment. In the figure, the same reference numerals as those in FIG. 6 indicate the same or corresponding portions. In the figure, 5A is a circuit breaker main body in the present embodiment. Further, 9A is an AL output circuit in this embodiment. 2 is a circuit diagram showing the internal configuration of the AL output circuit 9A. This AL output circuit 9A is an output line of the power supply circuit 7 plus (+)
A first charging circuit in which a capacitor C ₁ and a resistor R ₁ are connected in series in this order between a line and a ground (G) line, and a second charging circuit in which a resistor R ₂ and a capacitor C ₂ are connected in series are connected in parallel. At the same time, the negative terminal of the capacitor C ₁ is connected to the cathode of the thyristor SW1 which is the second switching means and the gate thereof via the current limiting resistor R ₆ , and the positive terminal of the capacitor C ₂ is connected to the anode of the thyristor SW1. And a gate for it, photo coupler PC1
Is connected via a resistor R ₇ connected in series with the phototransistor PC _1B .

The light emitting diode P of the photocoupler PC1
The anode of C _1A is connected to the + line via the resistor R ₅ , and the cathode is connected to one end of the coil 10A of the AL output relay 10 and is also connected to the G line via the electronic switch 8. Further, a connection point between the positive terminal of the capacitor C ₁ and the + line, and a diode D ₁ for preventing the capacitor voltage from being applied to the power supply circuit 7 between the + lines, a connection point between the resistor R ₂ and the + line. A diode D ₂ is connected between the other end of the coil and the coil to prevent a positive potential from being applied to the coil 10A when the electronic switch 8 as the first switching means is off.

Next, the operation of this embodiment will be described with reference to the charge / discharge characteristic diagrams shown in FIGS. In the state where the circuit breaker 5A does not detect the overcurrent or the ground fault current, the trip circuit does not output the trip signal to the electronic switch 8. Therefore, the power supply circuit 7 causes the resistor R5 and the electronic switch 8 to operate. No operating current flows through the light emitting diode PC _1A . Therefore, the phototransistor PC _1B is turned off and the thyristor S
The gate voltage is not applied to the gate of W1.

Therefore, the first and second charging circuits connected between the + line and the G line are not connected by the thyristor SW, and the capacitors C ₁ and C ₂ individually charge the power supply circuit 7. As a charging characteristic, when a voltage is applied from the power supply circuit 7 to each charging circuit through the diode D ₁ as shown in FIG. 3, as the capacitor C ₁ in the first charging circuit is charged with electric charge. The charging voltage lowers the potential between the charging circuits, and the potential V _R1 across the resistor R ₁
Gradually decreases as shown by the broken line.

At the same time, in the second charging circuit,
As shown by the solid line, the capacitor C ₂ is gradually charged by the power supply circuit 7 through the resistor R _2, and the charging voltage of the capacitor becomes V _C2 . Therefore, each of the capacitors C ₁ and C ₂ is charged with an electric charge corresponding to the output voltage value of the power supply circuit 7. The output voltage V _AL of the AL output circuit 9A has a value obtained by adding the potential V _R1 between the resistors R ₁ and the charging voltage V _C2 of the capacitor C ₂ when no trip signal is input.

However, when a trip signal is input to the electronic switch 8, the electronic switch 8 is turned on, and a current flows from the power supply circuit 7 through the resistor R ₅ , the light emitting diode PC _A and the electronic switch 8 to the G line. Flow to. Therefore, the phototransistor PC _1B is turned on by the light from the light emitting diode PC _1A, and the gate current is changed to the resistors R6, R7 and the phototransistor PC by the potential generated between the capacitors C ₁ and C _2.
Thyristor S flows through _{1B to} the gate of thyristor SW
W is turned on.

When the thyristor SW is turned on in this manner, the capacitor C ₂ is connected in series with the capacitor C ₁ through the thyristor SW, and the potential V _R1 across the resistor R ₁ is reached.
Rises all the way to the charging voltage V _C2 level of the capacitor C2. The output voltage V _AL of the AL output circuit applied to the coil 10A becomes a value obtained by adding the potential V _R1 and the charging voltage V _C2 , that is, twice the output voltage of the power supply circuit 7.

The coil 10A of the AL output relay 10 is excited by applying the output voltage V _AL , which is the first contact A.
The L output contact 10B is closed. At this time, since the exciting voltage (AL output voltage V _AL ) applied to the coil 10A is twice the normal voltage, the exciting voltage is generated even after the output of the power supply circuit 7 is stopped from the breaking of the breaker contact 2. Is AL relay 1
As shown in FIG. 4, the time required for the normal AL output voltage (V _AL / 2) to drop to 70% or less of the operating voltage of 0 is the coil 1
It takes a long time as compared with the case where the voltage is applied to 0A.

Therefore, the coil 10A is kept in the excited state for a long time, thereby prolonging the closed state of the AL output contact 10B. In this way, by prolonging the closed state, it is possible to obtain a sufficient time for engaging the operation of the AL output contact 10B and operating other circuits.

Example 2. In the first embodiment, two capacitors are connected in series to apply a voltage that is twice the output voltage of the power supply circuit to the coil. However, by configuring the charging circuit as shown in FIG. Double excitation voltage can be obtained. As its configuration, a first charging circuit in which a capacitor C ₁ and a resistor R ₁ are connected in series between a positive (+) line and a ground (G) line which are output lines of the power supply circuit 7, a resistor R ₂ , and a capacitor C. _{A second} charging circuit in which a resistor R ₃ and a resistor R ₃ are connected in series in this order and a _third charging circuit in which a resistor R ₄ and a capacitor C ₃ are connected in series are connected in parallel.

The negative terminal of the capacitor C ₁ is connected to the cathode of the thyristor SW1 which is the second switching element and the gate thereof via the current limiting resistor R ₆ , and the positive terminal of the capacitor C ₂ is connected to the thyristor SW1. The anode and the gate are connected via a resistor R ₇ connected in series with the phototransistor PC _1B of the photocoupler PC1.

Further, the negative terminal of the capacitor C ₂ is connected to the cathode of the thyristor SW2, which is the third switching element, and the gate thereof via the current limiting resistor R ₈ , and the positive terminal of the capacitor C ₃ is connected to the thyristor SW2. connecting the anode it via the phototransistor PC _2B series connected resistors R ₈ of the gate photocoupler PC2.

The light emitting diode P of the photocoupler PC1.
The anode of C _1A is connected to the + line via the resistor R ₅ , and the cathode is the light emitting diode PC of the photocoupler PC2.
Connected to the _2A anode. Further, the cathode of the light emitting diode PC _2A is the coil 10A of the AL output relay 10.
Is connected to one end of the
Connected to the line.

The AL output circuit 9B configured as described above
As in the first embodiment, while the electronic switch 8 is off, the capacitors C ₁ , C ₂ and C ₃ of each charging circuit are charged by the output voltage of the power supply circuit 7 and the electronic switch 8 is operated. 8 turns on and each photocoupler PC1,
When PC2 operates, the capacitors C ₁ , C ₂ and C ₃ are connected in series by the operation of the thyristors SW1 and SW2.

Therefore, the AL output voltage V _AL (excitation voltage) corresponding to three times the output voltage of the power supply circuit 7 is applied to the coil 10A.
Is applied. Therefore, even after the output of the power supply circuit 7 is cut off, the AL output voltage V _AL can be reduced to 70% or less of the operating voltage of the AL output relay 10 by applying a double output voltage or more. take time. As a result, it is possible to obtain a sufficient time for engaging the operation of the AL output contact 10B and operating other circuits.

[0029]

As described above, according to the present invention, a series circuit including the coil of the alarm signal output relay and the first switching means that is turned on by the trip signal, and a plurality of series circuits connected in parallel to the series circuit. Is connected between both ends of the power supply circuit, and different polarity terminals of adjacent capacitors among the plurality of capacitors are connected by the second switching means which is turned on in accordance with the turning on operation of the first switching means. By connecting the capacitors in series, it is possible to prolong the excitation state of the coil and prolong the alarm signal output time, thereby sufficiently obtaining the time for operating the other circuits.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the overall configuration of a circuit breaker according to the present invention.

FIG. 2 is a circuit diagram showing a configuration of an AL output circuit in this embodiment.

FIG. 3 is a characteristic diagram illustrating charge / discharge characteristics of the AL output circuit shown in FIG.

FIG. 4 is a characteristic diagram illustrating a difference in discharge characteristics between a conventional AL output circuit and an AL output circuit according to the present embodiment.

FIG. 5 is a circuit diagram showing a configuration of an AL output circuit according to another embodiment.

FIG. 6 is a block diagram showing an overall configuration of a conventional circuit breaker.

FIG. 7 is a circuit diagram showing a configuration of a conventional AL output circuit and its peripheral circuits.

FIG. 8 is a characteristic diagram of an exciting current flowing through a coil of a conventional AL output relay.

FIG. 9 is a characteristic diagram showing each trip characteristic of the circuit breaker.

FIG. 10 is a timing chart explaining the operation of the AL output relay.

[Explanation of symbols]

 8 Electronic Switch 9A, 9B AL Output Circuit 10 AL Output Relay 10A Coil 10B Contact C1, C2, C3 Capacitor R1, R2, R3 Resistance SW1, SW2 Thyristor

Claims (1)

[Claims] 1. A series circuit composed of a coil of an alarm signal output relay and a first switching means that is turned on by a trip signal, and a plurality of capacitors connected in parallel to the series circuit are connected between both ends of a power supply circuit. In the plurality of capacitors, different polarity terminals of adjacent capacitors are connected to each other by a second switching means that is turned on when the first switching means is turned on, and the capacitors are connected in series. Circuit breaker characterized by.