JPS6330189Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a current leakage circuit and disconnector that interrupts an electrical circuit in response to a leakage current flowing through the electrical circuit.

In general, this type of earth leakage or disconnection occurs when a leakage current ig flows through the electrical circuits C and C connecting AC power source A and load RO, and a secondary output voltage is generated at zero-phase current transformer D, as shown in Figure 2. The switching circuit performs a switching operation via the detection circuit E, and the trip coil trips the contacts A and C provided in the circuits C and C, immediately disconnecting the circuits C and C, and attaching current-limiting resistors to the circuits C and C. Turn off the energization indicator lamp N connected through the trip coil, and close the monitoring contact L, which is closed when the trip coil is tripped, to display an earth leakage indicator connected to the electrical circuits C and C via this monitoring contact L and the current limiting resistor. It was used to light a lamp.

With the above configuration, when the switching circuit is in the OFF state, the high voltage of the electric circuits C and C is applied to the switching circuit via the rectifier circuit C and the trip coil. There was a risk that stress due to this high voltage would accumulate and cause it to deteriorate quickly. However, the circuit for lighting the current status indicator lamp and the circuit for lighting the earth leakage indicator must be connected to the electrical circuits C and C separately from the circuit for performing the current leakage and disconnection functions. The drawback was that the heat generated by the current-limiting resistors deteriorated other electronic components.

In view of the above points, the present invention reduces stress accumulation due to high voltage by applying a low voltage when the switching circuit is in the OFF state. A circuit, an earth leakage detection circuit, a voltage detection circuit, a switching circuit, or a combination of these circuits includes a light emitting element so as to display current status and earth leakage, and is provided separately from the circuit for earth leakage and disconnection functions. The purpose is to reduce the amount of heat generated by the current limiting resistor of the conventional energization indicator and earth leakage indicator lamp.

The present invention will be explained below based on FIG. 1, which shows an embodiment of the present invention. 1 is an AC power source, 2 is a load, and electric lines 3, 3 connect the AC power source 1 and the load 2.
is connected to. 4, 4 are contacts provided in the electric circuits 3, 3, 5 is a trip coil for tripping and opening these contacts 4, 4, and 6 is a resistor, capacitor, coil, etc. that has an impedance much higher than the impedance of this trip coil 5. A high impedance element 7 is a rectifier circuit in which the input of a diode bridge 7a is connected to the electric circuits 3, 3 via a high impedance element 6, and the output of the diode bridge 7a is connected to a constant voltage element 7b and a smoothing capacitor 7.
e are connected in parallel. 8 is a zero-phase current transformer that detects the leakage current flowing in the electric lines 3, 3, and 9 is an earth leakage detection circuit, which inputs the secondary output of the zero-phase current transformer 8 to one input of the comparator 9a, and A reference voltage generated by a series circuit of a resistor 9b and a constant voltage element 9c is input to the other input of the comparator 9a, and a latch circuit 9d for holding this output signal is connected to the output of the comparator 9a, so that the output signal is zero. When the secondary output voltage generated in the phase current transformer 8 exceeds the reference voltage, the comparator 9a outputs a high level voltage signal, and the latch circuit 9d holds and outputs this voltage signal.

Note that a resistor 9e and a capacitor 9f connected in parallel to the secondary winding of the zero-phase current transformer 8 serve as a filter. 10 is a voltage detection circuit, which includes a comparator 10a.
The divided voltage of the voltage dividing resistors 10b and 10c is input to one input of the comparator 10a, and the reference voltage generated in the series circuit of the resistor 10d and the constant voltage element 10e is input to the other input of the comparator 10a. The output of the comparator 10a is fed back to one input via the resistor 10f to provide a hysteresis characteristic of a predetermined voltage for switching operation, and when the voltage of the smoothing capacitor 7c becomes higher than the predetermined voltage, a high level is applied to the output of the comparator 10a. It outputs a voltage signal, and when the voltage of the smoothing capacitor 7c becomes lower than a predetermined voltage, it operates to output a low-level voltage signal to the output of the comparator 10a. 11 is a switching circuit that connects the output signal of the earth leakage detection circuit 9 and the voltage detection circuit 1.
The output signal of 0 is input to the AND circuit 11a, and the output signal of this AND circuit 11a is input to the transistor 11.
It is input between the base and emitter of transistor 11b, and the collector and emitter of transistor 11b is connected in series to trip coil 5 as an output of switching circuit 11. 12 is a light emitting element such as a light emitting diode or a lamp. Thus, the power input of the earth leakage detection circuit 9, that is, the series circuit of the resistor 9b and the constant voltage element 9c, the power input of the comparator 9a, the power input of the latch circuit 9d, and the detection input of the voltage detection circuit 10, that is, the voltage dividing resistor 10b. , 10c, the power input of the voltage detection circuit 10, that is, the series circuit of the resistor 10d and the constant voltage element 10e, the power input of the comparator 10a, the power input of the switching circuit 11, that is, the power input of the AND circuit 10a, and the trip coil 5 and The series circuit of the switching circuit 11 is connected in parallel to the smoothing capacitor 7c via the light emitting elements 12, respectively.

In the embodiment, the detection input of the voltage detection circuit 10, the power input of the voltage detection circuit 10, the power input of the earth leakage detection circuit 9, and the power input of the switching circuit 11 are all connected to the smoothing capacitor 7c via the light emitting element 12. Although the light emitting element 12 is connected in parallel to
Since it is satisfied if some current flows through at least one of the above inputs,
All but one may be directly connected in parallel to the smoothing capacitor 7c. Furthermore, a shunt resistance may be provided to the light emitting element 12 according to its capacity.

To explain the operating state, the electric circuit 3,
Since the contacts 4, 4 provided at the terminal 3 are closed, power is supplied from the AC power source 1 to the load 2, and the smoothing capacitor 7c of the rectifying and smoothing circuit 7 is charged via the high impedance element 6, and the leakage detection circuit 9 is charged. Even though power is supplied to the voltage detection circuit 10 and the switching circuit 11, the light emitting element 1 is
2 lights up dimly to notify that the power is on. At this time, the voltage detection circuit 10 outputs a high-level voltage signal because the voltage of the smoothing capacitor 7c exceeds the predetermined high voltage.

Furthermore, when a leakage current ig flows on the load 2 side from the above state, a secondary output voltage of the zero-phase current transformer 8 is generated, and in response to this output voltage, the earth leakage detection circuit 9 outputs and holds a high-level voltage signal. At the same time, the switching circuit 11 performs a switching operation, and the trip coil 5
Then, the charges in the smoothing capacitor 7c are discharged, the contacts 4, 4 are tripped, and the electric circuits 3, 3 are opened. During this discharge, when the light emitting element 12 lights up brightly and the voltage of the smoothing capacitor 7c becomes lower than the predetermined voltage of the voltage detection circuit 10, the switching circuit 11
is switched to the OFF state, the smoothing capacitor 7c starts charging, and the light emitting element 12 is dimly lit. When the voltage of the smoothing capacitor 7c is further charged and exceeds the predetermined high voltage of the voltage detection circuit 10, the switching circuit 11 switches to the on state, and discharges the charge of the smoothing capacitor 7c to the trip coil 5 again, thereby turning on the light emitting element 12. Light it up brightly. That is, this smoothing capacitor 7c
In response to charging and discharging, the light emitting element 12 repeatedly blinks to display an earth leakage indication.

As described above, the present invention reduces the voltage of the electric circuits 3, 3 through the high impedance element 6, which has a higher impedance than the trip coil 5 which trips the contacts 4, 4 provided on the electric circuits 3, 3 that connect the power source 1 and the load 2. Smoothing capacitor 7c of rectifying and smoothing circuit 7 that rectifies and smoothes
The output signal of the voltage detection circuit 10 which compares the output voltage of the smoothing capacitor 7c with a predetermined voltage and outputs a signal via the light emitting element 12 and the electric circuit 3,
A series circuit of the trip coil 5 and a switching circuit 11 that performs a switching operation in response to an AND output of the output signal of the earth leakage detection circuit 9 which outputs and holds a signal in response to the leakage current flowing through the circuit 3, and the voltage detection circuit 3. Since at least one of the detection input of the circuit 10, the power input of the same voltage detection circuit 10, the power input of the earth leakage detection circuit 9, and the power input of the switching circuit 11 are connected in parallel, the high impedance element 6 closes the electric circuit. Since the voltage is dropped and a lower voltage is applied to the switching circuit 11,
Accumulation of high voltage stress is reduced, deterioration is reduced, and circuits for earth leakage and disconnection functions, that is, rectifier and smoothing circuit 7, earth leakage detection circuit 9, and voltage detection circuit 10
Alternatively, since the light-emitting element 12 is included in the switching circuit 11 or a combination of these circuits, it is possible to display current status and current leakage, so there is no need to provide a separate circuit for current leakage and disconnection functions. Furthermore, compared to the heat generated by the current-limiting resistor of the conventional energization indicator and leakage indicator lamp, the heat generated by the high-impedance element 6 can be reduced to the extent that the light-emitting element 12 is dimly lit, and the effect on other electronic components is minimal. In addition, when an earth leakage occurs, the smoothing capacitor 7c is repeatedly charged and discharged to flow current to the trip coil 5, so even if the tripping operation cannot be performed once, the tripping operation will be performed again at the next discharge. This has the effect of reducing the phenomenon in which leakage current continues to flow without being able to cut off the voltage.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the current leakage circuit breaker and circuit breaker of the present invention, and FIG. 2 is a circuit diagram of a conventional circuit leakage circuit breaker and circuit breaker of the present invention. 1...Power supply, 2...Load, 3...Electric circuit, 4...
Contact, 5... Trip coil, 6... High impedance element, 7... Rectifier smoothing circuit, 7c... Smoothing capacitor, 8... Zero-phase current transformer, 9... Leakage detection circuit, 10... Voltage detection circuit, 11...Switching circuit, 12...Light emitting element.

Claims (1)

[Scope of utility model registration request] The smoothing capacitor of the rectifying and smoothing circuit rectifies and smoothes the voltage of the electrical circuit through a high impedance element higher than the impedance of the trip coil that trips the contact provided in the electrical circuit connecting the power source and the load, and the smoothing capacitor is connected to the smoothing capacitor of the rectifying and smoothing circuit through the light emitting element. A logical product output of the output signal of a voltage detection circuit that compares the output voltage of the capacitor with a predetermined voltage and outputs a signal, and the output signal of the earth leakage detection circuit that outputs and holds a signal in response to the leakage current flowing in the electric path. A series circuit of a switching circuit that performs a switching operation in response to the trip coil, a detection input of the voltage detection circuit, a power input of the voltage detection circuit, a power input of the earth leakage detection circuit, and a power input of the switching circuit. Earth leakage or disconnection with at least one connected in parallel.