JP4845910B2 - Earth leakage breaker - Google Patents

Description

  The present invention relates to a leakage breaker that detects a leakage current flowing in an AC circuit such as a power distribution system to interrupt the AC circuit and prevent a leakage accident.

  As is well known, an earth leakage breaker includes a main circuit connected to an AC circuit, an open / close unit having an opening / closing mechanism for opening / closing the main circuit, an earth leakage detection circuit for detecting an earth leakage current flowing through the main circuit, and an earth leakage A trip device that trips the open / close mechanism of the switch when the detection circuit detects a leakage current and shuts off the main circuit, and a test to check the operation of the leakage trip function by supplying a test current to the leakage detection circuit A circuit is provided.

  The conventional general earth leakage breaker obtains the power of the earth leakage detection circuit and the trip device from the two-phase circuit of the main circuit, and the test circuit also uses the AC voltage before the two-phase rectification of the main circuit. A power supply is obtained, and a test current suppressed to a predetermined value with a resistor is supplied from the power supply to the test circuit (see, for example, Patent Document 1).

  Another conventional earth leakage breaker is configured to receive the power supply of the earth leakage detection circuit and the trip device from all of the three-phase electric circuit as the main circuit, and further, the three-phase electric circuit applied to the three-phase electric circuit. A test current, which is suppressed to a predetermined value by a resistor, is supplied to a test circuit using a DC voltage obtained by rectifying the AC voltage as a power supply, and a leakage detection circuit is operated using a ripple component of the test current, thereby allowing one phase to Even when the phase is lost, the leakage protection function is maintained, and a test operation is also possible (see, for example, Patent Document 2).

  Furthermore, as another conventional earth leakage breaker, as in Patent Document 2, the earth leakage detection circuit and all the three-phase electric circuits of the main circuit are provided so that the earth leakage protection function and the test operation can be performed even when one phase is missing. It is configured to receive power from the trip device, and a low-frequency oscillator that operates using the DC voltage after full-wave rectification of the three-phase AC voltage of the three-phase circuit as a power source is provided, and the output current of this oscillator is tested. The current is passed through the test circuit as a current (see, for example, Patent Document 3).

JP-A-5-182579 JP 2007-149603 A JP 2006-302601 A

  In the case of the conventional earth leakage circuit breaker described in Patent Document 1, even when used in a three-phase circuit, power is supplied only from two of the three phases. If this happens, the leakage protection function may be lost. Also, since the main circuit voltage is applied to the resistor and test switch that limit the test current flowing to the test circuit to a predetermined current value, it is necessary to ensure that the resistance and the test switch have sufficient withstand voltage. Has become difficult.

  Further, in the case of the conventional earth leakage circuit breaker described in the first embodiment of Patent Document 2, the test current is mainly composed of a DC component, and the AC component is extremely small. Therefore, the test current from the zero-phase current transformer is reduced. The output is very small compared to the output of a zero-phase current transformer using a normal sinusoidal alternating current, and the test current for performing the test operation needs to be a very large current. The test current is a three-phase full-wave rectified current and is a third harmonic current having a fundamental frequency that is three times the frequency of the main circuit. As a result, there is a problem that the test current required for the test operation needs to be further increased due to the influence of the low-pass filter for removing harmonics that is generally incorporated in the leakage detection circuit.

  Furthermore, in the case of the conventional earth leakage breaker described in Embodiment 2 of Patent Document 2, the basic frequency of the test current is the same as the frequency of the main circuit current, and the AC component of the test current is very large. The subsequent voltage always has a rectified waveform lacking one phase, and sufficient smoothing means is required for use as a power source for the leakage detection circuit. In addition, since a half-wave rectifier circuit is used, the reverse voltage is not suppressed in the two rectifier diodes provided only on one arm, so it is possible to suppress overvoltage individually using a surge absorber or the like for each phase on the AC side. There was a problem that a rectifier diode having a very high breakdown voltage had to be selected.

  Further, in the conventional leakage breaker described in Patent Document 3, when the phase of the main circuit current and the phase of the test current generated by the oscillator are not synchronized, the time for detecting the leakage varies. When the test operation is performed in a state in which a current leakage current that does not reach the leakage current is flowing through the main circuit, a swell (beat) occurs in the combined current of the test current and the current leakage current, There was a problem that the operation check of the earth leakage trip function by the test current became unstable.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a leakage breaker capable of supplying a stable power to a leakage detection circuit and a tripping device and capable of performing a stable test operation. It is what.

  An earth leakage breaker according to the present invention includes a main circuit connected to an AC circuit, an open / close unit that opens and closes the main circuit, a secondary winding that generates an output current based on a leakage current flowing through the main circuit, and a test current. A zero-phase current transformer having a tertiary winding that generates an output current in the secondary winding when energized by, a test circuit that supplies the test current to the tertiary winding during a test operation, and A leakage detection circuit that generates an output signal based on the output current of the secondary winding of the zero-phase current transformer, and a circuit that is driven based on the output signal of the leakage detection circuit to trip the open / close unit and shut off the main circuit A tripping device, a power supply circuit for supplying power to the leakage detection circuit and the tripping device, and a plurality of rectifying diodes connected in a bridge, and full-wave rectifying an AC voltage applied to the main circuit. To output DC voltage A full-wave rectifier circuit, and the power supply circuit supplies a predetermined DC control voltage generated by receiving the supply of the DC voltage output from the full-wave rectifier circuit to the leakage detection circuit and the tripping device. The test circuit detects the phase of the alternating current flowing through the main circuit by detecting an energization current or an applied voltage of at least one rectifier diode among the plurality of rectifier diodes constituting the full-wave rectifier circuit. A current having a phase synchronized with the current is generated, and the generated current is supplied to the tertiary winding as the test current.

  In the present invention, “leakage” includes a ground fault, and “leakage current” includes a ground fault current.

  According to the leakage breaker according to the present invention, the power supply circuit supplies the predetermined DC control voltage generated by receiving the supply of the DC voltage output from the full-wave rectifier circuit to the leakage detection circuit and the trip device, and performs the test. The circuit detects an energizing current or an applied voltage of at least one rectifying diode among a plurality of rectifying diodes constituting the full-wave rectifying circuit, thereby generating a current having a phase synchronized with the phase of the alternating current flowing in the main circuit. Since the generated current is supplied to the tertiary winding of the zero-phase current transformer as a test current, stable operation of the leakage detection circuit and trip device can be obtained and stable test operation can be performed. .

Embodiment 1 FIG.
1 is a circuit diagram showing an earth leakage circuit breaker according to Embodiment 1 of the present invention. In FIG. 1, an earth leakage breaker 1 includes a main circuit 4 composed of R-phase, S-phase, and T-phase electric circuits for connecting a power supply side connection terminal 2 and a load side connection terminal 3, and the main circuit 4. An open / close unit 5 that opens and closes and a conductor of all phases of the main circuit 4, and detects a leakage current or a ground fault current (hereinafter simply referred to as a leakage current) flowing through the main circuit 4 to detect from the secondary winding 6 a. The zero-phase current transformer 6 that outputs a detected current and the detected current of the secondary winding 6a of the zero-phase current transformer 6 are monitored to determine whether there is a leakage or a ground fault (hereinafter simply referred to as a leakage). A leakage detection circuit 7 that supplies power to the leakage detection circuit 7 and a tripping device 8 that trips the switching mechanism of the switching unit 5 by the output signal of the leakage detection circuit 7 and interrupts the main circuit 4 when the leakage occurs. 9 and a test circuit described later. The earth leakage breaker 1 is connected to a three-phase AC circuit (not shown) through which a leakage is to be detected by a power supply side connection terminal 2 and a load side connection terminal 3.

  The three-phase full-wave rectifier circuit 10 provided in the earth leakage breaker 1 is composed of six rectifier diodes D1, D2, D3, D4, D5, and D6, and rectifies the three-phase AC voltage of the main circuit 4. Then, power is supplied to the power supply circuit 9. The AC side of the three-phase full-wave rectifier circuit 10 is connected to the R-phase, S-phase, and T-phase circuits of the main circuit 4 via the impedance element 11, and the voltage suppression element 12 is connected to the DC side. Has been.

  The voltage suppression element 12 is in parallel with each of the two rectifier diodes D1 and D4, D2 and D5, and D3 and D6 constituting the positive and negative arms of each phase of the three-phase full-wave rectifier circuit 10, respectively. The internal circuit of the earth leakage circuit breaker 1 including the three-phase full-wave rectifier circuit 10 that is connected and suppresses the reverse voltage to all of these six rectifier diodes D1 to D6 from an overvoltage such as surge and impulse. It protects the whole.

  The power supply circuit 9 is supplied with the DC voltage VD that is full-wave rectified by the three-phase full-wave rectifier circuit 10, and steps down the DC voltage VD to a predetermined DC control voltage VS and supplies it to the leakage detection circuit 7 from the control power supply terminal. To do.

  Next, a test circuit for performing a leakage test operation will be described. The earth leakage test operation is to perform earth leakage trip by applying a test current to the tertiary winding 6 b provided in the zero-phase current transformer 6, and the test current is a direct current that has been stepped down by the power supply circuit 9. The control voltage VS is generated by the switching operation of the test current drive circuit 13. The switching operation of the test current drive circuit 13 is performed by the output of the AND circuit 14, and detection signals of the positive detector 15 and the negative detector 16 are input to the AND circuit 14. The test current drive circuit 13 performs an operation of generating a test current when the test switch 17 is turned on by an operator.

  Here, the positive-side detector 15 is a positive-side conductor that can detect the conduction of the R-phase and S-phase rectifier diodes D1 and D2 constituting the positive-side arm of the three-phase full-wave rectifier circuit 10. Is arranged. The negative electrode side detector 16 is a phase corresponding to one of the two phases of the R phase and the S phase corresponding to the rectifier diodes D1 and D2 in the negative side arm of the three-phase full-wave rectifier circuit 10. The S-phase rectifier diode D5 and the T-phase rectifier diode D6, which is a phase corresponding to a phase other than the two phases corresponding to the rectifier diodes D1 and D2, are disposed on the negative conductor. ing.

  The positive detector 15, the negative detector 16, the AND circuit 14, the test current drive circuit 13, and the test switch 17 constitute a test circuit for the leakage breaker 1 according to the first embodiment of the present invention.

  The positive electrode side detector 15 may be disposed on a positive electrode side conductor that can detect conduction of rectifier diodes of any two phases of the positive electrode side arm of the three-phase full-wave rectifier circuit 10, and the negative electrode side detector 16 is a rectifier diode of the phase of the negative arm corresponding to one of the two phases of the positive arm on which the positive detector 15 detects conduction, and the positive electrode on which the positive detector 15 detects conduction. The arrangement is not limited to the arrangement shown in FIG. 1, as long as it is arranged on the negative electrode conductor capable of detecting conduction with the rectifier diode in the phase of the negative electrode side arm corresponding to a phase other than the two phases of the side arm.

  The test operation is performed by turning on the test switch 17. Only when the test switch 17 is turned on, the test current is supplied from the test current drive circuit 13 to the tertiary winding 6b of the zero-phase current transformer 6.

  The earth leakage circuit breaker 1 according to Embodiment 1 of the present invention configured as described above has a zero-phase current transformer 6 when the earth leakage occurs in the AC circuit where the earth leakage should be detected and the earth leakage current flows in the main circuit. Detection current is output from the secondary winding 6 a and input to the leakage detection circuit 7. The leakage detection circuit 7 detects the occurrence of leakage based on the input detection current, supplies the DC control voltage VS stepped down by the power supply circuit 9 to the trip device 8 and activates it. The biased tripping device 8 trips the opening / closing mechanism of the opening / closing part 5 and shuts off the main circuit 4.

  Next, the operation of the leakage test of the leakage breaker 1 will be described. FIG. 2 is a waveform diagram of currents flowing through the rectifier diodes of the three-phase full-wave rectifier circuit 10 when a three-phase alternating current is passed through the main circuit 4 of the leakage breaker 1 shown in FIG. ) Shows waveforms of currents flowing through the rectifier diodes D1 to D6, respectively. 3A and 3B are waveform diagrams showing waveforms of respective parts in the test operation in the normal energized state shown in FIG. 2, wherein FIG. 3A is a current input to the positive detector 15 and FIG. 3B is a negative detector. (C) is an output signal of the positive detector 15, (d) is an output signal of the negative detector 16, (e) is an output signal of the AND circuit 14, and (f) is a test current. Test currents output from the drive circuit 13 are shown.

  As shown in FIG. 3 (a), the positive detector 15 receives a sum of currents flowing through the rectifier diodes D1 and D2, and the positive detector 15 is detected by a detection threshold set at a low level. An output signal which is a pulse signal shown in FIG. The output signal output from the positive detector 15 is output in synchronization with the conduction timing of the rectifier diodes D1 and D2, and becomes a signal synchronized with the phase of the sum of the energization currents of the rectifier diodes D1 and D2. It shows that the diodes D1 and D2 are in a conductive state.

  Further, as shown in FIG. 3B, the negative detector 16 is supplied with the sum of the energization currents of the rectifier diodes D5 and D6, and the negative detector 16 is set at a low level. An output signal which is a pulse signal shown in FIG. The output signal output from the negative electrode side detector 16 is output in synchronization with the conduction timing with the rectifier diodes D5 and D6, and becomes a signal synchronized with the phase of the sum of the energization currents of the rectifier diodes D5 and D6. It shows that the rectifier diodes D5 and D6 are in a conductive state.

  The output signal of the positive-side detector 15 and the output signal of the negative-side detector 16 are signals that detect the conduction state of the diode of the three-phase full-wave rectifier circuit 10 and are completely synchronized with the current phase of the main circuit 4. It becomes. That is, when the zero-cross point from negative to positive of the R-phase current is set to a phase angle of 0 °, the output signal of the positive-side detector 15 is output in synchronization with the phase angle of 60 ° to 300 °, and the negative-side detection The output signal of the device 16 is output in synchronization with the phase angle of 0 ° to 240 °.

The output signal of the AND circuit 14 shown in (e) of FIG. 3 is output when the output signal of the positive detector 15 and the output signal of the negative detector 16 are simultaneously input. The phase angle of the output signal of the AND circuit 14 is a rectangular wave of 60 ° to 240 °, that is, a signal width of 180 °. The test current drive circuit 13 generates a test current by switching the DC control voltage VS that is stepped down by the power supply circuit 9 based on the output signal of the AND circuit 14 and output from the control power supply terminal. ), A test current having a duty ratio of about 50% can be obtained.

  Since the test current drive circuit 13 switches the DC control voltage VS stepped down by the power supply circuit 9 shown in FIG. 1 and outputs a test current, the applied voltage to the tertiary winding 6b of the zero-phase current transformer 6 is reduced. Further, since one end of the tertiary winding 6b is connected to the ground line GND on the signal ground side, the potential difference between the tertiary winding 6b and the secondary winding 6a connected to the leakage detection circuit 7 In particular, when both the secondary winding 6a and the tertiary winding 6b are wound around the core of the zero-phase current transformer 6 and potted, insulation between the secondary winding 6a and the tertiary winding 6b is performed. Processing can be simplified.

  The test switch 17 shown in FIG. 1 is configured to open and close the circuit until the output signal of the AND circuit 14 is input to the test current drive circuit 13. The power supply circuit 9 supplies power to the test current drive circuit 13. The circuit for performing the above may be configured to open and close. Regardless of the configuration of the test switch 17, the test current drive circuit 13 and the AND circuit 14 can all have a low voltage configuration, and an inexpensive low-voltage switch can be used as the test switch 17. Become.

  Next, the operation of the leakage test of the leakage breaker 1 will be described. FIG. 4 is a waveform diagram for explaining the operation when the R phase of the three-phase AC power supply is lost in the configuration shown in FIG. 1, and (a) is input to the positive detector 15. (B) is a current input to the negative electrode side detector 16, (c) is an output signal of the positive electrode side detector 15, (d) is an output signal of the negative electrode side detector 16, and (e) is an AND circuit. 14 shows an output signal, and (f) shows a test current output from the test current drive circuit 13, respectively.

  When the R phase is lost, the supply of control power to the earth leakage circuit breaker 1 becomes the single-phase voltage of the ST phase of the main circuit 4, and the current input to the positive detector 15 is the S of the main circuit 4. Since only the current flowing from the phase to the rectifier diode D2 of the three-phase full-wave rectifier circuit 10 is obtained, the half-wave waveform shown in FIG. On the other hand, the current input to the negative detector 16 is the sum of the current flowing from the rectifier diode D5 to the S phase of the main circuit 4 and the current flowing from the rectifier diode D6 to the T phase of the main circuit 4. 4 (b), the single-phase full-wave rectified waveform is obtained.

  Therefore, the output signals of the positive electrode side detector 15 and the negative electrode side detector 16 have waveforms shown in FIGS. 4 (c) and 4 (d). Since the output signal of the AND circuit 14 is an AND of the outputs of the positive electrode side detector 15 and the negative electrode side detector 16, the result is the same as the output signal of the positive electrode side detector 15 as shown in FIG. It becomes. Therefore, the test current obtained from the test current drive circuit 13 that performs the switching operation based on the output signal of the AND circuit 14 has a half-wave waveform with a duty ratio of about 50% as shown by a solid line in FIG. .

  4 (e) shows the test current when the test current drive circuit 13 switches the unsmoothed DC control voltage VS that has been stepped down by the power supply circuit 9. If VS is sufficiently smoothed, the test current can be a rectangular wave with a duty ratio of about 50%.

  Next, the operation when the S phase of the main circuit 4 is lost will be described. FIG. 5 is a waveform diagram for explaining the operation when the S phase of the three-phase power supply is lost in the configuration shown in FIG. 1, and (a) is input to the positive detector 15. (B) is a current input to the negative detector 16, (c) is an output signal of the positive detector 15, (d) is an output signal of the negative detector 16, and (e) is an AND circuit 14. , (F) indicates the test current output from the test current drive circuit 13, respectively.

  When the S phase is lost, the supply of control power to the earth leakage breaker 1 becomes a single-phase voltage of the R-T phase of the main circuit 4, and the current input to the positive detector 15 is rectified from the R phase. Only the current flowing to the diode D1 is obtained, and the half-wave waveform shown in FIG. On the other hand, since the current input to the negative electrode side detector 16 is only the current flowing from the rectifier diode D6 to the T phase, the half wave waveform shown in FIG. Is the same as Accordingly, the output signals of the positive detector 15 and the negative detector 16 shown in FIGS. 5C and 5D and the output signal of the AND circuit 14 shown in FIG. Therefore, the test current output from the test current drive circuit 13 has a half-wave waveform with a duty ratio of about 50% as shown by the solid line in FIG.

  Next, the operation when the T phase of the main circuit 4 is lost will be described. FIG. 6 is a waveform diagram for explaining the operation when the T phase of the three-phase power supply is lost in the configuration shown in FIG. 1, and (a) is input to the positive detector 15. (B) is a current input to the negative detector 16, (c) is an output signal of the positive detector 15, (d) is an output signal of the negative detector 16, and (e) is an AND circuit 14. , (F) indicates the test current output from the test current drive circuit 13, respectively.

  When the T phase is lost, the supply of control power to the earth leakage breaker 1 becomes the single phase voltage of the R-S phase of the main circuit 4, and the current input to the positive detector 15 is rectified from the R phase. Since this is the sum of the current flowing to the diode D1 and the current flowing from the S phase to the rectifier diode D2, the single-phase full-wave rectified waveform shown in FIG. On the other hand, since the current input to the negative detector 16 is only the current flowing from the rectifier diode D5 to the S phase, the half-wave waveform shown in FIG. These currents are the same as those when the operations of the positive detector 15 and the negative detector 16 are reversed when the R phase is lost, and the test current drive circuit 13 is also used when the T phase is lost. As shown by the solid line in FIG. 6 (f), the test current output from is a half-wave waveform with a duty ratio of about 50%.

  As described above, according to the ground fault circuit breaker according to Embodiment 1 of the present invention, not only the state in which all phases of the three-phase power supply are energized but also the state in which one phase is lost is applied to the main circuit. In addition, the test operation is possible, and the test current can always obtain a waveform with a duty ratio of about 50% having the same frequency as the frequency of the power source energized in the main circuit.

Embodiment 2. FIG.
FIG. 7 is a circuit diagram showing a leakage breaker according to Embodiment 2 of the present invention. In FIG. 7, the positive detector 15 includes a photocoupler 18, a resistor 19, and a Zener diode 20. The photocoupler 18 is connected in series with the resistor 19 and is connected in parallel with the Zener diode 20, and the rectifier diode D 1 that constitutes the R-phase and S-phase positive-side arms of the three-phase full-wave rectifier circuit 10. It is inserted between the cathode of D2 and the positive output terminal of the three-phase full-wave rectifier circuit 10. The negative detector 16 is composed of a photocoupler 21, a resistor 22, and a Zener diode 23. The photocoupler 21 is connected in series with the resistor 22 and is connected in parallel with the Zener diode 23, and also constitutes the S-phase and T-phase negative-side arms of the three-phase full-wave rectifier circuit 10, It is inserted between the anode of D6 and the ground line GND that is the negative output terminal of the three-phase full-wave rectifier circuit 10.

  The output-side transistor of the photocoupler 18 and the output-side transistor of the photocoupler 21 are connected in series, and are connected between the DC control voltage VS and the base of the transistor 25 via the resistor 24 and the test switch 17. The emitter of the transistor 25 is connected to the ground line GND via the tertiary winding 6b of the zero-phase current transformer 6, and the collector is connected to the DC control voltage VS via the resistor 26. Thus, a test current of a predetermined magnitude set by the resistor 26 flows through the tertiary winding 6b to excite the tertiary winding 6b.

  Here, the circuit configuration of the transistor 25 and the resistor 26 constitutes the test current drive circuit 13. Further, the positive electrode side detector 15, the negative electrode side detector 16, the resistor 24, the test current drive circuit 13, and the test switch 17 constitute a test circuit for the leakage breaker 1 according to the second embodiment. Other configurations are the same as those of the circuit breaker 1 of the first embodiment shown in FIG.

  The leakage breaker 1 according to the second embodiment of the present invention configured as described above has a zero-phase current transformer 6 when a leakage occurs in the AC circuit where the leakage should be detected and a leakage current flows in the main circuit. Detection current is output from the secondary winding 6 a and input to the leakage detection circuit 7. The leakage detection circuit 7 detects the occurrence of leakage based on the input detection current, supplies the DC control voltage VS stepped down by the power supply circuit 9 to the trip device 8 and activates it. The biased tripping device 8 trips the opening / closing mechanism of the opening / closing part 5 and shuts off the main circuit 4.

  Next, the operation of the leakage test of the leakage breaker 1 will be described. The consumption current consumed by the leakage detection circuit 7 and the like flows through the rectifier diodes D1 to D6 constituting the three-phase full-wave rectifier circuit 10, but the R-phase and S-phase positive sides of the three-phase full-wave rectifier circuit 10 During the period when the consumption current flows through the rectifier diodes D1 and D2 constituting the arm, that is, when the rectifier diodes D1 and D2 are turned on, the current flows through the input side LED of the photocoupler 18 of the positive detector 15 and the output side transistor Turn on.

  On the other hand, the photocoupler 21 of the negative electrode side detector 16 supplies current to the input side LED of the photocoupler 21 when the rectifier diodes D5 and D6 constituting the negative phase side arms of the S phase and T phase of the three-phase full-wave rectifier circuit 10 are turned on. Flows, and the output side transistor is turned on. Accordingly, the ON / OFF output states of the output transistors of the respective photocouplers 18 and 21 appear as ON / OFF output states of the output signals of the positive-side detector 15 and the negative-side detector 16. Here, the resistors 19 and 22 suppress the current flowing through the input side LEDs of the photocouplers 18 and 21, and the allowable current of the input side LEDs of the photocouplers 18 and 21 is sufficiently large for the maximum current consumption of the circuit. If it is large, it may be omitted.

  The Zener diodes 20 and 23 suppress reverse breakdown of the input side LEDs of the photocouplers 18 and 21 to prevent breakdown, and bypass current consumption of the circuit by the resistors 19 and 22. By setting the Zener voltage as low as 2 to 3 V within a range that does not affect the drive of the power supply 18 and 21, voltage drop can be suppressed and loss as a rectifier circuit can be prevented.

  The output side transistors of the photocouplers 18 and 21 are connected in series, and the series circuit constitutes an AND circuit that can obtain an AND output of the output of each output side transistor. Therefore, when the test switch 17 is turned on, the transistor 25 of the test current drive circuit 13 is turned on only when both the photocouplers 18 and 21 are turned on, and the resistance 26 and transistor 25 from the DC control voltage VS from the power supply circuit 9 are turned on. A test current can be passed through the tertiary winding 6b of the zero-phase current transformer 6 via the.

The series of operations of the earth leakage test of the earth leakage breaker 1 is exactly the same as the operations shown in FIGS. 3 to 6 described in the first embodiment.

  As described above, according to the earth leakage breaker according to the second embodiment of the present invention, the test circuit that can operate even when one phase is lost with relatively few parts or only with small parts. Can be configured. If the test current flowing through the tertiary winding 6b is relatively small, a photocoupler with good conversion efficiency is used for the photocouplers 18 and 21, thereby omitting the switching transistor 25 and the photocouplers 18 and 21. It is also possible to directly switch the DC control voltage VS with the output transistor, and in this case, the number of components can be further reduced.

Embodiment 3 FIG.
FIG. 8 is a circuit diagram showing a leakage breaker according to Embodiment 3 of the present invention. In FIG. 8, the cathodes of the rectifier diodes D1 and D2 constituting the R-phase and S-phase positive arms of the three-phase full-wave rectifier circuit 10 are connected to a resistor 27 for stepping down the cathode voltage. At the same time, it is connected to the anode of the backflow prevention diode 28. The cathode of the backflow prevention diode 28 is connected to the cathode of the rectifier diode D3 constituting the T-phase positive arm.

  On the other hand, the anodes of the rectifier diodes D5 and D6 constituting the S-phase and T-phase negative-side arms of the full-wave rectifier circuit 10 are connected to the emitter of the first transistor 29 composed of an NPN transistor, The base of the first transistor 29 is connected to the ground line GND through the resistor 30 together with the anode of the rectifier diode D4 that constitutes the R-phase negative arm. Further, in order to prevent reverse bias between the base and emitter of the first transistor 29 and to limit the base current of the first transistor 29, the anode connection point of the rectifier diodes D5 and D6 and the ground line GND. A zener diode 31 is inserted between them. The collector of the first transistor 29 is connected to the emitter of the second transistor 32, which is composed of an NPN transistor whose base is connected to one end of the resistor 27.

  The first transistor 29, the Zener diode 31, and the resistor 30 correspond to the negative electrode side detector 16 in the first and second embodiments. The resistor 27 and the second transistor 32 correspond to the positive electrode detector 15 in the first and second embodiments. The second transistor 32 also functions as an AND circuit as will be described later.

  The collector of the second transistor 32 is connected to the base of a third transistor 34 constituted by a PNP type transistor via a resistor 33, and the collector current of the third transistor 34 that has been subjected to current amplification is connected to the resistor 35 and the test. The signal is input to the base of the transistor 25 constituting the test drive circuit 13 via the switch 17.

  The reverse current blocking diode 28, the Zener diodes 31, 36, the resistors 27, 30, 33, 35, the first transistor 29, the second transistor 32, the third transistor 34, and the test current drive circuit 13 are described in the embodiment. 3 constitutes a test circuit for the earth leakage circuit breaker 1 according to FIG. In addition, the other structure is the same as that of the earth-leakage circuit breaker of Embodiment 2 of FIG.

  The ground fault circuit breaker 1 according to Embodiment 3 of the present invention configured as described above has a zero phase current transformer 6 when a ground fault occurs in the AC circuit where the ground fault is to be detected and a ground fault current flows in the main circuit. Detection current is output from the secondary winding 6 a and input to the leakage detection circuit 7. The leakage detection circuit 7 detects the occurrence of leakage based on the input detection current, supplies the DC control voltage VS stepped down by the power supply circuit 9 to the trip device 8 and activates it. The biased tripping device 8 trips the opening / closing mechanism of the opening / closing part 5 and shuts off the main circuit 4.

  Next, the operation of the leakage test of the leakage breaker 1 will be described. The cathode voltages of the rectifier diodes D1 and D2 constituting the positive arm of the three-phase full-wave rectifier circuit 10 are stepped down by the resistor 27 and become the base current of the second transistor 32. Here, the cathode potential of the rectifier diodes D1 and D2 is higher than the potential of the ground line GND when the anode potential of either the rectifier diode D1 or D2 is increased, and the period Is equal to the period during which one of the rectifier diodes D1 and D2 is in a conductive state. Accordingly, the base current is supplied to the second transistor 32 only during a period in which the rectifier diode D1 or the rectifier diode D2 is in a conductive state.

  On the other hand, since the emitter of the first transistor 29 on the negative electrode side is connected to the rectifier diodes D5 and D6 and the base is connected to the ground line GND through the resistor 30, the first transistor 29 is connected to the rectifier diode D5 or the rectifier diode D6. When current flows, the collector current of the first transistor 29 flows.

  Here, since the collector of the first transistor 29 is connected to the emitter of the second transistor 32, the second transistor 32 is turned on because the first transistor 29 is turned on and the resistor This is a period in which the base current from 27 is supplied. This is a period in which the rectifier diode D1 or rectifier diode D2 is in a conductive state and the rectifier diode D5 or rectifier diode D6 is in a conductive state. This is the same as the output of the AND circuit 14 or the output of the AND circuit composed of the output side transistors of the photocouplers 18 and 21 described in the second embodiment.

  The third transistor 34 amplifies the collector current of the second transistor 32 and makes the waveform a complete pulse waveform. The output of the third transistor 34, that is, its collector current is used as the test current drive circuit 13. , The same test current as in the first and second embodiments can be obtained.

  According to the leakage breaker according to Embodiment 3 of the present invention described above, a test circuit capable of operating even when one phase is lost can be configured by a general-purpose transistor or resistor that operates with a small signal. The circuit space is equivalent to the case where the photocoupler in Embodiment 2 is used, and a stable operation can be expected from the photocoupler when used at a high temperature.

Embodiment 4 FIG.
FIG. 9 is a circuit diagram showing an earth leakage breaker according to Embodiment 4 of the present invention. The test circuit for earth leakage breaker 1 is an arbitrary rectifier diode that constitutes three-phase full-wave rectifier circuit 10. The AC component of the main circuit 4 is obtained from a rectifier diode connected to the two-phase ground line side.

  In FIG. 9, among the rectifier diodes constituting the three-phase full-wave rectifier circuit 10, the base-emitter of the transistor 29 is connected to the ground line of the T-phase rectifier diode D6 as an arbitrary one phase. And a resistor 30 are inserted in series, and a Zener diode 31 is connected in parallel to the series connector. In addition, a series connection body of the base / emitter of the transistor 37 and the resistor 38 is inserted at the connection point to the ground line of the R phase rectifier diode D4 as another arbitrary one phase excluding the arbitrary one phase, A zener diode 39 is connected in parallel to the series connection body.

  The configuration and operation of the transistor 29, the resistor 30, and the Zener diode 31 connected to the T-phase rectifier diode D6 are the same as those of the first transistor 29, the resistor 30, and the Zener diode 31 described in the third embodiment. Although the structure and operation are similar, the difference from the third embodiment is that the series connection body of the base / emitter of the transistor 29 and the resistor 30 and the Zener diode 31 are connected only to the T-phase rectifier diode D6. The S-phase rectifier diode D5 is directly connected to the ground line GND, and the configuration and operation of the transistor 37, resistor 38, and Zener diode 39 connected to the R-phase rectifier diode D4 are also connected. The configuration and operation of the transistor 29, the resistor 30, and the transistor are the same except that the phases are different. The same as the configuration and operation according to over diode 31.

  The collector of the transistor 37 is connected to the base of the transistor 25 via a resistor 40 and a diode 42. Similarly, the collector of the transistor 29 is connected to the base of the transistor 25 via the resistor 41 and the diode 43, the transistor 25 is turned on in conjunction with the ON operation of the transistor 37 and the transistor 29, and the zero phase change is performed via the resistor 26. The test current is configured to flow through the tertiary winding 6 b of the flow device 6.

  A resistor 44 is connected to the collector of the transistor 37 together with the resistor 40, and the collector current of the transistor 37 flows through the resistor 44 to the PNP transistor 46 and the capacitor 47 having the resistor 45 connected in series to the base. It is configured. The emitter of the transistor 46 is connected to the DC control voltage VS through the test switch 17 together with one end of the capacitor 47 and the emitter of the transistor 25, and the collector of the transistor 46 is connected to the connection point of the resistor 41 and the diode 43.

  Transistors 25, 29, 37, and 46, resistors 26, 30, 38, 40, 41, 44, and 45, Zener diodes 31 and 39, diodes 42 and 43, and a capacitor 47 are included in the leakage breaker 1 according to the fourth embodiment. A test circuit is configured. Other configurations are the same as those of the ground fault circuit breakers of the first to third embodiments.

  In FIG. 9, the transistors 29 and 37, the resistors 30 and 38, and the Zener diodes 31 and 39 are arranged on the negative side arm of the R phase and the T phase. Any two phases of the arm may be used, and the arrangement is not limited to that shown in FIG.

  The leakage breaker 1 according to the fourth embodiment of the present invention configured as described above has a zero-phase current transformer 6 when a leakage occurs in the AC circuit where leakage is to be detected and a leakage current flows in the main circuit. The detected current is output from the secondary winding 6a to the leakage detection circuit 7 from which the detected current is output. The leakage detection circuit 7 detects the occurrence of leakage based on the input detection current, supplies the DC control voltage VS stepped down by the power supply circuit 9 to the trip device 8 and activates it. The biased tripping device 8 trips the opening / closing mechanism of the opening / closing part 5 and shuts off the main circuit 4.

  Next, the operation of the leakage test of the leakage breaker 1 in the fourth embodiment will be described. FIG. 10 is a waveform diagram showing waveforms at various parts in a test operation in a normal energized state, where (a) is a current flowing through the rectifier diode D4, (b) is a current flowing through the rectifier diode D6, and (c) is a transistor. (D) is the collector current of the transistor 29, (e) is the voltage across the capacitor 47, (f) is the current flowing through the diode 42, (g) is the current flowing through the diode 43, and (h) is the transistor 25 shows a base current of 25, and (i) shows a collector current of the transistor 25 as a test current.

  FIG. 10A shows the current flowing through the rectifier diode D4. When a three-phase AC power supply is input, each of the rectifier diodes constituting the three-phase full-wave rectifier circuit 10 is shown in FIG. A current having a conduction angle of 120 ° flows. Similarly, FIG. 10B shows the current flowing through the rectifier diode D6, which has a 120 ° phase difference from the current flowing through the rectifier diode D4 shown in FIG.

  FIG. 10C shows the collector current of the transistor 37 connected to the rectifier diode D4. Since the emitter of the transistor 37 is connected to the rectifier diode D4 and the base is connected to the ground line GND via the resistor 38, the collector current of the transistor 37 flows when a current flows through the rectifier diode D4. Since the transistor 37 is turned on with a slight base current due to its amplification factor, the collector current of the transistor 37 has a pulse waveform synchronized with the conduction of the rectifier diode D4 as shown in FIG.

  FIG. 10 (d) shows the collector current of the transistor 29 connected to the rectifier diode D6. Since the emitter of the transistor 29 is connected to the rectifier diode D6 and the base is connected to the ground line GND via the resistor 30, the collector current of the transistor 29 flows when a current flows through the rectifier diode D6. Since the transistor 29 is turned on with a slight base current due to its amplification factor, the collector current of the transistor 29 has a pulse waveform synchronized with the conduction of the rectifier diode D6 as shown in FIG.

  The collector current of the transistor 29 becomes the base current of the transistor 25 through the resistor 41 and the diode 43, while the collector current of the transistor 37 has the resistance flowing together with the current flowing to the base of the transistor 25 through the resistor 40 and the diode 42. The current flows through a transistor 46 and a capacitor 47 having a resistor 45 connected in series to the base via 44, turning on the transistor 46 and charging the capacitor 47.

  As shown in FIG. 10 (e), the capacitor 47 is charged while the transistor 46 is in the on state, that is, the conduction period of the rectifier diode D4, and is discharged when the transistor 46 is in the off state, that is, the rectifier diode D4 is not conducting. The The charge / discharge time constant of the capacitor 47 is set to a predetermined time constant according to the capacitance of the capacitor 47 and the resistance values of the resistors 44 and 45. During the discharge of the capacitor 47, the charge of the capacitor 47 is reduced to the resistor 45. So that the voltage across the capacitor 47 is not lower than the base-emitter voltage (about 0.6 V) of the transistor 46 shown by the broken line in FIG. 10 (e). The transistor 46 remains on.

  Since the collector of the transistor 46 is connected to the connection point of the resistor 41 and the diode 43, when the transistor 46 is in the ON state, the diode 43 is in a reverse bias state, and the collector current of the transistor 29 does not flow to the diode 43. The current flows to the collector of the transistor 46. Accordingly, as shown in FIGS. 10F and 10G, when the transistor 37 is turned on, the signal from the transistor 29 is canceled for a certain period, so that the signal flows only to the diode 42 and the diode 43 No signal flows.

  Since the diodes 42 and 43 are diodes OR with respect to the base of the transistor 25, the base current of the transistor 25 is the same as the current flowing through the diode 42 as shown in FIG. Therefore, the test current obtained by the switching operation of the transistor 25 has a waveform with a duty ratio of about 33% synchronized with the conduction phase of the rectifier diode D4, as indicated by the solid line in FIG.

  Next, the operation of the earth leakage test of the earth leakage breaker 1 in a state where a phase failure has occurred in the three-phase AC power source will be described. FIG. 11 is a waveform diagram for explaining the operation when the R phase of the three-phase AC power supply is lost in the configuration shown in FIG. 9, where (a) shows the current flowing through the rectifier diode D4, b) is the current flowing through the rectifier diode D6, (c) is the collector current of the transistor 37, (d) is the collector current of the transistor 29, (e) is the voltage across the capacitor 47, (f) is the current flowing through the diode 42, (G) indicates the current flowing through the diode 43, (h) indicates the base current of the transistor 25, and (i) indicates the collector current of the transistor 25 that is the test current.

  When the R phase is lost, the control power supply to the earth leakage circuit breaker 1 becomes the single phase voltage of the ST phase of the main circuit 4, and a current flows through the rectifier diode D4 as shown in FIG. A current having a half-wave waveform flows through the rectifier diode D6 as shown in FIG. Therefore, the collector current of the transistor 37 does not flow as shown in FIG. 11C, and only the collector current of the transistor 29 flows as shown in FIG. 11D.

  As described above, since the collector current of the transistor 37 does not flow, the voltage across the capacitor 47 does not rise as shown in FIG. 11E, and the transistor 46 also remains off. Is not canceled, and the collector current of the transistor 29 flows to the base of the transistor 25 via the diode 43 as shown in FIGS. The base current of the transistor 25 is the same as the current flowing through the diode 43 as shown in FIG. Therefore, the test current obtained by the switching operation of the transistor 25 has a half-wave waveform with a duty ratio of about 50% in the same phase as the conduction phase of the rectifier diode D6, as shown by the solid line in FIG.

  Note that the waveform of FIG. 11 (i) shows the test current when the transistor 25 switches the non-smoothed DC control voltage VS that has just been stepped down by the power supply circuit 9, but the DC control voltage VS is sufficient. If smoothed, the test current can be a rectangular wave with a duty ratio of about 50%.

  Next, a leakage test operation in a state where the S phase of the main circuit 4 is lost will be described. FIG. 12 is a waveform diagram for explaining the operation in the case where the S phase of the three-phase power supply is lost in the configuration shown in FIG. 9, where (a) shows the current flowing through the rectifier diode D4, (b ) Is the current flowing through the rectifier diode D6, (c) is the collector current of the transistor 37, (d) is the collector current of the transistor 29, (e) is the voltage across the capacitor 47, (f) is the current flowing through the diode 42, ( g) indicates the current flowing through the diode 43, (h) indicates the base current of the transistor 25, and (i) indicates the collector current of the transistor 25 that is the test current.

  When the S phase is lost, the supply of the control power to the earth leakage breaker 1 becomes a single-phase voltage of the R-T phase of the main circuit 4, and the rectifier diodes D4 and D6 have (a) and (b) in FIG. As shown in FIG. 2, half-wave currents flow. Therefore, the collector currents of the transistors 37 and 29 have a current waveform in which pulses having opposite phases alternately appear as shown in FIGS.

  When a collector current having a pulse waveform flows through the transistor 37, the voltage across the capacitor 47 also has a waveform that repeats charging and discharging as shown in FIG. 12E. By maintaining the transistor 46 in the ON state, the voltage of FIG. As shown in (f) and (g), the signal on the diode 43 side is canceled, and only the signal on the diode 42 side is inputted to the base of the transistor 25 as shown in (h) of FIG. Therefore, the test current obtained by the switching operation of the transistor 25 has a half-wave waveform with a duty ratio of about 50% in the same phase as the conduction phase of the rectifier diode D4, as shown by the solid line in FIG.

  Next, the leakage test operation in the state where the T phase of the main circuit 4 is lost will be described. FIG. 13 is a waveform diagram for explaining the operation when the T-phase of the three-phase power supply is lost in the configuration shown in FIG. 9, where (a) shows the current flowing through the rectifier diode D4, ) Is the current flowing through the rectifier diode D6, (c) is the collector current of the transistor 37, (d) is the collector current of the transistor 29, (e) is the voltage across the capacitor 47, (f) is the current flowing through the diode 42, ( g) indicates the current flowing through the diode 43, (h) indicates the base current of the transistor 25, and (i) indicates the collector current of the transistor 25 that is the test current.

  When the T phase is lost, the supply of the control power to the earth leakage breaker 1 becomes a single-phase voltage of the RS phase of the main circuit 4, and rectification is performed as shown in FIGS. 13 (a) and 13 (b). A half-wave waveform current flows through the diode D4, but a half-wave waveform current does not flow through the rectifier diode D6. Therefore, as shown in FIGS. 13C and 13D, only the collector current of the transistor 37 flows, and the collector current of the transistor 29 does not flow.

  Since the collector current flows through the transistor 37, the voltage across the capacitor 47 is repeatedly charged and discharged as shown in FIG. 13E, and the transistor 46 is turned on to cancel the signal on the diode 43 side. Since the collector current does not originally flow through the transistor 29, only the collector current of the transistor 37 passes through the diode 42 as shown in FIG. 13 (h) as shown in FIGS. 13 (f) and 13 (g). And flows to the base of the transistor 25. Therefore, the test current obtained by the switching operation of the transistor 25 has a half-wave waveform with a duty ratio of about 50% in the same phase as the conduction phase of the rectifier diode D4, as shown by the solid line in FIG.

  As described above, according to the leakage breaker according to the fourth embodiment of the present invention, all the parts constituting the test circuit can be suppressed to a low voltage equal to or lower than the DC control voltage VS, and small signal parts are used. As a result, the circuit space can be reduced.

  In a normal state where there is no open phase in the three-phase AC circuit, the duty ratio of the test current is as small as about 33%. However, even if the duty ratio is about 33%, the leakage detection circuit 7 can detect leakage. However, since the energy consumption of the test current can be suppressed only by reducing the duty ratio, it is possible to reduce the capacity of the power supply circuit 9 and the components constituting the test circuit.

Embodiment 5 FIG.
In the first to fourth embodiments, the earth leakage circuit breaker capable of performing an earth leakage test operation even when one phase of the three-phase AC power supply is lost is shown. Therefore, it is not necessary to be able to perform a leakage test operation. In some cases, it is possible to perform a leakage breaker test operation as a means for determining an open phase accident.

  FIG. 14 shows an earth leakage circuit breaker according to Embodiment 5 of the present invention. The test circuit of earth leakage circuit breaker 1 is a main circuit only from a T phase which is a predetermined one phase among three-phase AC power supplies. 4 AC components are obtained. In FIG. 14, among the rectifier diodes constituting the three-phase full-wave rectifier circuit 10, the base emitter of the transistor 29 is connected to the ground line of the T-phase rectifier diode D6 as a predetermined one phase. And a resistor 30 are inserted in series, and a Zener diode 31 is connected in parallel to the series connector.

  The configuration and operation of the above-described transistor 29, resistor 30, and Zener diode 31 are the same as the configuration and operation of the first transistor 29, resistor 30, and Zener diode 31 described in the fourth embodiment. The difference from the fourth embodiment is that there is no circuit for detecting the conduction state of the rectifier diode D4, and only the conduction of the rectifier diode D6 is detected.

  The collector of the transistor 29 is connected to the base of the transistor 34 via the resistor 33, the transistor 34 is turned on in conjunction with the ON operation of the transistor 29, and the tertiary winding 6 b of the zero-phase current transformer 6 is connected via the resistor 26. Is configured so that a test current flows therethrough. Zener diode 31, resistors 26, 30 and 33, and transistors 29 and 34 constitute a test circuit for earth leakage circuit breaker 1 according to the fifth embodiment. Other configurations are the same as those of the earth leakage breakers of the first to fourth embodiments.

  The earth leakage breaker 1 according to the fifth embodiment of the present invention configured as described above has a zero-phase current transformer 6 when an earth leakage occurs in the AC circuit where the earth leakage should be detected and the earth leakage current flows in the main circuit. Detection current is output from the secondary winding 6 a and input to the leakage detection circuit 7. The leakage detection circuit 7 detects the occurrence of leakage based on the input detection current, supplies the DC control voltage VS stepped down by the power supply circuit 9 to the trip device 8 and activates it. The biased tripping device 8 trips the opening / closing mechanism of the opening / closing part 5 and shuts off the main circuit 4.

  In the test circuit configured as described above, the transistor 29 is turned on only during the period when the current flows through the rectifier diode D6, and the transistor 34 is turned on when the transistor 29 is turned on. Thus, the transistor 34 performs an on / off operation in synchronization with the on / off operation of the transistor 29, and switches the DC control voltage VS from the power supply circuit 9 to generate a test current. Accordingly, the test current when the three-phase AC power is supplied to the main circuit 4 is the same as the waveform shown in FIG. 10 (i), and a test current having a duty ratio of about 33% can be obtained. it can. Further, the test current in the state in which the R phase or the S phase is lost can obtain a test current having a duty ratio of 50% which is the same as (i) in FIG. 11 and (i) in FIG. Of course, when the T phase is lost, no test current is generated.

  In FIG. 14, the portion corresponding to the test current drive circuit 13 of the third embodiment shown in FIG. 8 is omitted, and the test current is directly driven by the transistor 34. This is because the collector current of the transistor 29 can be set larger than in the case of the third embodiment, and thereby the base current of the transistor 34 can be sufficiently secured. The transistor 29 having a high allowable collector current and a high amplification factor is used. If possible, the test current can be directly driven by the transistor 29.

  In FIG. 14, the test switch 17 is provided on the power supply line from the output terminal of the power supply circuit 9 to the transistor 34, but in addition to this, the transistor 29 to the tertiary winding 6 b of the zero-phase current transformer 6. Needless to say, even if the test signal is provided at a location where the test signal can be opened and closed, it functions as a test switch.

  As described above, according to the leakage breaker according to Embodiment 5 shown in FIG. 9, the test circuit does not perform the test operation when a specific one phase to which the test circuit is connected out of the three-phase power supply is lost. However, since all the components of the test circuit can be suppressed to the DC control voltage VS or less, and small-signal components can be used, power resistors are connected between the phases of the main circuit that have been conventionally used in test circuits. Therefore, the circuit space can be reduced as compared with the method for obtaining the test current. Also, a test switch that requires a withstand voltage higher than the main circuit voltage can use an inexpensive general-purpose switch with a small signal and a low voltage, so that it can be reduced in size and reduced in cost.

  Moreover, the earth leakage circuit breaker according to the fourth embodiment can be applied to an earth leakage circuit breaker for a single phase, but in that case, if one phase is lost, the earth leakage circuit breaker itself loses its function. Therefore, the ground fault circuit breaker according to the fifth embodiment, which obtains a test signal from only one phase, is reasonable and a great effect can be expected.

Embodiment 6 FIG.
FIG. 15 is a circuit diagram showing an electric leakage breaker according to Embodiment 6 of the present invention. In FIG. 15, the smoothing capacitor 48 smoothes the control power supplied from the DC control voltage VS from the power supply circuit 9 to the leakage detection circuit 7 via the diode 49, and further improves the initial drive of the trip device 8. It also serves as a backup capacitor to ensure that it is performed. The control power for the test current drive circuit 13 is supplied from the anode side of the diode 49, that is, the control power terminal side.

  With the above configuration, the electric energy necessary for generating the test current is supplied only from the DC control voltage VS of the power supply circuit 9, and the charge of the smoothing capacitor 48 is not consumed for generating the test current. A stable operation of the removal device 8 can be expected. In addition, when switching a non-smoothed control power supply, the test current waveform is obtained as a half-wave rectified waveform of the main circuit voltage, whereas when switching a smoothed control power supply, the test current waveform The waveform is close to a square wave. As a test function, there is no problem with either waveform, but switching the unsmoothed control power supply leaves more frequency components of the original main circuit voltage. It can be said that it is desirable to supply from the DC control voltage VS before smoothing as in the sixth embodiment.

  Next, in FIG. 15, the NOT circuit 50 has one end connected to the output side of the leakage detection circuit 7 and the other end connected to one end of the delay circuit 51. The other end of the delay circuit 51 is connected to one input terminal of the AND circuit 14. The delay circuit 51 is configured such that the output has a predetermined time delay only at the rising edge. The one-pulse circuit 52 outputs only when the test switch 17 is continuously turned on, and does not return to the initial state unless the test switch 17 is turned off or a sufficient pause time has elapsed. It is configured as follows.

  The positive detector 15, the negative detector 16, the AND circuit 14, the delay circuit 51, the NOT circuit 50, the test current drive circuit 13, the one pulse circuit 52, the test switch 17, etc. The test circuit of the device 1 is configured. In addition, the other structure is the same as that of the earth-leakage circuit breaker which concerns on Embodiment 1. FIG.

  The earth leakage breaker 1 according to Embodiment 6 of the present invention configured as described above has a zero-phase current transformer 6 when the earth leakage occurs in the AC circuit where the earth leakage should be detected and the earth leakage current flows in the main circuit. Detection current is output from the secondary winding 6 a and input to the leakage detection circuit 7. The leakage detection circuit 7 detects the occurrence of leakage based on the input detection current, supplies the DC control voltage VS stepped down by the power supply circuit 9 to the trip device 8 and activates it. The biased tripping device 8 trips the opening / closing mechanism of the opening / closing part 5 and shuts off the main circuit 4.

  Next, the operation of the test circuit after the leakage detection circuit 7 detects the test current and the tripping device 8 starts to be driven by this output will be described. The output of the leakage detection circuit 7 is sent to the trip device 8 and also sent to the input of the AND circuit 14 via the NOT circuit 50 and the delay circuit 51. The NOT circuit 50 simply inverts the logic, but in a state where the leakage detection circuit 7 does not output, that is, in a steady state, the output of the NOT circuit 50 is at the H level, and the AND circuit 14 becomes active. On the contrary, when the leakage detection circuit 7 detects leakage and is in the output state due to the test operation or the occurrence of a leakage accident, the output of the NOT circuit 50 becomes L level, and the AND circuit 14 is not output regardless of other input states. Therefore, even if the test button 17 is turned on in this state, no test current is generated.

  The delay circuit 51 is a circuit whose output has a predetermined time delay only at the rising edge, and only when the output of the NOT circuit 50 changes from L level to H level, that is, the leakage detection circuit 7 changes from the output state to the steady state. Only when returning, the timing is delayed and a signal is sent to the input of the AND circuit 14, so that the function of the test operation is stopped for a predetermined time after the leakage detection circuit 7 outputs.

  In general, in a state in which the power supply side and the load side of the earth leakage breaker 1 are connected in reverse (a state generally called reverse connection of the power load), the control power supply even after the earth leakage breaker 1 operates. Therefore, even if the output of the leakage detection circuit 7 is a one-pulse output circuit, if the test switch 7 is kept turned on, the leakage detection and tripping are repeated to repeat the trip device 8 and the power supply circuit. However, according to the leakage breaker according to the sixth embodiment, since the delay circuit 51 is provided, the return of the test function is delayed, and consequently the excitation time of the trip device 8 is reduced. Thus, the pause time can be extended, and the tripping device 8 and the power supply circuit 9 can be prevented from being burned out.

  As described above, the delay circuit 51 prevents burning of the trip device 8 and the power supply circuit 9 when the test switch 7 is continuously turned on when the power supply load is reversely connected. However, the delay circuit 51 increases the delay time. If set, there may be a problem that the test operation is not performed by temporarily repeating the test operation for a short time, and it may be difficult to reliably prevent burning.

  Therefore, the one-pulse circuit 52 outputs only the moment when the test switch 7 is continuously turned on even if the test switch 7 is continuously turned on. If the test switch 7 is turned off once or a sufficient pause time has not elapsed, The test operation is performed only once immediately after the test switch 7 is turned on by passing the signal of the test switch 7 through the one-pulse circuit 52, and even when the test switch 7 is left on. It becomes possible to repeat with sufficient intervals and to surely prevent the tripping device 8 and the power supply circuit 9 from being burned out.

  According to the leakage breaker according to the sixth embodiment of the present invention described above, it is possible to prevent the trip device 8 and the power circuit 9 from being burned out when the test switch 7 is continuously turned on when the power load is reversely connected. In addition, even when the test switch 7 is left on, it is possible to reliably prevent the trip device 8 and the power supply circuit 9 from being burned out.

  In the first to fifth embodiments, as in the case of the sixth embodiment, a smoothing capacitor for smoothing the output of the power supply circuit is provided, and the electric charge of the smoothing capacitor is consumed as the test current during the test operation. It is also possible to connect a diode in series with the smoothing capacitor so that this is not done.

  In the first to fifth embodiments, as in the sixth embodiment, the test circuit stops the function of generating the test current while the trip device is driven based on the output of the leakage detection circuit. Further, as in the case of the sixth embodiment, there is a time delay in returning the stopped function of the test circuit for a predetermined time after the trip device is driven. It is also possible to

  Further, in the first to fifth embodiments, as in the case of the sixth embodiment, the test circuit may include a one-pulse circuit that generates a test current only for a predetermined time during a test operation.

It is a circuit diagram which shows the earth-leakage circuit breaker by Embodiment 1 of this invention. It is a wave form diagram which shows the waveform of the electric current which flows into the rectifier diode of the earth leakage circuit breaker by Embodiment 1 of this invention. It is a wave form diagram which shows the waveform of each part in the test operation in the normal state of the earth leakage circuit breaker by Embodiment 1 of this invention. It is a wave form diagram which shows the waveform of each part in the test operation in the state where the R phase of the earth leakage circuit breaker according to Embodiment 1 of the present invention is open. It is a wave form diagram which shows the waveform of each part in the test operation in the state which the S phase of the earth-leakage circuit breaker by Embodiment 1 of this invention has lost phase. It is a wave form diagram which shows the waveform of each part in the test operation in the state which the phase T of the earth leakage circuit breaker by Embodiment 1 of this invention has missing. It is a circuit diagram which shows the earth-leakage circuit breaker by Embodiment 2 of this invention. It is a circuit diagram which shows the earth-leakage circuit breaker by Embodiment 3 of this invention. It is a circuit diagram which shows the earth-leakage circuit breaker by Embodiment 4 of this invention. It is a wave form diagram which shows the waveform of each part in the test operation in the normal state of the earth leakage circuit breaker by Embodiment 4 of this invention. It is a wave form diagram which shows the waveform of each part in the test operation | movement in the state which the R phase of the earth-leakage circuit breaker by Embodiment 4 of this invention has missing. It is a wave form diagram which shows the waveform of each part in the test operation in the state which the S phase of the earth-leakage circuit breaker by Embodiment 4 of this invention has missing. It is a wave form diagram which shows the waveform of each part in the test operation | movement in the state which the T phase of the earth-leakage circuit breaker by Embodiment 4 of this invention has lost phase. It is a circuit diagram which shows the earth-leakage circuit breaker by Embodiment 5 of this invention. It is a circuit diagram which shows the earth-leakage circuit breaker by Embodiment 6 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Earth leakage breaker 2 Power supply side connection terminal 3 Load side connection terminal 4 Main circuit 5 Opening and closing part 6 Zero phase current transformer 6a Secondary winding 6b Tertiary winding 7 Leakage detection circuit 8 Tripping device 9 Power supply circuit 10 Three-phase all Wave rectifier circuit 11 Impedance element 12 Voltage suppression element 13 Test current drive circuit 14 AND circuit 15 Positive side detector 16 Negative side detector 17 Test switch 18, 21 Photocoupler 19, 22, 24, 26, 27, 30, 33, 35, 38, 40, 41, 44, 45
Resistance 20, 23, 31, 36, 39 Zener diode,
25, 29, 32, 34, 37, 46 Transistor 28, 42, 43, 49 Diode 47 Capacitor 48 Smoothing capacitor 50 NOT circuit 51 Delay circuit 52 One-pulse circuit

Claims (12)

  A main circuit connected to an AC circuit; an open / close unit that opens and closes the main circuit; a secondary winding that generates an output current based on a leakage current flowing through the main circuit; A zero-phase current transformer having a tertiary winding for generating an output current in a secondary winding; a test circuit for supplying the test current to the tertiary winding during a test operation; and a secondary of the zero-phase current transformer A leakage detection circuit that generates an output signal based on an output current of the winding; a tripping device that is driven based on the output signal of the leakage detection circuit to trip the open / close portion and shut off the main circuit; and the leakage A power supply circuit that supplies power to the detection circuit and the trip device, and a full-wave rectified AC voltage applied to the main circuit that is composed of a plurality of bridge-connected rectifier diodes and outputs a DC voltage. A wave rectifier circuit, A source circuit supplies a predetermined DC control voltage generated by receiving the DC voltage output from the full-wave rectifier circuit to the leakage detection circuit and the trip device, and the test circuit A current having a phase synchronized with the phase of the alternating current flowing in the main circuit is generated by detecting an energization current or an applied voltage of at least one of the plurality of rectifier diodes constituting the wave rectifier circuit. The earth leakage circuit breaker is characterized in that the generated current is supplied to the tertiary winding as the test current.   The main circuit is constituted by a three-phase electric circuit to which a three-phase AC voltage is applied, the full-wave rectifier circuit is constituted by a three-phase full-wave rectifier circuit, and the test circuit is a positive side of the three-phase full-wave rectifier circuit A positive detector for detecting energization of two rectifier diodes connected to any two phases among a plurality of rectifier diodes constituting the arm, and a negative arm of the three-phase full-wave rectifier circuit are configured. Energization of two rectifier diodes respectively connected to one of the plurality of rectifier diodes other than the two arbitrary phases and one of the two arbitrary phases. The DC control in synchronization with the detection of the negative electrode side to be detected and the detection of the energization by the positive electrode side detector and the detection of the energization by the negative electrode side detector in synchronism with each other Switching voltage Earth leakage breaker according to claim 1, characterized in that a test current driving circuit for generating the test current by.   The positive-side detector and the negative-side detector are each configured by a photocoupler having a switching element whose conduction state changes when the rectifier diode is energized, and the test current drive circuit is a switching element of the respective photocoupler The earth leakage circuit breaker according to claim 2, wherein the DC control voltage is switched based on a drive signal input through a circuit connected in series.   The negative detector includes at least a part of energization currents of two rectifier diodes connected to any two phases among a plurality of rectifier diodes constituting a negative arm of the three-phase full-wave rectifier circuit. A first transistor that conducts when supplied as a base current, wherein the positive-side detector includes any two of the plurality of rectifier diodes that constitute the positive-side arm of the three-phase full-wave rectifier circuit; A base current is supplied based on a voltage applied to two rectifier diodes connected to one phase other than the phase and any one of the two arbitrary phases, and the first A second transistor that is turned on when the transistor is turned on; and the test current drive circuit switches the DC control voltage based on a turned-on state of the second transistor. Earth leakage breaker according to claim 2, characterized in that to generate the strike current.   The test circuit is based on at least a part of the energization current of each of the two rectifier diodes connected to any two phases of the plurality of rectifier diodes constituting the negative arm of the full-wave rectifier circuit. Each of the transistors that are turned on when supplied as a current and the test current is generated by switching the DC control voltage based on the conduction state of each of the transistors, and one of the two rectifier diodes The leakage current according to claim 1, further comprising: a test current driving circuit that suppresses a signal that conveys the conduction state of the other rectifier diode for a predetermined time when one rectifier diode is in the conduction state. Circuit breaker.   The test circuit includes a detection circuit that detects an energization of any one of a plurality of rectifier diodes constituting a negative arm of the full-wave rectifier circuit and generates an output signal, and the detection circuit The leakage detector according to claim 1, wherein the test current is generated by switching the DC control voltage generated by the power supply circuit based on an output signal generated by the power supply circuit.   In the detection circuit, a base and an emitter are inserted in series between a rectifier diode that constitutes one negative-side arm of the full-wave rectifier circuit and a negative-side output terminal of the full-wave rectifier circuit. The earth leakage breaker according to claim 6, further comprising a transistor that is driven by using at least a part of the energization current as a base current, and the collector current of the transistor is the output signal.   The power supply circuit supplies a DC voltage obtained by stepping down the DC voltage output from the full-wave rectifier circuit to a predetermined voltage as the DC control voltage to the leakage detection circuit and the trip device, and the test circuit includes: The earth leakage circuit breaker according to any one of claims 1 to 7, wherein the test current is generated by switching the DC control voltage.   A smoothing capacitor for smoothing a current flowing through the leakage detection circuit and the trip device by supplying the DC control voltage, and a diode for preventing the charge of the smoothing capacitor from being consumed as the test current during the test operation; The earth leakage circuit breaker according to any one of claims 1 to 8, further comprising:   10. The function of generating the test current in the test circuit is stopped while the trip device is driven based on the output of the leakage detection circuit. The earth leakage breaker described.   11. The method according to claim 10, wherein after the trip device is driven, a time delay is provided in the return of the function of generating the stopped test current in the test circuit for a predetermined time. Earth leakage circuit breaker.   The earth leakage circuit breaker according to any one of claims 1 to 9, wherein the test circuit includes a one-pulse circuit that generates the test current only for a predetermined time during the test operation.

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