JP5669100B2 - Earth leakage breaker - Google Patents

Description

  The present invention relates to a leakage breaker that detects a leakage or overcurrent and interrupts a main circuit.

  Conventionally, when a leakage or overcurrent has occurred in the main circuit, or when a neutral wire missing phase (N-phase missing phase) has occurred, the earth leakage circuit breaker is in either case of leakage detection or phase loss detection. In addition, the opening and closing of the main circuit was controlled using a common electromagnetic release mechanism. With this control, the conventional earth leakage breaker forcibly opens the main circuit. Furthermore, the conventional earth leakage circuit breaker has displayed the earth leakage state or the phase loss state by using a display member that can display the earth leakage and phase loss in common when the main circuit is forcibly opened.

  In such a conventional earth leakage breaker, since the same electromagnetic release mechanism and display member are used for the earth leakage and the open phase, the earth leakage occurs when the main circuit is forcibly opened, or There is a problem that it is difficult to determine whether a phase failure has occurred.

  For solving this problem, for example, Patent Document 1 is known. The leakage circuit breaker with phase loss protection in Patent Document 1 includes a leakage current protection circuit that drives an electromagnetic release device for detecting leakage and an phase loss protection circuit that drives an electromagnetic release device for detection of phase failure.

  In this leakage protection circuit, the output of the secondary winding of the zero-phase current transformer is converted into a voltage and input to the detection terminal of the leakage protection IC. When the leakage current flows, the input voltage of the detection terminal exceeds a predetermined level, and leakage detection is performed in the leakage protection IC. As a result, a leakage detection signal is output from the output terminal, the thyristor is turned on, an exciting current flows through the coil of the electromagnetic release device, the main contact is forcibly opened, and the load is protected.

  In the phase loss protection circuit in Patent Document 1, the input voltages from the two input terminals are full-wave rectified by a diode bridge and input to the phase loss protection IC. The detection line from the input terminal connected to the neutral line is connected to the voltage dividing point of the voltage dividing resistor connected between the two input terminals, and this voltage dividing point is further connected to the detection terminal for phase loss protection through the resistor. Connected. As the voltage at the detection terminal, a pulsating voltage with uniform amplitude appears when the power supply and the load are normally connected. If a neutral line is disconnected and a phase loss occurs, the pulsating voltage alternately increases or decreases depending on the voltage division ratio due to the load of each phase of the two voltage lines. Phase loss detection is performed in the IC. As a result, the phase loss detection signal is output from the output terminal, the thyristor is turned on, the exciting current flows through the coil of the electromagnetic release device, the main contact is opened, and the load is protected.

  Therefore, according to the leakage breaker with phase loss protection of Patent Document 1, it is possible to easily determine whether the main contact is forcibly opened due to leakage detection or forcibly opening the main contact due to phase loss detection.

Japanese Patent No. 3687543

  However, in the leakage breaker with phase loss protection described in Patent Document 1 described above, an electromagnet that controls the movement of each plunger provided in each electromagnetic release device is connected to each electromagnetic release device for leakage detection and phase loss detection. Coil).

  For this reason, the internal structure of the conventional leakage breaker with phase loss protection becomes complicated. For example, it is necessary to provide a plunger and an electromagnet (coil) for each electromagnetic release device for detecting leakage and detecting phase loss. The increase was inevitable.

  Accordingly, the present invention has been made in view of the above-described conventional circumstances, and displays the cause and cause for forced opening of the main contact with a simple configuration, and forcibly opens the main contact according to the cause and cause. The purpose is to provide an earth leakage circuit breaker.

  The present invention is an earth leakage breaker described above, which opens a main circuit including an AC power supply, and includes an earth leakage detection circuit for detecting an earth leakage current flowing in the main circuit, and a lack of a neutral wire. An open phase detection circuit for detecting a phase; an opening control mechanism for forcibly opening the main circuit in response to detection of the leakage current or the open phase of the neutral wire; and the leakage current or the neutral A display control mechanism that displays the cause of the forced opening of the main circuit in response to detection of an open phase of the wire, and a single coil, depending on the output from the leakage detection circuit or the open phase detection circuit And a display opening control unit that controls operations of the display control mechanism and the opening control mechanism, and an energization current in a predetermined direction is supplied to the coil in accordance with an output from the leakage detection circuit or the phase loss detection circuit. A first switching element and the leakage detection circuit or the phase loss detection circuit; A second switching element that causes an energization current in a direction opposite to the predetermined direction to flow through the coil in accordance with an output from the display, and the display opening control unit includes the first switching element or the second switching element. The operation of the display control mechanism and the opening control mechanism is controlled in accordance with the direction of the energization current and the energization time.

  Further, the present invention is the above-described earth leakage circuit breaker, wherein the display opening control unit is configured to cause leakage of the main circuit as a cause of forced opening of the main circuit according to the energization time of the output current to the coil. The display control mechanism is controlled so as to display an open phase.

  Further, the present invention is the above-described earth leakage circuit breaker, wherein the display opening control unit is configured to control the main circuit according to the output current of the earth leakage or the phase loss in which the energization time for the coil is short. The display control mechanism is controlled so as to display the leakage as a cause of forced opening.

  Further, the present invention is the above-described ground fault circuit interrupter, wherein the measurement end point of the energization time of the output current to the coil is a zero crossing point of the AC voltage in the AC power source.

  Further, the present invention is the above-described ground fault circuit interrupter, wherein the measurement start point of the energization time of the output current to the coil is a zero crossing point of the AC voltage in the AC power supply.

  Further, the present invention is the above-described earth leakage circuit breaker, wherein the display opening control unit switches the cause of the forced opening according to the number of half cycles of the energization current from the first switching element. The display control mechanism is controlled.

  The present invention is the above-described earth leakage breaker, wherein the display opening control unit operates the opening control mechanism according to the direction of the input current from the outside of the earth leakage breaker and the energization time. To control.

Furthermore, the present invention is the above-described leakage breaker, which is a leakage breaker that opens a main circuit including an AC power supply, and includes a leakage detection circuit that detects a leakage current flowing in the main circuit, and a neutral wire An open phase detection circuit for detecting an open phase of the main circuit, an abnormality detection circuit for detecting an overcurrent of the main circuit, and detection of any of the leakage current, the open phase of the neutral line, and the overcurrent of the main circuit An opening control mechanism for forcibly opening the main circuit, and the main circuit in response to detection of any one of the leakage current, the neutral wire phase loss, and the main circuit overcurrent. A display control mechanism for displaying a cause of forced opening of the circuit, and a single coil, and the display control according to an output of any one of the leakage detection circuit, the phase loss detection circuit, and the abnormality detection circuit. A display opening control unit for controlling the operation of the mechanism and the opening control mechanism; and A first switching element that causes a current to flow in a predetermined direction to the coil in response to an output of any one of an electricity detection circuit, the phase loss detection circuit, and the abnormality detection circuit; the leakage detection circuit; and the phase loss detection circuit And a second switching element that causes an energization current in a direction opposite to the predetermined direction to flow through the coil in response to an output of any one of the abnormality detection circuits, and the display opening control unit includes the first opening control unit. The operations of the display control mechanism and the opening control mechanism are controlled in accordance with the direction and time of the energization current from the switching element or the second switching element.

  According to the present invention, it is possible to display the cause and cause for forced opening of the main contact with a simple configuration and forcibly open the main contact according to the cause and cause.

The block diagram showing the whole structure of the earth-leakage circuit breaker of 1st Embodiment Explanatory drawing for demonstrating conceptually the operation | movement outline | summary of the display opening control part at the time of displaying the cause of forced opening in 1st Embodiment. Explanatory drawing for demonstrating conceptually the operation | movement outline | summary of the display opening control part at the time of forced opening in 1st Embodiment. Timing chart for explaining the operation of the earth leakage breaker of the first embodiment, (A) timing chart at the time of detection of earth leakage, (B) timing chart at the time of detection of phase loss of neutral wire The block diagram showing the whole structure of the earth-leakage circuit breaker of 2nd Embodiment Explanatory drawing for demonstrating conceptually the operation | movement outline | summary of the display opening control part at the time of displaying the cause of forced opening in 2nd Embodiment. Explanatory drawing for demonstrating conceptually the operation | movement outline | summary of the display opening control part at the time of forced opening in 2nd Embodiment. Timing chart for explaining the operation of the earth leakage circuit breaker according to the first embodiment, (A) timing chart at the time of detection of earth leakage, (B) timing chart at the time of detecting a phase failure of neutral wire, (C) detection of abnormal situation Timing chart

  Hereinafter, each embodiment of an earth leakage breaker according to the present invention will be described with reference to the drawings. The earth leakage breaker according to the present invention is used, for example, as a part of a main breaker of a residential distribution board.

(First embodiment)
In the first embodiment, the earth leakage circuit breaker is connected to the main circuit including the AC power source and the load, and protects the load when an event other than an earth leakage or an earth leakage (for example, an open phase such as a neutral wire open phase) is detected. For this purpose, the main circuit is forcibly opened (blocked). Thereby, the earth leakage circuit breaker can aim at protection of a load from reasons other than earth leakage or earth leakage.

  Furthermore, in the first embodiment, the earth leakage circuit breaker displays a leakage or open phase using the display control mechanism as a cause of the forced opening of the main circuit before forcibly opening the main circuit. . As a result, repair responders can easily confirm the cause of the forced open circuit when either a leakage or phase failure occurs in the main circuit, and can quickly perform repairs corresponding to the leakage or phase failure. it can.

  FIG. 1 is a block diagram illustrating an overall configuration of a leakage breaker 1 according to the first embodiment. The earth leakage breaker 1 includes a timer TM, an earth leakage detection circuit 11, an open phase detection circuit 12, diodes D1 to D4, a display thyristor SCR1 as a switching element, an opening thyristor SCR2 as a switching element, and a display opening control unit CU1. The display control mechanism 15 and the opening control mechanism 16 are included.

  When the load 5 is used, the switch S1 is turned on (conducted) by a user of the load 5 or a switch control unit (not shown), and the power from the AC power supply AC is switched to the switch S1, the terminal T1, the terminal T3, and the terminal T4. And is supplied to the load 5 via the terminal T2. The operation of the switch S1 is the same in each embodiment described later.

  One end of the AC power supply AC is connected to one end of the switch S1, and the other end of the AC power supply AC is connected to the other end of the load 5. One end of the load 5 is connected to the terminal T2, and the cathode terminal of the display thyristor SCR1 and the anode terminal of the opening thyristor SCR2 are connected to the terminal T2 via the terminal T4.

  The other end of the switch S1 is connected to the other end of the display opening control unit CU1 (see FIGS. 2 and 3), and one end of the display opening control unit CU1 is connected to the terminal T1. Further, the anode terminal of the display thyristor SCR1 and the cathode terminal of the opening thyristor SCR2 are connected to the terminal T1 via the terminal T3.

  The leakage detection circuit 11 is connected to the gate terminal of the display thyristor SCR1 via the diode D1 and to the gate terminal of the opening thyristor SCR2 via the diode D2. The leakage detection circuit 11 detects whether or not a leakage current is flowing in the main circuit MC, that is, whether or not a leakage has occurred in the main circuit MC. When the main circuit MC detects a leak, the leak detection circuit 11 displays a display control signal (specifically, a current) via the diode D1 so that the display control mechanism 15 displays the occurrence of the leak, and the display thyristor SCR1. Output to the gate terminal.

  The leakage detection method of the leakage detection circuit 11 can be a known leakage detection method. For example, the leakage detection circuit 11 includes a zero-phase current transformer and the output of the secondary winding of the zero-phase current transformer. When the value exceeds a predetermined level, it is detected that a leakage current flows in the main circuit MC.

  The diodes D1 and D2 are connected in the direction in which the output from the leakage detection circuit 11, that is, the display control signal and the opening control signal are reliably input to the gate terminals of the display thyristor SCR1 and the opening thyristor SCR2. ing. That is, the anode terminal of the diode D1 is connected to the leakage detection circuit 11, and the cathode terminal of the diode D1 is connected to the gate terminal of the display thyristor SCR1. Similarly, the anode terminal of the diode D2 is connected to the leakage detection circuit 11, and the cathode terminal of the diode D2 is connected to the gate terminal of the opening thyristor SCR2.

  Furthermore, when the leakage detection circuit 11 detects a leakage in the main circuit MC, the opening control mechanism 16 opens the main circuit MC so that the opening control signal (specifically, the current) ) Is output to the gate terminal of the opening thyristor SCR2.

  The phase loss detection circuit 12 is connected to the gate terminal of the display thyristor SCR1 through the diode D4 and to the gate terminal of the opening thyristor SCR2 through the diode D3. The phase loss detection circuit 12 detects whether or not a neutral phase phase loss has occurred in the main circuit MC. When the main circuit MC detects a neutral wire phase loss, the phase loss detection circuit 12 displays a display control signal (specifically) via the diode D4 so that the display control mechanism 15 displays the occurrence of the neutral wire phase loss. Current) is output to the gate terminal of the display thyristor SCR1.

  It should be noted that a method for detecting a neutral line phase loss of the phase loss detection circuit 12 is already known. For example, the phase loss detection circuit 12 includes a mechanism for measuring a voltage difference between the first phase voltage and the neutral line voltage and a voltage difference between the second phase voltage and the neutral line voltage in the single-phase three-wire AC circuit. Furthermore, when the neutral line is disconnected for some reason, the phase loss detection circuit 12 has a different value of each voltage difference and the balance of the three-phase AC voltage is lost. Detect the occurrence of a phase.

  The diodes D3 and D4 are connected in the direction in which the output from the phase loss detection circuit 12, that is, the opening control signal and the display control signal are surely input to the gate terminals of the opening thyristor SCR2 and the display thyristor SCR1. Has been. That is, the anode terminal of the diode D3 is connected to the phase loss detection circuit 12, and the cathode terminal of the diode D3 is connected to the gate terminal of the opening thyristor SCR2. Similarly, the anode terminal of the diode D4 is connected to the phase loss detection circuit 12, and the cathode terminal of the diode D4 is connected to the gate terminal of the display thyristor SCR1.

  Further, the phase loss detection circuit 12 controls the opening via the diode D3 so that the opening control mechanism 16 opens the main circuit MC when it detects the occurrence of a neutral phase loss in the main circuit MC. A signal (specifically, current) is output to the gate terminal of the opening thyristor SCR2.

  The display thyristor SCR1 energizes the display opening control unit CU1 in the direction from the anode terminal to the cathode terminal of the display thyristor SCR1 according to the input of the display control signal from the leakage detection circuit 11 or the phase loss detection circuit 12. Output (flow) current.

  The opening thyristor SCR2 is supplied to the display opening controller CU1 in the direction from the anode terminal to the cathode terminal of the opening thyristor SCR2 in response to the input of the display control signal from the leakage detection circuit 11 or the phase loss detection circuit 12. Output current (flow).

  The timer TM measures the energization current flowing through the display opening control unit CU1 (coil L1 thereof; see FIG. 2 or 3), that is, the energization time of the excitation current from the display thyristor SCR1 or the opening thyristor SCR2. The leakage detection circuit 11 and the phase loss detection circuit 12 each input the measured energization time.

  The leakage detection circuit 11 is configured to display the display control signal or the opening control signal thyristor SCR1 or the opening according to the output from the timer TM, that is, the energization time of the excitation current flowing through the display opening control unit CU1. Each output to the thyristor SCR2 is stopped.

  Similarly, the phase loss detection circuit 12 outputs the display control signal or the opening control signal display thyristor SCR1 or SCR1 according to the output from the timer TM, that is, the energization time of the excitation current flowing through the display opening control unit CU1. Each output to the opening thyristor SCR2 is stopped.

  Next, operations of the display opening control unit CU1, the display control mechanism 15, and the opening control mechanism 16 will be described with reference to FIGS.

  FIG. 2 is an explanatory diagram for conceptually explaining the operation outline of the display opening control unit CU1 when displaying the cause of the forced opening in the first embodiment. FIG. 3 is an explanatory diagram for conceptually explaining an operation outline of the display opening control unit CU1 when the forced opening is performed in the first embodiment.

  As shown in FIG. 2, the display opening control unit CU1 includes a coil L1, a plunger PJ, two permanent magnets PM1, PM2, two springs B1, B2, and two protrusions K1, K2. In a steady state in which no leakage or open phase occurs, the plunger PJ is spaced equidistant from each permanent magnet PM1, PM2 via each spring B1, B2 biased by each permanent magnet PM1, PM2. It is located stably so as to hold.

  That is, in the steady state, the plunger PJ is not affected by the electromagnetic force because the exciting current does not flow through the coil L1, so that the restoring forces received from the springs B1 and B2 are balanced.

  The coil L1 has both ends connected to the main circuit MC.

  Plunger PJ is comprised with an iron core etc., and is urged | biased by permanent magnet PM1, PM2 via each spring B1, B2 in the paper surface left-right direction of FIG. Furthermore, the plunger PJ is provided so as to penetrate the coil L1.

  As shown in FIG. 2, when the earth leakage breaker 1 displays the cause of the forced opening of the main circuit MC, the exciting current from the display thyristor SCR1 to the coil L1 is applied to the coil L1 in the right direction in FIG. Flowing. In response to the excitation current from the display thyristor SCR1, the plunger PJ in the coil L1 operates in the left direction in FIG. 2 by receiving an electromagnetic force exceeding the restoring force from the spring B1.

  In particular, when an excitation current corresponding to at least a half cycle flows by the measurement of the timer TM, the protrusion K1 provided on the plunger PJ is displayed on the display control mechanism according to the operation of the plunger PJ in the left direction in FIG. 15 count-up button CB is pressed.

  For example, it is assumed that an excitation current in the left direction in FIG. 2 corresponding to at least a half cycle flows through the coil L1 once. In this case, the plunger PJ presses the count-up button CB once through the projection K1 provided on the plunger PJ by the electromagnetic force generated based on the excitation current.

  As a result, the display control mechanism 15 displays a leakage status display window on the status display section CW for displaying the cause of the forced opening of the main circuit MC in response to the output of the count up button CB (one press). Control so that only EL can be displayed.

  Further, for example, as will be described later, it is assumed that an excitation current in the left direction in FIG. 2 corresponding to at least a half cycle flows through the coil L1 twice. In this case, the plunger PJ presses the count-up button CB twice through the protrusion K1 provided on the plunger PJ by the electromagnetic force generated based on the excitation current.

  As a result, the display control mechanism 15 displays the phase loss state display on the state display unit CW for displaying the cause of the forced opening of the main circuit MC in response to the output of the count up button CB (two presses). Control is performed so that only the window NL can be displayed.

  In each of the following embodiments, the reset button RB is pressed in response to an operation by a user of a handle (not shown) provided in the earth leakage breaker 1 or the earth leakage breaker 2 described later, and counts up in response to this depression. Reset the output of button CB.

  As shown in FIG. 3, when the earth leakage circuit breaker 1 forcibly opens the main circuit MC, an exciting current from the opening thyristor SCR2 to the coil L1 flows in the coil L1 in the left direction in FIG. In response to the excitation current from the opening thyristor SCR2, the plunger PJ in the coil L1 operates in the right direction in FIG. 3 by receiving an electromagnetic force exceeding the restoring force from the spring B2.

  In particular, when an excitation current corresponding to at least a half cycle flows by the measurement of the timer TM, the protrusion K2 provided on the plunger PJ is controlled to open according to the operation of the plunger PJ in the right direction in FIG. Press the mechanism 16. Thereby, the opening control mechanism 16 forcibly opens the main circuit MC in response to pressing of the protrusion K2 provided on the plunger PJ.

  In each of the following embodiments, when the earth leakage breaker 1 forcibly opens the main circuit MC, the power from the AC power supply AC is not supplied to the earth leakage breaker 1, so that the earth leakage breaker 1 is forcibly opened. It is preferable to forcibly open the main circuit MC after the display control of the cause of the failure is performed.

  In each of the following embodiments, a known technique can be applied to the operation of the display control mechanism 15 described above. For example, the display control method of the earth leakage display member and the phase failure display member in the above-described leakage circuit breaker with phase loss protection of Patent Document 1 can be applied.

  In each of the following embodiments, a known technique can be applied to the operation of the opening control mechanism 16 described above. For example, the method for forcibly opening the main contact in the above-described leakage circuit breaker with phase loss protection of Patent Document 1 can be applied.

  Next, the operation of forcibly opening the main circuit MC after displaying the cause of the cause of the earth leakage circuit breaker 1 forcibly opening the main contact MC (leakage, neutral wire phase loss) will be described with reference to FIG. To do. FIG. 4 is a timing chart for explaining the operation of the earth leakage circuit breaker 1 according to the first embodiment. FIG. 4A is a timing chart at the time of detecting electric leakage. FIG. 5B is a timing chart when a phase failure of the neutral line is detected.

  In FIG. 4A and FIG. 4B, the first stage represents the time change of the gate signal input to the display thyristor SCR1. The second stage represents the time change of the gate signal input to the opening thyristor SCR2. The third stage represents the time change of the excitation current to the coil L1. The fourth stage represents the position of the plunger PJ, and the horizontal axis represents the center position of the plunger PJ in the steady state. The fifth row represents the time change of the display state of the state display unit CW. The sixth stage represents the time change of the state of the main contact MC.

  In FIG. 4A, the leakage detection circuit 11 outputs a display control signal to the display thyristor SCR1 from time t1 to time t3 when leakage is detected in the main circuit MC. The display thyristor SCR1 causes the excitation current to the coil L1 to flow through the coil L1 for at least a half cycle time in accordance with the display control signal output by the leakage detection circuit 11 after time t1 (see FIG. 2). ).

  In the display opening control unit CU1, the plunger PJ has an electromagnetic force generated due to energization of the exciting current to the coil L1 larger than the restoring force of the spring B1, and from the center position of the plunger PJ in a steady state, as shown in FIG. Move left on the page. The movement distance of the plunger PJ becomes the maximum value in the left direction of the paper in FIG. 2 at time t2.

  When the plunger PJ moves to the position of the maximum value in the left direction in FIG. 2, the protrusion K1 provided on the plunger PJ presses the count-up button CB of the display control mechanism 15 once. As a result, the display control mechanism 15 controls to display only the leakage state display window EL as a cause for causing the main contact MC to be forcibly opened in the state display unit CW.

  In accordance with the output of the timer TM, the leakage detection circuit 11 stops outputting the display control signal to the display thyristor SCR1 at time t3 after the energization time of the excitation current of at least a half cycle has elapsed. Thereby, after the time t3, the exciting current flowing between the anode and the cathode of the display thyristor SCR1 decreases and becomes zero at the time t5. As the exciting current to the coil L1 decreases, the restoring force of the spring B1 exceeds the electromagnetic force, so that the position of the plunger PJ moves to the center position.

  After time t3, leakage detection circuit 11 outputs an opening control signal to opening thyristor SCR2 at time t4. After the time t4, the opening thyristor SCR2 causes the excitation current to the coil L1 to flow through the coil L1 for a time corresponding to at least a half cycle in accordance with the opening control signal output by the leakage detection circuit 11 (FIG. 3).

  In the display opening control unit CU1, the plunger PJ has an electromagnetic force generated due to the energization of the exciting current to the coil L1 larger than the restoring force of the spring B2, and the plunger PJ in FIG. Move right on the page. The movement distance of the plunger PJ becomes the maximum value in the right direction on the paper surface of FIG. 3 at time t6.

  When the plunger PJ moves to the position of the maximum value in the right direction in FIG. 3, the protrusion K <b> 2 provided on the plunger PJ presses down the opening control mechanism 16. Thereby, the opening control mechanism 16 forcibly opens the main contact MC. That is, as shown in the sixth stage of FIG. 4, the main contact MC changes from the conductive (on) state to the non-conductive (off) state.

  In accordance with the output of the timer TM, the leakage detection circuit 11 stops outputting the display control signal to the opening thyristor SCR2 at time t7 after the energization time of at least a half cycle has elapsed. Thereby, after time t7, the exciting current flowing between the anode and the cathode of the opening thyristor SCR2 decreases and becomes zero at time t8.

  In FIG. 4B, the phase loss detection circuit 12 outputs a display control signal to the display thyristor SCR1 at time t1 to time t4 when the neutral phase loss phase is detected in the main circuit MC. The display thyristor SCR1 causes an excitation current to the coil L1 to flow through the coil L1 for at least a half cycle time in accordance with the display control signal output by the phase loss detection circuit 12 after time t1 (FIG. 2). reference).

  In the display opening control unit CU1, the plunger PJ has an electromagnetic force generated due to energization of the exciting current to the coil L1 larger than the restoring force of the spring B1, and from the center position of the plunger PJ in a steady state, as shown in FIG. Move left on the page. The movement distance of the plunger PJ becomes the maximum value in the left direction of the paper in FIG. 2 at time t2.

  When the plunger PJ moves to the position of the maximum value in the left direction in FIG. 2, the protrusion K1 provided on the plunger PJ presses the count-up button CB of the display control mechanism 15 once. As a result, the display control mechanism 15 controls to display only the leakage state display window EL as a cause for causing the main contact MC to be forcibly opened in the state display unit CW. As the exciting current to the coil L1 decreases, the restoring force of the spring B1 exceeds the electromagnetic force, so that the position of the plunger PJ moves to the center position.

  Further, the display thyristor SCR1 applies the excitation current to the coil L1 during the second time period corresponding to at least a half cycle according to the fact that the phase loss detection circuit 12 outputs the display control signal until time t4. It flows to L1 (refer FIG. 2).

  In the display opening control unit CU1, the plunger PJ has an electromagnetic force generated due to energization of the exciting current to the coil L1 larger than the restoring force of the spring B1, and from the center position of the plunger PJ in a steady state, as shown in FIG. Move left on the page. The movement distance of the plunger PJ is the maximum value in the left direction of FIG. 2 at time t3.

  When the plunger PJ moves to the position of the maximum value in the left direction in FIG. 2, the protrusion K1 provided on the plunger PJ further presses the count-up button CB of the display control mechanism 15 once. Thereby, the display control mechanism 15 means that the count-up button CB has been pressed twice, and only the phase loss state display window NL is used as a cause for forcibly opening the main contact MC in the state display unit CW. Control to display.

  The phase loss detection circuit 12 stops outputting the display control signal to the display thyristor SCR1 at time t4 after the energization time of the excitation current of at least 1.5 cycles has elapsed according to the output of the timer TM. Thereby, after time t4, the excitation current flowing between the anode and the cathode of the display thyristor SCR1 decreases and becomes zero at time t6. As the exciting current to the coil L1 decreases, the restoring force of the spring B1 exceeds the electromagnetic force, so that the position of the plunger PJ moves to the center position.

  After time t4, the phase loss detection circuit 12 outputs an opening control signal to the opening thyristor SCR2 at time t5. The opening thyristor SCR2 causes an excitation current to the coil L1 to flow through the coil L1 for a time corresponding to at least a half cycle in accordance with the opening control signal output by the phase loss detection circuit 12 after time t5 ( (See FIG. 3).

  In the display opening control unit CU1, the plunger PJ has an electromagnetic force generated due to the energization of the exciting current to the coil L1 larger than the restoring force of the spring B2, and the plunger PJ in FIG. Move right on the page. The movement distance of the plunger PJ becomes the maximum value in the right direction on the paper surface of FIG. 3 at time t7.

  When the plunger PJ moves to the position of the maximum value in the right direction in FIG. 3, the protrusion K <b> 2 provided on the plunger PJ presses down the opening control mechanism 16. Thereby, the opening control mechanism 16 forcibly opens the main contact MC. That is, the main contact MC changes from a conductive (on) state to a non-conductive (off) state.

  The phase loss detection circuit 12 stops outputting the display control signal to the opening thyristor SCR2 at time t8 after the energization time of the excitation current of at least a half cycle has elapsed in accordance with the output of the timer TM. Thereby, after time t8, the exciting current flowing between the anode and the cathode of the opening thyristor SCR2 decreases and becomes zero at time t9. As the exciting current to the coil L1 decreases, the restoring force of the spring B2 exceeds the electromagnetic force, so that the position of the plunger PJ moves to the center position.

  From the above, according to the earth leakage breaker 1 of the first embodiment, with a simple configuration using the display opening control unit CU1 including the coil L1, according to the direction of the excitation current and the energization time to the coil L1, The cause and cause of forced opening of the main contact can be displayed. Furthermore, according to the earth leakage circuit breaker 1, after displaying the cause and cause for forced opening of the main contact, the main contact can be forcibly opened according to the cause and cause.

(Second Embodiment)
In the second embodiment, the earth leakage circuit breaker is not only caused by the leakage and phase loss described in the first embodiment as another cause of forced opening of the main circuit, but also when other abnormal situations occur. The main circuit is forcibly opened. Other abnormal situations include, for example, overcurrent caused by lightning surge. Thereby, the earth leakage circuit breaker can aim at protection of a load from reasons other than earth leakage or earth leakage.

  Furthermore, in the second embodiment, before the main circuit is forcibly opened, the earth leakage circuit breaker uses the display control mechanism as a cause of the forcible opening of the main circuit. Display one of them. As a result, the repair operator can easily check the cause of the forced open circuit when any of the leakage, phase failure, or abnormality occurs in the main circuit. Responding to repairs can be performed quickly.

  FIG. 5 is a block diagram illustrating the overall configuration of the earth leakage breaker 2 of the second embodiment. The earth leakage breaker 2 includes a timer TM, an earth leakage detection circuit 11, an open phase detection circuit 12, an abnormality detection circuit 13, diodes D1 to D6, a display thyristor SCR1 as a switching element, a contact opening thyristor SCR2 as a switching element, a display The configuration includes the opening control unit CU2, the display control mechanism 17, and the opening control mechanism 16.

  In the configuration and operation of the earth leakage breaker 2 in FIG. 5, the same components as those in the earth leakage breaker 1 in FIG. Hereinafter, in the configuration and operation of the earth leakage breaker 2, description of the same contents as the configuration and operation of the earth leakage breaker 1 will be omitted, and contents different from the configuration and operation of the earth leakage breaker 1 will be described.

  The other end of the switch S1 is connected to the other end of the display opening control unit CU2 (see FIGS. 6 and 7), and one end of the display opening control unit CU2 is connected to the terminal T1.

  When the main circuit MC detects a leak, the leak detection circuit 11 displays a display control signal (specifically, a current) via the diode D1 so that the display control mechanism 17 displays the occurrence of the leak, and the display thyristor SCR1. Output to the gate terminal.

  When the main circuit MC detects the occurrence of a neutral wire phase loss, the phase loss detection circuit 12 displays a display control signal via the diode D4 so that the display control mechanism 17 displays the occurrence of the neutral wire phase loss. (Specifically, current) is output to the gate terminal of the display thyristor SCR1.

  The abnormality detection circuit 13 is connected to the gate terminal of the display thyristor SCR1 through the diode D6 and to the gate terminal of the opening thyristor SCR2 through the diode D5. The abnormality detection circuit 13 detects whether or not an abnormal situation (for example, an overcurrent due to the occurrence of a lightning surge) has occurred in the main circuit MC, excluding electric leakage and neutral wire phase loss. The abnormality detection circuit 13 sends a display control signal (specifically, a current) to the display thyristor via the diode D6 so that the display control mechanism 17 displays the occurrence of the abnormal situation when the main circuit MC detects a leakage. Output to the gate terminal of SCR1.

  Note that a known detection method can be applied to the abnormality detection method of the abnormality detection circuit 13, for example, the abnormality detection circuit 13 includes a zero-phase current transformer, and the output of the secondary winding of the zero-phase current transformer. When the value exceeds a predetermined level, it is detected that an overcurrent flows through the main circuit MC.

  The diodes D5 and D6 are connected in the direction in which the output from the abnormality detection circuit 13, that is, the opening control signal and the display control signal are surely input to the gate terminals of the opening thyristor SCR2 and the display thyristor SCR1. ing. That is, the anode terminal of the diode D5 is connected to the abnormality detection circuit 13, and the cathode terminal of the diode D5 is connected to the gate terminal of the opening thyristor SCR2. Similarly, the anode terminal of the diode D6 is connected to the abnormality detection circuit 13, and the cathode terminal of the diode D6 is connected to the gate terminal of the display thyristor SCR1.

  Further, when the leakage detection is detected in the main circuit MC, the abnormality detection circuit 13 causes the opening control mechanism 16 to open the main circuit MC. ) Is output to the gate terminal of the opening thyristor SCR2.

  The display thyristor SCR1 displays in the direction from the anode terminal to the cathode terminal of the display thyristor SCR1 in accordance with the input of the display control signal from any of the leakage detection circuit 11, the phase loss detection circuit 12 and the abnormality detection circuit 13. An energizing current to the opening control unit CU2 is output (flowed).

  The opening thyristor SCR2 is arranged in the direction from the anode terminal to the cathode terminal of the opening thyristor SCR2 according to the input of the display control signal from any of the leakage detection circuit 11, the phase loss detection circuit 12 and the abnormality detection circuit 13. Then, an energization current to the display opening control unit CU2 is output (flowed).

  The timer TM measures the energization current flowing through the display opening control unit CU2 (coil L1 thereof; see FIG. 6 or 7), that is, the energization time of the excitation current from the display thyristor SCR1 or the opening thyristor SCR2. The leakage detection circuit 11, the phase loss detection circuit 12, and the abnormality detection circuit 13 each input the measured energization time.

  In addition, the leakage detection circuit 11 is the display thyristor SCR1 for opening the display control signal or the opening control signal described above or the opening according to the output from the timer TM, that is, the energization time of the exciting current flowing through the display opening control unit CU2. Each output to the thyristor SCR2 is stopped.

  Similarly, the phase loss detection circuit 12 outputs the display control signal or the opening control signal display thyristor SCR1 or SCR1 according to the output from the timer TM, that is, the energization time of the excitation current flowing in the display opening control unit CU2. Each output to the opening thyristor SCR2 is stopped.

  Similarly, the abnormality detection circuit 13 outputs the display thyristor SCR1 or the opening control signal thyristor SCR1 described above according to the output from the timer TM, that is, the energization time of the exciting current flowing in the display opening control unit CU2. Each output to the polar thyristor SCR2 is stopped.

  Next, operations of the display opening control unit CU2, the display control mechanism 17, and the opening control mechanism 16 will be described with reference to FIGS.

  FIG. 6 is an explanatory diagram for conceptually explaining the operation outline of the display opening control unit CU2 when displaying the cause of forced opening in the second embodiment. FIG. 7 is an explanatory diagram for conceptually explaining the operation outline of the display opening control unit CU2 when forced opening is performed in the second embodiment.

  Since the display opening control unit CU2 has the same configuration and operation as the display opening control unit CU1 of the first embodiment, the description regarding the same content is omitted, and the content is different from the operation of the display opening control unit CU1. Will be described.

  As shown in FIG. 6, when the earth leakage breaker 2 displays the cause of the forced opening of the main circuit MC, the exciting current from the display thyristor SCR1 to the coil L1 is applied to the coil L1 in the right direction in FIG. Flowing. In response to the excitation current from the display thyristor SCR1, the plunger PJ in the coil L1 operates in the left direction in FIG. 6 by receiving an electromagnetic force exceeding the restoring force from the spring B1.

  In particular, when an excitation current corresponding to at least a half cycle or more flows by the measurement of the timer TM, the protrusion K1 provided on the plunger PJ is displayed on the display control mechanism according to the operation of the plunger PJ in the left direction in FIG. 15 count-up button CB is pressed.

  For example, it is assumed that an excitation current in the left direction in FIG. 6 corresponding to at least a half cycle flows through the coil L1 once. In this case, the plunger PJ presses the count-up button CB once through the projection K1 provided on the plunger PJ by the electromagnetic force generated based on the excitation current.

  As a result, the display control mechanism 17 displays a ground leakage state display window on the state display unit CW for displaying the cause of the forced opening of the main circuit MC in accordance with the output (one press) of the count-up button CB. Control so that only EL can be displayed.

  Further, for example, as will be described later, it is assumed that an output current in the left direction in FIG. 6 corresponding to at least a half cycle flows through the coil L1 twice. In this case, the plunger PJ presses the count-up button CB twice through the protrusion K1 provided on the plunger PJ by the electromagnetic force generated based on the excitation current.

  As a result, the display control mechanism 17 displays the phase loss state display on the state display unit CW for displaying the cause of the forced opening of the main circuit MC in response to the output of the count-up button CB (two presses). Control is performed so that only the window NL can be displayed.

  Further, for example, as described later, it is assumed that an output current in the left direction in FIG. 6 corresponding to at least a half cycle flows through the coil L1 three times. In this case, the plunger PJ presses the count-up button CB three times through the protrusion K1 provided on the plunger PJ by the electromagnetic force generated based on the excitation current.

  Thereby, the display control mechanism 17 displays an abnormal state display window on the state display unit CW for displaying the cause of the forced opening of the main circuit MC in response to the output of the count-up button CB (three presses). Control to display only AL.

  As shown in FIG. 7, when the earth leakage circuit breaker 2 forcibly opens the main circuit MC, an exciting current from the opening thyristor SCR2 to the coil L1 flows in the coil L1 in the left direction in FIG. In response to the excitation current from the opening thyristor SCR2, the plunger PJ in the coil L1 operates in the right direction in FIG. 7 by receiving an electromagnetic force exceeding the restoring force from the spring B2.

  In particular, when an excitation current corresponding to at least a half cycle flows by the measurement of the timer TM, the protrusion K2 provided on the plunger PJ is controlled to open according to the operation of the plunger PJ in the right direction in FIG. Press the mechanism 16. Thereby, the opening control mechanism 16 forcibly opens the main circuit MC in response to pressing of the protrusion K2 provided on the plunger PJ.

  Next, refer to FIG. 8 for the operation for forcibly opening the main circuit MC after displaying the cause of the earth leakage circuit breaker 2 forcibly opening the main contact MC (leakage, neutral wire phase loss, abnormal situation). To explain. FIG. 8 is a timing chart for explaining the operation of the earth leakage breaker 2 of the second embodiment. FIG. 4A is a timing chart at the time of detecting electric leakage. FIG. 5B is a timing chart when a phase failure of the neutral line is detected. FIG. 4C is a timing chart when an abnormal situation is detected.

  8A, FIG. 8B, and FIG. 8C, the first stage represents the time change of the gate signal input to the display thyristor SCR1. The second stage represents the time change of the gate signal input to the opening thyristor SCR2. The third stage represents the time change of the excitation current to the coil L1. The fourth stage represents the position of the plunger PJ, and the horizontal axis represents the center position of the plunger PJ in the steady state. The fifth row represents the time change of the display state of the state display unit CW. The sixth stage represents the time change of the state of the main contact MC.

  Note that the description of the timing chart at the time of leakage detection and the detection of the phase failure of the neutral wire in FIGS. 8A and 8B is the same as in the first embodiment, and thus the description thereof is omitted. Hereinafter, a timing chart when an abnormal situation is detected in FIG. 8C will be described.

  In FIG. 8C, the abnormality detection circuit 13 outputs a display control signal to the display thyristor SCR1 from time t1 to time t5 when detecting an abnormal situation such as the occurrence of a lightning surge in the main circuit MC. The display thyristor SCR1 causes the excitation current to the coil L1 to flow through the coil L1 for at least a half cycle in accordance with the display control signal output by the abnormality detection circuit 13 after time t1 (see FIG. 6). ).

  In the display opening control unit CU2, the plunger PJ has an electromagnetic force generated due to energization of the exciting current to the coil L1 larger than the restoring force of the spring B1, and from the center position of the plunger PJ in a steady state, FIG. Move left on the page. The movement distance of the plunger PJ becomes the maximum value in the left direction of FIG. 6 at time t2.

  When the plunger PJ moves to the position of the maximum value in the left direction in FIG. 6, the protrusion K1 provided on the plunger PJ presses the count-up button CB of the display control mechanism 17 once. Thereby, the display control mechanism 17 controls so that only the electric leakage state display window EL can be displayed as a cause for causing the main contact MC to be forcibly opened in the state display unit CW. As the exciting current to the coil L1 decreases, the restoring force of the spring B1 exceeds the electromagnetic force, so that the position of the plunger PJ moves to the center position.

  Further, the display thyristor SCR1 applies the excitation current to the coil L1 for the time corresponding to the second half of the coil L1 in response to the abnormality detection circuit 13 outputting the display control signal until time t5. (See FIG. 6).

  In the display opening control unit CU2, the plunger PJ has an electromagnetic force generated due to energization of the exciting current to the coil L1 larger than the restoring force of the spring B1, and from the center position of the plunger PJ in a steady state, FIG. Move left on the page. The movement distance of the plunger PJ becomes the maximum value in the left direction of FIG. 6 at time t3.

  When the plunger PJ moves to the position of the maximum value in the left direction in FIG. 6, the projection K1 provided on the plunger PJ further presses the count-up button CB of the display control mechanism 17 once more. As a result, the display control mechanism 17 indicates that the count-up button CB has been pressed twice, and only the phase loss state display window NL is used as a cause for forcibly opening the main contact MC in the state display unit CW. Control to display.

  Further, the display thyristor SCR1 supplies the exciting current to the coil L1 for the time corresponding to at least a half cycle of the third time according to the abnormality detection circuit 13 outputting the display control signal until the time t5. (See FIG. 6).

  In the display opening control unit CU2, the plunger PJ has an electromagnetic force generated due to energization of the exciting current to the coil L1 larger than the restoring force of the spring B1, and from the center position of the plunger PJ in a steady state, FIG. Move left on the page. The movement distance of the plunger PJ becomes the maximum value in the left direction of the paper in FIG. 6 at time t4.

  When the plunger PJ moves to the position of the maximum value in the left direction in FIG. 6, the projection K1 provided on the plunger PJ further presses the count-up button CB of the display control mechanism 17 once more. As a result, the display control mechanism 17 indicates that the count-up button CB has been pressed three times, and displays only the abnormal state display window AL as a cause for causing the main contact MC to be forcibly opened in the state display unit CW. Control as possible.

  The abnormality detection circuit 13 stops outputting the display control signal to the display thyristor SCR1 at time t5 after the energization time of at least 2.5 cycles of excitation current has elapsed in accordance with the output of the timer TM. Thereby, after the time t5, the exciting current flowing between the anode and the cathode of the display thyristor SCR1 decreases and becomes zero at the time t7. As the exciting current to the coil L1 decreases, the restoring force of the spring B1 exceeds the electromagnetic force, so that the position of the plunger PJ moves to the center position.

  After time t5, the abnormality detection circuit 13 outputs an opening control signal to the opening thyristor SCR2 at time t6. After the time t6, the opening thyristor SCR2 causes the excitation current to the coil L1 to flow through the coil L1 for a time corresponding to at least a half cycle in accordance with the opening control signal output by the abnormality detection circuit 13 (FIG. 7).

  In the display opening control unit CU2, the plunger PJ has an electromagnetic force generated due to the energization of the exciting current to the coil L1 larger than the restoring force of the spring B2, and from the center position of the plunger PJ in the steady state, FIG. Move right on the page. The movement distance of the plunger PJ becomes the maximum value in the right direction on the paper surface of FIG. 7 at time t8.

  When the plunger PJ moves to the position of the maximum value in the right direction in FIG. 7, the protrusion K2 provided on the plunger PJ presses down the opening control mechanism 16. Thereby, the opening control mechanism 16 forcibly opens the main contact MC. That is, the main contact MC changes from a conductive (on) state to a non-conductive (off) state.

  The abnormality detection circuit 13 stops outputting the display control signal to the opening thyristor SCR2 at time t9 after the energization time of the excitation current of at least a half cycle has elapsed in accordance with the output of the timer TM. Thereby, after time t9, the exciting current flowing between the anode and the cathode of the opening thyristor SCR2 decreases and becomes zero at time t10. As the exciting current to the coil L1 decreases, the restoring force of the spring B2 exceeds the electromagnetic force, so that the position of the plunger PJ moves to the center position.

  As described above, according to the earth leakage breaker 2 of the second embodiment, with a simple configuration using the display opening control unit CU2 including the coil L1, according to the direction and energization time of the excitation current to the coil L1, The cause and cause of forced opening of the main contact can be displayed. Furthermore, according to the earth leakage circuit breaker 2, after displaying the cause and cause for forced opening of the main contact, the main contact can be forcibly opened according to the cause and cause.

  While various embodiments have been described with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  It is preferable that the measurement end point of the energization time of the exciting current from the display thyristor SCR1 or the opening thyristor SCR2 to the coil L1 described above is the zero crossing point of the AC voltage in the AC power supply AC. In this case, each of the leakage detection circuit 11, the phase loss detection circuit 12, and the abnormality detection circuit 13 includes a measuring instrument that can detect the zero-cross time of the AC voltage.

  As a result, the leakage detection circuit 11, the phase loss detection circuit 12, and the abnormality detection circuit 13 need to have a separate timer for controlling the energization time of the excitation current from the display thyristor SCR1 or the opening thyristor SCR2 to the coil L1. Disappears. For this reason, the earth leakage breaker 1 and the earth leakage breaker 2 can be configured at low cost.

  It should be noted that the measurement start point of the energization time of the exciting current from the display thyristor SCR1 or the opening thyristor SCR2 to the coil L1 is preferably the zero crossing point of the AC voltage in the AC power supply AC. As a result, the earth leakage breaker 1 and the earth leakage breaker 2 can reliably secure the half-period energization time of the excitation current from the display thyristor SCR1 or the opening thyristor SC2, and can reliably control the operation of the plunger PJ. is there.

  In each of the embodiments described above, a thyristor is used as a switching element, but a transistor may be used as another switching element. In this case, as described in each of the embodiments described above, a timer is required, but the earth leakage breaker 1 and the earth leakage breaker 2 can be configured at low cost.

1, 2 Leakage breaker 5 Load 11 Leakage detection circuit 12 Phase loss detection circuit 13 Abnormality detection circuit 15, 17 Display control mechanism 16 Opening control mechanism AC AC power supply AL Abnormal state display window B1, B2 Spring CB Count up button CU1, CU2 Display opening control unit CW Status display unit EL Leakage status display window K1, K2 Projection L1 Coil NL Phase loss status display window PJ Plunger PM1, PM2 Permanent magnet RB Reset button S1 Switch SCR1, SCR3 Display thyristor SCR2, SCR4 Open Thyristors for poles T1, T2, T3, T4 terminals

Claims (8)

An earth leakage circuit breaker that opens a main circuit including an AC power source,
A leakage detection circuit for detecting a leakage current flowing in the main circuit;
A phase loss detection circuit for detecting a phase loss of a neutral wire;
An opening control mechanism for forcibly opening the main circuit in response to detection of the leakage current or the phase failure of the neutral wire;
A display control mechanism for displaying the cause of forced opening of the main circuit in response to detection of the leakage current or the phase failure of the neutral wire;
A display opening control unit that includes a single coil and controls the operation of the display control mechanism and the opening control mechanism according to the output from the leakage detection circuit or the phase loss detection circuit;
A first switching element that causes an energization current in a predetermined direction to flow through the coil in response to an output from the leakage detection circuit or the phase loss detection circuit;
A second switching element that causes an energization current in a direction opposite to the predetermined direction to flow in the coil in response to an output from the leakage detection circuit or the phase loss detection circuit,
The display opening control unit is configured to control an operation of the display control mechanism and the opening control mechanism according to a direction and an energization time of the energization current from the first switching element or the second switching element. vessel. The earth leakage circuit breaker according to claim 1,
The display opening control unit controls the display control mechanism to display a leakage or the open phase as a cause of the forced opening of the main circuit according to the energization time of the output current to the coil. Circuit breaker. The earth leakage circuit breaker according to claim 2,
The display opening control unit is configured to display the leakage as a cause of forced opening of the main circuit according to the output current of the leakage current or the open phase that has a short energization time to the coil. Earth leakage breaker that controls the control mechanism. The earth leakage breaker according to any one of claims 1 to 3,
The earth leakage circuit breaker when the measurement of the energization time of the output current to the coil is the zero crossing point of the AC voltage in the AC power supply. The earth leakage breaker according to any one of claims 1 to 4,
An earth leakage breaker in which the measurement start point of the energization time of the output current to the coil is a zero crossing point of the AC voltage in the AC power supply. The earth leakage circuit breaker according to claim 1,
The display opening control unit is a leakage breaker that controls the display control mechanism so as to switch the cause of the forced opening according to the number of half periods of the energization current from the first switching element. The earth leakage circuit breaker according to claim 1,
The display opening control unit is a leakage breaker that controls the operation of the opening control mechanism according to the direction of the input current from the outside of the leakage breaker and the energization time. An earth leakage circuit breaker that opens a main circuit including an AC power source,
A leakage detection circuit for detecting a leakage current flowing in the main circuit;
A phase loss detection circuit for detecting a phase loss of a neutral wire;
An abnormality detection circuit for detecting an overcurrent of the main circuit ;
An opening control mechanism for forcibly opening the main circuit in response to detection of any of the leakage current, the phase loss of the neutral wire, and the overcurrent of the main circuit;
A display control mechanism for displaying a cause of forced opening of the main circuit in response to detection of any one of the leakage current, the phase loss of the neutral wire, and the overcurrent of the main circuit;
Display opening that includes a single coil and controls the operation of the display control mechanism and the opening control mechanism according to the output of any one of the leakage detection circuit, the phase loss detection circuit, and the abnormality detection circuit A control unit;
A first switching element that causes an energization current in a predetermined direction to flow through the coil in response to an output of any one of the leakage detection circuit, the phase loss detection circuit, and the abnormality detection circuit;
A second switching element that causes an energization current in a direction opposite to the predetermined direction to flow in the coil in response to an output of any of the leakage detection circuit, the phase loss detection circuit, and the abnormality detection circuit,
The display opening control unit is configured to control an operation of the display control mechanism and the opening control mechanism according to a direction and an energization time of the energization current from the first switching element or the second switching element. vessel.

Images