JP2009048864A - Circuit breaker with single-phase three-wire neutral line phase interruption protection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit breaker with a single-phase three-wire neutral line phase interruption protection, which does not operate even when a power meter is replaced, ensures that a power supply to a load is not left disconnected when a power meter of an empty house is replaced, requires low component costs and enables a simple circuit configuration. <P>SOLUTION: According to the circuit breaker 1 with single-phase three-wire neutral line phase interruption protection, an X-N phase voltage and a Y-N phase voltage on a single-phase three-wire electric path are monitored by an abnormal voltage detecting circuit 9. When the X-N phase voltage or the Y-N phase voltage becomes an excessive voltage because of neutral line interruption, the abnormal voltage detecting circuit 9 detects the excessive voltage to break connection to a main circuit 4. A constant voltage diode ZD1 is provided in series with a power supply path which supplies power from an X-Y phase to the abnormal voltage detecting circuit 9, so that power supply to the abnormal voltage detecting circuit 9 is interrupted when an X-Y phase voltage drops below a voltage of a given value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a circuit breaker with AA neutral wire phase loss protection that protects a load device by detecting an overvoltage due to a phase failure of a neutral phase of a single phase three-wire circuit and interrupting a main circuit.

  As shown in FIG. 2, the AA neutral line breaker with phase loss protection 21 is connected to the neutral phase N phase of the single-phase three-wire circuit and the X phase and Y phase of the voltage line. , 22, 22 and the load side terminals 23, 23, 23 are provided in the main circuits 24, 24, 24 with switching contacts 25, 25, 25 interposed between the load side terminals 23, 23, 23. A phase detection lead wire 26 is connected. The phase loss detection lead wire 26 is connected to the X phase and the Y phase via a voltage dividing circuit 27 composed of the first resistor R11 and the second resistor R12, and divides the voltage between the XN phase and the YN phase. The voltage is divided by the voltage circuit 27 and input to an abnormal voltage detection circuit 29 that is integrated into an IC to monitor the voltage. When the neutral line N is lost, the voltage between the X-N phase or the Y-N phase increases, and the divided voltage of the voltage dividing circuit 27 input to the abnormal voltage detection circuit 29 exceeds the reference voltage. Is determined to be out of phase, the thyristor SCR11 is turned on by the output of the abnormal voltage detection circuit 29, the trip coil 28 is excited by turning on the thyristor SCR11, and the tripping mechanism 31 is driven by the excitation of the trip coil 28. The open / close contact 25 of the circuit 24 is opened and cut off. The abnormal voltage detection circuit 29 is current-limited by the current-limiting resistor R13 from between the XY phases, and is voltage-limited by the constant voltage diode ZD12 and supplied with power (see, for example, Patent Document 1).

JP 2001-136653 A

  Normally, when replacing the watt hour meter 32, the wires are removed in the order of the X phase, the Y phase, and the N phase, and after replacing the watt hour meter 32, the wires are connected in the order of the N phase, the Y phase, and the X phase. When the X-phase wire is removed to replace the watt-hour meter 32, the voltage between the Y and N phases remains at 100 V, and the load 1 connected to the load side of the circuit breaker 21 is between the XY phases. A low voltage of 100 V or less divided by the load 3 is applied. For this reason, the power supply voltage of the abnormal voltage detection circuit 29 becomes lower than normal, and the reference voltage also decreases. On the other hand, since the voltage between the Y and N phases remains 100V, the divided voltage of the voltage dividing circuit 27 is input to the abnormal voltage detection circuit 29 as usual, and the divided voltage exceeds the reference voltage. The thyristor SCR 11 is turned on by the output of 29 to excite the trip coil 28, and the tripping mechanism 31 is driven by the excitation of the trip coil 28 to shut off the main circuit 24. For this reason, even if the single-phase three-wire circuit is interrupted when the watt-hour meter 32 in the answering house is replaced, the circuit breaker 21 with AA neutral wire phase loss protection is installed indoors so that it can be restored. Since the breaker 21 with AA neutral wire phase loss protection is used as a main breaker, the power supply of all the loads remains cut off due to the main breaker being cut off. There was a problem that the power supply of the troubled device was also turned off.

  According to the present invention, the voltage between the X-N phase and the Y-N phase of the single-phase three-wire circuit is monitored by the abnormal voltage detection circuit, and the voltage between the X-N phase or the Y-N phase is detected by the neutral line missing phase. Power supply path for supplying power from the XY phase to the abnormal voltage detection circuit in a circuit breaker with AA neutral line phase loss protection that detects the abnormal voltage detection circuit and shuts off the main circuit when overvoltage occurs And a constant voltage diode is provided in series.

  According to the present invention, when the watt hour meter is replaced, the breaker with AA neutral line phase loss protection does not shut off, and the load power is turned off even when the watt hour meter is replaced. In addition, there is an effect that the circuit cost is low and the circuit can be simply configured.

  When the voltage between the X-N phase and the Y-N phase of the single-phase three-wire circuit is monitored by the abnormal voltage detection circuit, and the voltage between the X-N phase or the Y-N phase becomes overvoltage due to the neutral wire missing phase In a circuit breaker with AA neutral line phase loss protection, which is detected by the abnormal voltage detection circuit at the same time, a constant voltage diode in series with the power supply path for supplying power from the XY phase to the abnormal voltage detection circuit The power supply to the abnormal voltage detection circuit is stopped when the voltage between the XY phases drops below a predetermined value.

  A first embodiment of a circuit breaker with AA neutral wire phase loss protection according to the present invention will be described with reference to the attached drawing of FIG.

  The circuit breaker 1 with AA neutral wire phase loss protection is connected to a single-phase three-wire circuit consisting of two voltage lines X-phase, Y-phase and one neutral line N-phase. , 2 and main circuits 4, 4 and 4 connecting the load side terminals 3, 3 and 3 are provided with switching contacts 5, 5 and 5 to detect an open phase in the N phase on the load side outside the circuit breaker. Lead wire 6 is connected.

  The phase loss detection lead 6 is connected to a voltage dividing circuit 7 composed of a first resistor R1 and a second resistor R2, and the voltage dividing circuit 7 is connected via a trip coil 8 and the first diode D1 or the second diode D2. It is connected to the X phase and the Y phase. Then, the voltage between the X-N phase and the Y-N phase is divided by the voltage dividing circuit 7 and inputted to the abnormal voltage detection circuit 9 which is made into an IC to monitor the voltage.

  Further, the power supply of the abnormal voltage detection circuit 9 is supplied from the XY phase with the current limited by the current limiting resistor R3 and the voltage limited by the constant voltage diode ZD2. A constant voltage diode ZD1 is connected in series with the power supply path of the abnormal voltage detection circuit 9.

  When the neutral line N is lost and the load balance is lost, the voltage between the X-N phase or the Y-N phase rises, and the divided voltage of the voltage dividing circuit 7 input to the abnormal voltage detection circuit 9 is the reference. When the voltage exceeds the voltage, it is determined that the phase is open, the thyristor SCR is turned on by the output of the abnormal voltage detection circuit 9, the trip coil 8 is excited by turning on the thyristor SCR, and the trip mechanism is excited by the excitation of the trip coil 8. 11 is driven to open and close the switching contact 5 of the main circuit 4.

  When replacing the watt-hour meter 12 installed upstream of the single-phase three-wire electric circuit to which the AA neutral line breaker-protected circuit breaker 1 is connected, it is first removed from the X-phase voltage line. When the X-phase wire is removed, the voltage between the Y and N phases remains at 100 V, and the voltage between the X and Y phases is 100 V or less divided by the load 1 and the load 3 connected to the load side of the circuit breaker 1. A low voltage is applied.

  At this time, the voltage between the XY phases becomes lower than the Zener voltage of the constant voltage diode ZD1 provided in the power supply path, and therefore the constant voltage diode ZD1 stops the power supply to the abnormal voltage detection circuit 9. As a result, even when the watt-hour meter 12 in the absence home is replaced, the power source of the load does not remain off.

It is a circuit diagram which shows the circuit breaker with an AA neutral wire phase loss protection based on this invention. It is a circuit diagram which shows the conventional breaker with AA neutral wire phase loss protection.

Explanation of symbols

1 Circuit Breaker with AA Neutral Wire Phase Loss Protection 7 Voltage Dividing Circuit 8 Trip Coil 9 Abnormal Voltage Detection Circuit 10 Divided Voltage Reduction Circuit 12 Energy Meter ZD1 Constant Voltage Diode

Claims (1)

  When the voltage between the X-N phase and the Y-N phase of the single-phase three-wire circuit is monitored by the abnormal voltage detection circuit, and the voltage between the X-N phase or the Y-N phase becomes overvoltage due to the neutral wire missing phase In the circuit breaker with AA neutral line phase loss protection, which is detected by the abnormal voltage detection circuit at the same time, the circuit is fixed in series with the power supply path for supplying power from the XY phase to the abnormal voltage detection circuit. A breaker with AA neutral wire phase loss protection, characterized by providing a voltage diode.

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