JP2004023850A - Circuit breaker for single-phase three-wires with neutral conductor phase-interruption protection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit breaker for a single-phase three-wires with neutral conductor phase-interruption protection, capable of preventing omission of the connection of a lead wire for phase interruption detection to the neutral wire. <P>SOLUTION: A voltage-dividing circuit 3 which outputs voltages obtained by dividing voltage from a main circuit to a failed-voltage detection circuit 2 is formed by connecting a third resistor R3 between one L2 of a voltage line and a lead wire 6 for phase interruption detection, in addition to a first resistor R1 and a second resistor R2 for dividing the voltage of the main circuit. The resistance value of the third resistor R3 is selected so that the voltage divider voltage with a total sum of the third resistor R3 and the first resistor R1 under a condition where the lead wire 6 for phase interruption detection connected with one end of the first resistor R1 is not connected with a neutral wire N and by the second resistor R2 may exceed a trip voltage determined as failure. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a circuit breaker with a single-phase three-wire neutral-phase missing-phase protection circuit, which detects the application of an unbalanced voltage to a load device due to a neutral-phase missing phase of a single-phase three-wire electrical circuit and cuts off a main circuit.
[0002]
[Prior art]
A conventional circuit breaker with a single-phase three-wire neutral-wire open-phase protection function is an abnormal voltage detection circuit for detecting the application of an abnormal voltage to a single-phase three-wire circuit as disclosed in Japanese Patent No. 3124452. (IC1), a trip coil (TC1) excited by the output of the abnormal voltage detection circuit (IC1), and a trip mechanism (2) for shutting off a main circuit operated by excitation of the trip coil (TC1). The voltage of the main circuit is divided by a voltage dividing circuit (4) composed of a first resistor (R1) and a second resistor (R2) and applied to an abnormal voltage detecting circuit (IC1). When an abnormal voltage is applied to the main circuit, the divided voltage of the voltage dividing circuit (4) exceeds the trip voltage and is applied to the abnormal voltage input terminal of the abnormal voltage detecting circuit (IC1). Then, the trip coil (TC1) is excited by the output of the abnormal voltage detection circuit (IC1), and the tripping mechanism (2) is operated by exciting the trip coil (TC1) to shut off the main circuit.
[0003]
[Problems to be solved by the invention]
The open phase detection lead wire connected to one end of the voltage dividing circuit (4) is used by being connected to a neutral wire. The vessel can be turned on. Therefore, if a circuit breaker that does not have the phase loss detection lead wire connected to the neutral wire is turned on, the abnormal voltage detection circuit will not operate even in a circuit with a neutral wire loss, and the circuit breaker will continue to turn on. There is a problem that an overvoltage is applied to the device and the device is damaged.
[0004]
SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a circuit breaker with a single-phase three-wire neutral-wire open-phase protection that prevents forgetting to connect a lead for detecting an open phase to a neutral wire.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a divided voltage obtained by dividing a voltage of a main circuit of a single-phase three-wire circuit by a voltage dividing circuit including a first resistor and a second resistor forms a trip voltage set in advance. When the voltage exceeds the limit, the trip coil is excited by the output of the abnormal voltage detection circuit, and the tripping mechanism is activated by the excitation of the trip coil to shut off the main circuit. A third resistor is connected between the first resistor and the open-phase detecting lead wire, and the voltage is divided by a voltage dividing circuit composed of a sum of the third resistor and the first resistor and a second resistor. The voltage is set to exceed the trip voltage.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
A voltage dividing circuit that divides the voltage of the main circuit to the abnormal voltage detection circuit and outputs the divided voltage is used for detecting one of the voltage lines and open phase in addition to the first and second resistors for dividing the voltage of the main circuit. A third resistor is connected between the lead wires. The resistance value of the third resistor is a sum of the third resistor and the first resistor in a state where the open-phase detecting lead wire connected to one end of the first resistor is not connected to the neutral wire, The voltage divided with the second resistor is selected so as to exceed the trip voltage determined by the abnormal voltage detection circuit to be abnormal.
[0007]
【Example】
An embodiment of the circuit breaker with single-phase three-wire neutral-phase-loss protection according to the present invention will be described with reference to the accompanying drawings in FIG.
[0008]
The circuit breaker 1 with single-phase three-wire neutral-wire open-phase protection includes an abnormal voltage detection circuit 2 for detecting the application of an abnormal voltage to the single-phase three-wire circuit, and a main circuit including the abnormal voltage detection circuit 2. A voltage dividing circuit 3 for dividing and outputting a voltage; a trip coil 4 which is excited by an output of the abnormal voltage detecting circuit 2 when the divided voltage of the voltage dividing circuit 3 exceeds a preset trip voltage; And a trip mechanism 5 which operates by excitation of the main circuit to cut off the main circuit.
[0009]
The voltage dividing circuit 3 includes a first resistor R1 and a second resistor R2 for dividing the voltage of the main circuit, and a third resistor R3 connected between one of the voltage lines L2 and the lead 6 for detecting phase loss. Made up of The resistance value of the third resistor R3 is equal to that of the third resistor R3 and the first resistor R3 when the lead wire 6 for phase loss detection connected to one end of the first resistor R1 is not connected to the neutral line N. The sum of the resistors R1 and the divided voltage of the second resistor R2 are selected so as to exceed the trip voltage.
[0010]
Therefore, in the case where the lead 6 for phase loss detection is forgotten to be connected to the neutral line N, the circuit breaker 1 is turned on regardless of whether the phase of the neutral line N is missing or not. Since the divided voltage exceeds the trip voltage, the abnormal voltage detection circuit 2 operates the trip coil 4 to cut off the main circuit.
[0011]
After the lead 6 for phase loss detection is connected to the neutral line N, the third resistor is simply connected between one of the voltage lines L2 and the neutral line N, so that the third phase resistance has no effect on the phase loss protection function. Without being affected, the voltage of the main circuit is divided by the first resistor R1 and the second resistor R2 to detect an abnormality of the main circuit.
[0012]
In the present embodiment, the third resistor R3 is connected between one of the voltage lines L2 and the lead wire 6 for detecting phase loss, but may be connected between the voltage line L1 and the lead wire 6 for detecting phase loss. .
[0013]
【The invention's effect】
As described above, when the divided voltage obtained by dividing the voltage of the main circuit of the single-phase three-wire circuit by the voltage dividing circuit including the first resistor and the second resistor exceeds a preset trip voltage. The tripping coil is energized by the output of the abnormal voltage detection circuit, and the tripping mechanism is actuated by exciting the trip coil to shut off the main circuit. And a third resistor connected between the open-phase detection lead wire and a divided voltage divided by a voltage dividing circuit composed of the sum of the third resistor and the first resistor and the second resistor. In addition, when the trip voltage is exceeded, when the lead wire for detecting the open phase is forgotten to be connected to the neutral wire, the circuit breaker is turned off, so that there is an excellent effect that the forgetting of the connection can be prevented.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a circuit breaker with single-phase three-wire neutral-phase-loss protection according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Single-phase three-wire neutral circuit breaker with phase loss protection 2 ... Abnormal voltage detection circuit 3 ... Voltage dividing circuit 4 ... Trip coil 5 ... Tripping mechanism 6 ... Lead wire R1 for phase loss detection ... First resistor R2 ... Second resistor R3 ... Third resistor

Claims (1)

When the divided voltage obtained by dividing the voltage of the main circuit of the single-phase three-wire circuit by the voltage dividing circuit including the first resistor and the second resistor exceeds a preset trip voltage, the abnormal voltage detecting circuit is activated. A single-phase three-wire neutral-wire open-phase protection circuit breaker that excites the trip coil by the output and activates the tripping mechanism by exciting the trip coil to cut off the main circuit. A third resistor is connected between the lead wires, and a divided voltage divided by a voltage dividing circuit composed of a sum of the third resistor and the first resistor and a second resistor is connected to the trip circuit. A circuit breaker with a single-phase three-wire neutral-wire open-phase protection characterized by exceeding the voltage.

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