JPH02294216A - Circuit breaker - Google Patents

Abstract

PURPOSE:To allow a circuit breaker to perform the test easily whether or not an overvoltage detection circuit itself is normally operated by connecting a false overvoltage generation circuit connected to a single phase three line cable run and a test switch connected to the false overvoltage generation circuit to an overvoltage detection circuit. CONSTITUTION:A false overvoltage generation circuit 16 connected to a single phase three line cable run 1 and a test switch 17 connected to this false overvoltage generation circuit 16 are connected to an overvoltage detection circuit 5. As a result, by turning ON the test switch 17, the output from the false overvoltage generation circuit 16 connected to the single phase three line cable run 1 is forcibly applied to the overvoltage detection circuit 5. The test can thereby easily be performed whether or not a circuit breaker itself is normally operated with the overvoltage.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a circuit breaker for use in single-phase three-wire electrical circuits.

2. Description of the Related Art In general, earth leakage circuit breakers include a test switch for checking whether or not the earth leakage circuit breaker normally performs a current leakage operation, so that its operation can be checked.

However, in a single-phase three-wire circuit breaker, there is no means to test whether the circuit breaker operates normally due to overvoltage.

Problem to be Solved by the Invention A single-phase three-wire circuit breaker equipped with an overvoltage detection circuit lacks reliability because it is not possible to test whether the circuit breaker operates normally due to overvoltage. It was something.

Means for Solving the Problems: An overvoltage detection circuit that is connected to a single-phase three-wire electric circuit and detects overvoltage, an operating coil that is energized by the output from this overvoltage detection circuit, and a switch mechanism that interrupts the circuit using this operating coil. In the circuit breaker, a pseudo overvoltage generation circuit connected to the single-phase three-wire electric circuit and a test switch connected to the pseudo overvoltage generation circuit were connected to the overvoltage detection circuit.

By turning on the action test switch, the output from the pseudo-overvoltage generation circuit connected to the single-phase three-wire circuit is forcibly applied to the overvoltage detection circuit, thereby testing whether the circuit breaker itself operates normally due to overvoltage. It is possible to easily test whether or not it is true, thereby improving reliability.

Example An embodiment of the present invention will be described based on the drawings.

First, the single-phase three-wire electric line 1 consists of live wires 2.
3 and N neutral MA4. An overvoltage detection circuit 5 is connected to such a single-phase three-wire electric line 1. That is, this overvoltage detection circuit 5 has a power supply circuit 6 connected to the single-phase three-wire electric circuit 1, and a reference voltage generation circuit 8 is connected to this power supply circuit 6 via a waveform shaping circuit 7. It has a comparator 9 to which a circuit 8 is connected. The other input of this comparator 9 is connected to the connection midpoint of voltage dividing resistors 10.11, labeled R, , R, connected to the neutral line 4. An output circuit 13 is connected to the output side of the comparator 9 via a delay circuit 12, and a switching circuit 14 is connected to the output circuit 13. This switching circuit 14 is connected to an operating coil 15 that drives a switch mechanism (not shown).

Next, the pseudo overvoltage generating circuit l6 and the test switch 17
The test switch 17 is connected to one input terminal of the comparator 9 via a resistor 18 R3. The pseudo overvoltage generating circuit 16 is formed of resistors 19.20, R4 and R, each having a resistance value of 3.2 or 41, respectively.
20 is connected to the live wires 2 and 3.

In a configuration like 2, the test switch 17 is normally open, and the comparator 9 has a reference voltage generating circuit 8 and a resistor t.
o and 11 are connected. And single-phase three-wire electric line 1
When the voltage is normal, the voltage generated at the midpoint of the connection between the resistors 10 and 11 has a constant voltage waveform as shown in FIG. It never exceeds the voltage V REF. Therefore, no output is produced from the comparator 9.

If an overvoltage occurs in the single-phase three-wire circuit 1 in this state, the voltage waveform at the neutral wire 4 will be unbalanced as shown in Figure 3, and the voltage will exceed the reference voltage V REF. Become. In this state, an output is generated via the output circuit 13 and the switching circuit 14, and the operating coil 15 is energized. As a result, a switch mechanism (not shown) operates to open the contacts inserted into the single-phase three-wire electrical circuit 1, thereby interrupting the electrical circuit.

Next, when the voltage of the single-phase three-wire electric line 1 is normal,
In order to test whether the overvoltage detection circuit 5 operates normally, the test switch 17 is turned on. This results in
Due to the unbalanced resistors 19 and 20 connected to the live currents m2 and 3, a voltage with a waveform as shown in FIG. 3 is applied to the comparator 9, thereby forcibly creating an overvoltage application state. It will be. As a result, if the overvoltage detection circuit 5 is normal, an output power is output from the switching circuit 14, energizing the operating coil 15, and the switch mechanism is turned off. At this time, if there is an abnormality in the overvoltage detection circuit 5, the switch mechanism is not turned off. Therefore, a test is performed to see if the overvoltage detection circuit 5 is normal.

Effects of the Invention As described above, the present invention comprises an overvoltage detection circuit that is connected to a single-phase three-wire electrical circuit and detects overvoltage, an operating coil that is energized by the output from the overvoltage detection circuit, and a switch that interrupts the circuit using the operating coil. In the circuit breaker equipped with a mechanism, the pseudo overvoltage generation circuit connected to the single-phase three-wire electric circuit and the test switch connected to the pseudo overvoltage generation circuit are connected to the overvoltage detection circuit, so that the test switch is turned on. By doing this, the output from the pseudo overvoltage generation circuit connected to the single-phase three-wire circuit is forcibly applied to the overvoltage detection circuit, and by observing the resulting operation,
This has the effect that it is possible to easily test whether or not the overvoltage detection circuit itself operates normally, thereby improving reliability.

be.

1 ・Single-phase three-wire electrical circuit, ...Operating coil, 16 7.Test switch applicant 5... Overvoltage detection circuit, Pseudo overvoltage generation circuit, Toshiba Lighting Corporation

[Brief explanation of drawings]

Claims (1)

[Claims] The circuit breaker includes an overvoltage detection circuit that is connected to a single-phase three-wire electrical circuit and detects overvoltage, an operating coil that is energized by the output from the overvoltage detection circuit, and a switch mechanism that interrupts the circuit by the operating coil. A circuit breaker characterized in that a pseudo overvoltage generation circuit connected to a single-phase three-wire electric circuit and a test switch connected to the pseudo overvoltage generation circuit are connected to the overvoltage detection circuit.