JPH08203413A - Earth leakage breaker - Google Patents

Abstract

PURPOSE: To provide an earth leakage breaker with a built-in tester, which current is prevented from continuing to flow to a test circuit when the ON condition of a test switch continues, and capable of reverse connection. CONSTITUTION: A test resistor 1 and a switching means 2 are connected in series to a power connection 3, and this earth leakage breaker is equipped with a ZCT 4, which detects a test current in a noncontact manner, and also test switching means 2 is connected to a control circuit 6 which includes a test switch 5. The control circuit 6 is equipped with a timer 7 which turns off the switching means 2 when a specified time passes after start of test.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth leakage breaker incorporating an improved test device for checking the interruption performance of an earth leakage breaker.

[0002]

2. Description of the Related Art Conventionally, in an earth leakage breaker having a built-in test device, a test device having a circuit as shown in FIG. 3 (A) has been used. In this test device, when the test switch 5 is turned on, current flows in the test circuit,
The ZCT 4 detects the current and activates an earth leakage breaker (not shown) to check the interruption performance of the earth leakage breaker. When the earth leakage breaker is connected in sequence, the test equipment uses the output side of the earth leakage breaker as the power source, so the earth leakage breaker is activated and the power of the test equipment also turns off. No current flows. However, in such a test device, when the earth leakage breaker is reversely connected, the power source of the test device is connected to the input side, so that the breaker trips if the ON state of the test switch 5 continues. However, the power does not turn off. Therefore, the circuit current of the rated value will continue to flow in the test circuit, but since the test resistor 1 is not designed to normally withstand the rated current for a long time, this continuous current may deteriorate the quality. Sometimes there was a risk of burning.

As a test device for an earth leakage breaker that can be reversely connected, there is a test device having a circuit shown in FIG. 3 (B). In this circuit, since the interlock switch 51 that performs the on / off operation in conjunction with the on / off operation of the breaker of the circuit breaker is incorporated in the circuit in series, even in the case of the reverse connection,
If the circuit breaker operates, the interlock switch 51 will interlock and become OF
It becomes F, and the current of the test circuit is cut off. However, in any of the circuits (A) and (B) described above, when the breaker does not operate for some reason when the test switch 5 remains ON, the current in the test circuit continues to flow. So there was a problem similar to the above.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and prevents the current from continuously flowing in the test circuit when the ON state of the test switch continues. (EN) Provided is an earth leakage breaker with a built-in test device and capable of reverse connection.

[0005]

The above problem is caused by the switching means which is controlled by a control circuit having a timer that turns on the test current when the test switch is turned on and then turns off after a predetermined time has passed. This can be solved by an earth leakage breaker characterized by having a built-in test device.

[0006]

According to the present invention, as described above, the ONOF of the switching means is controlled by the control circuit having the timer for turning on the test current and turning it off after the elapse of a predetermined time in the present invention.
Since it is performed by F, it can be applied to both forward connection and reverse connection. Further, even if the circuit breaker does not operate during the test for some reason, the test current does not flow for a predetermined time or longer. Therefore, it is possible to eliminate the possibility that the quality of the test resistor is deteriorated.

[0007]

EXAMPLES The present invention will be described in detail with reference to the examples shown in FIGS. (Embodiment 1) First, FIG. 1 shows an outline of an electric circuit relating to a test device incorporated in an earth leakage breaker of the present invention.
The test resistor 1 and the switching means 2 are configured so that a part of an electric circuit connected in series to the power supply connecting portion 3 passes through the ZCT 4 which detects the test current in a contactless manner. The switching means 2 is connected to the control circuit 6 including the test switch 5 and has a timer 7 so as to function as follows.

The control circuit 6 controls the O of the test switch 5.
Although the switching means 2 is controlled to be turned on by N, the timer 7 is provided to turn off the switching means 2 after a predetermined time has elapsed. With this timer 7, the energization time of the test current can be variably set to the time required for the breaker to operate, for example, from 0.05 seconds to 2 seconds. As the switching means 2, either a mechanical switch such as a relay switch or an electronic switch such as a triac can be applied. As the timer 7, a mechanical timer such as a bimetal contact type timer or an electronic timer such as an electronic clock type or an electronic timer in which a resistor, a capacitor and a transistor are combined can be applied as necessary.

(Embodiment 2) Next, a description will be given with reference to an embodiment shown in FIG. 2 in which the present invention is further embodied by providing an electronic timer. Similar to the first embodiment, the test resistor 1 and the switching means 2 are configured so that a part of the electric circuit connected in series to the power supply connecting portion 3 passes through the ZCT 4 that detects the test current in a contactless manner. However, the switching means 2 in this case uses a triac capable of turning on and off the alternating current.

Diode E1, resistor R1, capacitor C
A series of circuits composed of 1 and the constant voltage element E2 is a direct current constant voltage circuit which constitutes a part of the control circuit including the test switch 5 and supplies a current to a timer circuit described later. As a timer circuit, the test switch 5 includes a resistor R2 and a resistor R3 and a capacitor C2 on the bus A of the constant voltage circuit.
It is connected to the bus bar B of the constant voltage circuit with a pin in between. The base of the transistor T1 is connected between the resistor R3 and the capacitor C2 in the middle, the collector is connected to the base of the transistor T2, and the emitter is connected to the bus B of the constant voltage circuit. The base of the transistor T2 is connected between the resistor R4 connected to the middle of the test switch 5 and the resistor R3 and the resistor R5 connected to the bus B of the constant voltage circuit, and the emitter is connected to the bus of the constant voltage circuit. In addition to being connected to B, the collector is connected to the bus A of the constant voltage circuit via resistors R6 and R7. The gate of the triac 2 is connected between the resistors R6 and R7.

In the circuit thus constructed, when the test switch 5 is turned on, the transistor T1 remains off because of the presence of the capacitor C2, but the transistor T2 is turned on by the voltage determined by the resistors R4 and R5. Then, since the gate of the triac 2 is energized and the triac 2 is turned on, the test current flows through the test resistor 1 and the ZCT 4 senses the test current and operates the circuit breaker. However, even when the breaker does not operate for some reason while the test switch 5 remains ON, the capacitor C2 is charged after a certain period of time and the transistor T1 is ON, so that the operating voltage of the transistor T2 decreases. After that, the triac 2 is released from the ON state, and the test current is stopped. The time required for such a timer to function can be determined by the values of the resistor R3 and the capacitor C2.
The range of 5 seconds to 2 seconds is preferable.

As described above, also in the second embodiment, the test current is turned on by turning on the test switch.
This is performed by turning ON / OFF the switching means triac controlled by a control circuit having an electronic timer that becomes N and then turns OFF after a lapse of a predetermined time. Therefore, as in the case of the first embodiment, in both cases of forward connection and reverse connection. It is applicable, and even if the circuit breaker does not work during the test for some reason, the test current will not flow for more than the predetermined time. Furthermore, a small switch capable of lowering the operating voltage of the switching means can be used, and the device can be downsized. In addition, since the test equipment can be energized for the minimum time required to operate the circuit breaker, if there is an abnormality in the electronic element used in the leakage detection circuit of this test equipment, the circuit breaker will There is an advantage in that the reliability of the test itself is improved, such as the detection of abnormalities by not tripping the device.

[0013]

According to the present invention, the test current is passed through
When a predetermined time elapses after the test starts, it is turned off by the switching means controlled by the control circuit equipped with the timer
Therefore, it is applicable to both forward connection and reverse connection, and the test current does not flow for a predetermined time or longer even if the breaker does not operate for some reason. Therefore, there is an excellent effect that the possibility of causing the deterioration of the quality of the test resistance can be eliminated, so that the industrial value thereof is great.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a test apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a test device according to a second embodiment.

FIG. 3 is an explanatory diagram of a conventional test device.

[Explanation of symbols]

1: Test resistance, 2: Switching means, 3: Power supply connection part, 4: ZCT, 5: Test switch, 6: Control circuit,
7: Timer.

Claims (2)

[Claims] 1. A test switch is turned on when a test current is applied.
The circuit breaker has a built-in test device which is turned on by a control circuit having a timer which is turned off after a predetermined time has elapsed. 2. The earth leakage breaker according to claim 1, wherein the timer comprises an electronic circuit and the switching means is a semiconductor switching element.