JPH025615Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Industrial application field] This invention is related to electric leakage and disconnection.
In particular, it concerns the protection of the test circuit.

[Conventional technology]

FIG. 2 is an electrical wiring diagram showing a conventional leakage and disconnection circuit. In FIG. 2, when the test switch 12 is closed, the terminal U on the load side → the resistor 13 → the test switch 12 → the test winding 11 → the terminal W on the load side.
A closed circuit is formed, and the zero-phase current transformer 3 produces an output of a predetermined value or more in its secondary winding 4. This output is amplified by an amplifier 5 and makes a switching element 6, for example a thyristor, conductive. When this switching element 6 becomes conductive, a closed circuit is formed from the load side U terminal → trip coil 8 → rectifier 9 → switching element 6 → rectifier 9 → load side W terminal, which excites the trip coil 8 and opens the main contact 1. If there is a current leakage, the disconnector will be tripped. When the main contact 1 is opened in this way, the load side terminals U and W become voltage-free, so the test circuit 10 consisting of the series circuit of the test winding 11, the test switch 12, and the resistor 13 automatically becomes voltage-free. becomes.

In this way, the test circuit 10 closes the test switch 12 and when a leak occurs or the disconnector is tripped,
Since there is no voltage automatically, the power consumption of the leakage or disconnection including the test circuit 10 is calculated based on the power consumption required for the operation time (within 0.1 seconds) of the leakage or disconnection, and it is different from the continuous rating. It has not been aged and is rated for a short time.

[Problem that the invention attempts to solve]

As mentioned above, the power consumption of leakage and disconnection switches is set taking into account the operating time (within 0.1 seconds) of the leakage and disconnection, which causes the following problems. (a) If there is a current leakage or the disconnector is inoperable due to a malfunction or the like, if the test switch 12 is kept closed, the resistor 13 may overheat and become disconnected. (b) For example, if the main contact 1 is connected incorrectly at a consumer and is inserted on the load side from the connection position of the test circuit 10 to the main circuit 2 in FIG. 2, the test switch 12 is closed and the main contact 1 is Even if it is opened, the test circuit 10 does not become voltage-free. Therefore, while the test switch 12 is closed, current flows through the test circuit 10 for longer than the operating time (within 0.1 seconds) for leakage or disconnection, and as the current flows for longer than the rated operating time, the resistor 13 is deteriorated. , and depending on the frequency of operation of the test switch 12, etc., disconnection may occur.

This idea was made to solve this problem, and even if the test switch is kept closed,
It prevents deterioration of the resistance and disconnection of the test circuit, and provides current leakage and disconnection for the purpose of protecting the test circuit.

[Means for solving problems]

The current leakage and disconnection device according to this invention has a switching element that excites a trip coil when conductive and a test circuit connected in parallel, and this parallel circuit is connected in series to the trip coil.

[Effect]

In this invention, a switching element and a test circuit are connected in parallel, and this parallel circuit is connected in series with a trip coil, so that when the switching element is non-conducting, the trip coil and the test circuit are connected in series, and when the switching element is conducting, the trip coil and the test circuit are connected in series. Prevent current from flowing into the test circuit.

〔Example〕

FIG. 1 is an electrical wiring diagram showing an embodiment of the earth leakage and disconnection circuit according to this invention. In FIG. 1, a main contact 1 is inserted into a main circuit 2, and the main circuit 2 is inserted through the hollow part of a zero-phase current transformer 3 as a primary winding. The secondary winding 4 of the zero-phase current transformer 3 produces an output when a leakage occurs in the main circuit 2, and the output is amplified by the amplifier 5. The switching element 6 is, for example, a thyristor, and becomes conductive when the output of the amplifier 5 exceeds a predetermined value, and is maintained in the conductive state by the charge in the capacitor 7. The trip coil 8 is
The main contact 1 is excited by the current flowing through the closed circuit of the U terminal on the load side → trip coil 8 → rectifier 9 → switching element 6 → rectifier 9 → W terminal on the load side, which is formed when the switching element 6 is conductive. Open it to prevent current leakage and trip the disconnector. Test circuit 10
is composed of a series circuit of a test winding 11, a test switch 12, and a resistor 13 connected to a zero-phase current transformer 3, one end of which is connected between the trip coil 8 and the rectifier 9, and the other end connected to W on the load side. connected to the terminal.

That is, when the switching element 6 is non-conductive, the test circuit 10 is connected in series with the trip coil 8 between the load side terminals U and W, and when the test switch 12 is closed, the connection is made from the load side U terminal to the trip coil 8.
→ Test winding 11 → Test switch 12 → Resistor 1
3→A closed circuit of the W terminal on the load side is formed. In this case, since the resistance value of the resistor 13 (approximately 2.7KΩ) is sufficiently large compared to the resistance value of the trip coil 8 (approximately 100Ω), most of the voltage is applied to the resistor 13,
The trip coil 8 does not operate even with the instantaneous rush current that closes the test switch 12. If the test switch 12 is kept closed in this state, the induced output of the secondary winding 4 will eventually exceed a predetermined value, and the switching element 6 will become conductive. When the switching element 6 becomes conductive, the U terminal on the load side → trip coil 8 → rectifier 9 → switching element 6 → rectifier 9
→A closed circuit of the W terminal on the load side is formed, and the trip coil 8 is energized to open the main contact 1. In this case, the test circuit 10 is connected in parallel to the switching element 6 via the rectifier 9, and no current flows through the test circuit 10 even if the test switch 12 is kept closed.

[Effect of idea]

As explained above, in this invention, since the test circuit is connected in parallel to the switching element when the switching element is conductive, the test circuit does not deteriorate or burn out even if the test switch is kept closed.

[Brief explanation of drawings]

FIG. 1 is an electrical wiring diagram showing an embodiment of the current leakage breaker and disconnector according to the present invention, and FIG. 2 is an electrical wiring diagram showing a conventional leakage breaker and breaker. In the figure, 3 is a zero-phase current transformer, 6 is a switching element, 8 is a trip coil, 10 is a test circuit, 11 is a test winding, 12 is a test switch,
13 is a resistance. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] a zero-phase current transformer that detects leakage current; a switching element that becomes conductive when the output of the zero-phase current transformer exceeds a predetermined value; a trip coil that trips the energized circuit breaker when the switching element is conductive; A test circuit that causes the zero-phase current transformer to generate an output of the predetermined value or more when the test switch is closed, in a circuit including a series circuit of a test winding applied to the phase current transformer, a test button, and a resistor. An earth leakage or disconnection device comprising: the test circuit is connected in parallel to the switching element, and the parallel circuit of the switching element and the test circuit is connected in series with the trip coil.