JPH04111140U - earth leakage breaker - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an earth leakage breaker that issues an alarm before the earth leakage breaker performs a breaking operation. [Configuration] Zero-phase current transformer 4 that detects leakage in the main electric circuit 10
An alarm circuit 7 is connected to the secondary coil 4B of the earth leakage circuit breaker 3 and is set to issue an alarm at an operating current below a predetermined earth leakage current value at which the earth leakage breaker 3 performs a breaking operation.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention detects leakage current in the main electric circuit, and when this leakage current exceeds a predetermined current value. This invention relates to an earth leakage breaker that cuts off the main electrical circuit when the earth leakage occurs.

0002

[Conventional technology]

FIG. 2 shows an example of an electric circuit using a conventional earth leakage breaker. In Figure 2, For example, the main electric circuit 10 consisting of three phases R, S, and T is connected from the power supply 1 to the earth leakage breaker 3. The ring-shaped cores of the zero-phase current transformers 4 are connected in series through the interrupting section 6B of the interrupting circuit 6. -4A and is connected to load 2. It is wound around this ring-shaped core 4A. The secondary coil 4B is connected to the operating coil of the cutoff circuit 6 via the amplifier circuit 5 as necessary. Connected to 6A.

0003 When a current leak occurs on the load side of the main electric circuit 10 to which the earth leakage breaker 3 is connected, the main power An unbalanced current is generated in the air circuit 10, and this unbalanced current causes the secondary current of the zero-phase current transformer 4 to A current proportional to the leakage current is generated in the coil 4B. This current is transmitted by the amplifier circuit 5. The signal is amplified and applied to the operating coil 6A of the cutoff circuit 6. The leakage current is the specified current When the value is reached, the cutoff section 6B operates and the main electric circuit 1 is cut off.

0004 In addition, 8 is the operation test circuit of the earth leakage breaker, and it is activated by pressing the switch 8A. A current corresponding to the leakage current is caused to flow through the resistor 8B to operate the interrupting circuit 6. The sea urchin is turning.

[0005]

[Problem that the idea aims to solve]

Electrical leakage occurs due to poor insulation of the main electrical circuit or load electrical equipment. Generally, leakage current often increases gradually over time. however In the earth leakage circuit breaker mentioned above, when the earth leakage current reaches a predetermined current value, the circuit breaker suddenly shuts off. For example, if a factory's production line stops, the impact is extremely large.

[0006] The purpose of this invention is to provide an earth leakage circuit breaker that issues an alarm before the earth leakage breaker performs the interrupting operation. Our goal is to provide circuit breakers.

[0007]

[Means to solve the problem]

In order to achieve the above-mentioned purpose, the present invention uses a zero-phase current transformer to detect earth leakage in the main electric circuit. connected to the secondary coil of this zero-phase current transformer, and the leakage current reaches a predetermined current value. In the earth leakage breaker, the earth leakage breaker is equipped with a cutoff circuit that cuts off the main electric circuit when the zero-phase Below the predetermined leakage current value that is connected to the secondary coil of the current transformer and operates the cutoff circuit. An alarm circuit should be provided that is set to issue an alarm at the operating current.

[0008]

[Effect]

In the earth leakage breaker of the present invention, the second zero-phase current transformer that detects earth leakage in the main electric circuit Next, connect an alarm circuit to the coil, and cut off the operating current of this alarm circuit with this earth leakage breaker. Since the earth leakage current is set below the specified earth leakage current value at which the circuit operates, the earth leakage breaker will not perform the breaking operation. You can give a warning before doing so.

[0009]

【Example】

FIG. 1 shows an electric circuit using an earth leakage breaker according to an embodiment of the present invention. figure The difference from the conventional earth leakage breaker shown in 2 is that the second zero-phase current transformer 4 detects earth leakage. This is because the alarm circuit 7 is connected to the amplifier circuit 5 connected to the next coil 4B. this The alarm circuit 7 is, for example, a relay whose operating coil 7A is connected to the amplifier circuit 5. 7B and the power supply 7D connected in series to the a contact of the switching contact 7C of this relay 7B. A cutoff circuit 6 operates to cut off the operating current of this relay 7B. Set below the specified leakage current value.

0010 On the load side of the main electric circuit 10, there is a If the current leakage occurs due to the First, when the operating current falls below a predetermined current value for operating the interrupting circuit 6 of this earth leakage breaker 3. The set relay 7B operates, and the switching contact 7C changes due to the operation of relay 7B. It switches to the a contact side and is activated by a circuit consisting of power supply 7D, switching contact 7C, and indicator light 7E. The indicator light 7E lights up. This causes the earth leakage breaker 3 to warn before performing the interrupting operation. issue a report. If the alarm is left unattended, the leakage will continue over time. When the current increases and reaches a predetermined current value, the cutoff circuit 6 is activated and the main electric circuit 1 is cut off. It will be done. Note that the operating current of the relay 7B of the alarm circuit 7 is changed from the operating current of the cutoff circuit 6, i.e. In other words, if the earth leakage breaker is set to approximately 1/2 of the predetermined earth leakage current value at which it operates to interrupt, In addition to being able to detect leakage in the main electrical circuit, there is enough This is preferable because there is time and it is possible to deal with it.

[0011]

[Effect of the idea]

The earth leakage breaker of the present invention issues an alarm before it performs the interrupting operation, so if the main electric circuit is The main electrical circuit, e.g. line or load, is This makes it possible to perform maintenance inspections for insulation deterioration in electrical equipment, etc., and this enables factory production lines to be This is very effective as it prevents sudden stops such as in the case of an engine.

[Brief explanation of drawings]

[Fig. 1] Fig. 1 is an electrical circuit diagram using an earth leakage breaker according to an embodiment of the present invention.

[Figure 2] Figure 2 is an electrical circuit diagram using a conventional earth leakage breaker

[Explanation of symbols]

3 Earth leakage breaker 4 Zero phase current transformer 5 Width increase circuit 6 Breaking circuit 7 Alarm circuit 7A operating coil (of relay 7B) 7B Relay 7C switching contact (of relay 7C) 7D power supply 7E indicator light 10 Main electrical circuit

Claims (3)

[Scope of utility model registration request] Claim 1: A zero-phase current transformer that detects leakage in a main electric circuit, and a zero-phase current transformer that is connected to a secondary coil of the zero-phase current transformer and shuts off the main electric circuit when the leakage current reaches a predetermined current value. an alarm circuit connected to the secondary coil of the zero-phase current transformer and set to issue an alarm at an operating current below a predetermined earth leakage current value that operates the interrupting circuit; An earth leakage breaker characterized by being provided with. 2. The earth leakage breaker according to claim 1, wherein the operating current of the alarm circuit is set to approximately 1/2 of a predetermined earth leakage current value for operating the interrupting circuit. 3. The earth leakage breaker according to claim 1, wherein the alarm circuit comprises a relay whose operating coil is connected to a secondary coil of a zero-phase current transformer, and a power supply connected in series to the switching contact of this relay. and an indicator light.