JPS6347054B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuseless protector developed for household equipment such as telephones.

The purpose of this type of protector is to activate the lightning arrester to promptly discharge the fault current (shock wave) caused by lightning to the ground, and to prevent fault current (continuous wave) caused by contact with power lines, etc. The best way to do this is to block the circuit and prevent it from flowing into your home equipment.

Conventionally, in response to the inflow of continuous waves, the circuit was cut off by inserting a fuse F into the line L-I between the outside line terminal L and the extension line terminal I, and blowing it out, as shown in Figure 1. However, shock waves caused by lightning, etc., often cause fuses to blow if they have a large amount of energy, and fuses often blow out at once over a wide area, especially in mountainous regions where there is a lot of lightning. The drawback was that it required a lot of effort to maintain and operate it, and it took a long time to repair it, causing inconvenience to users. In order to deal with this problem of lightning damage, various types of fuseless protectors, ie, protectors that can achieve the purpose of interrupting circuits without using fuses, which have the disadvantage of being easily blown by shock waves, have been developed in recent years.

The present invention was proposed as a part of these developments, and has the purpose of preventing circuit breakage in response to shock waves such as lightning surges, and the purpose of preventing circuit breakage in response to continuous waves caused by power line interference, etc. This is achieved more reliably and effectively by applying a circuit connection method.

That is, as shown in Fig. 2, the three connection points of the external line terminal L, internal line terminal I, and lightning arrester A are connected to a contact _S1 provided on the external line terminal L side, a contact _S2 provided on the internal line terminal I side, and the lightning arrester. A three-contact contact mechanism is provided with a contact S ₃ provided on the A side, and a safety circuit is constructed by the contact of the three contacts S ₁ , S ₂ , S ₃ , and an external line terminal L as shown in the figure.
Contacts S ₁ and S ₂ of extension line terminal I are placed apart as fixed contacts, and contact S ₃ of lightning arrester A is connected between both fixed contacts S ₁ and S ₂ as a movable contact. and lightning arrester A are connected through the contact between the fixed contact _S1 and the movable contact _S3 , and the external line terminal L and the internal line terminal I are connected through the contact between the fixed contact _S1 and the movable contact _S3 and the movable contact _S3.
and the fixed contact _S2 is connected to each other through contact. In this way, when shock waves such as lightning flow in,
External line terminal L - Fixed contact S ₁ - Movable contact S ₃ - Lightning arrester A
- Eliminate this using a grounding circuit, and if a continuous wave due to power line contact etc. arrives, move the movable contact S ₃ attached between the fixed contacts S ₁ and S ₂ to both fixed contacts S ₁ , S ₂ in the direction away from the line (blocking side) to open the three contacts S ₁ , S ₂ , S ₃ , thereby disconnecting the lightning arrester A from the line L-I and at the same time disconnecting the line L-
I is completely cut off between the outside line terminal L and the extension line terminal I.

FIG. 5 illustrates a mechanism for operating the movable contact _S3 to the blocking side.

That is, the first and second contact pieces 1 and 2 constitute a line L-I, and the first and second contact pieces 1 and 2 are fixed contacts S ₁ and S ₂
The tips of the arresters are spaced apart and facing each other, and the arrester A is a known hermet type gas entry arrester.
A movable contact piece 3 is brought into elastic contact with the line electrode a ₁ via a low-melting point metal (metal that melts with discharge heat) 4 (SP indicates a spring for elastic contact), and the movable contact piece 3 is brought into elastic contact with the above-mentioned movable contact S. ₃ , the tip is placed in intervening contact with the fixed contacts S ₁ and S ₂ . In this way, when a continuous wave arrives, a discharge operation is performed via the first contact piece 1 - movable contact piece 3 - low melting point metal 4 - lightning arrester A, and the discharge generated as the discharge operation continues. The low melting point metal 4 is melted by heat, and as the metal 4 melts, the movable contact piece 3 is moved in a direction away from the first and second contact pieces 1 and 2 by a spring _S3 . As a result, the first and second
The contact pieces 1 and 2 and the movable contact piece 3 are simultaneously in an open state at the connection point between the external line terminal L, the internal line terminal I, and the lightning arrester A.

By adopting the three-contact mechanism as described above at the connection point of the external line terminal L, internal line terminal I, and lightning arrester A, the purpose of shock wave removal can be achieved,
When a continuous wave arrives, it is possible to open the communication line side, the home equipment side, and the lightning arrester side at the connection point of the three at once. That is, by disposing the three-contact mechanism at the connection point of the three, and connecting the contact _S3 on the lightning arrester A side between the other stationary contacts _S1 and _S2 on the line side, the contact _S3 The purpose of breaking the circuit can be achieved by simply moving the circuits apart. In the present invention, not only is the lightning arrester A disconnected from both the outside line terminal L and the extension terminal I to stop the discharge, but also the connection between the outside line terminal L and the extension terminal I is accurately cut off to prevent continuous waves from flowing into the telephone set, etc. definitely prevent it. As described above, the present invention achieves the purpose of interrupting the circuit in place of conventional fuses for continuous waves, while safely discharging shock waves to the ground without causing inconvenient circuit interrupts like fuses. This makes it possible to put into practical use a so-called fuseless protector.

Figure 3 shows a basic circuit that employs the three-contact mechanism described above, in which a current limiter B such as a positive temperature coefficient thermistor is inserted between the extension terminal I and the fixed contact S ₂ , and a current exceeding a certain value flows into the home equipment side. This shows the case where it is set not to be used.

Also, Figure 4 shows lines L ₁ -I ₁ and L ₂ -I ₂ and a shared lightning arrester.
The above three-contact contact mechanism is adopted for each connection point of A′,
An example in which current limiters B ₁ and B ₂ are used together will be shown.

If one of the contacts S ₂ and S ₃ is cut off, the circuit that quickly rotates the equipment through the other line will also be cut off, making the security purpose more reliable. This is effective, for example, when a lightning arrester is destroyed. Note that the number of electrodes of the lightning arrester can be arbitrarily set depending on the implementation.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a conventional telephone protector, FIG. 2 is a basic circuit diagram of a telephone protector of the present invention, and FIG. 3 is a circuit diagram showing an example in which a current limiter is used in the same basic circuit. Fig. 4 is a circuit diagram showing an example in which the same basic circuit is applied to lines L ₁ - I ₁ and L ₂ - I ₂ , and Figs. 5 A and B show the operating mechanism of the movable contact on the lightning arrester side before and after operation. FIG. L...External line terminal, I...Internal line terminal, A...Surge arrester, _S1 ...Fixed contact on the external line terminal side, _S2 ...Surge arrester on the internal line terminal side, _S3 ...Fixed contact on the lightning arrester side.

Claims (1)

[Claims] 1. In a communication protector in which a lightning arrester A is connected and grounded to the line L-I between the external line terminal L that connects to the communication line and the internal line terminal I that connects to the in-house equipment, the above-mentioned external line terminals I, L and the lightning arrester A A fixed contact _S1 is provided on the external line terminal L side, a fixed contact S2 is provided on the internal line terminal I side, and _a movable contact _S3 is provided on the lightning arrester A side.
In addition, a movable contact S3 on the lightning arrester A side is connected between the fixed contact _S1 on the external line terminal L side and the fixed contact _S2 on the internal line terminal I side, and the movable contact _{S3 is} When a continuous wave arrives, both fixed contacts S ₁ and S ₂ are moved away from each other to open the three contacts, and at the same time, the lightning arrester A is disconnected from the line L-I and the line L-I is connected to the external line terminal L internal line. A fuseless protector for communication characterized by cutting off between terminals I.