JP3092926B2 - Contact protection circuit - Google Patents
Contact protection circuitInfo
- Publication number
- JP3092926B2 JP3092926B2 JP01261989A JP26198989A JP3092926B2 JP 3092926 B2 JP3092926 B2 JP 3092926B2 JP 01261989 A JP01261989 A JP 01261989A JP 26198989 A JP26198989 A JP 26198989A JP 3092926 B2 JP3092926 B2 JP 3092926B2
- Authority
- JP
- Japan
- Prior art keywords
- resistor
- contact
- current
- circuit
- surge
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Emergency Protection Circuit Devices (AREA)
- Protection Of Static Devices (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、通信回線に直列に挿入される接点、例えば
電話回線が故障したとき、故障個所が電話機側か通信線
路側かを識別するに際し、両者間を切離すための接点が
用いられるが、かかる接点を雷サージ等の大電流から保
護するための接点防護回路に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a contact inserted in series in a communication line, for example, when a telephone line breaks down, it is necessary to identify whether the failure point is on the telephone side or the communication line side. The present invention relates to a contact protection circuit for protecting such a contact from a large current such as a lightning surge.
従来この種接点の防護は、接点の通信回線側に防護素
子を接続するとともに、端末装置（電話機）側の対地イ
ンピーダンスを大とすることにより実現していた。Conventionally, protection of this type of contact has been realized by connecting a protection element to the communication line side of the contact and increasing the impedance to ground on the terminal device (telephone) side.
第３図は、従来のかかる接点防護回路を説明するため
の回路図であって、Ｔは端末装置、Sa,Sbは接点、La,Lb
は通信回線、EXは交換装置、ARRは防護素子、Ｇは接地
を表わす。FIG. 3 is a circuit diagram for explaining such a conventional contact protection circuit, where T is a terminal device, Sa and Sb are contacts, and La and Lb.
Is a communication line, EX is a switching device, ARR is a protection element, and G is ground.
通信回線La,Lbに誘起された雷サージ等のサージ電流
は防護素子ARRを介して接地Ｇに流通する。このとき通
信回線La,Lbの端末装置Ｔ側の電位は、接地Ｇの接地抵
抗RG（Ω）が零でないため、サージ電流IS（Ａ）が流れ
ると、オームの法則により、RG×IS（Ｖ）だけ上昇し、
この電圧は例えばRG＝10Ω,IS＝1,000Aとしても、10,00
0Vにも及ぶ大きなものとになる。A surge current such as a lightning surge induced in the communication lines La and Lb flows to the ground G via the protection element ARR. At this time, since the ground resistance R G (Ω) of the ground G is not zero, the potential of the communication lines La and Lb on the terminal device T side is R G × according to Ohm's law when the surge current I S (A) flows. Rises by I S (V),
For example, even if R G = 10Ω and I S = 1,000 A, this voltage is 10,000
It will be as large as 0V.
基本機能のみを有する一般的な電話機は、交換装置EX
から通信回線La,Lbを介して供給される電力のみで動作
可能であり、端末装置Ｔは大地から絶縁して設置するこ
とが可能であり、サージ電流は防護素子ARRを通じて大
地に流通するため、接点Sa,Sbに大電流が流れることは
無く、接点の防護の目的が達成されている。A general telephone with only basic functions is the exchange device EX.
From the power supply via the communication lines La and Lb, the terminal device T can be installed insulated from the ground, and the surge current flows to the ground through the protection element ARR. No large current flows through the contacts Sa and Sb, and the purpose of protecting the contacts has been achieved.
しかし、近年電話機の高機能化が進み、交換装置EXか
ら供給される電力のみでは不足するため、商用電源を併
用する機種が増大しつつある。However, in recent years, the functions of telephones have become more sophisticated, and only electric power supplied from the exchange device EX is insufficient. Therefore, models using a commercial power supply together are increasing.
かかる電話機では、商用電源回路を保護するために通
信回線と商用電源回路間にバリスタ等の防護素子を接続
しているものがあり、通信回線の電位が上昇すると、前
記防護素子が動作して通信回線に生じたサージ電流は商
用電源の配電線にも流通し、接点Sa,Sbに大電流が流
れ、結局従来の防護回路では接点Sa,Sbの保護ができな
くなるという欠点が生じ、その解決手段の開発が望まれ
ていた。更には保安のため接点に直列にヒューズが挿入
される場合があるが、このヒューズには耐量の大きなも
のが要求されるという問題もあった。In some of such telephones, a protection element such as a varistor is connected between the communication line and the commercial power supply circuit to protect the commercial power supply circuit. When the potential of the communication line rises, the protection element operates to perform communication. The surge current generated in the line also circulates in the distribution line of the commercial power supply, and a large current flows through the contacts Sa and Sb, and as a result, the conventional protective circuit cannot protect the contacts Sa and Sb. The development of was desired. Further, a fuse may be inserted in series with the contact for security. However, there is a problem that a fuse having a high withstand capacity is required.
本発明の目的は、上記欠点及び問題点を解決し、サー
ジ電流等に起因する大電流が接点に流入してもその防護
が可能であると共に、保安のために該接点に直列に接続
するヒューズに、保安の目的に反するような耐量の大き
なものを要求しなくとも済むような接点防護回路を提供
することにある。SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks and problems, and to protect a large current caused by a surge current or the like from flowing into a contact and to connect the fuse in series to the contact for security. Another object of the present invention is to provide a contact protection circuit which does not require a large withstand voltage that is contrary to the purpose of security.
上記目的達成のため本発明では、通信回線に直列に挿
入された接点の防護回路において、前記接点と直列に、
雷サージの如き比較的大きなサージ電流に対して溶断し
ない定格電流の大きなヒューズエレメントと、抵抗体を
接続して直列回路を形成するとともに、前記抵抗体を前
記ヒューズエレメントに巻回する形をとって両者を密に
熱結合させ、前記抵抗体が前記接点保護のための電流制
限用抵抗として機能するだけではなく、該抵抗体を長期
間に渡って流れる事故電流により発熱して前記ヒューズ
エレメントを溶断させる際、速やかな溶断を可能にする
機能をも前記抵抗体に持たせ、更に前記直列回路にサー
ジ防護素子を並列接続することとした。In order to achieve the above object, according to the present invention, in a protection circuit for a contact inserted in series in a communication line, in series with the contact,
A fuse element having a large rated current that does not blow against a relatively large surge current such as a lightning surge is connected to a resistor to form a series circuit, and the resistor is wound around the fuse element. The two elements are tightly thermally coupled, and not only does the resistor function as a current limiting resistor for protecting the contact point, but also the fuse element is blown by being heated by an accidental current flowing through the resistor for a long period of time. At this time, the resistor also has a function of enabling quick fusing, and a surge protection element is connected in parallel to the series circuit.
その結果接点に流れる電流を接点の耐量以下に制限で
きる上、ヒューズエレメントは抵抗体と密に熱結合され
ていることから、長時間連続する事故電流に対しては、
小電流でも作動するので保安の機能を果たすことができ
る。As a result, the current flowing through the contact can be limited to the withstand value of the contact or less, and the fuse element is tightly thermally coupled with the resistor.
Since it operates even with a small current, it can perform a security function.
第１図は本発明の一実施例を説明するための回路図で
あって、前出の記号は同種対象を表わし、そのほかARR1
は前置防護素子、VRa,VRbは防護素子、Fa,Fbはヒューズ
エレメント、Ra,Rbは抵抗体、G1,G2は接地である。FIG. 1 is a circuit diagram for explaining an embodiment of the present invention, wherein the above-mentioned symbols represent the same kind of object, and in addition, ARR 1
Is a front protection element, VRa and VRb are protection elements, Fa and Fb are fuse elements, Ra and Rb are resistors, and G 1 and G 2 are grounds.
接点Sa（Sb）とヒューズエレメントFa（Fb）と抵抗体
Ra（Rb）は直列接続されており、この直列回路には更に
防護素子VRa（VRb）が並列に接続されている。更に後述
する如く、ヒューズエレメントFa（Fb）と抵抗体Ra（R
b）は熱結合されている。Contact Sa (Sb), fuse element Fa (Fb) and resistor
Ra (Rb) is connected in series, and a protection element VRa (VRb) is further connected in parallel to this series circuit. As described further below, the fuse element Fa (Fb) and the resistor Ra (R
b) is thermally bonded.
次に動作を説明すると、端末Ｔが図示していない内部
防護回路を介して通信回線La,Lbを接地G2に接続してい
る場合、通信回線に生じたサージ電流は前記回路にて流
れることとなる。サージ電流は値が小さい場合は抵抗体
Ra（Rb），ヒューズエレメントFa（Fb），接点Sa（Sb）
の経路で流通する。このとき前記直列回路の両端にはサ
ージ電流をＩ（Ａ），抵抗体Ra,Rbの値をＲ（Ω）で表
わすと、Ｉ×Ｒ（Ｖ）の電圧が発生する。該電圧が防護
素子VRa（VRb）の動作電圧以上になると防護素子は電流
を通じるようになり、その結果前記直列回路の両端電圧
は防護素子VRa（VRb）の動作電圧Vrに制限される。Now be described the operation, when the terminal T is connected communication line La via the internal protection circuit (not shown), and Lb to the ground G 2, surge current generated in the communication line to flow in the circuit Becomes If the surge current is small, use a resistor
Ra (Rb), fuse element Fa (Fb), contact Sa (Sb)
It is distributed by the route of. At this time, if the surge current is represented by I (A) and the values of the resistors Ra and Rb are represented by R (Ω), a voltage of I × R (V) is generated at both ends of the series circuit. When the voltage becomes equal to or higher than the operating voltage of the protection element VRa (VRb), the protection element conducts current, so that the voltage across the series circuit is limited to the operating voltage Vr of the protection element VRa (VRb).
換言すると、直列回路に流通する電流はVr/Rに制限さ
れ、この電流値が接点Sa（Sb）の耐量以下となるように
Vr,Rを選定すれば接点に流れる電流を該接点の耐量以下
とすることができ、本発明の主目的が達成される。更に
本発明によればヒューズエレメントに流れる電流も同時
に制限されることとなり、従来より耐量の小さな小形で
安価なものの使用が可能となる。In other words, the current flowing through the series circuit is limited to Vr / R, and the current value is set to be equal to or less than the withstand voltage of the contact Sa (Sb).
If Vr and R are selected, the current flowing through the contact can be reduced to the withstand value of the contact or less, and the main object of the present invention is achieved. Further, according to the present invention, the current flowing through the fuse element is also limited at the same time, so that a small-sized and inexpensive device having a small withstand capability can be used.
又、抵抗体Ra（Rb）とヒューズエレメントFa（Fb）と
は熱結合されており、通信回線が電力線に接触した場合
等の事故電流に対しては、該事故電流によって抵抗体Ra
（Rb）が発熱して温度が上昇し、該温度上昇はヒューズ
エレメントに伝導するためヒューズエレメントの温度も
上昇し、ヒューズエレメントが溶断する。Further, the resistor Ra (Rb) and the fuse element Fa (Fb) are thermally coupled to each other.
(Rb) generates heat and its temperature rises, and this rise in temperature is conducted to the fuse element, so that the temperature of the fuse element also rises and the fuse element is blown.
即ち雷サージの如き比較的大きな電流に対して溶断し
ない定格電流の大きなヒューズエレメントを使用して
も、長時間継続する事故電流に対しては小電流でも作動
するので良好な保安機能が実現できる。That is, even if a fuse element having a large rated current that does not blow for a relatively large current such as a lightning surge is used, a small current can be operated for a fault current that continues for a long time, so that a good security function can be realized.
第２図はヒューズエレメントと抵抗体との熱結合を説
明するための図であって、Ｆはヒューズエレメント、RR
は抵抗体である。FIG. 2 is a view for explaining the thermal coupling between the fuse element and the resistor.
Is a resistor.
第２図（ａ）は、ヒューズエレメントＦと抵抗体RRを
隣接させたもので、熱伝導を更に良好とするため、相互
を接着材で接着しても良い。第２図（ｂ）は特に本発明
によりヒューズエレメントに抵抗線を抵抗体RRとして巻
回したものである。FIG. 2 (a) shows a fuse element F and a resistor RR adjacent to each other, and they may be bonded to each other with an adhesive to further improve heat conduction. FIG. 2B shows a fuse element in which a resistance wire is wound as a resistor RR in accordance with the present invention.
又、通信回線は通常平衡回路であって２線で構成され
ているが、熱結合は両線間、即ち第１図におけるヒュー
ズエレメントFa,Fb、抵抗体Ra,Rb相互間で有していても
良い。The communication line is usually a balanced circuit and is composed of two wires, but the thermal coupling is provided between both wires, that is, between the fuse elements Fa and Fb and the resistors Ra and Rb in FIG. Is also good.
以上の説明において接点Sa,Sbは電磁リレーの如く機
械的接点に限定されることは無く半導体接点でも良く、
防護素子VRa,VRbはバリスタ，避雷管，半導体防護素子
等種々のものが適用でき、更に前置防護素子ARR1を設け
て端末装置Ｔに流入する電流を軽減することも可能であ
る。In the above description, the contacts Sa and Sb are not limited to mechanical contacts like electromagnetic relays, and may be semiconductor contacts,
Protective element VRa, VRb varistor, lightning arrester can be applied those semiconductor protection element or the like of various, it is also possible to reduce the current flowing into the terminal device T is provided further a pre-protection element ARR 1.
以上説明したように本発明によれば、端末装置側に雷
サージ電流が流通するような場合でも、直列に挿入され
た接点に流れる電流を接点の耐量以下に制限でき、接点
の損傷を防止できる上、保安の機能も有効に達成できる
という利点がある。As described above, according to the present invention, even when a lightning surge current flows to the terminal device side, the current flowing through the contacts inserted in series can be limited to the withstand voltage of the contacts or less, and damage to the contacts can be prevented. In addition, there is an advantage that the security function can be effectively achieved.
第１図は本発明の一実施例を示す回路図、第２図はヒュ
ーズエレメントと抵抗体の熱結合を説明するための斜視
図、第３図は従来の防護回路の一例を示す回路図、であ
る。 符号の説明 Ｔ……端末装置、Sa,Sb……接点、La,Lb……通信回線、
ARR1……前置防護素子、VRa,VRb……防護素子、Fa,Fb,F
……ヒューズエレメント、Ra,Rb,RR……抵抗体、G1,G2
……接地FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIG. 2 is a perspective view for explaining thermal coupling between a fuse element and a resistor, FIG. 3 is a circuit diagram showing an example of a conventional protection circuit, It is. Description of symbols T: terminal device, Sa, Sb ... contact, La, Lb ... communication line,
ARR 1 … Front protection element, VRa, VRb… Protection element, Fa, Fb, F
…… Fuse element, Ra, Rb, RR …… Resistance element, G 1 , G 2
……ground
───────────────────────────────────────────────────── フロントページの続き (72)発明者 江間 恒尊 東京都千代田区内幸町１丁目１番６号 日本電信電話株式会社内 (72)発明者 前田 正彦 埼玉県入間市大字狭山ケ原108番地３ 株式会社日辰電機製作所内 (56)参考文献 特開 昭59−162715（ＪＰ，Ａ) 特開 昭54−65350（ＪＰ，Ａ) 実開 昭51−87241（ＪＰ，Ｕ) 実開 昭53−81524（ＪＰ，Ｕ) 実開 昭54−6537（ＪＰ，Ｕ) ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsunetaka Ema 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Masahiko Maeda 108-3, Oyama Sayamagahara, Iruma City, Saitama Prefecture Nisshin Electric Works, Ltd. (56) References JP-A-59-162715 (JP, A) JP-A-54-65350 (JP, A) Full-scale production 51-87241 (JP, U) 81524 (JP, U) Actually open 1979-6537 (JP, U)
Claims (2)
路であって、 前記接点と直列に、雷サージの如き比較的大きなサージ
電流に対して溶断しない定格電流の大きなヒューズエレ
メントと、抵抗体を接続して直列回路を形成するととも
に、前記抵抗体を前記ヒューズエレメントに巻回する形
をとって両者を熱結合させ、前記抵抗体は前記接点保護
のための電流制限抵抗として用いるとともに、該抵抗体
を流れる事故電流により発熱して前記ヒューズエレメン
トを溶断させるようにし、 更に前記直列回路に第１のサージ防護素子を並列接続し
て成ることを特徴とする接点防護回路。1. A protection circuit for a contact inserted in series in a communication line, comprising: a fuse element having a large rated current that does not blow for a relatively large surge current such as a lightning surge; Along with connecting a body to form a series circuit, the resistor is wound around the fuse element to thermally couple them together, and the resistor is used as a current limiting resistor for protecting the contact, A contact protection circuit, wherein the fuse element is blown by generating heat by an accident current flowing through the resistor, and a first surge protection element is connected in parallel to the series circuit.
おいて、故障発生時、故障箇所が端末装置側か通信線路
側かを識別するため両者間を切り離す際に用いられる接
点の防護回路であって、 前記接点と直列に、雷サージの如き比較的大きなサージ
電流に対して溶断しない定格電流の大きなヒューズエレ
メントと、抵抗体を接続して直列回路を形成するととも
に、前記抵抗体を前記ヒューズエレメントに巻回する形
をとって両者を熱結合させ、前記抵抗体は前記接点保護
のための電流制限抵抗として用いるとともに、該抵抗体
を流れる事故電流により発熱して前記ヒューズエレメン
トを溶断させるようにし、 更に前記直列回路に第１のサージ防護素子を並列接続す
ると共に、通信回路側にも第２のサージ防護素子を接続
して成ることを特徴とする接点防護回路。2. In a communication line connecting a terminal device side and a switching device side, when a failure occurs, a protection circuit of a contact used when disconnecting the faulty portion to identify the terminal device side or the communication line side in order to identify whether the faulty portion is the terminal side or the communication line side. A series connection with the contact, a fuse element having a large rated current that does not blow against a relatively large surge current such as a lightning surge, and a resistor connected to form a series circuit, and the resistor is connected to the fuse. The resistor is used as a current limiting resistor for protecting the contact point, and is heated by an accident current flowing through the resistor to blow the fuse element. A first surge protection element is connected in parallel to the series circuit, and a second surge protection element is also connected to the communication circuit side. Contact protection circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01261989A JP3092926B2 (en) | 1989-10-09 | 1989-10-09 | Contact protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01261989A JP3092926B2 (en) | 1989-10-09 | 1989-10-09 | Contact protection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03124220A JPH03124220A (en) | 1991-05-27 |
| JP3092926B2 true JP3092926B2 (en) | 2000-09-25 |
Family
ID=17369460
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP01261989A Expired - Lifetime JP3092926B2 (en) | 1989-10-09 | 1989-10-09 | Contact protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3092926B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2002951888A0 (en) | 2002-10-08 | 2002-10-24 | Fultec Pty Ltd | A protection device for preventing the flow of undersirable transients |
-
1989
- 1989-10-09 JP JP01261989A patent/JP3092926B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03124220A (en) | 1991-05-27 |
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