JPH0275123A - Device for preventing overheating of apparatus - Google Patents
Device for preventing overheating of apparatusInfo
- Publication number
- JPH0275123A JPH0275123A JP22464088A JP22464088A JPH0275123A JP H0275123 A JPH0275123 A JP H0275123A JP 22464088 A JP22464088 A JP 22464088A JP 22464088 A JP22464088 A JP 22464088A JP H0275123 A JPH0275123 A JP H0275123A
- Authority
- JP
- Japan
- Prior art keywords
- superconducting
- relay
- electromagnetic relay
- switch
- coil
- 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.)
- Pending
Links
- 238000013021 overheating Methods 0.000 title claims description 16
- 239000000463 material Substances 0.000 claims abstract description 17
- 230000002085 persistent effect Effects 0.000 claims description 4
- 230000002265 prevention Effects 0.000 claims description 4
- 239000004020 conductor Substances 0.000 claims 2
- 230000005856 abnormality Effects 0.000 claims 1
- 238000009792 diffusion process Methods 0.000 abstract 1
- 238000001514 detection method Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 2
- 238000004870 electrical engineering Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000000284 resting effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H3/00—Mechanisms for operating contacts
- H01H3/005—Mechanisms for operating contacts making use of superconductivity, e.g. levitation switch
Landscapes
- Relay Circuits (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は機器の安全保持に係り、特に、機器の連続運転
等に好適な機器加熱防止装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to maintaining the safety of equipment, and particularly to an equipment overheating prevention device suitable for continuous operation of equipment.
應
〔従来の技術〕
ものである。この装置では、過熱をサーモスタット等の
熱検知式スイッチにより検知し、リレー保持用の電源を
遮断すると同時に、制御対象となる負荷装置側の電源も
遮断して自動復帰はせず、復帰は人間が加熱の原因製除
去した後に手動で行な憩
う方式をとっている。従って、リレー保持のため通常は
通電しておかなければならず、そのための電力を零にで
きない欠点があった。[Conventional technology] This device detects overheating using a heat-detecting switch such as a thermostat, cuts off the power for holding the relay, and at the same time cuts off the power to the load device that is being controlled, and does not automatically recover. After removing the cause of the heating, we use a method of manually performing the process and resting. Therefore, in order to hold the relay, it is usually necessary to keep it energized, and there is a drawback that the electric power for this cannot be reduced to zero.
電気工学ハンドブック電気学会（昭和５９年１月２０日
）１８編開閉・保護および制御装置２「；を電力用保護
継電器Ｐ９３８−Ｐ９４５
〔発明が解決しようとする課題〕
上記従来技術は、リレーの閉状態保持を行なうためにコ
イルに一定の電流を流しておかなければならず、省電力
の点について問題があった。さらに、負荷装置の過熱を
検知し、負荷装置の電源を遮断するための過熱検知セン
サは、バイメタル等が分離して配置された離散型センサ
であるため、センサが配置されていない場所以外の過熱
には、当然のことながら、対処できないという問題点が
あった。Electrical Engineering Handbook, Institute of Electrical Engineers of Japan (January 20, 1980), Volume 18, Switching/Closing/Protection and Control Devices 2: Protective Relays for Power P938-P945 [Problem to be Solved by the Invention] The above prior art In order to maintain the state, a constant current must be passed through the coil, which poses a problem in terms of power saving.Furthermore, overheating is required to detect overheating of the load device and cut off the power to the load device. Since the detection sensor is a discrete sensor in which bimetals and the like are separately arranged, there is a problem in that it cannot deal with overheating in areas other than those where the sensor is not arranged.
本発明の目的は、リレー保持用電源を不要にし、かつ、
温度検知センサを離散型から分布型へと変換する機器過
熱防止装置を提供することにある。An object of the present invention is to eliminate the need for a power supply for holding a relay, and
An object of the present invention is to provide an equipment overheat prevention device that converts a temperature detection sensor from a discrete type to a distributed type.
上記目的は、電磁リレー用コイル、温度センサとして超
電導材を用いることにより達成される。The above object is achieved by using superconducting material as the electromagnetic relay coil and temperature sensor.
電磁リレーでリレーを閉状態に保持するために、リレー
のコイルを超電導材にして閉ループを形成させて、永久
電流を流すことで、常時、通電する必要がなくなる。ま
た、ある特定の温度（負荷電源を遮断したい温度）を超
えた時に常電導となる超電導材を過熱検知スイッチとし
て利用すれば良い。もちろん、過熱検知スイッチはコイ
ルが形成する閉ループに直列に挿入されてなければなら
ず、過熱を防ぎたい装置ｔの近傍に設置することで解決
できる。In order to keep an electromagnetic relay closed, the coil of the relay is made of superconducting material to form a closed loop, which allows a persistent current to flow, eliminating the need for constant electrical current. Additionally, a superconducting material that becomes normally conductive when a certain temperature (temperature at which the load power supply is to be cut off) is exceeded may be used as an overheat detection switch. Of course, the overheat detection switch must be inserted in series in the closed loop formed by the coil, and this can be solved by installing it near the device t whose overheating is to be prevented.
以下、本発明の−・実施例を第１図により説明する。電
磁リレー１はリレー保持コイル２の通電時にオンどなり
、遮断時にオフとなる構成にする。Embodiments of the present invention will be described below with reference to FIG. The electromagnetic relay 1 is configured to turn on when the relay holding coil 2 is energized and turn off when the relay holding coil 2 is cut off.
リレー保持コイル２の通電、および、遮断はリレー保持
コイル２に直列に接続された電磁リレー用電源３および
電磁リレー用スイッチ８、ならびに、超電導用抵抗７に
より実行される。電磁リレー１のオンは電磁リレー用ス
イッチ８を閉じて電磁リレー１を第１図（ａ）の様に下
方向に押せば、電磁リレー１保持用の電流は電磁リレー
用電源３、電磁リレー用スイッチ８、電磁リレー１、リ
レー保持コイル、および、超電導用抵抗７を通る閉ルー
プを形成し、電磁リレー１が通電状態となることで達成
できる。次に、電磁リレー］のオン状態維持および過熱
を検知して電磁リレー１をオフ状態に戻す回路を形成す
るために、リレー保持コイル２に流れる電流が一定とな
った後に、超電導用スイッチ９を閉じ、電磁リレー用ス
イッチ８を開けば、電磁リレー用電源３、電磁リレー用
スイッチ８、電磁リレー１、リレー保持コイル２、およ
び、超電導用抵抗７を流れていた電流は、リレー保持コ
イル２、および、超電導用スイッチ９を直列に接続した
超電導ループ６に流れ、永久電流となる。超電導用抵抗
７は、電磁リレー用スイッチ８が閉じられている時は、
電磁リレー用電源３の保護抵抗、および、超電導用スイ
ッチ９を閉した時に電磁リレー用電源３側にリレー保持
コイルに＝４−
流れていた電流を流さないための抵抗である。超電導ル
ープ６は、ある特定の温度（負荷電源を遮断したい温度
）を越えた時に、常電導となる超電導線で構成されてお
り、過熱を防ぎたい負荷装置５の近傍を経由して配線し
ておく。電磁リレー１には、過熱を検知し、負荷用電源
４を遮断したい負荷装置５とが電磁リレー用電源３とは
別系で接続されており、電磁リレー］がオン状態である
時に負荷装置５に負荷用電源４から電流が流れ、過熱時
には電磁リレー１がオフとなって、負荷用電源４と負荷
装置５とを遮断して負荷装置５の損障を防ぐ。通常のオ
ン状態時には、永久電流がリレー保持コイル２、超電導
用スイッチおよび超電導ループ６を流れている。負荷装
置５の過熱時には、負荷装置５の近傍に配線された超電
導ループ６の一部が熱せられ、第３図に示すように、あ
る温度Ｔｏを越えると超電導状態から常電導状態に変化
して抵抗分を持つようになる。すると、リレー保持コイ
ルを流れていた電流は電磁リレー用電源３が電磁リレー
用スイッチ９により切離されているため、補給がなく、
発生した抵抗分で消費されるのみである。従って、ある
程度以上に電流が消費されると、リレー保持用コイル２
には電磁リレー１を保持するための磁力がなくなり、電
磁リレー１はバネ等の力によりオフ状態へと移行し、負
荷装置５を負荷用電源から切り離して、負荷装置５の電
流に起因した過熱を止めて負荷装置５の損傷を防ぐ。過
熱が止まり、もとの状態に温度が戻った時には超電導ル
ープ６は超電導状態に戻るが、既に電流は全て消費され
ているため、電磁リレー１が自動復帰する事はなく安全
であり、電磁リレー１をオンにするには手動でオン手続
きをしなければならない。本実施例によれば、電磁リレ
ー１をオン状態に保つため電流をリレー保持コイルを外
部から、常時、流し続ける必要がなく、省電力の効果が
ある。また、第２図に示す様に、温度検知スイッチ１０
が離散型ではなく分布型の過熱検知スイッチにできるた
め、超電導ループ６を構成したどの部分の温度が上昇し
ても反応するため、安全性の向上について効果がある。The relay holding coil 2 is energized and cut off by an electromagnetic relay power source 3 and an electromagnetic relay switch 8, which are connected in series to the relay holding coil 2, and a superconducting resistor 7. To turn on the electromagnetic relay 1, close the electromagnetic relay switch 8 and push the electromagnetic relay 1 downward as shown in Figure 1 (a). This can be achieved by forming a closed loop passing through the switch 8, the electromagnetic relay 1, the relay holding coil, and the superconducting resistor 7, and making the electromagnetic relay 1 energized. Next, in order to maintain the ON state of the electromagnetic relay and to form a circuit that detects overheating and returns the electromagnetic relay 1 to the OFF state, after the current flowing through the relay holding coil 2 becomes constant, the superconducting switch 9 is turned on. When the electromagnetic relay switch 8 is closed and the electromagnetic relay switch 8 is opened, the current flowing through the electromagnetic relay power supply 3, the electromagnetic relay switch 8, the electromagnetic relay 1, the relay holding coil 2, and the superconducting resistor 7 is transferred to the relay holding coil 2, Then, it flows through the superconducting loop 6 in which the superconducting switches 9 are connected in series, and becomes a persistent current. When the electromagnetic relay switch 8 is closed, the superconducting resistor 7
This is a protection resistor for the electromagnetic relay power source 3 and a resistor for preventing the current flowing through the relay holding coil from the electromagnetic relay power source 3 side when the superconducting switch 9 is closed. The superconducting loop 6 is made of superconducting wire that becomes normal conductive when a certain temperature (the temperature at which you want to cut off the load power supply) is exceeded, and it is wired through the vicinity of the load device 5 that you want to prevent overheating. put. A load device 5 that detects overheating and wants to shut off the load power source 4 is connected to the electromagnetic relay 1 in a separate system from the electromagnetic relay power source 3, and when the electromagnetic relay is in the on state, the load device 5 A current flows from the load power source 4, and when overheating occurs, the electromagnetic relay 1 is turned off to cut off the load power source 4 and the load device 5 to prevent damage to the load device 5. In the normal on state, persistent current flows through the relay holding coil 2, the superconducting switch, and the superconducting loop 6. When the load device 5 overheats, a part of the superconducting loop 6 wired near the load device 5 is heated, and as shown in FIG. 3, when a certain temperature To is exceeded, the superconducting state changes to the normal conducting state. It will have some resistance. Then, the current flowing through the relay holding coil is not supplied because the electromagnetic relay power supply 3 is disconnected by the electromagnetic relay switch 9.
It is only consumed by the generated resistance. Therefore, when the current is consumed beyond a certain level, the relay holding coil 2
The magnetic force for holding the electromagnetic relay 1 disappears, and the electromagnetic relay 1 shifts to the OFF state by the force of the spring, disconnects the load device 5 from the load power supply, and eliminates the overheating caused by the current in the load device 5. to prevent damage to the load device 5. When the overheating stops and the temperature returns to the original state, the superconducting loop 6 returns to the superconducting state, but since all the current has already been consumed, the electromagnetic relay 1 will not return automatically and is safe, and the electromagnetic relay To turn on 1, you have to manually turn it on. According to this embodiment, it is not necessary to keep current flowing from the outside through the relay holding coil in order to keep the electromagnetic relay 1 in the ON state, and there is an effect of power saving. Further, as shown in FIG. 2, a temperature detection switch 10
Since the superconducting loop 6 can be made into a distributed type overheat detection switch instead of a discrete type, it reacts even if the temperature of any part of the superconducting loop 6 increases, which is effective in improving safety.
第４図は第二の実施例を示す。ここでは簡単のため、第
１図で示したリレー保持コイル２、超電導用スイッチ９
を含む超電導ループ６と負荷装置５の部分のみを表現し
ている。第一の実施例との大きな違いは、超電導ループ
６に種々の超電導材１２と動作温度切換スイッチを直列
に挿入した点である。これは、第５図に示した種々の超
電導材の温度特性１１′を示すもので、種々の超電導材
１２は超電導ループ６の他の部分と同じ温度、もしくは
、それ以下の温度で超電導から常電導へと移行する事を
利用し、電磁リレー］のオフ温度を変更できるようにし
たものである。従って、効果は第一の実施例の効果に合
わせて、一つの動作温度切換スイッチ１３を付加するこ
とで、動作温度範囲が広げられるため、種々の負荷装置
５に対する汎用性が増す効果がある。FIG. 4 shows a second embodiment. For simplicity, we will explain the relay holding coil 2 and superconducting switch 9 shown in Figure 1.
Only the superconducting loop 6 including the superconducting loop 6 and the load device 5 are shown. The major difference from the first embodiment is that various superconducting materials 12 and operating temperature changeover switches are inserted in series in the superconducting loop 6. This shows the temperature characteristics 11' of the various superconducting materials shown in FIG. By utilizing the transition to conductivity, it is possible to change the off temperature of an electromagnetic relay. Therefore, in addition to the effects of the first embodiment, by adding one operating temperature changeover switch 13, the operating temperature range can be expanded, which has the effect of increasing versatility for various load devices 5.
第６図に第三の実施例を示す。第一の実施例との違いは
、超電導ループ６を構成する超電導材の線を負荷装置５
の近傍ばかりでなく、負荷装置５が設置されている建物
１４にも張り巡らせ、負荷装置５の過熱ばかりでなく、
建物１４の何らかの原因による温度上昇を検知して、す
みやかに、電源を遮断させてしまう事を口論んだ点であ
る。この場合には、第一の実施例の効果の他に建物１４
自体の温度上昇に対しても負荷用電源４を遮断できるた
め、負荷装置５、および、建物１４の損傷可能性を低下
できる効果がある。FIG. 6 shows a third embodiment. The difference from the first embodiment is that the superconducting material wire constituting the superconducting loop 6 is connected to the load device 5.
It is installed not only in the vicinity of the load device 5 but also in the building 14 where the load device 5 is installed.
The point is that the power supply should be shut off immediately upon detection of a rise in temperature in the building 14 due to some cause. In this case, in addition to the effect of the first embodiment, the building 14
Since the load power source 4 can be cut off even when the temperature of the load device increases, the possibility of damage to the load device 5 and the building 14 can be reduced.
第７図に第四の実施例を示す。第三の実施例との違いは
、電磁リレー１に警報装置１５用の接点がついて、電磁
リレー１がオフの時に、警報用電源１６と警報装置１５
とを接続して、負荷装置５、または、建物１４で過熱、
または、何らかの原因で温度上昇があったことを示す点
である。この場合には、第三の実施例の効果の他に警報
装置１５によって安全性が向上できる効果がある。FIG. 7 shows a fourth embodiment. The difference from the third embodiment is that the electromagnetic relay 1 has a contact for the alarm device 15, and when the electromagnetic relay 1 is off, the alarm power source 16 and the alarm device 15 are connected.
If the load device 5 or the building 14 overheats,
Alternatively, it is a point indicating that the temperature has increased for some reason. In this case, in addition to the effect of the third embodiment, the alarm device 15 has the effect of improving safety.
その他、第一の実施例から第四の実施例を組合わせた実
施例も容易に類推できるので、ここでは割愛する。Other embodiments that combine the first to fourth embodiments can also be easily inferred, so they will not be discussed here.
本発明によれば、コイルに常時電流を送り続ける必要が
なくなり、電磁リレー維持のための電力を零にできる効
果があり、機器、または、建物の温度上昇に伴い超電導
材が超電導から常電導に移行することにより電磁リレー
をオフ状態にできるため、機器および建物の損傷を早期
に防げる。According to the present invention, there is no need to constantly send current to the coil, the power required to maintain the electromagnetic relay can be reduced to zero, and the superconducting material changes from superconductivity to normal conductivity as the temperature of equipment or buildings rises. This allows the electromagnetic relay to be turned off, thereby preventing damage to equipment and buildings at an early stage.
第１図は本発明の一実施例の電気回路図、第２図は従来
例の電気回路図、第３図は超電導材の温度抵抗特性図、
第４図は種々の超電導材の温度抵抗特性図、第５図は動
作温度切換えのできる温度検知センサを備えた超電導ル
ープの実施例の電気回路図、第６図は導線として用いた
超電導線自体を温度検知センサとして用いた実施例の電
気回路図、第７図は第６図で示した実施例に警報装置を
付加した他の実施例の電気回路図である。
１・・・電磁リレー、２・・・リレー保持コイル、３・
・・電磁リレー用電源、４・・・負荷用電源、５・・・
負荷装置、６・・・超電導ループ、７・・・超電導用抵
抗、８・・・電磁リレー用スイッチ、９・・・超電導用
スイッチ、１０・・温度検知スイッチ、１１・超電導材
の温度抵抗特性、１１′ 種々の超電導材の温度抵抗特
性、１２・・・種々の超電導材、１３ 動作温度切換ス
イッチ、１４・・・建物、１５・・警報装置、１６・警
報用電源。FIG. 1 is an electric circuit diagram of an embodiment of the present invention, FIG. 2 is an electric circuit diagram of a conventional example, and FIG. 3 is a temperature resistance characteristic diagram of a superconducting material.
Figure 4 is a temperature resistance characteristic diagram of various superconducting materials, Figure 5 is an electrical circuit diagram of an example of a superconducting loop equipped with a temperature detection sensor that can switch operating temperatures, and Figure 6 is the superconducting wire itself used as a conducting wire. FIG. 7 is an electrical circuit diagram of another embodiment in which an alarm device is added to the embodiment shown in FIG. 6. 1... Electromagnetic relay, 2... Relay holding coil, 3...
... Power supply for electromagnetic relay, 4... Power supply for load, 5...
Load device, 6... Superconducting loop, 7... Resistor for superconducting, 8... Switch for electromagnetic relay, 9... Switch for superconducting, 10... Temperature detection switch, 11. Temperature resistance characteristics of superconducting material. , 11' Temperature resistance characteristics of various superconducting materials, 12...Various superconducting materials, 13. Operating temperature selector switch, 14.. Building, 15.. Alarm device, 16. Power source for alarm.
Claims (1)
あるいは複数の超電導材でループ状に構成し、リレー保
持電流を永久電流としたことを特徴とする機器過熱防止
装置。 ２、特許請求の範囲第１項において、 前記超電導材によるループ状の前記リレー保持コイルに
、異なる温度で常伝導となる前記複数の超電導材を温度
検知素子として超電導ループを破壊することなく直列に
挿入し、これらを超電導性スイッチで切り換えることを
特徴とする機器過熱防止装置。 ３、特許請求の範囲第２項において、 前記リレー保持コイルと前記温度検知素子を結ぶ前記超
電導材の導線を、負荷装置が設置されている建物全体を
おおうように配線し、火災等の熱で導線が常電導体とな
つて負荷装置用電源をすみやかに遮断して被害の拡大を
押えることを特徴とする機器過熱防止装置。４、特許請
求の範囲第３項において、 前記負荷装置の電源を切ると同時に電磁リレーの電源を
遮断すると同時に警報装置が異常を知らせることを特徴
とする機器過熱防止装置。[Claims] 1. In an electromagnetic relay for load control, the relay holding coil is constructed in a loop of one or more superconducting materials that become normally conductive at a certain temperature or higher, and the relay holding current is a persistent current. An equipment overheat prevention device featuring: 2. In claim 1, the plurality of superconducting materials that become normal conductive at different temperatures are connected in series to the loop-shaped relay holding coil made of the superconducting material as temperature sensing elements without destroying the superconducting loop. A device for preventing overheating of equipment, which is characterized by inserting a superconducting switch into the device and switching between them using a superconducting switch. 3. In claim 2, the conductive wire of the superconducting material connecting the relay holding coil and the temperature sensing element is wired so as to cover the entire building in which the load device is installed, and is protected from heat caused by fire or the like. An equipment overheating prevention device characterized in that the conductor becomes a normal conductor and promptly shuts off the power supply for the load device to suppress the spread of damage. 4. The apparatus for preventing overheating of equipment according to claim 3, characterized in that an alarm device notifies an abnormality at the same time as the power to the electromagnetic relay is cut off at the same time as the power to the load device is cut off.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22464088A JPH0275123A (en) | 1988-09-09 | 1988-09-09 | Device for preventing overheating of apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22464088A JPH0275123A (en) | 1988-09-09 | 1988-09-09 | Device for preventing overheating of apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0275123A true JPH0275123A (en) | 1990-03-14 |
Family
ID=16816883
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22464088A Pending JPH0275123A (en) | 1988-09-09 | 1988-09-09 | Device for preventing overheating of apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0275123A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2661775A1 (en) * | 1990-05-04 | 1991-11-08 | Telemecanique | CONTACTOR-CIRCUIT-BREAKER. |
-
1988
- 1988-09-09 JP JP22464088A patent/JPH0275123A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2661775A1 (en) * | 1990-05-04 | 1991-11-08 | Telemecanique | CONTACTOR-CIRCUIT-BREAKER. |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3977425B2 (en) | Overcurrent protection circuit | |
| US6738246B1 (en) | Electrical circuit breaker for protecting against overcurrents | |
| EP0850505A1 (en) | Overcurrent protection circuit | |
| JP4119491B2 (en) | Overcurrent protection circuit | |
| US6355912B2 (en) | Safety circuit for heating devices using PTC wire | |
| US6421216B1 (en) | Resetable overcurrent protection arrangement | |
| CA2744397C (en) | Overload protection of a voltage reduction device | |
| NL7906369A (en) | HEATING SWITCH. | |
| EP2621043B1 (en) | Current Limiter | |
| US2758255A (en) | Polyphase motor protector | |
| JPH0275123A (en) | Device for preventing overheating of apparatus | |
| US2801317A (en) | Temperature responsive protective device for electric circuits | |
| US4023072A (en) | Electrical protection means and method | |
| JPH079782B2 (en) | Circuit breaker with overheat prevention device | |
| EP0661790B2 (en) | overcurrent protection circuit | |
| US5978196A (en) | Control system for thermal protection of high wattage lighting | |
| JP3247325B2 (en) | Thermal relay and control circuit using the same | |
| JPH11206002A (en) | Thermal overloading-protected motor and method for protecting thermal overloading in the motor | |
| WO2007142394A1 (en) | Magnetic field-free temperature controller and temperature control method using timing signal | |
| JPH0547288A (en) | Electromagnetic switch | |
| US2903548A (en) | Electric blanket control | |
| GB2186134A (en) | Heating circuits with protective arrangements | |
| JPH06313606A (en) | Protection control device for air conditioner | |
| WO2000042821A2 (en) | Improvements relating to thermal controls | |
| JPH06275183A (en) | Circuit protecting system |