JP5506770B2

JP5506770B2 - Air conditioner

Info

Publication number: JP5506770B2
Application number: JP2011275559A
Authority: JP
Inventors: 宏典永井
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2011-12-16
Filing date: 2011-12-16
Publication date: 2014-05-28
Anticipated expiration: 2031-12-16
Also published as: JP2013124848A

Description

本発明は、空気調和機に関し、特に、冷房専用で圧縮機を一定の回転数（例えば電源周波数）で運転する空気調和機（以下、冷専一定速エアコンという）に関するものである。 The present invention relates to an air conditioner, and more particularly, to an air conditioner (hereinafter referred to as a cooling-only constant-speed air conditioner) that operates exclusively at a constant speed (for example, a power supply frequency).

従来の冷専一定速エアコンで最も簡単なシステム構成のものとして、例えば以下の図４に示すような冷専一定速エアコンがある。 For example, a conventional cold-only constant-speed air conditioner has the simplest system configuration as shown in FIG.

図４は、従来の冷専一定速エアコンの一例を示すシステム構成図である。なお、図４に示す太線は冷媒配管を示し、図４に示す細線は制御配線を示している。
図４に示す従来の冷専一定速エアコン１００は、室内機１１０及び室外機１２０で構成されている。室外機１２０には、ガス冷媒を高圧に圧縮して吐出する圧縮機１２１、圧縮機１２１で圧縮された高圧ガス冷媒と室外空気とを熱交換させ、高圧ガス冷媒を凝縮液化する室外熱交換器１２４（凝縮器）、室外熱交換器１２４で凝縮液化した高圧の液冷媒を低圧の気液二相冷媒に膨張させるキャピラリーチューブ１２５等が設けられている。また、室外機１２０には、室外熱交換器１２４に室外空気を供給する室外送風機（室外ファン１２３、及び室外ファン１２３を回転駆動する室外ファンモーター１２２）も設けられている。 FIG. 4 is a system configuration diagram illustrating an example of a conventional cold-only constant-speed air conditioner. In addition, the thick line shown in FIG. 4 has shown refrigerant | coolant piping, and the thin line shown in FIG. 4 has shown control wiring.
A conventional cold-only constant-speed air conditioner 100 shown in FIG. 4 includes an indoor unit 110 and an outdoor unit 120. The outdoor unit 120 includes a compressor 121 that compresses and discharges the gas refrigerant to a high pressure, and an outdoor heat exchanger that condenses and liquefies the high-pressure gas refrigerant by exchanging heat between the high-pressure gas refrigerant compressed by the compressor 121 and the outdoor air. 124 (condenser), a capillary tube 125 for expanding the high-pressure liquid refrigerant condensed and liquefied by the outdoor heat exchanger 124 into a low-pressure gas-liquid two-phase refrigerant, and the like. The outdoor unit 120 is also provided with an outdoor fan (outdoor fan 123 and an outdoor fan motor 122 that rotationally drives the outdoor fan 123) that supplies outdoor air to the outdoor heat exchanger 124.

一方、室内機１１０には、室外機１２０のキャピラリーチューブ１２５で膨張した低圧の気液二相冷媒と室内空気とを熱交換させ、当該冷媒を蒸発させる室内熱交換器１１６（蒸発器）、及び、室内熱交換器１１６に室内空気を供給する室内送風機（室内ファン１１３、及び室内ファン１１３を回転駆動する室内ファンモーター１１２）が設けられている。また、室内機１１０には、室内機１１０に吸い込まれた室内空気の温度を検出する室内吸込み温度センサー１１４も設けられている。 On the other hand, the indoor unit 110 includes an indoor heat exchanger 116 (evaporator) for exchanging heat between the low-pressure gas-liquid two-phase refrigerant expanded in the capillary tube 125 of the outdoor unit 120 and room air and evaporating the refrigerant, and In addition, an indoor fan (indoor fan 113 and indoor fan motor 112 that rotationally drives the indoor fan 113) for supplying indoor air to the indoor heat exchanger 116 is provided. The indoor unit 110 is also provided with an indoor suction temperature sensor 114 that detects the temperature of the indoor air sucked into the indoor unit 110.

また、従来の冷専一定速エアコン１００は、室内機１１０内に制御部１１１を備えている。そして、制御部１１１は、室内吸込み温度センサー１１４の検出温度に基づいて、室内ファンモーター１１２、圧縮機１２１及び室外ファンモーター１２２の回転数等を制御する。つまり、冷専一定速エアコン１００は、圧縮機１２１及び室外ファンモーター１２２を制御する制御部を室外機１２０内に有しておらず、室外機１２０に設けられた圧縮機１２１及び室外ファンモーター１２２は、室内機１１０内に設けられた制御部１１１から運転及び停止の指令を受ける構成となっている。そして、制御部１１１から運転の指令を受けた圧縮機１２１及び室外ファンモーター１２２は、一定の回転数（例えば電源周波数）で運転される。このような構成の冷専一定速エアコン１００は、室外機１２０側に制御部を持つことなく安価にシステム構成が可能となるため、特に市場価格要求が厳しい小容量タイプに多い。 Further, the conventional cold-only constant-speed air conditioner 100 includes a control unit 111 in the indoor unit 110. Then, the control unit 111 controls the rotational speed of the indoor fan motor 112, the compressor 121, and the outdoor fan motor 122 based on the temperature detected by the indoor suction temperature sensor 114. That is, the constant temperature air conditioner 100 does not have a control unit for controlling the compressor 121 and the outdoor fan motor 122 in the outdoor unit 120, and the compressor 121 and the outdoor fan motor 122 provided in the outdoor unit 120. Is configured to receive operation and stop commands from a control unit 111 provided in the indoor unit 110. The compressor 121 and the outdoor fan motor 122 that have received an operation command from the control unit 111 are operated at a constant rotational speed (for example, a power supply frequency). The cold-constant constant-speed air conditioner 100 having such a configuration can be configured at a low cost without having a control unit on the outdoor unit 120 side, and is therefore often used for small capacity types that are particularly demanding on the market price.

このように構成された従来の冷専一定速エアコン１００は、制御部１１１によって、以下の図５（１）に示すように運転制御される。また、冷専一定速エアコン１００は、室内熱交換器１１６の温度を検出する室内熱交換器温度センサー１１５を備えている。このため、制御部１１１は、以下の図５（２）に示す室内熱交換器１１６の凍結防止制御も可能となっている。以下、図５を用いて、従来の冷専一定速エアコン１００の制御例について説明する。 The conventional cold-only constant-speed air conditioner 100 configured as described above is operated and controlled by the control unit 111 as shown in FIG. In addition, the constant temperature air conditioner 100 is equipped with an indoor heat exchanger temperature sensor 115 that detects the temperature of the indoor heat exchanger 116. For this reason, the control part 111 can also perform anti-freezing control of the indoor heat exchanger 116 shown in FIG. Hereinafter, a control example of the conventional cold-only constant-speed air conditioner 100 will be described with reference to FIG.

図５は、従来の冷専一定速エアコンの制御アルゴリズムの一例を示すフローチャートである。 FIG. 5 is a flowchart showing an example of a control algorithm for a conventional cold-only constant-speed air conditioner.

まず、冷専一定速エアコン１００の運転制御アルゴリズムの例について、図５（１）で説明する。室内機１１０にある制御部１１１は使用者からの運転要求をリモコン１０１の信号として受信する（ステップＳ１０１）。そして、制御部１１１は、リモコン信号が運転オンであるか否かを判定する（ステップＳ１０２）。リモコン信号が運転オンの場合には、制御部１１１は、室内ファンモーター１１２にオン指令（運転指令）を出して室内ファン１１３を回転させることで室内機１１０に室内空気を循環させ、室内吸込み温度センサー１１４によって正確な室内温度を室内吸込み温度として検出する（ステップＳ１０３）。一方、リモコン信号が運転オンでない場合（つまり、リモコン信号が運転オフの場合）、制御部１１１は、ステップＳ１０４で冷専一定速エアコン１００の運転（つまり、室内ファンモーター１１２、圧縮機１２１及び室外ファンモーター１２２の運転）を停止し（ステップＳ１０４）、ステップＳ１０２に戻る。 First, an example of an operation control algorithm of the cold-only constant-speed air conditioner 100 will be described with reference to FIG. The control unit 111 in the indoor unit 110 receives an operation request from the user as a signal from the remote controller 101 (step S101). Then, control unit 111 determines whether or not the remote control signal is on (step S102). When the remote control signal is on, the control unit 111 issues an on command (operation command) to the indoor fan motor 112 and rotates the indoor fan 113 to circulate the indoor air to the indoor unit 110, and the indoor suction temperature. The sensor 114 detects the accurate indoor temperature as the indoor suction temperature (step S103). On the other hand, when the remote control signal is not on (that is, when the remote control signal is off), the control unit 111 operates the constant temperature air conditioner 100 (ie, the indoor fan motor 112, the compressor 121, and the outdoor) in step S104. The operation of the fan motor 122 is stopped (step S104), and the process returns to step S102.

ステップＳ１０３の後、制御部１１１は、受信したリモコン信号の中の設定温度と室内吸込み温度とを比較する（ステップＳ１０５）。そして、リモコン設定温度が室内吸込み温度以下の場合には、制御部１１１は、室外機１２０の圧縮機１２１と室外ファンモーター１２２にオン指令（運転指令）を送信し、冷房運転を開始する（ステップＳ１０６）。一方、ステップＳ１０５においてリモコン設定温度が室内吸込み温度よりも高い場合には、制御部１１１は、室外機１２０の圧縮機１２１と室外ファンモーター１２２にオフ指令（停止指令）を送信し、圧縮機１２１及び室外ファンモーター１２２を停止させ（ステップＳ１０７）、ステップＳ１０２に戻る。このように、室内機１１０にある制御部１１１は、室内吸込み温度とリモコン信号の中の設定温度を常時比較して、室外機１２０の運転制御を行う。 After step S103, control unit 111 compares the set temperature in the received remote control signal with the indoor suction temperature (step S105). When the remote controller set temperature is equal to or lower than the indoor suction temperature, the control unit 111 transmits an ON command (operation command) to the compressor 121 and the outdoor fan motor 122 of the outdoor unit 120, and starts the cooling operation (step). S106). On the other hand, when the remote control set temperature is higher than the indoor suction temperature in step S105, the control unit 111 transmits an off command (stop command) to the compressor 121 and the outdoor fan motor 122 of the outdoor unit 120, and the compressor 121 And the outdoor fan motor 122 is stopped (step S107), and it returns to step S102. As described above, the control unit 111 in the indoor unit 110 controls the operation of the outdoor unit 120 by constantly comparing the indoor suction temperature with the set temperature in the remote control signal.

次に、室内熱交換器１１６が凍結するような異常を防止するための制御アルゴリズムの例について、図５（２）で説明する。冷専一定速エアコン１００においては、室内温度及び／又は室外温度が想定外に低い状態で使用されたり、室内熱交換器１１６が埃で詰まった状態等によって室内空気と冷媒の熱交換が阻害されるような場合、室内熱交換器１１６の温度が氷点下になってしまう場合がある。室内熱交換器１１６の温度が氷点下になると室内熱交換器１１６に凝縮した水が凍ってしまい、室内機１１０からの水漏れや最悪は氷が落ちるような不具合を引き起こす恐れがある。そこで、制御部１１１は、図５（２）に示す室内熱交換器１１６の凍結防止制御を行う。 Next, an example of a control algorithm for preventing an abnormality in which the indoor heat exchanger 116 is frozen will be described with reference to FIG. In the cold-only constant-speed air conditioner 100, the indoor air and / or the outdoor temperature are used in an unexpectedly low state, or the heat exchange between the indoor air and the refrigerant is hindered due to the indoor heat exchanger 116 being clogged with dust or the like. In such a case, the temperature of the indoor heat exchanger 116 may become below freezing point. When the temperature of the indoor heat exchanger 116 becomes below freezing point, the water condensed in the indoor heat exchanger 116 is frozen, and there is a possibility that water leaks from the indoor unit 110 or worst, that the ice falls. Therefore, the control unit 111 performs anti-freezing control of the indoor heat exchanger 116 shown in FIG.

具体的には、ステップＳ１０６の後、制御部１１１は、冷房運転中の室内熱交換器温度を室内熱交換器温度センサー１１５から検出し、室内熱交換器温度が所定温度（例えば０℃）以下となっている状態が所定時間（例えば５分）以上継続しているか否かを判定する（ステップＳ２０１）。室内熱交換器温度が所定温度（例えば０℃）以下となっている状態が所定時間（例えば５分）以上継続している場合、制御部１１１は、室内熱交換器１１６が凍結する可能性があると判断し、室外機１２０の圧縮機１２１と室外ファンモーター１２２にオフ指令（停止指令）を送信し、圧縮機１２１及び室外ファンモーター１２２を停止させる（ステップＳ２０２）。一方、室内熱交換器温度が所定温度（例えば０℃）以下となっている状態が所定時間（例えば５分）以上継続していない場合、制御部１１１は、室外機１２０の圧縮機１２１及び室外ファンモーター１２２へのオン指令（運転指令）を継続し（ステップＳ２０３）、ステップＳ１０２に戻る。 Specifically, after step S106, the control unit 111 detects the indoor heat exchanger temperature during the cooling operation from the indoor heat exchanger temperature sensor 115, and the indoor heat exchanger temperature is equal to or lower than a predetermined temperature (for example, 0 ° C.). It is determined whether or not this state continues for a predetermined time (for example, 5 minutes) or longer (step S201). When the state in which the indoor heat exchanger temperature is equal to or lower than a predetermined temperature (for example, 0 ° C.) continues for a predetermined time (for example, 5 minutes) or longer, the controller 111 may cause the indoor heat exchanger 116 to freeze. It is judged that there is, and an off command (stop command) is transmitted to the compressor 121 and the outdoor fan motor 122 of the outdoor unit 120, and the compressor 121 and the outdoor fan motor 122 are stopped (step S202). On the other hand, when the indoor heat exchanger temperature is not higher than a predetermined temperature (for example, 0 ° C.) for a predetermined time (for example, 5 minutes), the control unit 111 determines that the compressor 121 of the outdoor unit 120 and the outdoor The on command (operation command) to the fan motor 122 is continued (step S203), and the process returns to step S102.

ステップＳ２０２の後、制御部１１１は、室内熱交換器温度が凍結しない所定温度（例えば５℃）以上になったか否かを判定する（ステップＳ２０４）。そして、室内熱交換器温度が凍結しない所定温度（例えば５℃）以上になった場合、制御部１１１は、圧縮機１２１及び室外ファンモーター１２２に再度オン信号を送信し、圧縮機１２１及び室外ファンモーター１２２の運転を開始する（ステップＳ２０５）。その後、制御部１１１は、ステップＳ２０１に戻る。一方、室内熱交換器温度が凍結しない所定温度（例えば５℃）よりも低い場合、制御部１１１は、圧縮機１２１及び室外ファンモーター１２２へのオフ信号を継続し（ステップＳ２０６）、ステップＳ２０４へ戻る。 After step S202, the control unit 111 determines whether or not the indoor heat exchanger temperature has become equal to or higher than a predetermined temperature (for example, 5 ° C.) that does not freeze (step S204). When the indoor heat exchanger temperature becomes equal to or higher than a predetermined temperature (eg, 5 ° C.) that does not freeze, the control unit 111 transmits an ON signal to the compressor 121 and the outdoor fan motor 122 again, and the compressor 121 and the outdoor fan. The operation of the motor 122 is started (step S205). Thereafter, the control unit 111 returns to step S201. On the other hand, when the indoor heat exchanger temperature is lower than a predetermined temperature that does not freeze (for example, 5 ° C.), the control unit 111 continues the off signal to the compressor 121 and the outdoor fan motor 122 (step S206), and proceeds to step S204. Return.

以上のように、制御部１１１は、冷房運転中の室内熱交換器温度を検出して制御することで、室内熱交換器１１４の凍結不具合を未然に防止している。しかしながら、冷専一定速エアコン１００は、室外機１２０に制御部、つまり室外機１２０内の機器の異常検出手段を備えていないため、室外機１２０内の異常を検知することができない。例えば、室外機１２０において室外ファンモーター１２２の故障が発生すると、室外ファン１２３が回転できず、室外熱交換器１２４での放熱が阻害されてしまう。このため、圧縮機１２１及び室外熱交換器１２４の温度と圧力が異常に上昇してしまう。しかしながら、冷専一定速エアコン１００は、この圧力と温度の上昇が室外機１２０側で発生しているため、当該異常を検出することができない。 As described above, the control unit 111 detects and controls the temperature of the indoor heat exchanger during the cooling operation, thereby preventing a freezing failure of the indoor heat exchanger 114 in advance. However, the constant temperature constant-speed air conditioner 100 does not include a control unit in the outdoor unit 120, that is, a device abnormality detection unit in the outdoor unit 120, and thus cannot detect an abnormality in the outdoor unit 120. For example, when a failure of the outdoor fan motor 122 occurs in the outdoor unit 120, the outdoor fan 123 cannot rotate, and heat dissipation in the outdoor heat exchanger 124 is hindered. For this reason, the temperature and pressure of the compressor 121 and the outdoor heat exchanger 124 will rise abnormally. However, the cold-specific constant-speed air conditioner 100 cannot detect the abnormality because the increase in pressure and temperature occurs on the outdoor unit 120 side.

そこで、このような異常から圧縮機１２１や室外ファンモーター１２２を保護するために、一般的に、従来の冷専一定速エアコン１００には、保護装置として圧縮機１２１内部のモーターに圧縮機モータープロテクタ１２１ａを搭載している。この圧縮機モータープロテクタ１２１ａは、圧縮機１２１のモーターのモーター巻き線や当該モーターへの電力供給線等（つまり、電流通路）に例えば直列接続される開閉器である。この開閉器は、自身に流れる電流や自身の温度が所定値を超えると、制御部１１１からの指令にかかわらず接点を開き、圧縮機１２１のモーターへの通電を機械的に遮断するものである。例えば、この開閉器は、図６に示すような作動特性を有するもの（換言すると、図６に示すような作動特性のバイメタルを有するもの）である。つまり、この開閉器は、自身（より詳しくはバイメタル）が図６において温度１５０℃と電流１５Ａを結んだ直線よりも上方の状態となったとき（例えば自身の温度が１５０℃以上となったときや、自身に流れる電流が１５Ａ以上となったとき）に接点を開き、自身が図６において温度１５０℃と電流１５Ａを結んだ直線よりも下方の状態となったときに接点を閉じるものである。ここで、圧縮機１２１の圧力が上昇すると圧縮機１２１のモーターに流れる電流も上昇するため、圧縮機１２１の圧力上昇に対する保護としても圧縮機モータープロテクタ１２１ａは有効となる。 Therefore, in order to protect the compressor 121 and the outdoor fan motor 122 from such an abnormality, in general, in the conventional cold-specific constant-speed air conditioner 100, a compressor motor protector is added to the motor inside the compressor 121 as a protection device. 121a is installed. The compressor motor protector 121a is a switch connected in series, for example, to a motor winding of a motor of the compressor 121, a power supply line to the motor, or the like (that is, a current path). This switch opens the contact regardless of the command from the control unit 111 and mechanically cuts off the power to the motor of the compressor 121 when the current flowing through the switch or the temperature of the switch exceeds a predetermined value. . For example, this switch has an operation characteristic as shown in FIG. 6 (in other words, has a bimetal having an operation characteristic as shown in FIG. 6). In other words, this switch (in more detail, bimetal) is in a state above the straight line connecting the temperature 150 ° C. and the current 15A in FIG. 6 (for example, when its own temperature is 150 ° C. or higher). Or when the current flowing through itself becomes 15A or more), and the contact is closed when the contact is lower than the straight line connecting the temperature 150 ° C. and the current 15A in FIG. . Here, when the pressure of the compressor 121 rises, the current flowing through the motor of the compressor 121 also rises, so that the compressor motor protector 121a is effective as a protection against the pressure rise of the compressor 121.

このような圧縮機モータープロテクタ１２１ａを備えることにより、冷専一定速エアコン１００は、図７のような動作となる。なお、図７は、室外ファンモーター１２２の故障が発生した場合を例として示している。 By providing such a compressor motor protector 121a, the cold-specific constant-speed air conditioner 100 operates as shown in FIG. FIG. 7 shows an example in which a failure of the outdoor fan motor 122 occurs.

つまり、時間ｔ０で冷専一定速エアコン１００が運転を開始すると、制御部１１１は、室外機１２０の圧縮機１２１及び室外ファンモーター１２２に運転指令を送信する（指令オン）。これにより、時間ｔ０で、室外機１２０の圧縮機１２１及び室外ファンモーター１２２は、動作を開始する（動作オン）。時間ｔ１で室外ファンモーター１２２の故障が発生した場合、時間ｔ１以降は圧縮機１２１の温度と圧力が上昇し続ける。そして、時間ｔ２で圧縮機モータープロテクタ１２１ａの開条件になると、圧縮機モータープロテクタ１２１ａの接点が開くことで圧縮機１２１に流れる電流を遮断し、圧縮機１２１は自主的に停止する（動作オフ）。このとき、制御部１１１からは圧縮機１２１に運転指令が継続されているままである。その後、圧縮機１２１の温度と圧力が低下すると、時間ｔ３で圧縮機モータープロテクタ１２１ａの接点が閉じる。これにより、圧縮機１２１に再び電流が流れて自主的に動作を開始する（動作オン）。しかしながら、室外ファンモーター１２２の故障が継続すれば、圧縮機モータープロテクタ１２１ａは、開と閉を延々と繰り返し続けることになる。 That is, when the constant temperature air conditioner 100 starts operation at time t0, the control unit 111 transmits an operation command to the compressor 121 and the outdoor fan motor 122 of the outdoor unit 120 (command ON). Thereby, at time t0, the compressor 121 and the outdoor fan motor 122 of the outdoor unit 120 start operation (operation on). When the failure of the outdoor fan motor 122 occurs at time t1, the temperature and pressure of the compressor 121 continue to rise after time t1. Then, when the opening condition of the compressor motor protector 121a is reached at time t2, the contact of the compressor motor protector 121a is opened to interrupt the current flowing through the compressor 121, and the compressor 121 stops autonomously (operation off). . At this time, the operation command is continued from the control unit 111 to the compressor 121. Thereafter, when the temperature and pressure of the compressor 121 decrease, the contact of the compressor motor protector 121a is closed at time t3. As a result, a current flows again to the compressor 121 and the operation starts autonomously (operation on). However, if the failure of the outdoor fan motor 122 continues, the compressor motor protector 121a repeats opening and closing endlessly.

このため、室外ファンモーター１２２の故障のように圧縮機１２１の温度と圧力が異常に上昇する状態が継続し、かつ、冷専一定速エアコン１００の能力がでないことに使用者が気付かない状態で使用される場合は、過負荷状態での圧縮機１２１の自主的なオフとオンが繰り返されるため、圧縮機１２１に接続される冷媒配管に過度のストレスが繰り返し発生することになり、冷媒配管が疲労破壊して冷媒漏れに至る恐れがあった。また、圧縮機モータープロテクタ１２１ａの開閉を延々と繰り返すことで、圧縮機モータープロテクタ１２１ａの接点が寿命により溶着し、圧縮機２１への電流を遮断できずに更なる冷媒回路の不具合に至る恐れがあった。つまり、室外機１２０に異常検出手段を持たない冷専一定速エアコン１００は、想定以上の過負荷状態になった時の保護手段が圧縮機モータープロテクタ１２１ａしかないため、使用者が冷房能力不足に気付かない場合は冷媒配管の疲労破壊や圧縮機モータープロテクタ１２１ａの故障等の２次被害を発生させてしまう可能性があった。 For this reason, the state in which the temperature and pressure of the compressor 121 rise abnormally like a failure of the outdoor fan motor 122 continues, and the user is not aware that the constant temperature air conditioner 100 is not capable of cooling. When used, since the compressor 121 is repeatedly turned off and on repeatedly in an overload state, excessive stress is repeatedly generated in the refrigerant pipe connected to the compressor 121, and the refrigerant pipe is There was a risk of fatigue failure leading to refrigerant leakage. In addition, by repeatedly opening and closing the compressor motor protector 121a, the contacts of the compressor motor protector 121a are welded due to their lifetime, and the current to the compressor 21 may not be cut off, which may lead to further refrigerant circuit failure. there were. That is, the constant-speed air conditioner 100 that does not have an abnormality detection means in the outdoor unit 120 has only the compressor motor protector 121a as the protection means when the overload state is higher than expected. If it is not noticed, there is a possibility that secondary damage such as fatigue destruction of the refrigerant piping or failure of the compressor motor protector 121a may occur.

そこで、室外機に異常検出手段を持たない従来の空気調和機においては、室内熱交換器温度センサーを利用して、室外機に設けられた機器の異常を検出する方法が提案されている（例えば、特許文献１参照）。 Therefore, in a conventional air conditioner that does not have an abnormality detection means in the outdoor unit, a method for detecting an abnormality in a device provided in the outdoor unit using an indoor heat exchanger temperature sensor has been proposed (for example, , See Patent Document 1).

上記特許文献１に記載の空気調和機は、圧縮機への運転指令を継続中に室外機の機器に異常が発生していると判断するため、当該異常を判断するための室内熱交換器の温度範囲を設定している。そして、圧縮機への運転指令から一定時間内、又は一定時間経過後の室内熱交換器の温度が異常と判断する温度範囲に入っている場合、室外機の機器に異常が発生していると判断している。 Since the air conditioner described in Patent Document 1 determines that an abnormality has occurred in the outdoor unit while continuing the operation command to the compressor, the air conditioner of the indoor heat exchanger for determining the abnormality The temperature range is set. And if the temperature of the indoor heat exchanger within a certain time or after a certain time elapses from the operation command to the compressor is in the temperature range that is judged to be abnormal, there is an abnormality in the outdoor unit equipment Deciding.

特開昭５８−７５６４９号公報JP 58-75649 A

しかしながら、上記特許文献１に記載された室外機内の機器の異常検出方法では、圧縮機への運転指令中に室内熱交換器の温度が機器の異常と判断する温度範囲を脱して一回正常と判断してしまうと、その後、異常の温度範囲に再度変化した時に異常と判断できないという課題があった。例えば、室外ファンモーターが故障して室外機に凝縮阻害が発生した場合、圧縮機運転開始後のしばらくの間は冷媒回路内に存在する液冷媒が蒸発するため、一時的に室内熱交換器の温度は正常と同じ程度の温度まで下がる。しかしながら、その後は冷媒の凝縮が不充分であるため、徐々に室内熱交換器の温度は上昇していく。ここで、圧縮機運転開始後の室内熱交換器の温度が正常と同じ程度の温度でいる時間内に正常と判断してしまうと、その後の圧縮機の運転継続中に室内熱交換器の温度が異常と判断する温度範囲に変化しても異常と判断することができない。 However, in the method for detecting an abnormality of the equipment in the outdoor unit described in Patent Document 1, the temperature of the indoor heat exchanger is outside the temperature range in which it is determined that the equipment is abnormal during the operation command to the compressor. If it is determined, there is a problem that it cannot be determined as abnormal when the temperature is changed again to the abnormal temperature range. For example, if the outdoor fan motor breaks down and the outdoor unit condenses, the liquid refrigerant in the refrigerant circuit evaporates for a while after starting the compressor operation. The temperature drops to the same level as normal. However, since the refrigerant is not sufficiently condensed thereafter, the temperature of the indoor heat exchanger gradually increases. Here, if it is determined that the temperature of the indoor heat exchanger after starting the compressor operation is normal within the time when the temperature is about the same as normal, the temperature of the indoor heat exchanger will continue during the subsequent operation of the compressor. Even if the temperature changes to a temperature range that is determined to be abnormal, it cannot be determined to be abnormal.

また、上記特許文献１に記載された室外機内の機器の異常検出方法は、室内熱交換器の温度のみを機器異常の判断指標としているため、次のような課題もあった。つまり、室内温度や室外温度の気温変化等の外乱に応じて、室内熱交換器の温度は変化する。また、同気温で空気調和機を運転する場合でも、室内機と室外機を接続する接続配管の長さの違いやそれに伴う封入冷媒量の違い等の外乱によっても、室内熱交換器の温度は異なってくる。このため、これらの外乱を考慮して誤検知しないように異常と判定する温度範囲を設定しようとすると、異常と判定する温度範囲が小さくなってしまい、異常を検知できない場合が発生するという課題があった。 Moreover, since the abnormality detection method of the apparatus in the outdoor unit described in the said patent document 1 uses only the temperature of an indoor heat exchanger as the determination parameter | index of apparatus abnormality, there also existed the following subjects. That is, the temperature of the indoor heat exchanger changes in accordance with disturbances such as the indoor temperature and the temperature change of the outdoor temperature. Even when the air conditioner is operated at the same temperature, the temperature of the indoor heat exchanger is also affected by disturbances such as the difference in the length of the connecting pipe connecting the indoor unit and the outdoor unit, and the accompanying difference in the amount of enclosed refrigerant. Come different. For this reason, considering these disturbances, if an attempt is made to set a temperature range that is determined to be abnormal so as not to be erroneously detected, the temperature range that is determined to be abnormal becomes small, and there is a problem that a case in which the abnormality cannot be detected occurs. there were.

つまり、上記特許文献１に記載された室外機内の機器の異常検出方法では、依然として、冷媒配管の疲労破壊等の２次被害を十分に防止できないという課題があった。 In other words, the abnormality detection method for the equipment in the outdoor unit described in Patent Document 1 still has a problem that secondary damage such as fatigue failure of the refrigerant pipe cannot be sufficiently prevented.

本発明は、上記のような課題を解決するためになされたもので、室外機に異常検出手段を備えない冷専一定速エアコンにおいて、従来よりも確実に冷媒配管の疲労破壊等の２次被害を防止することが可能な冷専一定速エアコンを提供することを目的とする。 The present invention has been made in order to solve the above-described problems, and in a cold-only constant-speed air conditioner that does not have an abnormality detection means in an outdoor unit, secondary damage such as fatigue failure of refrigerant pipes is more reliable than before. An object of the present invention is to provide a constant temperature air conditioner that can prevent cold.

本発明に係る空気調和機は、圧縮機、凝縮器となる室外熱交換器、キャピラリーチューブ、及び前記室外熱交換器に室外空気を供給する室外送風機を有する室外機と、蒸発器となる室内熱交換器、及び該室内熱交換器に室内空気を供給する室内送風機を有する室内機と、前記室内機に設けられ、前記室内送風機、前記圧縮機及び前記室外送風機に運転及び停止の指令を行う制御部と、を備え、前記圧縮機及び前記室外送風機を一定の回転数で運転する空気調和機において、前記室内熱交換器の温度を検出する室内熱交換器温度センサーと、前記室内機に吸い込まれた室内空気の温度を検出する室内吸込み温度センサーと、を備え、前記制御部は、前記室内吸込み温度センサーの検出温度と前記室内熱交換器温度センサーの検出温度との温度差が所定の閾値よりも高い状態から低い状態へ変化した回数をカウントし、当該回数が所定回数以上となった際、前記室内送風機、前記圧縮機及び前記室外送風機に停止の指令を行うものである。 An air conditioner according to the present invention includes a compressor, an outdoor heat exchanger serving as a condenser, a capillary tube, and an outdoor unit having an outdoor fan for supplying outdoor air to the outdoor heat exchanger, and an indoor heat serving as an evaporator. An indoor unit having an exchanger and an indoor fan that supplies indoor air to the indoor heat exchanger, and a control that is provided in the indoor unit and that commands operation and stop to the indoor fan, the compressor, and the outdoor fan comprising a part, an, in the air conditioner to operate the compressor and the outdoor fan at a constant rotational speed, and the indoor heat exchanger temperature sensor for detecting the temperature of the pre-Symbol indoor heat exchanger, sucked into the indoor unit A temperature difference between a detected temperature of the indoor suction temperature sensor and a detected temperature of the indoor heat exchanger temperature sensor. Counts the number of times the state changes from a state higher than a predetermined threshold to a lower state, and when the number of times has reached a predetermined number or more, instructs the indoor blower, the compressor and the outdoor blower to stop. .

また、本発明に係る空気調和機は、圧縮機、凝縮器となる室外熱交換器、キャピラリーチューブ、及び前記室外熱交換器に室外空気を供給する室外送風機を有する室外機と、蒸発器となる室内熱交換器、及び該室内熱交換器に室内空気を供給する室内送風機を有する室内機と、前記室内機に設けられ、前記室内送風機、前記圧縮機及び前記室外送風機に運転及び停止の指令を行う制御部と、前記圧縮機から吐出される冷媒の圧力に応じて前記制御部からの指令にかかわらず前記圧縮機のモーターへの電流通路を開閉動作するものであり、前記圧縮機から吐出される冷媒の圧力が所定値を超えた際、前記圧縮機のモーターへの通電を遮断して前記圧縮機を保護する開閉器と、を備え、前記圧縮機及び前記室外送風機を一定の回転数で運転する空気調和機において、前記室内熱交換器の温度を検出する室内熱交換器温度センサーと、前記室内機に吸い込まれた室内空気の温度を検出する室内吸込み温度センサーと、を備え、前記制御部は、前記室内吸込み温度センサーの検出温度と前記室内熱交換器温度センサーの検出温度との温度差が所定の閾値よりも高い状態から低い状態へ変化した回数をカウントし、当該回数が所定回数以上となった際、前記室内送風機、前記圧縮機及び前記室外送風機に停止の指令を行うものである。 In addition, the air conditioner according to the present invention serves as an evaporator, an outdoor unit having an outdoor heat exchanger that serves as a compressor, a condenser, a capillary tube, and an outdoor fan that supplies outdoor air to the outdoor heat exchanger. An indoor unit having an indoor heat exchanger and an indoor fan for supplying indoor air to the indoor heat exchanger, and an instruction to operate and stop the indoor fan, the compressor, and the outdoor fan provided in the indoor unit. A control unit that performs and opens and closes a current path to the motor of the compressor regardless of a command from the control unit according to the pressure of the refrigerant discharged from the compressor, and is discharged from the compressor And a switch that protects the compressor by shutting off power to the motor of the compressor when the pressure of the refrigerant exceeds a predetermined value, and the compressor and the outdoor blower are rotated at a constant rotational speed. Driving sky In conditioner, comprising pre SL and the indoor heat exchanger temperature sensor for detecting the temperature of the indoor heat exchanger, and an indoor suction temperature sensor for detecting the temperature of the indoor air sucked into the indoor unit, wherein the control unit The number of times the temperature difference between the detected temperature of the indoor suction temperature sensor and the detected temperature of the indoor heat exchanger temperature sensor has changed from a state higher than a predetermined threshold to a lower state is counted, and the number of times is equal to or greater than a predetermined number of times. When this happens, the indoor blower, the compressor, and the outdoor blower are instructed to stop.

また、本発明に係る空気調和機は、圧縮機、凝縮器となる室外熱交換器、キャピラリーチューブ、及び前記室外熱交換器に室外空気を供給する室外送風機を有する室外機と、蒸発器となる室内熱交換器、及び該室内熱交換器に室内空気を供給する室内送風機を有する室内機と、前記室内機に設けられ、前記室内送風機、前記圧縮機及び前記室外送風機に運転及び停止の指令を行う制御部と、前記圧縮機のモーター内又は該モーターへの電流通路に設けられ、電流及び温度に応じて前記制御部からの指令にかかわらず開閉動作するものであり、自身に流れる電流及び自身の温度のうちの少なくとも一方が所定値を超えた際、前記圧縮機のモーターへの通電を遮断して前記圧縮機を保護する開閉器と、を備え、前記圧縮機及び前記室外送風機を一定の回転数で運転する空気調和機において、前記室内熱交換器の温度を検出する室内熱交換器温度センサーと、前記室内機に吸い込まれた室内空気の温度を検出する室内吸込み温度センサーと、を備え、前記制御部は、前記室内吸込み温度センサーの検出温度と前記室内熱交換器温度センサーの検出温度との温度差が所定の閾値よりも高い状態から低い状態へ変化した回数をカウントし、当該回数が所定回数以上となった際、前記室内送風機、前記圧縮機及び前記室外送風機に停止の指令を行うものである。 In addition, the air conditioner according to the present invention serves as an evaporator, an outdoor unit having an outdoor heat exchanger that serves as a compressor, a condenser, a capillary tube, and an outdoor fan that supplies outdoor air to the outdoor heat exchanger. An indoor unit having an indoor heat exchanger and an indoor fan for supplying indoor air to the indoor heat exchanger, and an instruction to operate and stop the indoor fan, the compressor, and the outdoor fan provided in the indoor unit. A control unit for performing the opening and closing operation regardless of a command from the control unit according to the current and temperature, provided in a current path to or in the motor of the compressor. when at least one of the temperature exceeds a predetermined value, and a switch to protect the compressor to shut off the power supply to the motor of the compressor, one of said compressor and said outdoor blower An air conditioner that operates at a rotational speed of: an indoor heat exchanger temperature sensor that detects the temperature of the indoor heat exchanger; and an indoor suction temperature sensor that detects the temperature of the indoor air sucked into the indoor unit. The controller counts the number of times the temperature difference between the detected temperature of the indoor suction temperature sensor and the detected temperature of the indoor heat exchanger temperature sensor has changed from a state higher than a predetermined threshold to a lower state, When the number of times reaches a predetermined number or more, a stop command is issued to the indoor blower, the compressor, and the outdoor blower.

本発明においては、制御部は、室内吸込み温度センサーの検出温度（室内吸込み温度）と室内熱交換器温度センサーの検出温度（室内熱交換器温度）との温度差が所定の閾値よりも高い状態から低い状態へ変化した回数をカウントし、当該回数が所定回数以上となった際、システムを停止する（室内送風機、圧縮機及び室外送風機に停止の指令を行う）。このため、本発明は、従来よりも確実に冷媒配管の疲労破壊等の２次被害を未然に防止することができる。 In the present invention, the control unit is in a state where the temperature difference between the detected temperature of the indoor suction temperature sensor (indoor suction temperature) and the detected temperature of the indoor heat exchanger temperature sensor (indoor heat exchanger temperature) is higher than a predetermined threshold value. The number of times of change from low to low is counted, and when the number of times reaches a predetermined number or more, the system is stopped (stop is given to the indoor blower, the compressor, and the outdoor blower). For this reason, the present invention can prevent secondary damage such as fatigue failure of the refrigerant piping more reliably than before.

本発明の実施の形態に係る冷専一定速エアコンを示すシステム構成図である。1 is a system configuration diagram showing a cold-only constant-speed air conditioner according to an embodiment of the present invention. 本発明の実施の形態に係る冷専一定速エアコンの制御アルゴリズムを示すフローチャートである。It is a flowchart which shows the control algorithm of the cold exclusive constant speed air conditioner which concerns on embodiment of this invention. 本発明の実施の形態に係る冷専一定速エアコンの動作を説明するためのタイムチャートである。It is a time chart for demonstrating operation | movement of the cold-only constant speed air conditioner which concerns on embodiment of this invention. 従来の冷専一定速エアコンの一例を示すシステム構成図である。It is a system block diagram which shows an example of the conventional cold-specific constant-speed air conditioner. 従来の冷専一定速エアコンの制御アルゴリズムの一例を示すフローチャートである。It is a flowchart which shows an example of the control algorithm of the conventional cold-specific constant speed air conditioner. 圧縮機モータープロテクタの作動特性の一例を示す特性図である。It is a characteristic view which shows an example of the operation characteristic of a compressor motor protector. 圧縮機モータープロテクタを備えた従来の冷専一定速エアコンの動作を説明するためのタイムチャートである。It is a time chart for demonstrating operation | movement of the conventional cold-specific constant speed air conditioner provided with the compressor motor protector.

実施の形態．
図１は、本発明の実施の形態に係る冷専一定速エアコンを示すシステム構成図である。また、図２は、この冷専一定速エアコンの制御アルゴリズムを示すフローチャートである。
図１及び図２に示すように、本実施の形態に係る冷専一定速エアコン５０は、制御部１１が図２（３）に示す室外機２０の異常判定制御を行う以外、上記の従来の冷専一定速エアコン１００と同様の構成になっている。 Embodiment.
FIG. 1 is a system configuration diagram showing a cold-only constant-speed air conditioner according to an embodiment of the present invention. FIG. 2 is a flowchart showing a control algorithm of the constant temperature constant air conditioner.
As shown in FIGS. 1 and 2, the constant temperature constant-speed air conditioner 50 according to the present embodiment has the above-described conventional configuration except that the control unit 11 performs the abnormality determination control of the outdoor unit 20 shown in FIG. 2 (3). The configuration is the same as that of the cold-only constant speed air conditioner 100.

つまり、本実施の形態に係る冷専一定速エアコン５０は、室内機１０及び室外機２０で構成されている。室外機２０には、ガス冷媒を高圧に圧縮して吐出する圧縮機２１、圧縮機２１で圧縮された高圧ガス冷媒と室外空気とを熱交換させ、高圧ガス冷媒を凝縮液化する室外熱交換器２４（凝縮器）、室外熱交換器２４で凝縮液化した高圧の液冷媒を低圧の気液二相冷媒に膨張させるキャピラリーチューブ２５等が設けられている。そして、圧縮機２１には、保護装置として圧縮機２１内部のモーターに圧縮機モータープロテクタ２１ａが搭載されている。この圧縮機モータープロテクタ２１ａは、圧縮機２１のモーターのモーター巻き線や当該モーターへの電力供給線等（つまり、電流通路）に例えば直列接続される開閉器である。この開閉器は、自身に流れる電流や自身の温度が所定値を超えると、制御部１１からの指令にかかわらず接点を開き、圧縮機２１のモーターへの通電を機械的に遮断するものである。例えば、この開閉器は、従来と同様、図６に示すような作動特性を有するもの（換言すると、図６に示すような作動特性のバイメタルを有するもの）である。また、室外機２０には、室外熱交換器２４に室外空気を供給する室外送風機（室外ファン２３、及び室外ファン２３を回転駆動する室外ファンモーター２２）も設けられている。 That is, the cold-specific constant-speed air conditioner 50 according to the present embodiment includes the indoor unit 10 and the outdoor unit 20. The outdoor unit 20 includes a compressor 21 that compresses and discharges the gas refrigerant to a high pressure, an outdoor heat exchanger that heat-exchanges the high-pressure gas refrigerant compressed by the compressor 21 and outdoor air, and condenses and liquefies the high-pressure gas refrigerant. 24 (condenser), a capillary tube 25 for expanding the high-pressure liquid refrigerant condensed and liquefied by the outdoor heat exchanger 24 into a low-pressure gas-liquid two-phase refrigerant, and the like. In the compressor 21, a compressor motor protector 21a is mounted on a motor inside the compressor 21 as a protective device. The compressor motor protector 21a is a switch connected in series to, for example, a motor winding of the motor of the compressor 21 or a power supply line to the motor (that is, a current path). When the current flowing through the switch or the temperature of the switch exceeds a predetermined value, the switch opens the contact regardless of a command from the control unit 11 and mechanically cuts off the power supply to the motor of the compressor 21. . For example, this switch has an operating characteristic as shown in FIG. 6 (in other words, has a bimetal having an operating characteristic as shown in FIG. 6), as in the prior art. The outdoor unit 20 is also provided with an outdoor blower (an outdoor fan 23 and an outdoor fan motor 22 that rotationally drives the outdoor fan 23) that supplies outdoor air to the outdoor heat exchanger 24.

一方、室内機１０には、室外機２０のキャピラリーチューブ２５で膨張した低圧の気液二相冷媒と室内空気とを熱交換させ、当該冷媒を蒸発させる室内熱交換器１６（蒸発器）、及び、室内熱交換器１６に室内空気を供給する室内送風機（室内ファン１３、及び室内ファン１３を回転駆動する室内ファンモーター１２）が設けられている。また、室内機１０には、室内機１０に吸い込まれた室内空気の温度を検出する室内吸込み温度センサー１４、及び、室内熱交換器１６の温度を検出する室内熱交換器温度センサー１５も設けられている。室内熱交換器温度センサー１５は、室内熱交換器１６の入口部や中間部等、室内熱交換器１６内を流れる冷媒が気液二相状態になっている位置（スーパーヒートがついていない位置）に設けられている。 On the other hand, the indoor unit 10 includes an indoor heat exchanger 16 (evaporator) that exchanges heat between the low-pressure gas-liquid two-phase refrigerant expanded in the capillary tube 25 of the outdoor unit 20 and the room air, and evaporates the refrigerant. An indoor blower (indoor fan 13 and indoor fan motor 12 that rotationally drives the indoor fan 13) is provided to supply indoor air to the indoor heat exchanger 16. The indoor unit 10 is also provided with an indoor suction temperature sensor 14 that detects the temperature of indoor air sucked into the indoor unit 10, and an indoor heat exchanger temperature sensor 15 that detects the temperature of the indoor heat exchanger 16. ing. The indoor heat exchanger temperature sensor 15 is a position where the refrigerant flowing in the indoor heat exchanger 16 is in a gas-liquid two-phase state, such as an inlet portion or an intermediate portion of the indoor heat exchanger 16 (a position where no superheat is attached). Is provided.

また、本実施の形態に係る冷専一定速エアコン５０は、室内機１０内に制御部１１を備えている。そして、制御部１１は、室内吸込み温度センサー１４の検出温度に基づいて、室内ファンモーター１２、圧縮機２１及び室外ファンモーター２２の回転数等を制御する。つまり、冷専一定速エアコン５０は、圧縮機２１及び室外ファンモーター２２を制御する制御部を室外機２０内に有しておらず、室外機２０に設けられた圧縮機２１及び室外ファンモーター２２は、室内機１０内に設けられた制御部１１から運転及び停止の指令を受ける構成となっている。そして、制御部１１から運転の指令を受けた圧縮機２１及び室外ファンモーター２２は、一定の回転数（例えば電源周波数）で運転される。 Further, the cold-only constant-speed air conditioner 50 according to the present embodiment includes a control unit 11 in the indoor unit 10. Then, the control unit 11 controls the rotational speed and the like of the indoor fan motor 12, the compressor 21, and the outdoor fan motor 22 based on the temperature detected by the indoor suction temperature sensor 14. In other words, the constant temperature air conditioner 50 that does not have the control unit for controlling the compressor 21 and the outdoor fan motor 22 is not provided in the outdoor unit 20, and the compressor 21 and the outdoor fan motor 22 provided in the outdoor unit 20. Is configured to receive operation and stop commands from the control unit 11 provided in the indoor unit 10. The compressor 21 and the outdoor fan motor 22 that have received an operation command from the control unit 11 are operated at a constant rotational speed (for example, a power supply frequency).

このように構成された冷専一定速エアコン５０は、制御部１１が使用者からの運転要求をリモコン１の信号として受信すると、制御部１１によって、図２に示すように制御される。なお、図２（１）に示すエアコン運転制御及び図２（２）に示す室内熱交換器１６の凍結防止制御は、図５（１）で説明したエアコン運転制御及び図５（２）で説明した室内熱交換器１１６の凍結防止制御と同様の制御である。このため、以下では、本実施の形態に係る冷専一定速エアコン５０の特徴の一つである室外機２０の異常判定制御（図２（３））について説明する。 When the control unit 11 receives an operation request from a user as a signal of the remote controller 1, the cold-constant constant-speed air conditioner 50 configured as described above is controlled by the control unit 11 as shown in FIG. The air conditioner operation control shown in FIG. 2 (1) and the freeze prevention control of the indoor heat exchanger 16 shown in FIG. 2 (2) are explained in the air conditioner operation control explained in FIG. 5 (1) and FIG. 5 (2). The control is the same as the freeze prevention control of the indoor heat exchanger 116. For this reason, below, the abnormality determination control (FIG. 2 (3)) of the outdoor unit 20 which is one of the features of the cold-only constant-speed air conditioner 50 according to the present embodiment will be described.

図２（３）に示すように、ステップＳ２０３の後、つまり室外機２０の圧縮機２１及び室外ファンモーター２２へのオン指令（運転指令）を継続中、室内機１０にある制御部１１は、室内吸込み温度（室内吸込み温度センサー１４の検出温度）と室内熱交換器温度（室内熱交換器温度センサー１５の検出温度）との温度差が所定の閾値（例えば５ｄｅｇ）より高い状態から低い状態に変化したか否かを判定する（ステップＳ３０１）。そして、室内吸込み温度と室内熱交換器温度との温度差が所定の閾値（例えば５ｄｅｇ）より高い状態から低い状態に変化した場合、制御部１１は、上記の発生回数をカウントし（ステップＳ３０２）、ステップＳ３０４へ進む。一方、室内吸込み温度と室内熱交換器温度との温度差が所定の閾値（例えば５ｄｅｇ）より高い状態から低い状態に変化していない場合、制御部１１は、室外機２０の圧縮機２１及び室外ファンモーター２２へのオン指令（運転指令）を継続し（ステップＳ３０３）、ステップＳ１０２に戻る。 As shown in FIG. 2 (3), after step S203, that is, while the ON command (operation command) to the compressor 21 and the outdoor fan motor 22 of the outdoor unit 20 is continued, the control unit 11 in the indoor unit 10 The temperature difference between the indoor intake temperature (detected temperature of the indoor intake temperature sensor 14) and the indoor heat exchanger temperature (detected temperature of the indoor heat exchanger temperature sensor 15) is higher than a predetermined threshold value (for example, 5 deg) to a lower state. It is determined whether or not it has changed (step S301). When the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature changes from a state higher than a predetermined threshold (for example, 5 deg) to a lower state, the control unit 11 counts the number of occurrences (step S302). The process proceeds to step S304. On the other hand, when the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature does not change from a state higher than a predetermined threshold (for example, 5 deg) to a lower state, the control unit 11 performs the compressor 21 of the outdoor unit 20 and the outdoor unit. The ON command (operation command) to the fan motor 22 is continued (step S303), and the process returns to step S102.

ステップＳ３０４において、制御部１１は、「室内吸込み温度と室内熱交換器温度との温度差が所定の閾値（例えば５ｄｅｇ）より高い状態から低い状態に変化」が連続で所定回数（例えば５回）発生したか否かを判定する。例えば、制御部１１は、冷専一定速エアコン５０の運転中（リモコン１より運転要求の指令を受けてから、停止要求の指令を受けるまでの間）に「室内吸込み温度と室内熱交換器温度との温度差が所定の閾値（例えば５ｄｅｇ）より高い状態から低い状態に変化」が所定回数（例えば５回）発生したか否かを判定する。「室内吸込み温度と室内熱交換器温度との温度差が所定の閾値（例えば５ｄｅｇ）より高い状態から低い状態に変化」が連続で所定回数（例えば５回）発生した場合、制御部１１は、圧縮機モータープロテクタ２１ａの開閉が発生していると判断し、システム全体に異常停止を指令する。つまり、制御部１１は、室内機１０の室内ファンモーター１２、室外機２０の圧縮機２１及び室外ファンモーター２２へオフ指令（停止指令）を送信する（ステップＳ３０５）。一方、「室内吸込み温度と室内熱交換器温度との温度差が所定の閾値（例えば５ｄｅｇ）より高い状態から低い状態に変化」が連続で所定回数（例えば５回）発生していない場合、制御部１１は、室外機２０の圧縮機２１及び室外ファンモーター２２へのオン指令（運転指令）を継続し（ステップＳ３０６）、ステップＳ１０２に戻る。 In step S304, the control unit 11 continuously changes the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature from a state higher than a predetermined threshold (for example, 5 deg) to a lower state for a predetermined number of times (for example, 5 times). It is determined whether or not it has occurred. For example, the control unit 11 performs “indoor suction temperature and indoor heat exchanger temperature” during operation of the constant temperature air conditioner 50 of cold temperature (between receiving an operation request command from the remote controller 1 and receiving a stop request command). It is determined whether or not a “change from a state in which the temperature difference from a higher than a predetermined threshold value (eg, 5 deg) to a lower state” occurs a predetermined number of times (eg, 5 times). When the “change in the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature from a state higher than a predetermined threshold value (for example, 5 deg) to a low state” continuously occurs a predetermined number of times (for example, 5 times), the control unit 11 It is determined that the compressor motor protector 21a has been opened and closed, and the system is commanded to stop abnormally. That is, the control unit 11 transmits an off command (stop command) to the indoor fan motor 12 of the indoor unit 10, the compressor 21 of the outdoor unit 20, and the outdoor fan motor 22 (step S305). On the other hand, if the “change in the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature from a state higher than a predetermined threshold (for example, 5 degrees) to a lower state” does not occur continuously for a predetermined number of times (for example, 5 times), The unit 11 continues the on command (operation command) to the compressor 21 and the outdoor fan motor 22 of the outdoor unit 20 (step S306), and returns to step S102.

次に、このように制御された冷専一定速エアコン５０において、圧縮機２１の温度と圧力が異常に上昇する場合の動作について説明する。なお、以下では、室外ファンモーター２２の故障が発生した場合を例として説明する。 Next, the operation in the case where the temperature and pressure of the compressor 21 abnormally rise in the controlled cold constant speed air conditioner 50 will be described. In the following, a case where a failure of the outdoor fan motor 22 occurs will be described as an example.

図３は、本発明の実施の形態に係る冷専一定速エアコンの動作を説明するためのタイムチャートである。
時間ｔ０で冷専一定速エアコン５０が運転を開始すると、制御部１１は、室外機２０の圧縮機２１及び室外ファンモーター２２に運転指令を送信する（指令オン）。これにより、時間ｔ０で、室外機２０の圧縮機２１及び室外ファンモーター２２は、動作を開始する（動作オン）。時間ｔ１で室外ファンモーター２２の故障が発生した場合、室外熱交換器２４において凝縮阻害が発生するため、時間ｔ１以降は圧縮機２１の温度と圧力が上昇し続ける。また、時間ｔ１で室外ファンモーター２２の故障が発生した場合、室外熱交換器２４での凝縮阻害の発生によって室内熱交換器１６への冷媒供給量が減少するため、時間ｔ１以降は室内熱交換器１６の温度が徐々に上昇する。このため、室内吸込み温度と室内熱交換器温度との温度差は徐々に小さくなっていく。 FIG. 3 is a time chart for explaining the operation of the constant temperature constant speed air conditioner according to the embodiment of the present invention.
When the constant temperature air conditioner 50 starts operation at time t0, the control unit 11 transmits an operation command to the compressor 21 and the outdoor fan motor 22 of the outdoor unit 20 (command ON). Thereby, at time t0, the compressor 21 and the outdoor fan motor 22 of the outdoor unit 20 start operation (operation on). When a failure of the outdoor fan motor 22 occurs at time t1, condensation inhibition occurs in the outdoor heat exchanger 24, so that the temperature and pressure of the compressor 21 continue to rise after time t1. When the failure of the outdoor fan motor 22 occurs at time t1, the amount of refrigerant supplied to the indoor heat exchanger 16 decreases due to the occurrence of condensation inhibition in the outdoor heat exchanger 24. Therefore, after time t1, indoor heat exchange is performed. The temperature of the vessel 16 rises gradually. For this reason, the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature gradually decreases.

そして、時間ｔ２で圧縮機モータープロテクタ２１ａの開条件になると、圧縮機モータープロテクタ２１ａの接点が開くことで圧縮機２１に流れる電流を遮断し、圧縮機２１は自主的に停止する（動作オフ）。なお、制御部１１からは圧縮機２１に運転指令が継続されているままである。一方、室内ファンモーター１２は動作を継続しているため（オンを継続しているため）、室内熱交換器１６は室内空気から熱を吸収し、室内熱交換器温度は急上昇する。このため、室内吸込み温度と室内熱交換器温度との温度差は急低下し、時間ｔｅ１で５ｄｅｇより小さくなる。このとき、制御部１１は、室内吸込み温度と室内熱交換器温度との温度差が５ｄｅｇより高い温度から低い温度に変化した回数として１回をカウントする。 When the opening condition of the compressor motor protector 21a is reached at time t2, the contact of the compressor motor protector 21a is opened to cut off the current flowing to the compressor 21, and the compressor 21 stops autonomously (operation off). . Note that the operation command from the control unit 11 continues to the compressor 21. On the other hand, since the indoor fan motor 12 continues to operate (being kept on), the indoor heat exchanger 16 absorbs heat from the indoor air, and the indoor heat exchanger temperature rapidly rises. For this reason, the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature rapidly decreases and becomes smaller than 5 deg at time te1. At this time, the controller 11 counts once as the number of times that the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature has changed from a temperature higher than 5 deg to a lower temperature.

その後、圧縮機２１の温度と圧力が低下すると、時間ｔ３で圧縮機モータープロテクタ２１ａの接点が閉じる。これにより、圧縮機２１に再び電流が流れて自主的に動作を開始する（動作オン）。すると、室内機１０側に存在した冷媒（圧縮機２１の停止中、圧力バランスのために室内機１０側に流れ込んできた冷媒）が蒸発するため、一時的に室内熱交換器温度は下がる。しかしながら、冷媒が蒸発しきった後は徐々に室内熱交換器の温度は上昇し、室内吸込み温度と室内熱交換器温度との差は再び小さくなっていく。 Thereafter, when the temperature and pressure of the compressor 21 are reduced, the contact of the compressor motor protector 21a is closed at time t3. As a result, a current flows again to the compressor 21 and the operation starts autonomously (operation on). Then, the refrigerant present on the indoor unit 10 side (refrigerant that has flowed into the indoor unit 10 for pressure balance while the compressor 21 is stopped) evaporates, so the indoor heat exchanger temperature temporarily decreases. However, after the refrigerant has completely evaporated, the temperature of the indoor heat exchanger gradually increases, and the difference between the indoor suction temperature and the indoor heat exchanger temperature decreases again.

そして、時間ｔ４で再び圧縮機モータープロテクタ２１ａが開になると、圧縮機２１は自主的に停止し（動作オフ）、室内吸込み温度と室内熱交換器温度との温度差は急低下して、時間ｔｅ２で５ｄｅｇより小さくなる。このとき、制御部１１は、室内吸込み温度と室内熱交換器温度との温度差が５ｄｅｇより高い温度から低い温度に変化した回数として２回目をカウントする。 Then, when the compressor motor protector 21a is opened again at time t4, the compressor 21 is automatically stopped (operation is off), and the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature rapidly decreases, It becomes smaller than 5 deg at te2. At this time, the control unit 11 counts the second time as the number of times the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature has changed from a temperature higher than 5 deg to a lower temperature.

その後も圧縮機モータープロテクタ２１ａが繰り返し作動し続けると、制御部１１は、時間ｔｅ３，ｔｅ４で、室内吸込み温度と室内熱交換器温度との温度差が５ｄｅｇより高い温度から低い温度に変化した回数をカウントし続ける。そして、制御部１１は、時間ｔｅ５における５回目のカウントの時点で、制御部１１は圧縮機モータープロテクタ２１ａが繰り返し作動するような異常が発生していると判断し、圧縮機２１に運転の停止を指令する（オフ指令）する。 After that, if the compressor motor protector 21a continues to operate repeatedly, the controller 11 will change the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature from a temperature higher than 5 deg to a lower temperature at times te3 and te4. Keep counting. Then, at the time of the fifth count at time te5, the control unit 11 determines that an abnormality that causes the compressor motor protector 21a to operate repeatedly has occurred, and the compressor 21 stops operating. Is commanded (off command).

以上、本実施の形態のように構成された冷専一定速エアコン５０においては、圧縮機モータープロテクタ２１ａが繰り返し作動するような異常が発生しても、それを確実に異常として判定してシステム停止させ、更なる２次被害（冷媒配管の疲労破壊、圧縮機モータープロテクタ２１ａの故障等）を未然に防止することができる。 As described above, in the cold-only constant-speed air conditioner 50 configured as in the present embodiment, even if an abnormality occurs such that the compressor motor protector 21a repeatedly operates, it is reliably determined as an abnormality and the system is stopped. Thus, further secondary damage (fatigue failure of the refrigerant piping, failure of the compressor motor protector 21a, etc.) can be prevented in advance.

なお、本実施の形態では、保護装置となる開閉器として圧縮機モータープロテクタ２１ａを備えた冷専一定速エアコン５０を例に本発明を説明したが、本発明に係る冷専一定速エアコンは本実施の形態で説明した冷専一定速エアコン５０の構成に限定されるものではない。例えば、保護装置となる開閉器として、圧縮機２１から吐出される冷媒の圧力が所定圧力以上になると制御部１１からの指令にかかわらず圧縮機２１のモーターへの電流通路を開閉動作する所謂ハイプレッシャースイッチを用いてもよい。例えば、このハイプレッシャースイッチとは、圧縮機２１の吐出側配管に設けられ、所定の圧力以上になると作動する弁と、圧縮機２１のモーターへの電流通路に設けられ、該弁に機械的に連動して当該電流通路を開状態にするスイッチとを備えたものである。このような開閉器を備えた冷専一定速エアコンにおいても、例えば室外ファンモーター２２が故障して室外熱交換器２６に凝縮阻害が発生すると、圧縮機２１の吐出圧力が上昇して当該開閉器が開条件になり、圧縮機２１は自主的に停止する。そして、圧縮機２１が自主的に停止すると、室内吸込み温度と室内熱交換器温度との温度差は急低下し、室内吸込み温度と室内熱交換器温度との温度差は、所定の閾値（例えば５ｄｅｇ）より高い温度から低い温度に変化する。したがって、この閾値を跨ぐ温度変化をカウントすることにより、更なる２次被害（冷媒配管の疲労破壊、ハイプレッシャースイッチの故障等）を未然に防止することができる。 In the present embodiment, the present invention has been described by taking the cold-only constant-speed air conditioner 50 provided with the compressor motor protector 21a as a protective device as a switch, but the cold-only constant-speed air conditioner according to the present invention is It is not limited to the configuration of the cold-only constant-speed air conditioner 50 described in the embodiment. For example, as a switch serving as a protective device, when the pressure of the refrigerant discharged from the compressor 21 becomes equal to or higher than a predetermined pressure, the so-called high circuit that opens and closes the current path to the motor of the compressor 21 regardless of a command from the control unit 11. A pressure switch may be used. For example, the high pressure switch is provided in a discharge side piping of the compressor 21 and is provided in a current path to a motor that operates when the pressure exceeds a predetermined pressure and a motor of the compressor 21. And a switch for interlockingly opening the current path. Even in a constant temperature constant-speed air conditioner equipped with such a switch, for example, when the outdoor fan motor 22 fails and the outdoor heat exchanger 26 is prevented from condensing, the discharge pressure of the compressor 21 rises and the switch Becomes an open condition, and the compressor 21 stops autonomously. When the compressor 21 is automatically stopped, the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature rapidly decreases, and the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature is a predetermined threshold (for example, 5 deg) changes from a higher temperature to a lower temperature. Therefore, by counting the temperature change across this threshold, further secondary damage (fatigue failure of the refrigerant piping, failure of the high pressure switch, etc.) can be prevented in advance.

また、保護装置となる開閉器を備えない冷専一定速エアコンにおいても本発明を実施することができる。例えば、室外ファンモーター２２が故障して圧縮機２１の温度と圧力が上昇すると、圧縮機２１の構成部品が熱膨張して摺動部が一時的にロックし、ロックが解除されるまでの間圧縮機２１が停止する場合がある。このように圧縮機２１が停止すると、室内吸込み温度と室内熱交換器温度との温度差は急低下し、室内吸込み温度と室内熱交換器温度との温度差は、所定の閾値（例えば５ｄｅｇ）より高い温度から低い温度に変化する。したがって、この閾値を跨ぐ温度変化をカウントすることにより、更なる２次被害（冷媒配管の疲労破壊等）を未然に防止することができる。 Further, the present invention can also be implemented in a cold-specific constant-speed air conditioner that does not include a switch serving as a protection device. For example, when the outdoor fan motor 22 breaks down and the temperature and pressure of the compressor 21 rises, the components of the compressor 21 are thermally expanded and the sliding portion is temporarily locked until the lock is released. The compressor 21 may stop. When the compressor 21 stops in this manner, the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature rapidly decreases, and the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature is a predetermined threshold (for example, 5 deg). Change from higher temperature to lower temperature. Therefore, by counting the temperature change across this threshold, further secondary damage (such as fatigue failure of the refrigerant piping) can be prevented in advance.

また、本実施の形態では、２次被害が発生する異常の一例として室外ファンモーター２２の故障を例に説明したが、本発明は、室外ファンモーター２２以外の構成機器に異常が発生した場合でも、２次被害を未然に防止することができる。例えばキャピラリーチューブ２５につまりが発生した場合、室内機１０の制御部１１では当該つまりを検出することはできない。また例えば、室内機１０と室外機２０を設置する際に用いられる開閉弁が、室内機１０や室外機２０に設けられている。この開閉弁は、室内機１０と室外機２０を冷媒配管で接続するときには閉じられており、室内機１０及び室外機２０の接続後に開かれるものである。室内機１０と室外機２０を配管接続した後にこの開閉弁を開くことを忘れた場合も、室内機１０の制御部１１では当該開閉弁の閉状態を検出することはできない。これらキャピラリーチューブ２５や開閉弁によって冷媒の流れが阻害されると、圧縮機２１の吐出側（キャピラリーチューブ２５や開閉弁の上流側）は圧力が上昇する。また、圧縮機２１の吸入側（キャピラリーチューブ２５や開閉弁の下流側）は冷媒不足となり、室内熱交換器１６での過熱度が過度に上昇する。このため、圧縮機２１の圧力及び温度が上昇して保護装置が作動すること等により、圧縮機２１は、制御部１１の運転指令にかかわらず自主的に停止する。そして、圧縮機２１の圧力及び温度が低下すると、圧縮機２１は再び動作を開始する。つまり、このような異常が発生している場合でも、室内吸込み温度と室内熱交換器温度との温度差は、所定の閾値（例えば５ｄｅｇ）より高い温度から低い温度に変化する。したがって、この閾値を跨ぐ温度変化をカウントすることにより、更なる２次被害（冷媒配管の疲労破壊等）を未然に防止することができる。 In the present embodiment, the failure of the outdoor fan motor 22 has been described as an example of an abnormality that causes secondary damage. However, the present invention may be applied even when an abnormality occurs in a component device other than the outdoor fan motor 22. Secondary damage can be prevented in advance. For example, when clogging occurs in the capillary tube 25, the clogging cannot be detected by the control unit 11 of the indoor unit 10. In addition, for example, an opening / closing valve used when installing the indoor unit 10 and the outdoor unit 20 is provided in the indoor unit 10 and the outdoor unit 20. The on-off valve is closed when the indoor unit 10 and the outdoor unit 20 are connected by refrigerant piping, and is opened after the indoor unit 10 and the outdoor unit 20 are connected. Even when the on-off valve is forgotten to be opened after the indoor unit 10 and the outdoor unit 20 are connected by piping, the control unit 11 of the indoor unit 10 cannot detect the closed state of the on-off valve. When the flow of the refrigerant is inhibited by the capillary tube 25 or the opening / closing valve, the pressure increases on the discharge side of the compressor 21 (upstream side of the capillary tube 25 or the opening / closing valve). Further, the suction side of the compressor 21 (downstream side of the capillary tube 25 and the on-off valve) is short of refrigerant, and the degree of superheat in the indoor heat exchanger 16 is excessively increased. For this reason, when the pressure and temperature of the compressor 21 rise and the protection device is activated, the compressor 21 stops independently regardless of the operation command of the control unit 11. And if the pressure and temperature of the compressor 21 fall, the compressor 21 will start operation | movement again. That is, even when such an abnormality occurs, the temperature difference between the indoor suction temperature and the indoor heat exchanger temperature changes from a temperature higher than a predetermined threshold (for example, 5 deg) to a lower temperature. Therefore, by counting the temperature change across this threshold, further secondary damage (such as fatigue failure of the refrigerant piping) can be prevented in advance.

また、本実施の形態では、室内機１０の制御部１１は室外機２０の圧縮機２１及び室外ファンモーター２２へ同時に運転指令及び停止指令を送信していたが、圧縮機２１への運転指令及び停止指令と、室外ファンモーター２２への運転指令及び停止指令とを別々に送信しても勿論よい。 In the present embodiment, the control unit 11 of the indoor unit 10 transmits the operation command and the stop command to the compressor 21 and the outdoor fan motor 22 of the outdoor unit 20 at the same time. Of course, the stop command and the operation command and the stop command for the outdoor fan motor 22 may be transmitted separately.

また、本実施の形態で示した所定の閾値（例えば５ｄｅｇ）や、システム停止までに当該閾値を跨ぐ温度変化をカウントする回数（例えば５回）は、あくまでも一例である。なお、システム停止までに当該閾値を跨ぐ温度変化をカウントする回数を複数回とすることにより、２次被害の発生原因となる異常が発生していないにもかかわらずシステムを停止してしまうという誤動作を防止することができる。 Moreover, the predetermined threshold value (for example, 5 degrees) shown in the present embodiment and the number of times (for example, 5 times) of counting the temperature change across the threshold value until the system is stopped are merely examples. In addition, the malfunction that the system is stopped even if the abnormality that causes the secondary damage has not occurred by setting the number of times that the temperature change across the threshold value is counted multiple times before the system is stopped. Can be prevented.

１リモコン、１０室内機、１１制御部、１２室内ファンモーター、１３室内ファン、１４室内吸込み温度センサー、１５室内熱交換器温度センサー、１６室内熱交換器、２０室外機、２１圧縮機、２１ａ圧縮機モータープロテクタ、２２室外ファンモーター、２３室外ファン、２４室外熱交換器、２５キャピラリーチューブ、５０冷専一定速エアコン、１００冷専一定速エアコン（従来）、１０１リモコン（従来）、１１０室内機（従来）、１１１制御部（従来）、１１２室内ファンモーター（従来）、１１３室内ファン（従来）、１１４室内吸込み温度センサー（従来）、１１５室内熱交換器温度センサー（従来）、１１６室内熱交換器（従来）、１２０室外機（従来）、１２１圧縮機（従来）、１２１ａ圧縮機モータープロテクタ、１２２室外ファンモーター（従来）、１２３室外ファン（従来）、１２４室外熱交換器（従来）、１２５キャピラリーチューブ（従来）。 DESCRIPTION OF SYMBOLS 1 Remote control, 10 Indoor unit, 11 Control part, 12 Indoor fan motor, 13 Indoor fan, 14 Indoor suction temperature sensor, 15 Indoor heat exchanger temperature sensor, 16 Indoor heat exchanger, 20 Outdoor unit, 21 Compressor, 21a Compression Machine motor protector, 22 outdoor fan motor, 23 outdoor fan, 24 outdoor heat exchanger, 25 capillary tube, 50 constant temperature air conditioner, 100 constant speed air conditioner (conventional), 101 remote control (conventional), 110 indoor unit ( Conventional), 111 Control unit (conventional), 112 Indoor fan motor (conventional), 113 Indoor fan (conventional), 114 Indoor suction temperature sensor (conventional), 115 Indoor heat exchanger temperature sensor (conventional), 116 Indoor heat exchanger (Conventional), 120 Outdoor unit (Conventional), 121 Compressor (Conventional), 1 1a compressor motor protector, 122 outdoor fan motor (prior art), 123 outdoor fan (conventional), 124 outdoor heat exchanger (conventional), 125 capillary tube (prior art).

Claims

An outdoor unit having a compressor, an outdoor heat exchanger serving as a condenser, a capillary tube, and an outdoor fan for supplying outdoor air to the outdoor heat exchanger;
An indoor unit having an indoor heat exchanger serving as an evaporator, and an indoor fan for supplying indoor air to the indoor heat exchanger;
A control unit that is provided in the indoor unit, and commands the operation and stop of the indoor fan, the compressor, and the outdoor fan;
In an air conditioner that operates the compressor and the outdoor fan at a constant rotational speed,
An indoor heat exchanger temperature sensor for detecting the temperature of the indoor heat exchanger;
An indoor suction temperature sensor for detecting the temperature of indoor air sucked into the indoor unit;
With
The controller is
Count the number of times the temperature difference between the detected temperature of the indoor suction temperature sensor and the detected temperature of the indoor heat exchanger temperature sensor has changed from a state higher than a predetermined threshold to a lower state,
An air conditioner characterized by issuing a stop command to the indoor blower, the compressor, and the outdoor blower when the number of times reaches a predetermined number or more.

An outdoor unit having a compressor, an outdoor heat exchanger serving as a condenser, a capillary tube, and an outdoor fan for supplying outdoor air to the outdoor heat exchanger;
An indoor unit having an indoor heat exchanger serving as an evaporator, and an indoor fan for supplying indoor air to the indoor heat exchanger;
A control unit that is provided in the indoor unit, and commands the operation and stop of the indoor fan, the compressor, and the outdoor fan;
Depending on the pressure of the refrigerant discharged from the compressor, the current path to the motor of the compressor is opened and closed regardless of the command from the control unit, and the pressure of the refrigerant discharged from the compressor is A switch that protects the compressor by shutting off the power to the motor of the compressor when a predetermined value is exceeded;
In an air conditioner that operates the compressor and the outdoor fan at a constant rotational speed,
An indoor heat exchanger temperature sensor for detecting the temperature of the pre-Symbol indoor heat exchanger,
An indoor suction temperature sensor for detecting the temperature of indoor air sucked into the indoor unit;
With
The controller is
Count the number of times the temperature difference between the detected temperature of the indoor suction temperature sensor and the detected temperature of the indoor heat exchanger temperature sensor has changed from a state higher than a predetermined threshold to a lower state,
An air conditioner characterized by issuing a stop command to the indoor blower, the compressor, and the outdoor blower when the number of times reaches a predetermined number or more.

An outdoor unit having a compressor, an outdoor heat exchanger serving as a condenser, a capillary tube, and an outdoor fan for supplying outdoor air to the outdoor heat exchanger;
An indoor unit having an indoor heat exchanger serving as an evaporator, and an indoor fan for supplying indoor air to the indoor heat exchanger;
A control unit that is provided in the indoor unit, and commands the operation and stop of the indoor fan, the compressor, and the outdoor fan;
It is provided in a current path to the motor of the compressor or to the motor, and opens and closes regardless of a command from the control unit according to the current and temperature. When at least one exceeds a predetermined value, a switch that cuts off power to the motor of the compressor and protects the compressor;
In an air conditioner that operates the compressor and the outdoor fan at a constant rotational speed,
An indoor heat exchanger temperature sensor for detecting the temperature of the pre-Symbol indoor heat exchanger,
An indoor suction temperature sensor for detecting the temperature of indoor air sucked into the indoor unit;
With
The controller is
Count the number of times the temperature difference between the detected temperature of the indoor suction temperature sensor and the detected temperature of the indoor heat exchanger temperature sensor has changed from a state higher than a predetermined threshold to a lower state,
An air conditioner characterized by issuing a stop command to the indoor blower, the compressor, and the outdoor blower when the number of times reaches a predetermined number or more.