JPH06213171A - Lock detecting device for compressor of inverter-driven air-conditioner - Google Patents

Abstract

PURPOSE:To surely detect the lock of a motor at the time of a start and during operation. CONSTITUTION:A compressor 1 is judged to have a defective start, i.e., to be kept in the lock state, and its operation is stopped when the following relation exists: #>=P>P2-P1, where P1 is the pressure value of a pressure sensor 41 at the time and prior to the start of the compressor 1, P2 is the pressure value when a certain time elapses after a start command, and DELTAP is the difference pressure set in advance. The lock of the compressor 1 at the time of the start can be detected in the whole area, and the seizure of a motor 42 can be prevented. The lock is detected during operation in consideration of the increase of the input current and the reduction of the pressure additionally.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter type air conditioner, and more particularly to a compressor lock detecting device for an inverter drive type air conditioner for detecting a lock state of a motor driving a compressor.

[0002]

2. Description of the Related Art Locking of a compressor means that the motor driving the compressor is energized but the rotation of the motor is stopped. If the compressor locks up, overcurrent may flow through the motor and damage it. That is, the input current of the motor increases, and if left as it is, the coil of the motor will be burned and the power transistor of the inverter will be destroyed. Therefore, it is necessary to stop the operation of the compressor by the lock detection.

Therefore, conventionally, for example, Japanese Patent Laid-Open No. 63-2127.
A lock detection method as described in Japanese Patent Publication No. 85 has been proposed. In such a conventional example, a current sensor is provided on the input side and the output side of the inverter for driving and controlling the motor, and the lock is detected based on the detected current by these.

[0004]

SUMMARY OF THE INVENTION In the above conventional example,
The lock detection of the compressor during operation is detected by the output side current (output peak) and the input current as described above. These detected currents are the coil temperature of the compressor, or operating conditions such as frequency and pressure conditions. However, even if the lock is generated, it may not be detected in some cases.

Further, in detecting the start-up failure of the compressor, the current detection (the peak value of the output current and the increase of the input current, etc.) is also detected. However, the detection by the current differs depending on the motor temperature of the compressor. Further, since it also varies depending on the voltage, when the reference current value is set so as not to malfunction during normal operation, it is impossible to detect startup failure in all operating areas.

The present invention has been made to solve the above-mentioned conventional drawbacks, and an object thereof is an inverter-driven air conditioner capable of surely detecting lock of a motor at the time of start-up and operation. In order to provide a compressor lock detection device of the above.

[0007]

Therefore, in the compressor lock detection device for an inverter-driven air conditioner according to claim 1, an inverter 2 whose output can be changed by a change in frequency, and a motor 42 controlled by this inverter 2 are provided. In the inverter-driven air conditioner equipped with the compressor 1 driven by, and the pressure sensor 41 for detecting the pressure of the discharge pipe 3 connected to the compressor 1, Control for comparing the pressure value with the pressure value from the pressure sensor 41 after a lapse of a predetermined time after startup, and determining that the motor 42 is in the locked state when the pressure increase width is smaller than the preset pressure width. It is characterized in that means 43 is provided.

The compressor lock detection device for an inverter-driven air conditioner according to a second aspect of the present invention is a compressor that is driven by an inverter 2 whose output can be changed by a change in frequency and a motor 42 controlled by the inverter 2. In the inverter-driven air conditioner equipped with the machine 1 and the pressure sensor 41 for detecting the pressure of the discharge pipe 3 connected to the compressor 1, the detection means 44 for detecting the input current of the motor 42 is provided, It is determined that the motor 42 is in the locked state when the input current of the motor 42 is increased by a predetermined amount or more and the pressure value of the pressure sensor 41 is decreased more than the predetermined pressure width by the signal from the detection means 44 during operation. The second control means 43 is provided.

Further, the compressor lock detection device for an inverter-driven air conditioner according to a third aspect of the present invention is a compressor driven by an inverter 2 whose output can be changed by a change in frequency and a motor 42 controlled by this inverter 2. In an inverter-driven air conditioner equipped with a machine 1 and a temperature sensor 51 for detecting the temperature of a discharge pipe 3 connected to the compressor 1, the operating frequency F of the inverter 2 and the temperature sensor 51 When the reference lock current value I _L is corrected by a value according to the discharge pipe temperature D _OT and the input current I _i is larger than the corrected reference lock current value I _L ,
The third control means 43 for determining that the motor 42 is in the locked state is provided.

According to a fourth aspect of the present invention, there is provided a compressor lock detection device for an inverter-driven air conditioner, which comprises an inverter 2 whose output can be changed by a change in frequency, and a compressor 42 which is driven by a motor 42 controlled by the inverter 2. 1 and a temperature sensor 51 for detecting the temperature of the discharge pipe 3 connected to the compressor 1, in an inverter drive type air conditioner, a detection means 44 for detecting an input current of a motor 42.
The motor 42 is provided with a signal from the detection means 44.
Input current increases more than a predetermined amount, and the temperature sensor 5
It is characterized in that the fourth control means 43 is provided to judge that the motor 42 is in the locked state when the temperature D _OT detected by 1 has dropped by a predetermined value or more.

According to a fifth aspect of the present invention, there is provided a compressor lock detecting device for an air conditioner driven by an inverter, wherein a compressor driven by an inverter 2 whose output can be changed by changing a frequency and a motor 42 controlled by the inverter 2. 1 and a pressure sensor 41 for detecting the pressure of the discharge pipe 3 connected to the compressor 1, in an inverter-driven air conditioner, a sensor 52 for detecting the suction pipe equivalent saturation temperature D _E or the pressure. , A detection means 44 for detecting an input current of the motor 42 is provided, and the suction pipe equivalent saturation temperature D _E or the pressure is increased by a signal or more by the signal from the sensor 52, and the signal of the motor 42 is detected by the signal from the detection means 44. When the input current increases by a predetermined amount or more and the pressure of the discharge pipe 3 decreases by a predetermined value or more by the signal from the pressure sensor 41, the motor 4 There is characterized in that a fifth control means 43 determines that the locked state.

[0002]

According to the compressor lock detection device for an inverter-driven air conditioner of claim 1, the start failure (lock) is determined by comparing the pressure values of the pressure sensor 41 before and after the start. The operation stop processing of the compressor 1 is performed. Therefore, the lock detection at the time of starting the compressor 1 can be performed in all areas, and the burn of the motor 42 of the compressor 1 can be prevented in advance.

Further, according to the compressor lock detecting device of the inverter-driven air conditioner of the second aspect, the input current increases during operation, and the pressure value detected by the pressure sensor 41 falls much below the predetermined pressure range. In this case, the operation is stopped because the motor 42 of the compressor 1 is locked, and the lock of the motor 42 of the compressor 1 can be reliably detected.

Further, according to the compressor lock detecting device of the inverter-driven air conditioner of the third aspect, the reference lock current value _IL is set in advance to change the operating frequency F of the inverter 2, when the temperature D _OT of the discharge pipe 3 is changed, by correcting the reference lock current value I _L in accordance with the operation frequency F and piping temperature D _OT, when the operating frequency F and piping temperature D _OT changes But, it is possible to accurately lock detection compared corrected the lock current value I _L and the input current I _i. Therefore, it is possible to prevent the motor 42 of the compressor 1 from burning. In order to make comparisons with the lock detecting the lock current value I _L obtained by correcting the input current I _i, can only lock detection input current I _i, as a result, it is possible to simplify the configuration of the lock detection .

According to the compressor lock detection device for an inverter-driven air conditioner of claim 4, lock detection is performed by decreasing the temperature D _OT of the discharge pipe 3 and increasing the input current during operation. Therefore, even when the number of operating rooms is increased, the lock can be detected by the large decrease in the pipe temperature _DOT .

According to the compressor lock detection device of the inverter-driven air conditioner of claim 5, the saturation temperature D equivalent to the suction pipe is obtained.
Lock detection is performed under the three conditions of _E or pressure increase, input current increase, and discharge pipe 3 pressure decrease. Therefore, even if the number of rooms increases or decreases, lock detection can be accurately performed. Is.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of a compressor lock detecting device for an inverter-driven air conditioner according to the present invention will be described in detail with reference to the drawings. FIG. 2 shows a refrigerant circuit diagram of a multi-type air conditioner having four indoor units. In the figure, X indicates an outdoor unit, and A to D indicate first to fourth indoor units, respectively.

The outdoor unit X has a compressor 1. The capacity of the compressor 1 is controlled by an inverter 2, and its discharge pipe 3 and suction pipe 4 are:
It is connected to the four-way switching valve 5. A first gas pipe 6 and a second gas pipe 7 are connected to the four-way switching valve 5, and an outdoor heat exchanger 8 is connected to the second gas pipe 7. An outdoor fan 9 is attached to the outdoor heat exchanger 8. The outdoor heat exchanger 8 has a first liquid pipe 1
0, the liquid receiver 11, and the second liquid pipe 12 are sequentially connected,
A first electric expansion valve 13 is interposed in the first liquid pipe 10. The second liquid pipe 12 is connected to a header 14, but from this header 14 four liquid side branch pipes 15 ...
15 is branched, and second electric expansion valves 16 ... 16 are provided in each liquid side branch pipe 15. On the other hand, the header 2 also corresponds to the above from the first gas pipe 6.
Four gas side branch pipes 17 are branched through 4 and an indoor heat exchanger 18 is formed between the branch pipes 15 and 17.
・ 18 is connected. In addition, an indoor fan 19 is attached to each indoor heat exchanger 18, and the indoor units A to D are configured by the both fans 18 and 19. In addition, the liquid receiver 1
1 and the suction pipe 4 of the compressor 1 are connected by a pipe 20, and a capillary tube 21 is provided in the pipe 20. In FIG. 2, 22 is a gas closing valve, 23 is a liquid closing valve, 25 is a muffler, and 26 is an accumulator. 27-29 again
Is a solenoid valve, 30 is a muffler, and 31 is a capillary tube. Further, 51 is a temperature sensor for detecting the temperature of the discharge pipe 3, and 52 is a temperature sensor for detecting the saturation temperature corresponding to the suction pipe in the pipe 20.

In the above air conditioner, the refrigerant discharged from the compressor 1 is transferred from the outdoor heat exchanger 8 serving as a condenser to the indoor heat exchanger 1 serving as an evaporator, as indicated by a dashed arrow in the figure.
The cooling operation is performed by circulating it to 8 ... 18.
In contrast to the above, the heating operation is performed by circulating the refrigerant discharged from the compressor 1 from the indoor heat exchanger 18 serving as a condenser to the outdoor heat exchanger 8 serving as an evaporator (in the figure). Solid arrow).

The discharge pipe 3 connected to the compressor 1 is conventionally provided with a pressure sensor 41 for detecting pressure. The original function of this pressure sensor 41 is
This is for detecting the pressure and stopping the high pressure of the compressor 1. Further, the pressure sensor 41 performs heating peak cut control in which what is conventionally performed on the indoor heat exchanger side is controlled by the discharge pressure, and what is conventionally performed on the outdoor heat exchanger side is set as the discharge pressure. It is also provided to perform heating high pressure control.

Therefore, in the present invention, the lock of the motor of the compressor 1 is detected by positively utilizing the pressure sensor 41 provided conventionally. That is, FIG. 1 shows a block diagram in the case of performing lock detection. An AC power supply 45 is applied to the inverter 2, and the output of the inverter 2 is applied to the motor 42 to change the frequency of the inverter 2 to change the frequency of the motor. The voltage applied to 42 is adjusted. An input current sensor 44 that detects an input current to the inverter 2 is interposed between the AC power supply 45 and the inverter 2, and a signal from the input current sensor 44 is an A / D signal of a microcomputer (microcomputer) 43. It is entered in the port.

The output of the pressure sensor 41 is the microcomputer 4
3, the lock detection of the compressor 1 is performed by the signal from the pressure sensor 41 at the time of starting the compressor 1 and the signal from the pressure sensor 41 and the input current sensor 44 at the time of operation. I have to. The microcomputer 43 constitutes control means for detecting and determining the locked state at the time of startup, and second control means for detecting and determining the locked state at the time of operation.

Next, a method of lock detection at the time of activation will be described. First, at the time of starting the compressor 1, the pressure value of the pressure sensor 41 before starting is set to P _1, and the pressure value after a certain time after the start command is set to P ₂ , and the pressure difference between before starting and after starting is determined. , In relation to the preset reference differential pressure ΔP,
When ΔP> P ₂ −P ₁ , it is determined that the startup is defective, that is, the locked state. Therefore, when the microcomputer 43 receives the signal from the pressure sensor 41 before and after the activation and the microcomputer 43 calculates the differential pressure from the pressure value and the above equation is satisfied, the microcomputer 43 is in the locked state, and therefore the microcomputer 43 drives the inverter 2. To stop the operation of the compressor 1. Therefore, the lock detection at the time of starting the compressor 1 can be performed in all areas, and the burn of the motor 42 and the like can be prevented in advance.

Further, lock detection when the compressor 1 is in operation is performed as follows. In this case, when considering the multi-type as shown in FIG. 2 as an example of the condition for detecting the lock, the number of rooms, that is, the indoor heat exchanger 18 is not changed and the operating frequency is not changed, and the heating state or the cooling state is It is assumed to be continued. If the motor 42 locks in this state, the pressure sensor 4
The pressure value of 1 decreases. Further, when the motor 42 is locked during operation, the input current increases. At this time, a signal is input from the input current sensor 44 to the microcomputer 43, and the microcomputer 43, which performs sampling at regular intervals or constantly monitors, detects an increase in the input current by a predetermined value or more based on the signal from the input current sensor 44. At the same time, when the pressure value from the pressure sensor 41 drops significantly below the predetermined pressure range, the microcomputer 43 causes the motor 42 to
It is determined that is locked, and the inverter 2 is stopped. In other words, in the lock detection during operation, when the input current value increases more than a preset value and the value of the pressure sensor 41 greatly decreases, the microcomputer 43 determines that the motor 42 is locked and stops the operation. To do.

Next, a method of detecting the lock of the third compressor 1 will be described. By the way, the motor 4 that drives the compressor 1
The control of No. 2 is performed by changing the frequency of the inverter 2. As shown in FIG. 3, the input current I depends on the operating frequency and the temperature of the motor 42 (motor coil temperature).
_i is different. For example, when the operating frequency F is high, the input current I _i rises, and when the operating frequency is low, the input current I _{i is high.}
Also decreases. When the temperature D _{OT of the} motor 42 is low (COLD), the input current I _i is large, and when the temperature is high (HOT), the input current I _i is small. Therefore, as shown in FIG.
The input current of the compressor 1 fluctuates depending on whether the temperature of 2 is high or low. Therefore, if lock detection during operation is set at a certain input current value, the input current value changes depending on the operating frequency, temperature, etc., and thus such lock detection may not be an effective method. Therefore, in this embodiment,
Paying attention to the fact that the factor of change in the input current value changes depending on the coil temperature and the operating frequency of the motor 42, the reference lock current value is corrected by the temperature of the discharge pipe 3 which is almost proportional to the coil temperature of the motor 42 and the operating frequency. Lock detection is performed.

A detailed description will be given below. As shown in FIG. 3, the temperature of the discharge pipe 3 by the temperature sensor 51 (see FIGS. 1 and 2) is D _OT , the operating frequency is F, the reference lock current is I _L , and the above D _OT is a coefficient. When the input current is I _i by multiplying x ₁ and multiplying F by the coefficient x ₂ , the lock is determined when the following formula is satisfied. I _i > I _L −x ₁ D _OT + x ₂ F ...

[0027] That is because the input current I _i by the temperature D _OT of the discharge pipe 3 and the value of the operation frequency F fluctuates, lock current I values of _L in accordance with the change in the operating frequency F and the temperature D _OT of the discharge pipe 3 Is to change. That is, FIG.
In the case where the operating frequency F is low, the discharge pipe temperature D
If the lock current when _OT is low and the _{I L,} the operating frequency F will by adding _{x 2} F to _{I L} as increases, also the discharge pipe temperature _{D OT x} 1 from _{I L} as increases _{D OT} The lock current value I corresponding to a certain operating frequency F and a certain discharge pipe temperature D _OT.
L (I _L −x ₁ D _OT + x ₂ F) is determined, and when the input current value I _i is larger than the lock current value at that time, it is determined that the motor 42 is locked, and the inverter 2 and the compressor 1 are determined.
To stop. The above control is performed by the microcomputer 43 shown in FIG. 1, and this microcomputer 43 constitutes the third control means.

Next, a method of detecting the lock of the fourth compressor 1 will be described. By the way, in the second embodiment,
The lock is detected only when the number of driving rooms is constant, but there is a drawback that the lock cannot be detected when the number of driving rooms changes. Therefore, in the present embodiment, the lock detection can be accurately detected even if the number of rooms is increased or decreased. When the number of rooms increases, the frequency of the inverter 2 is increased to increase the output of the compressor 1, and the operation is performed. At this time, the discharge pipe 3
The temperature D _{OT of} is decreased, but it is further decreased when locked. When the motor 42 is locked, since the compressor 1 is not driven, the temperature D _OT of the discharge pipe 3 greatly decreases as described above, and the input current value increases.
Therefore, in the present embodiment, as shown in FIG. 1, the signals from the input current sensor 44 and the temperature sensor 51 for detecting the temperature D _OT of the discharge pipe 3 are input to the microcomputer 43, and the fourth signal is supplied to the microcomputer 43.
The lock is detected by the microcomputer 43 that constitutes the control means.

[0029] As described above, in the time of locking of the motor 42, the temperature D _OT of the discharge pipe 3 is reduced, in order to be temperature D _OT of the discharge pipe 3 is lowered at the time of stopping the operation, the operation and the stop In order to determine the time, it is confirmed that the vehicle is in operation by increasing the input current, and then lock detection is performed. Therefore, when the temperature D _OT of the discharge pipe 3 decreases by a predetermined value or more and the input current value increases by a predetermined value or more, the microcomputer 43 determines that the motor 42 is locked, and the inverter 2 and the compressor 1 are turned on. Stop. The above determination is made for each sampling during operation.

Next, a method of detecting the lock of the fifth compressor 1 will be described. Also in this embodiment, the lock detection can be accurately detected even if the number of driving rooms is increased or decreased. In the present embodiment, signals from the temperature sensor 52 that detects the suction pipe equivalent saturation temperature of the refrigerant, the input current sensor 44, and the pressure sensor 41 that detects the pressure of the discharge pipe 3 are input to the microcomputer 43, and the fifth control is performed. The microcomputer 43 constituting the means detects the lock of the motor 42. At the time of lock, the suction pipe equivalent saturation temperature D _E rises, the input current rises, and the pressure of the discharge pipe 3 decreases, so even if the number of rooms increases or decreases, the lock is detected by these three states. Is.

That is, the temperature D _E (or pressure) detected by the temperature sensor 52 in the pipe 20 and the input current sensor 44
Input current value and pressure sensor 41 of the discharge pipe 3
The pressure value due to is detected at every sampling during operation and judged, the detected value of the previous time and the detected value of this time are compared, the detected temperature D _E rises by a predetermined value or more, and the input current value is Is higher than a predetermined value and the pressure in the discharge pipe 3 is lower than a predetermined value, the microcomputer 43 determines that the motor 42 is locked. Then, the microcomputer 43 stops the inverter 2 and the compressor 1. It should be noted that the lock detection may be performed under the four conditions including the condition in the locked state in the present embodiment and the condition when the temperature D _OT of the discharge pipe 3 is _lowered .

[0032]

As described above, according to the compressor lock detecting device for the inverter-driven air conditioner of the first aspect, the pressure increase width is determined by comparing the pressure values of the pressure sensor before and after starting. If the value is smaller than the value of, it is possible to determine that the startup is defective (locked) and perform the operation stop process of the compressor. Therefore, the lock detection at the time of starting the compressor can be performed in all areas, and the burn of the motor of the compressor can be prevented in advance.

According to the compressor lock detecting device of the inverter-driven air conditioner of the second aspect, the input current is increased by a predetermined value or more during operation, and the pressure value detected by the pressure sensor is larger than the predetermined pressure range. When it goes down, the operation is stopped assuming that the compressor motor is locked, and even in this case, the lock of the compressor motor can be reliably detected.

Further, according to the compressor lock detecting device of the inverter-driven air conditioner of the third aspect, the reference lock current value is set in advance, the operating frequency of the inverter is changed, and the temperature of the discharge pipe is changed. If the operating frequency or piping temperature changes, the reference lock current value is corrected according to the operating frequency or piping temperature to compare the corrected locking current value with the input current even if the operating frequency or piping temperature changes. The lock can be detected accurately. Therefore, it is possible to prevent burning of the compressor motor. Further, since the lock detection is performed by comparing the corrected lock current and the input current, the lock can be detected only by the input current, and as a result, the configuration of the lock detection can be simplified.

According to the compressor lock detection device for an inverter-driven air conditioner of claim 4, lock detection is performed by lowering the temperature of the discharge pipe and increasing the input current during operation. In particular, even when the number of operating rooms is increased, lock detection can be performed due to a significant decrease in piping temperature.

According to the compressor lock detecting device of the inverter-driven air conditioner of the fifth aspect, the suction pipe equivalent saturation temperature or pressure rises, the input current rises, and the discharge pipe pressure falls. The lock detection is performed according to the condition, and the lock detection can be accurately performed even when the number of rooms is increased or decreased as described above.

[Brief description of drawings]

FIG. 1 is a block diagram for performing lock detection according to an embodiment of the present invention.

FIG. 2 is a refrigerant circuit diagram of an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a relationship between an operating frequency, a motor temperature, and an input current according to the embodiment of this invention.

[Explanation of symbols]

 1 Compressor 2 Inverter 3 Discharge piping 5 Four way switching valve 8 Outdoor heat exchanger 18 Indoor heat exchanger 41 Pressure sensor 42 Motor 43 Microcomputer 44 Input current sensor 51 Temperature sensor 52 Temperature sensor

Front page continued (72) Inventor Go Kitagawa 2 at 1000 Otani, Okamoto-cho, Kusatsu-shi, Shiga Daikin Industry Co., Ltd. Shiga Works (72) Yoshiaki Okubo 2 at 1000 Otani, Okamoto-cho, Kusatsu-shi, Shiga Prefecture Industrial Co., Ltd. Shiga Works (72) Inventor Shinji Yoshikawa, 1000, Otani, Okamoto-cho, Kusatsu City, Shiga Prefecture 2 Daikin Industries, Ltd. Shiga Works

Claims (5)

[Claims] 1. An inverter (2) whose output can be changed by a change in frequency, a compressor (1) driven by a motor (42) controlled by this inverter (2), and this compressor (1). ), A pressure sensor (41) for detecting the pressure of the discharge pipe (3) connected to the pressure sensor (4).
The pressure value from 1) is compared with the pressure value from the pressure sensor (41) after a lapse of a predetermined time after startup, and if the pressure increase width is smaller than the preset pressure width, the motor (4
A compressor lock detection device for an inverter-driven air conditioner, characterized in that a control means (43) for judging that (2) is in a locked state is provided. 2. An inverter (2) whose output can be changed by a change in frequency, a compressor (1) driven by a motor (42) controlled by this inverter (2), and this compressor (1). In the inverter-driven air conditioner equipped with a pressure sensor (41) for detecting the pressure of the discharge pipe (3) connected to the (4), a detection means (44) for detecting the input current of the motor (42) is provided. During operation, the input current of the motor (42) increases by a predetermined amount or more by the signal from the detection means (44), and the pressure sensor (41)
Of the inverter-driven air conditioner, which is provided with a second control means (43) for determining that the motor (42) is in a locked state when the pressure value of the pressure falls below a predetermined pressure range. Machine lock detection device. 3. An inverter (2) whose output can be changed by a change in frequency, a compressor (1) driven by a motor (42) controlled by this inverter (2), and this compressor (1). ), A temperature sensor (51) for detecting the temperature of the discharge pipe (3) connected to the air conditioner, the operating frequency (F) of the inverter (2) and the temperature sensor (51). ), The reference lock current value (I _L ) is corrected by a value according to the discharge pipe temperature (D _OT ), and the corrected reference lock current value (I _L ) is corrected.
_{When the} input current (I _i ) is larger than _L ), the motor (4
Third control means (4) for judging that (2) is in a locked state
A compressor lock detection device for an inverter-driven air conditioner, which is provided with 3). 4. An inverter (2) whose output can be changed by a change in frequency, a compressor (1) driven by a motor (42) controlled by this inverter (2), and this compressor (1). ), An inverter-driven air conditioner equipped with a temperature sensor (51) for detecting the temperature of the discharge pipe (3), and a detection means (44) for detecting the input current of the motor (42). , The detection means (4
The motor (42) is locked when the input current of the motor (42) is increased by a predetermined value or more and the temperature (D _OT ) detected by the temperature sensor (51) is decreased by a predetermined value or more by a signal from 4). A compressor lock detection device for an inverter-driven air conditioner, which is provided with a fourth control means (43) for determining that 5. An inverter (2) whose output can be changed by a change in frequency, a compressor (1) driven by a motor (42) controlled by this inverter (2), and this compressor (1). ), A pressure sensor (41) for detecting the pressure of the discharge pipe (3), and a sensor (52) for detecting the suction pipe equivalent saturation temperature (D _E ) or the pressure. ) And a detection means (44) for detecting the input current of the motor (42), and the suction pipe equivalent saturation temperature (D _E ) or pressure is increased by a predetermined amount or more by the signal from the sensor (52), and When the input current of the motor (42) is increased by a predetermined value or more by the signal from the detection means (44) and the pressure of the discharge pipe (3) is decreased by a predetermined value or more by the signal from the pressure sensor (41), Chromatography data (42) is a compressor lock detection device of the inverter-driven air conditioner, characterized in that a fifth control means (43) determines that the locked state.