JPH05141847A - Device for indicating malfunction in constant temperature-maintaining apparatus - Google Patents

Abstract

PURPOSE:To shorten the time for which the operation is suspended owing to a malfunction and improve the operation rate of a constant temperature-maintaining apparatus by providing an indicating means which indicates the kind of a malfunction as judged by means of judging the kind of a malfunction on the basis of the condition of the controlled operation of an electric motor-operated compressor. CONSTITUTION:When, during the cooling operation of a constant temperature-maintaining apparatus, a malfunction causes an overload in the electric motor-operated compressor 1, a means of cutting off power 4 shuts off the supply of power to the compressor 1 and, responding to the power cut to the compressor 1, a means of judging the kind of malfunction 7 judges the kind of the malfunction on the basis of the condition of the operation of the compressor 1 which has been under control of an operation-controlling means 6. For example, malfunctioning immediately following the start of the electric motor-operated compressor 1 is judged to be locking of the motor of the compressor 1 or the like and malfunctioning at a later time is dealt with, in one possibility, as abnormal condition of the gas pressure in the piping such as choking of the condenser 2 or evaporator 3. The means of judging the kind of malfunction 7 judges such malfunctioning, for example, with regard to whether the malfunctioning is an occurrence immediately following the start or not in the controlled operation, and the result is shown on an indicating means 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interior of a refrigerator by alternately operating and stopping an electric compressor which is rotatably driven according to electric power supply and circulates a compressed refrigerant through a condenser and an evaporator. The present invention relates to a constant temperature machine such as a refrigerator or a freezer whose temperature is maintained between an upper limit temperature and a lower limit temperature, and particularly relates to an abnormality display device that displays the abnormality when an abnormality occurs in the constant temperature machine.

[0002]

2. Description of the Related Art Conventionally, an abnormality display device of this type has been provided with an electric power interruption means provided in an electric power supply path of an electric compressor when the load of the electric compressor becomes excessive due to various abnormalities of a constant temperature machine. The power supply to the compressor was cut off, and in response to the cutoff of the power supply, these various abnormalities were displayed by a single error code on the display.

[0003]

However, in the above-mentioned conventional apparatus, since the same error code is displayed even for different abnormalities of the thermostat, it is difficult to find the location where the abnormality occurred. Therefore, there is a problem that it takes time to repair an abnormality of the thermostatic chamber, which increases repair cost and lowers the operating rate of the thermostatic chamber. SUMMARY OF THE INVENTION The present invention is intended to solve the above-described problem, and an object thereof is to provide an abnormality display device for a thermostatic machine that can easily find the cause of abnormality in the thermostatic machine.

[0004]

In order to achieve the above object, the structural feature of the invention according to claim 1 is that the refrigerant compressed by being rotationally driven according to the power supply is condensed in the condenser 2 and the evaporator. The electric compressor 1 that circulates through the electric compressor 3, and the electric power supply path of the electric compressor 1 that supplies electric power to the normal compressor 1 and also supplies electric power to the compressor 1 when the load of the compressor 1 is excessive. An electric power cut-off means 4 for cutting off the electric power, an internal temperature detection means 5 for detecting the temperature of the internal cold storage 5a cooled by the evaporator 3, and an operation of the electric compressor 1 based on the temperature detected by the internal temperature detection means 5. In the thermostatic machine including the operation control means 6 for controlling the alternate operation of the stop and maintaining the internal cold storage temperature between the predetermined upper limit temperature and the lower limit temperature, the power cutoff means 4 supplies electric power to the electric compressor 1. In response to the interruption of the supply, the operation control means 6 The abnormality type determination means 7 for determining the type of abnormality according to the operation control state of the electric compressor 1 and the display means 8 for displaying the type of abnormality based on the determination result by the abnormality type determination means 7 are provided. It is in.

Further, the constitutional feature of the invention according to claim 2 is that the abnormality type judging means 7 and the display means 8 which are the characteristic parts of the invention according to claim 1 are provided in the thermostatic chamber according to the invention as an electromagnetic valve. 9 and the evaporator temperature detecting means 3a are added to the thermostat.

[0006]

In the invention according to claim 1 configured as described above, in the case where an abnormality occurs in the constant temperature machine during the cooling operation of the constant temperature machine and the load of the electric compressor 1 becomes excessive, the electric power is reduced. The cutoff means 4 cuts off the electric power supply to the electric compressor 1, and in response to the cutoff of the electric power supply to the compressor 1, the abnormality type determination means 7 responds to the operation state of the compressor 1 by the operation control means 6. Determine the type of anomaly. For example, the abnormality that occurs immediately after the electric compressor 1 is started is determined to be due to the locking of the motor of the electric compressor 1 or the like. Further, the abnormality that occurs thereafter is determined to be a gas pressure abnormality in the piping system of the refrigerant, such as a failure of the condenser 2 and the evaporator 3. Then, the abnormality type determination means 7 can determine the type of abnormality as described above based on whether the operation control state is immediately after the electric compressor is activated, and the result is displayed on the display means 8.

Thus, according to the first aspect of the present invention, the user can accurately grasp the type of abnormality that occurs during the cooling operation of the thermostat by means of the display means 8, so that the abnormality is immediately detected. Can be dealt with. Therefore, the repair time of the thermostatic machine can be shortened, the repair cost can be reduced, and the operation stop time due to the occurrence of an abnormality can be shortened to improve the operating rate of the thermostatic machine.

Further, in the invention of claim 2 configured as described above, as described in the invention of claim 1, the type of abnormality occurring during the cooling operation is displayed by the display means 8. In addition, when an abnormality occurs in the thermostat during the defrosting operation of the thermostat and the load on the electric compressor 1 becomes excessive, the power cutoff unit 4 cuts off the electric power supply to the compressor 1 and the compressor 1 In response to the power cutoff, the abnormality type determination means 7 determines the type of abnormality according to the operation state of the compressor 1 by the operation control means 6. For example, it is determined that the abnormality that occurs immediately after the start of the electric compressor 1 is due to locking of the motor of the electric compressor. Further, the abnormality that occurs during the subsequent defrosting operation is determined to be a gas pressure abnormality of the hot gas piping system such as the evaporation of the evaporator 3 or a failure of the evaporator temperature detecting means 3a. Then, the abnormality type determination means 7 can determine the type of abnormality as described above based on whether the operation control state is immediately after the electric compressor is activated, and the result is displayed on the display means 8.

Thus, according to the invention of claim 2, in addition to the effect of the invention of claim 1, the user can:
Even during the defrosting operation, the type of abnormality that has occurred in the thermostat can be immediately known by the display means 8 and the abnormality can be promptly dealt with.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 schematically shows an entire thermostatic machine such as a refrigerator and a freezer by a block diagram. This thermostat is equipped with a cooling device including an electric compressor 11, a condenser 12, and a throttle 13 provided outside the refrigerator and an evaporator 14 provided inside the refrigerator, and the refrigerant pressure-fed from the electric compressor 11 is supplied in this order. It is circulated and the inside of the refrigerator is cooled by the evaporator 14. The electric compressor 11 includes a relay 16 from an AC power supply 15
Power is supplied through the normally open contacts X11, X12 and the overload relay 17. Normally open contacts X11, X
The relay 12 is turned on / off by energizing / de-energizing the coil X1 of the relay 16. The overload relay 17
The electric compressor 11 is turned on / off by turning on / off a thermo switch (not shown) provided in the case, and the overload relay 17 is normally turned on. When the case temperature of the machine 11 rises and the thermo switch is turned off, the thermo switch is turned off and the power supply path is cut off.

An electromagnetic valve 18 is provided between the discharge port of the electric compressor 11 and the upstream side of the evaporator 14, and hot gas from the electric compressor 11 is supplied to the evaporator 14 when the valve 18 is in conduction. It is supposed to be done. Solenoid valve 1
Reference numeral 8 is connected to a power supply path from the AC power supply 15 via normally open contacts X21 and X22 of the relay 19 and is set to a conductive state when power is supplied and a non-conductive state when power is not supplied. It Normally open contacts X21, X22 of relay 19
Is turned on / off by energizing / de-energizing the coil X2 of the relay 19.

The coils X1 and X2 of the relays 16 and 19 and the overload relay 17 are connected to a microcomputer 20. The microcomputer 20 includes a transformer 2
A DC voltage is supplied from a power supply circuit 22 connected to the AC power supply 15 via 1, and the microcomputer 20 operates by the supply of this DC voltage. The DC voltage is also connected to the display control circuit 25, the display 26, etc., which will be described later.

The microcomputer 20 has a bus 20a.
ROM20b, CPU20c, R respectively connected to
The AM 20d, the first timer 20e, the second timer 20f, and the I / O 20g are included. ROM 20b
3 stores a program corresponding to the flowcharts of FIGS. 3 to 6, the CPU 20c executes the program, and the RAM 20d temporarily stores variables necessary for the execution of the program. The first timer 20e determines the cycle of defrosting and counts up after a predetermined time (for example, 6 to 8 hours) from the start of operation. The second timer 20f is used for detecting an abnormality in the electric compressor 11, and counts up 30 seconds after the start of operation. The I / O 20g exchanges signals with the outside, and the I / O 20g includes, in addition to the coils X1 and X2 of the relays 16 and 19, an internal temperature sensor 23, a defrost thermoswitch 24, and a display control circuit 25. And a display 26 is connected.

The inside temperature sensor 23 is provided in the inside of a refrigerator or a freezer, and detects the inside temperature T and outputs a detection signal indicating the same temperature T. The defrost thermoswitch 24 is composed of a temperature-sensitive switch attached to the evaporator 14, and is normally in the ON state (when the cooling device is repeatedly operated and stopped), and the evaporator 14 completes defrosting. It is turned off for the first time when the temperature rises to a certain temperature, and a signal indicating this on / off state is output. Display 2
6 is composed of a liquid crystal display or the like for displaying alphanumeric characters, and is controlled by the display control circuit 25 to control the temperature T in the refrigerator.
And error codes E1 to E3 indicating the type of abnormality are displayed.

Next, the operation of the embodiment configured as described above will be described. When a power switch (not shown) is turned on, a DC voltage is supplied from the power circuit 22 to the CPU 20c, the CPU 20c starts executing the program in step 100 of FIG. 3, and the cooling flag CFLG in step 101.
The variables in the RAM 30d are set to initial values including the initial setting of "0" to "0".

First, the case where no abnormality has occurred in the thermostat will be described.
The circulation process consisting of 2 to 107 is repeatedly executed. In the circulation process, the CPU 20c first performs step 10
At step 2, the operation of the first timer 20e is started, and step 1
At 03, it is determined whether or not the first timer 20e is counting up (whether or not 6 to 8 hours have elapsed from the start of the operation). In this case, since the first timer 20e has just started to operate, it is determined to be "NO" in the step 103, and the CPU 20c determines that the step 1
In 04, it is determined to be "YES" based on the cooling flag CFLG which is initially set to "0", and in step 105, the "operation stop routine" is executed.

This "shutdown routine" is shown in detail in FIG. 4, and the CPU 20c starts its execution at step 110, and at step 111 the inside temperature sensor 23.
Whether a temperature T is equal to or higher than a predetermined upper limit temperature TH (eg, −2 ° C. in a refrigerator, −17 ° C. in a freezer) by inputting a detection signal indicating the temperature T in the refrigerator. To determine. In the thermostat, since the internal temperature T is equal to or higher than the upper limit temperature TH immediately after the power switch is turned on, the CPU 20c causes “YES” in step 111.
Then, in step 112, the coil X1 of the relay 16 is determined.
Power on and the cooling flag CFLG is set to "1" in step 113.
In step 114, the operation of the second timer 20f is started, and in step 115, the process of the "operation stop routine" is ended. As a result, the normally open contacts X11, X12 of the relay 16 are set to the ON state, and the electric compressor 11
Power from the AC power supply 15 is supplied to the compressor 1
1 starts operating, cold refrigerant is supplied to the evaporator 14, and the inside of the refrigerator begins to be cooled.

Next, the CPU 20c returns the program to step 103 in FIG.
After determining "O", in step 104, it is determined to be "NO" based on the cooling flag CFLG changed to "1",
In step 106, the process of "cooling operation routine" is executed. The details of this "cooling operation routine" are shown in FIG. 5, and the CPU 20c starts its execution in step 120, and the inside temperature T detected by the inside temperature sensor 23 in step 121 is the lower limit temperature. Less than TL (for example,
(-4 ° C in a refrigerator, -19 ° C in a freezer)
Or not. In this case, since the inside of the refrigerator has just started to be cooled and the temperature inside the refrigerator is equal to or higher than the lower limit temperature TL, the CPU 20c returns “NO” in step 121.
It is determined to be “NO” based on that the overload relay 17 is turned on in step 122, and step 1
The display data indicating the internal temperature T is displayed by the display control circuit 2
5, and the processing of this "cooling operation routine" is ended in step 124. The display control circuit 25 controls the display device 26 based on the display data, and the display device 26 numerically displays the internal temperature T (for example, "-1.5.
° C ").

After completion of the "cooling operation routine", the CP
U20c returns the program to step 103 in FIG.
After that, the circulation process including steps 103, 104 and 106 is repeatedly executed. During this circulation process, the coil X1 of the relay 16 is continuously energized, so that the inside of the cold storage is continuously cooled by the evaporator 14, and the internal temperature T gradually drops. Further, the internal temperature T continues to be displayed on the display 26.

When the internal temperature T drops below the lower limit temperature TL in this way, the CPU 20c determines "YES" in step 121 of FIG. 5, and energizes the coil X1 of the relay 16 in step 125. Cancel, Step 1
The cooling flag CFLG is changed to "0" at 26, and the processing of this "cooling operation routine" is ended at step 124. As a result, the normally open contacts X11, X12 of the relay 16 are set to the off state, the supply of electric power from the AC power supply 15 to the electric compressor 11 is stopped, and the compressor 11 is stopped.
The cooling of the inside of the refrigerator by the evaporator 14 is stopped, and the temperature T inside the refrigerator starts to rise.

Next, the program is step 103 in FIG.
After the determination of “NO” in step 103, the determination is “YES” based on the cooling flag CFLG changed to “0” in step 104, and therefore the circulation process including steps 103 to 105 is performed. Will be executed repeatedly. In this case, in the “operation stop routine of step 105” (FIG. 4), the CPU 20c determines “NO” in step 111 until the internal temperature T becomes equal to or higher than the upper limit temperature TH, and in step 116, the internal temperature. The display data representing T is output to the display control circuit 25. As a result, in this case, the operation of the electric compressor 11 is stopped, the temperature T in the refrigerator gradually rises, and the temperature T in the refrigerator continues to be displayed numerically on the display 26.

Then, when the internal temperature T becomes equal to or higher than the upper limit temperature TH, the CPU 20c causes the "operation stop routine" (FIG. 4).
In step 111, it is determined to be “YES”, and the process in step 112 starts cooling the inside of the refrigerator. By the circulation processing including such steps 103 to 106 (FIG. 3), the operation and stop of the cooling device are repeatedly controlled, and the internal temperature T is kept between the lower limit temperature TL and the upper limit temperature TH.

On the other hand, during the circulation process consisting of the steps 103 to 106, 6 to 8 hours have passed and the first timer 20e
Is counted up, the CPU 20c proceeds to step 10
It is determined to be "YES" in 3 and the process of "defrosting routine" is executed in step 107. Details of this "defrosting routine" are shown in FIG.
The execution is started at 40, the operation of the second timer 20f is started at step 141, and the coil X1 of the relay 16 is energized at step 142. As a result, even when the constant temperature machine is at rest and the electric compressor 11 is stopped,
The compressor 11 starts operating.

Next, the CPU 20c makes a "NO" determination at step 143 based on the overload relay 17 being in the ON state, and at step 144 displays the display data for displaying that defrosting is in progress. It is output to the display control circuit 25, and in step 145, the coil X2 of the relay 19 is energized. As a result, the display control circuit 25 controls the display device 26 based on the display data, and the display device displays characters indicating that defrosting is being performed (for example, "dF"). Further, since the normally-open contacts X21, X22 of the relay 19 are set to the ON state, electric power is supplied to the electromagnetic valve 18 from the AC power supply 15, the valve 18 is turned on, and the hot gas from the compressor 11 is electromagnetically generated. It is supplied upstream of the evaporator 14 via a valve 18. As a result, the temperature of the evaporator 14 starts to rise, and the frost attached to the evaporator 14 is removed.

After the processing of step 145, the CPU 20
In step 146, c determines whether or not the defrost thermoswitch 24 is in the off state. In this case, immediately after the defrosting is started, the temperature of the evaporator 14 is low and the defrosting thermo-switch 24 is in the ON state.
Is determined to be "NO", the temperature is increased to such an extent that defrosting is completed, and the circulation process including steps 143-146 is repeatedly executed until the defrosting thermoswitch 24 is turned off. During the circulation process, the display device 26 displays the fact that defrosting is being performed, as described above.

When the defrost thermoswitch 24 is turned off during the circulation process consisting of steps 143 to 146, the CPU 20c determines "YES" in step 146, and energizes the coil X2 of the relay 19 in step 147. The processing is canceled and the processing of this "defrosting routine" is ended in step 148. As a result, the normally open contacts X21, X22 of the relay 19 are turned off and the electromagnetic valve 18 is turned off, so that the supply of hot gas to the upstream of the evaporator 14 is stopped.

After the completion of this "defrosting routine", the CPU2
0c returns the program to step 102 of FIG. 3, starts the operation of the first timer 20e for the next defrost in step 102, and operates and stops the cooling device by the circulation process including steps 103 to 106 described above. The alternate operation of is restarted and the operation as described above is continuously controlled.

Next, a case where an abnormality occurs in the thermostat will be described. First, the case where an abnormality occurs during the cooling operation of the thermostat will be described. Immediately after the electric compressor 11 starts up, a mechanical abnormality occurs in the electric compressor 11 itself, such as the motor of the electric compressor 11 locking.
When the case temperature rises, the overload relay 17 shuts off the power supply path to stop the power supply to the electric compressor 11. In this case, the overload relay 17 reacts immediately after the electric current flows into the electric compressor 11 (within at least 30 seconds after the start of activation), so during the alternating operation of operating and stopping the cooling device, that is, step 103 to FIG. During the circulation processing of 106, step 112 of the "operation stop routine" of FIG.
The coil X1 of the relay 16 is energized and the abnormality is detected in the "cooling operation routine" of FIG. 5 immediately after the second timer 20f is started in step 114. That is, "N" in step 121 of FIG.
After determining "O", it is determined in step 122 that "YES", that is, the overload relay 17 is off, and in step 127 that "NO", that is, the second timer 2
0f is judged not to count up yet, and CP
U20c outputs the display data showing "E1" to the display control circuit 25 in step 128, and stops energizing the relay X1 in step 130. As a result, the display control circuit 25 controls the display device 26 based on the display data, and the display device 26 displays “E” indicating an abnormality of the electric compressor 11.
The character "1" is displayed. Further, the operation of the cooling device is stopped by stopping the energization of the coil X1.

Further, after the electric compressor 11 is started, a rattling abnormality occurs in the condenser 12, the throttle 13, the evaporator 14 and their piping system, that is, the refrigerant piping system, and the electric compressor 11 When the case temperature abnormally increases, the overload relay 17 shuts off the power supply path to protect the compressor 11 and stops the supply to the electric compressor 11. In this case, even if the electric compressor 11 operates, the case temperature does not suddenly increase due to the increase in the refrigerant gas pressure, so that the cooling device is alternately operated and stopped, that is, step 1 in FIG.
During the circulation processing of 03 to 106, at least 30 seconds have passed since the coil X1 of the relay 16 was energized in step 112 of the "operation stop routine" of FIG. 4 and the second timer 20f was started in step 114. The abnormality is detected in the "cooling operation routine" of FIG. That is, after the determination of “NO” in step 121 of FIG. 5, it is determined in step 122 that “YES”, that is, the overload relay 17 is off, and the step 1
It is determined at 27 that “YES”, that is, the second timer 20 f is counting up, the CPU 20 c outputs the display data representing “E2” to the display control circuit 25 at step 129, and the relay 16 at step 130. Stop energizing coil X1 of. As a result, the display control circuit 25
Controls the display 26 based on the display data, and the display 36 displays the letter "E2" indicating an abnormality in the refrigerant piping system. Further, the operation of the cooling device is stopped by stopping the energization of the coil X1.

On the other hand, during the defrosting operation of the cooling device,
When the electric compressor 11 itself has an abnormality, the CPU 20c
6 starts the operation of the second timer 20f in step 141 of FIG. 6 and immediately after energizing the coil X1 of the relay 16 in step 142 (within at least 30 seconds after starting the electric compressor), the abnormality of the electric compressor 11 occurs. Is detected. That is, in step 143, it is determined that the overload relay 17 is off, and in step 149, it is determined that "NO", that is, the second timer 20f has not yet counted up, and the CPU 20c determines in step 15.
The display unit 26 is based on the display data representing "E1" at 0.
The display 26 displays the character "E1" indicating the abnormality of the electric compressor 11. Further, the operation of the cooling device is stopped by stopping the energization of the coil X1.

When a malfunction occurs in the electromagnetic valve 18, the evaporator 14 and the piping system thereof, that is, the piping system of the hot gas, or when the defrosting thermoswitch 24 malfunctions, the gas pressure on the high pressure side is increased. Ascend and electric compressor 11
Case temperature increases abnormally, so the overload relay 17
Operates to stop the operation of the electric compressor 11. In this case, even if the electric compressor 11 operates, the case temperature does not suddenly rise, so during the defrosting operation of the cooling device, that is, steps 143 to 146 and 149 to 152 in FIG.
During the circulation process, the second timer 30f is started in step 141 before the circulation process, and at least 30 seconds after the coil X1 of the relay 16 is energized in step 142, the abnormality is detected. To be detected. That is, in step 143, "YES", that is, it is determined that the overload relay 17 is off, and in step 149, "YES", that is, it is determined that the second timer 20f is counting up, and the CPU 20c determines in step 151. The display data representing "E3" is output to the display control circuit 25 at, and the energization of the coil X1 of the relay 16 is stopped at step 152. As a result, the display control circuit 25
Controls the display unit 26 based on the display data, and the display unit 26 displays the character "E3" indicating an abnormality in the hot gas pipe or a failure of the defrosting thermoswitch 24.
Also, the operation of the cooling device is stopped by stopping the energization of the coil X1.

As can be understood from the above description, according to the above embodiment, the overload relay 17 for detecting various abnormalities of the thermostat is provided in the electric power supply path of the electric compressor 11, and various thermostats are provided. The overload relay 17 is turned off in response to the abnormal increase in the case temperature of the compressor caused by the occurrence of the abnormality, and the power supply to the compressor 11 is cut off, and a signal indicating the occurrence of the abnormality is sent to the microcomputer 20. I am trying to output. Since the timing of occurrence of various abnormalities varies depending on the operating state of the cooling device as described above, the type of abnormality can be determined by considering the operating state, and this type is displayed as error codes E1 to E3. Therefore, even if an abnormality occurs in the thermostat, the user and the repairer can take appropriate measures. Therefore, the repair time of the thermostatic machine can be shortened, the repair cost can be reduced, and the operation stop time due to the occurrence of an abnormality can be shortened to improve the operating rate of the thermostatic machine.

In the above embodiment, the overload relay 17 is turned on / off by turning on / off a thermoswitch (not shown) provided in the case of the electric compressor 11.
Although the type that turns off is used, a type that turns off and shuts off the circuit when an excessive current flows due to an abnormality may be used.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of the invention described in the claims of the present invention.

FIG. 2 is an overall schematic block diagram of a thermostatic machine showing an embodiment of the present invention.

3 is a flowchart of a program executed by the microcomputer of FIG.

FIG. 4 is a detailed flowchart of the operation stop routine of FIG.

5 is a detailed flowchart of the cooling operation routine of FIG.

FIG. 6 is a detailed flowchart of a defrosting routine of FIG.

[Explanation of symbols]

11 ... electric compressor, 12 ... condenser, 13 ... throttle, 14 ...
Evaporator, 16, 19 ... Relay, 17 ... Overload relay, 1
8 ... Electromagnetic valve, 20 ... Microcomputer, 23 ...
Internal temperature sensor, 24 ... Defrost thermoswitch, 26 ... Indicator.

Claims (2)

[Claims] 1. An electric compressor that rotatably drives in accordance with electric power supply and circulates a compressed refrigerant through a condenser and an evaporator, and an electric power supply path of the electric compressor, which normally supplies electric power to the compressor. And a power cutoff means for cutting off the power supply to the compressor when the load on the compressor is excessive.
Inside temperature control means for detecting the temperature inside the refrigerator cooled by the evaporator, and by controlling the alternate operation of the operation and stop of the electric compressor based on the temperature detected by the inside temperature detection means In a thermostatic machine having an operation control means for maintaining a temperature between a predetermined upper limit temperature and a lower limit temperature, the operation control is performed in response to the power cutoff means cutting off the power supply to the electric compressor. An abnormality type determination means for determining the type of abnormality according to the operation control state of the electric compressor by means, and a display means for displaying the type of abnormality based on the determination result by the abnormality type determination means. Characteristic thermostat abnormality display device. 2. An electric compressor that rotatably drives in response to power supply and circulates a compressed refrigerant through a condenser and an evaporator, and a hot gas is selected from a downstream of the electric compressor to an upstream of the evaporator. Power supply to the electric compressor, which is provided in the electric power supply path of the electric compressor and normally supplies electric power to the electric compressor, and cuts off the electric power supply to the compressor when the load of the compressor is excessive. Means, and an in-compartment temperature detecting means for detecting a temperature in the interior cooled by the evaporator,
An evaporator temperature detecting means for detecting the temperature of the evaporator, and an upper limit of the inside temperature which is predetermined by controlling the alternating operation of the operation and stop of the electric compressor based on the temperature detected by the inside temperature detecting means. While maintaining between the temperature and the lower limit temperature, the operation control means for controlling the electric compressor and the electromagnetic valve by utilizing the temperature detection result by the evaporator temperature detection means to control the defrosting of the evaporator. In a constant temperature machine provided, in response to the power cutoff means cutting off the power supply to the electric compressor, the type of abnormality is determined according to the operation control state of the electric compressor and the electromagnetic valve by the operation control means. An abnormality display device for a thermostatic machine, comprising: an abnormality type determining unit that performs the above; and a display unit that displays the type of abnormality based on the determination result by the abnormality type determining unit.