JP3333000B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner provided with an abnormality detecting circuit including an overheat prevention relay for protecting a compressor and a high pressure switch.

[0002]

2. Description of the Related Art An air conditioner is usually provided with an overheat prevention relay (IOL) for protecting a compressor and a high pressure switch. The overheat prevention relay detects a rise in the winding temperature of the compressor motor and performs a protection operation when the compressor is locked or when an overvoltage of the input power supply rises. The high-pressure switch performs a protection operation by detecting an abnormal stoppage of the outdoor fan, a decrease in the amount of cooling air, or an abnormal increase in the high-pressure side of the refrigerant circuit due to dirt on the heat radiation surface of the condenser.

[0003] In the conventional air conditioner, the above-mentioned over
An abnormality detection circuit is formed by a combination of the heat prevention relay and the high-voltage switch, and when an abnormality detection signal is output by any of the operations, the operation of the compressor is immediately stopped.

[0004]

The measures taken after stopping the compressor operation based on the above protection operation are left to service personnel. In this case, it is determined whether the overheat prevention relay or the high pressure switch has been operated. If it is known, the location and the cause of the abnormality can be quickly identified.

[0005] However, there are two types of overheat prevention relays and high voltage switches, an automatic return type and a manual return type. In the former type, after a certain period of time has elapsed after operation, Will return to the state before the operation.

Therefore, when the service worker inspects the outdoor unit, it is not known whether the overheat prevention relay or the high-voltage switch has been operated. The result was wasted effort.

In order to avoid such a situation, it is conceivable to provide two abnormality detection circuits, a detection circuit including only an overheat prevention relay and a detection circuit including only a high-voltage switch. Is increased.

Therefore, for example, Japanese Patent Laid-Open No. 1-138385
As disclosed in Japanese Unexamined Patent Publication, a configuration is proposed in which an abnormal temperature rise of a compressor motor or an abnormal rise of the high pressure side pressure of a refrigerant circuit is detected by one abnormality detection circuit. However, this proposal attempts to determine which abnormality is based on the time from the time of startup to the time of occurrence of an abnormality. The possibility was not so small, and it was hard to say that it had sufficient reliability.

The present invention has been made in view of the above circumstances, has sufficient reliability, and is capable of easily specifying the contents of abnormalities during service work without increasing costs. It aims to provide an air conditioner that can be used.

The present invention, as a means for solving the above problems, has a relay for protecting the compressor from overheating and a high-voltage switch, and outputs an abnormal signal when any one of the relay and the high-pressure switch operates. In an air conditioner having an abnormality detection circuit, when an abnormality signal from the abnormality detection circuit is input, a pressure at a high pressure side in the refrigerant circuit is detected, and the detected value is a constant value. when the above determined that the high-pressure switch is operated, also, its
If the detected value of
Abnormality content determining means for determining that the key has operated;
The display of the determination result of the abnormality content determination means
Continues even after the pressure switch or overheat prevention relay automatically returns
And display means for performing the operation.

[0011]

[0012]

In the above arrangement, when the abnormality detection circuit outputs an abnormality signal, the abnormality content determining means detects the pressure at a predetermined point in the refrigerant circuit at that time.

If the high-voltage switch has been activated, this detection value should be above a certain value.
If the overheat prevention relay has been activated, it should have fallen below a certain value. Therefore, it is possible to determine which of the overheat prevention relay and the high pressure switch has been operated based on the magnitude relationship between the pressure detection value at the time of output of the abnormal signal and the fixed value.

Further , according to the above configuration, since the display means displays the above-described determination result, it is possible to quickly identify the location of the abnormality and the cause of the abnormality during the service work.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing the configuration of this embodiment.

In FIG. 1, AC power from an AC power supply 1 is sent to a converter unit 3 via an abnormality detection circuit 2, where it is converted into DC power. After the converted DC power is smoothed by the smoothing capacitor 4, the converted DC power is converted into AC power by the inverter unit 5 and supplied to the compressor motor 6 for driving the compressor 7. The inverter unit 5
Is controlled by switching of the transistor by the base control signal from the inverter control circuit 8,
The frequency of the output is controlled.

The refrigerant circuit will be described. At the time of heating, the refrigerant discharged from the compressor 7 is sent to the indoor heat exchanger 10 via the four-way valve 9 where heat is exchanged (condensation). The heat-exchanged refrigerant is sent to the outdoor heat exchanger 12 through the expansion valve 11, where the refrigerant is heat-exchanged (evaporation), and then circulated again through the four-way valve 9 to the suction port of the compressor 7. You. On the other hand, at the time of cooling, the four-way valve is inverted, and the refrigerant is circulated in a cycle opposite to that of the heating. The abnormality detection circuit 2 includes the overheat prevention relay 13 and the high-voltage switch 14 described above. Overheat prevention relay 13
The heat sensing portion is mounted near the winding of the compressor motor 6, and the pressure detecting portion of the high pressure switch 14 is mounted at a predetermined location on the high pressure side of the refrigerant circuit (for example, a discharge side pipe of the compressor). The operation set value of the high-voltage switch 14 is, for example, 30 [kg / cm ² ]. A pressure sensor 15 is mounted near the position where the high-voltage switch 14 is mounted.

The inverter control circuit 8 is constituted by a microcomputer, in which an abnormality content judging means 16 is provided. This abnormal content determining means 16
It reads the detection value of the pressure capacitors 15 at the time you enter the abnormality detection signal from the abnormality detecting circuit 2, the overheat preventing relay 1
A determination signal is output as to which of the high-voltage switch 3 and the high-voltage switch 14 has operated.

When the overheat prevention relay 13 operates based on the input of the discrimination signal, the LED drive circuit 17 turns on the red LED 18 as a display means.
When the high-voltage switch 14 operates, a green LED 19 as a display means is turned on.

FIG. 2 is a circuit diagram showing details of the abnormality detection circuit 2. Between the upper and lower power lines, the overheat prevention relay 13, the high voltage switch 14, and the photodiode of the photocoupler 20 are connected in series. The phototransistor of the photocoupler 20 is connected to a DC power supply of 5 V, and the collector side of the phototransistor is connected to abnormality content discriminating means.

Overheat prevention relay 13 and high voltage switch 14
Is normally closed. Therefore, in the normal state, a pulse signal as shown in FIG. 3A is output from the abnormality detection circuit 2 to the abnormality content determination means 16, while
In the case of an abnormality, a flat voltage signal as shown in FIG. 3B is output from the abnormality detection circuit 2 to the abnormality content determining means 16.

Next, the operation of this embodiment configured as described above will be described with reference to the flowchart of FIG.

The abnormality content judging means 16 always receives a signal from the abnormality detecting circuit 2 to judge whether or not an abnormality has occurred (step 1). Now, for example, it is assumed that the high pressure side pressure of the refrigerant circuit is abnormally increased and the high pressure switch 14 is turned off. Then, a flat voltage signal, that is, an abnormal signal as shown in FIG. 3B is sent from the abnormality detecting circuit 2, so that the abnormality content determining means 16 determines that an abnormality has occurred, and the inverter control circuit 8 The output of the inverter unit 5 is stopped (Step 2).

At this time, the abnormality content judging means 16 detects the pressure value of the pressure sensor 15 at the time of inputting the abnormality signal (step 3), and determines whether or not the detected value is 26 [kg / cm ² ] or more. A determination is made (step 4). Here, in the present embodiment, although the operation set value of the high-voltage switch 14 is 30 [kg / cm ² ], the determination is made based on the value of 26 [kg / cm ² ] which is a predetermined value lower than the predetermined value. The certainty of the discriminating operation is intended in consideration of the pressure drop during the time from the stoppage of operation due to the abnormality to the detection of the pressure value and the error of the detected value. In addition,
Overheat prevention relay 13 when it becomes 26 [kg / cm ² ] or more
In practice, it is almost impossible to consider that only the high-voltage switch 14 operates and the high-voltage switch 14 does not operate. Therefore, no particular problem arises even if the determination is made based on such a value.

In this case, since the high pressure switch 14 has been operated, the pressure value of the pressure sensor 15 is 26 [k].
g / cm ² ] or more, and the abnormality content determination means 16 should output a determination signal to that effect. LE
The D drive circuit 17 turns on the red LED 18 based on the input of the determination signal (switch 5). The above explanation is
This is the case where an abnormality signal is output from the abnormality detection circuit 2 due to the operation of the high-voltage switch 14. However, if the overheat prevention relay 13 operates, the determination in step 4 is NO, and the green LED 19 is turned on. (Step 6).

The lighting of the LED 18 or the LED 19 after the operation is stopped due to the occurrence of such an abnormality is continued even after the high pressure switch 14 or the overheat prevention relay 13 is automatically reset. It is possible to quickly identify the abnormal part.

In the above embodiment, LE is used as the display means.
Although the case where D is used has been described, an ordinary miniature bulb may be used. Further, if the liquid crystal display is attached to the indoor unit, a configuration may be adopted in which a symbol or a character indicating the content of the abnormality is displayed.

Further, 30 [kg / cm ² ] in the above description is used.
, 26 [kg / cm ² ], of course, are values that can be freely set according to the refrigerant cycle of various capacities.

[0029]

As described above, according to the present invention, whether one of the overheat prevention relay and the high-pressure switch has been activated is detected by one detection circuit based on the detection of the pressure at a predetermined point in the refrigerant circuit when an abnormality occurs. Since the detection is performed, it is possible to easily identify the contents of the abnormality at the time of the service work without having to increase the cost with sufficient reliability.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of an abnormality detection circuit in FIG. 1;

FIG. 3 is a waveform chart showing a waveform of an output signal of the abnormality detection circuit of FIG. 2;

FIG. 4 is a flowchart for explaining the operation of FIG. 1;

[Explanation of symbols]

 2 Abnormality detection circuit 6 Compressor motor 7 Compressor 13 Overheat prevention relay 14 High pressure switch 15 Pressure sensor 16 Abnormality determination means 18, 19 Display means (LED)

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F25B 49/02 570 F24F 11/02 102

Claims (1)

(57) [Claims] An air conditioner having an overheat prevention relay for protecting a compressor and a high-voltage switch, and an abnormality detection circuit that outputs an abnormality signal when any one of the overheat prevention relay and the high-pressure switch operates. When an abnormality signal from the abnormality detection circuit is input, the pressure at a predetermined location on the high pressure side in the refrigerant circuit is detected, and when the detected value is equal to or more than a predetermined value, it is determined that the high pressure switch has been operated, and , If the detected value is below a certain value
The abnormal condition to determine that the overheat relay has been activated.
The display of the determination result of the content determination means and the abnormality content determination means is
Even after the high-voltage switch or overheat prevention relay automatically returns
An air conditioner comprising: a display unit that performs a continuous operation.