JPH08247589A - Air conditioning equipment - Google Patents

Abstract

PURPOSE: To secure the safety of refrigerating cycle parts sufficiently by providing a welding-detecting means to detect a contact welding of an electromagnetic contactor and a protection means to set a refrigerating cycle to a specified operating position when the contact welding is detected on the occasion of requiring the stopping of the operation of a compressor. CONSTITUTION: An outdoor unit A has an inverter-driven capacity varying compressor, a capacity fixed compressor driven by a commercial power source and the like. On the other hand, a room unit B is arranged through an electric expansion valve 21, a room heat exchanger 22 and the like and one end of the room heat exchanger is connected to a liquid side piping through the electric expansion valve 21 while the other end thereof connected to a gas side piping. At the start of the operation, the temperature of a refrigerant delivered is detected by refrigerant temperature sensors 12 and 14 and when the detected temperature exceeds a set value, the welding of contacts 41a and 42a of a contactor is determined to occur and the electric expansion valve 21 being fully opened is held at a specified opening. This secures a flow path of the refrigerant to release vacuum operation of the compressor thereby preventing burning loss in windings of compressor motors 1M and 2M.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner equipped with an electromagnetic contactor for controlling energization of a compressor by opening and closing contacts.

[0002]

2. Description of the Related Art There is an air conditioner in which a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducer such as an electric expansion valve, and an indoor heat exchanger are sequentially connected by piping to form a heat pump type refrigeration cycle. In the cooling operation, the refrigerant discharged from the compressor is caused to flow from the four-way valve to the outdoor heat exchanger, the electric expansion valve, and the indoor heat exchanger, and the outdoor heat exchanger functions as a condenser and the indoor heat exchanger functions as an evaporator. In the heating operation, the refrigerant discharged from the compressor is caused to flow from the four-way valve to the indoor heat exchanger, the electric expansion valve, and the outdoor heat exchanger, and the indoor heat exchanger functions as a condenser and the outdoor heat exchanger functions as an evaporator.

During operation, the room temperature is detected, and the operation of the compressor is controlled by comparing the detected temperature with the set room temperature. An electromagnetic contactor is often used for this operation control. That is, the compressor motor is connected to the power source through the contact of the electromagnetic contactor, and the operation of the compressor is started by energizing the electromagnetic contactor and closing the contact. The compressor operation is stopped by deactivating the electromagnetic contactor and opening its contacts.

Further, the opening degree of the electric expansion valve is adjusted so that the degree of superheat or the degree of subcooling of the refrigerant in the heat exchanger has an optimum value. In a multi-type air conditioner with multiple indoor heat exchangers, the opening of the electric expansion valve corresponding to the indoor heat exchanger that is not operating can be reduced or fully closed to distribute the refrigerant to the indoor heat exchanger. I try to limit or block it.

[0005]

The operation of the compressor is stopped by deenergizing the electromagnetic contactor. However, even if the compressor is deenergized, the contactor contact may be welded and may not open. In this case, the operation of the compressor cannot be stopped and continues unnecessarily.If the electric expansion valve is throttled or fully closed, the pressure on the high-pressure side of the refrigeration cycle rises abnormally, causing heat exchangers, piping, etc. There is a risk that the life of the refrigeration cycle parts will be adversely affected, and that the compressor will be in vacuum operation and the windings of the compressor motor will be burned out.

The present invention takes the above circumstances into consideration,
It is an object of the present invention to provide an air conditioner that can sufficiently secure the safety of refrigeration cycle parts such as a compressor even when the contacts of an electromagnetic contactor are welded.

[0007]

The air conditioner of the first invention comprises a refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, an electric expansion valve, and an indoor heat exchanger are sequentially connected, and an outdoor blower. An indoor blower and an electromagnetic contactor that controls the energization of the compressor by opening and closing the contacts, and this electromagnetic contactor controls the operation of the compressor and the opening of the electric expansion valve, the operation of the outdoor blower, and the operation of the indoor blower. In particular, the control device includes a welding detection means for detecting the contact welding of the electromagnetic contactor, and the welding detection means for contact welding when it is necessary to stop the operation of the compressor. And a protection means for setting the refrigeration cycle to a predetermined operating state.

An air conditioner according to a second aspect of the present invention is the air conditioner according to the first aspect of the present invention, wherein the protection means is provided with means for holding the electric expansion valve at a predetermined opening state in a predetermined operating state. Third
In the air conditioner according to the first aspect of the present invention, the control device further includes pressure detection means for detecting the high-pressure side pressure of the refrigeration cycle. Further, in the first aspect of the invention, the protection means first operates the outdoor blower as a predetermined operating state, and the detected pressure of the pressure detection means becomes a predetermined value or more in spite of the operation of the outdoor blower. It is equipped with a means for reversing the four-way valve when it continues for a certain period of time.

An air conditioner according to a fourth aspect of the present invention is the air conditioner according to the first aspect of the present invention, wherein the protection means includes means for continuing the immediately preceding operation mode as a predetermined operation state. An air conditioner of a fifth invention is a refrigeration cycle in which a plurality of compressors, a four-way valve, an outdoor heat exchanger, an electric expansion valve, and a plurality of parallel indoor heat exchangers are sequentially connected to circulate a refrigerant, and an outdoor air conditioner. Blower, a plurality of indoor blowers, a plurality of electromagnetic contactors that control the energization of each compressor by opening and closing the contacts, the operation of each compressor with these electromagnetic contactors and the opening degree of the electric expansion valve, A control device for controlling the operation of the outdoor blower and the operation of each indoor blower, in which the control device is one of the welding detection means for detecting contact welding of each electromagnetic contactor and each compressor. When the contact detection of the electromagnetic contactor corresponding to the compressor is detected by the welding detection means when it is necessary to stop the operation of the compressor, the indoor heat exchanger is connected to each indoor heat exchanger so that the refrigerant circulation amount according to the operating capacity of the compressor can be secured. And a protection means for controlling the flow of the refrigerant of There.

The air conditioner of the sixth invention is the air conditioner of the fifth invention, wherein the control device detects the temperature of the room, and the difference between the temperature detected by the temperature detection means and the set room temperature is a predetermined value. And a means for reversing the four-way valve when exceeding the above.

An air conditioner of a seventh invention is the air conditioner according to the first or fifth invention, wherein the welding detection means includes a discharge refrigerant temperature of the compressor, a pressure on the low pressure side of the refrigeration cycle, a current supplied to the compressor, and a refrigeration. The contact welding is detected using at least one of the differences between the high pressure side pressure and the low pressure side pressure of the cycle.

An air conditioner according to an eighth aspect of the present invention is the air conditioner according to the first or fifth aspect of the present invention, further including a notifying means for notifying that the contact welding is detected by the welding detecting means.

[0013]

In the air conditioner of the first invention, when the contact welding of the electromagnetic contactor is detected when it is necessary to stop the operation of the compressor,
Set the refrigeration cycle to a predetermined operating state. In the air conditioner of the second invention, the electric expansion valve is maintained at a predetermined opening state as the predetermined operating state of the first invention.

In the air conditioner of the third aspect of the invention, as the predetermined operating state of the first aspect of the invention, the outdoor blower is continuously operated, and the high pressure side pressure is equal to or higher than the predetermined value despite the operation of the outdoor blower. Then, when that state continues for a certain time, the four-way valve is reversed.

In the air conditioner of the fourth invention, the immediately preceding operation mode is continued as the predetermined operation state of the first invention. In the air conditioner of the fifth invention, when the contact welding of the electromagnetic contactor corresponding to the compressor is detected when it is necessary to stop the operation of any of the compressors, the refrigerant according to the operating capacity of the compressor is detected. The circulation of the refrigerant to each indoor heat exchanger is controlled so that the circulation amount can be secured.

In the air conditioner of the sixth invention, in addition to the operation of the fifth invention, the four-way valve is reversed when the difference between the indoor temperature and the set indoor temperature exceeds a predetermined value. An air conditioner according to a seventh aspect of the present invention is the air conditioner according to the first or fifth aspect, wherein the refrigerant discharge temperature of the compressor, the low-pressure side pressure of the refrigeration cycle, the current supplied to the compressor, and the high-pressure side pressure and low-pressure side of the refrigeration cycle. At least one of the differences from the pressure is used to detect contact welding. In the air conditioner of the eighth invention, the first or the fifth
In the invention, when contact welding is detected, the fact is notified.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 2, the outdoor unit A
Has a variable capacity compressor 1 driven by an inverter and a fixed capacity compressor 2 driven by a commercial power source. This compressor 1,
The high pressure side pipe 3 is connected to the discharge port 2 and the low pressure side pipe 4 is connected to the suction ports of the compressors 1 and 2.

An outdoor heat exchanger 6 is connected to the high-pressure side pipe 3 via a four-way valve 5, and a liquid tank 10 is connected to the outdoor heat exchanger 6 via a check valve 8 and a heating expansion valve 9. The end of the liquid tank 10 is the liquid side pipe W.

The low pressure side pipe 4 is connected to the gas side pipe G through the accumulator 11 and the four-way valve 5. A plurality of indoor units B are connected in parallel to each other between the liquid side pipe W and the gas side pipe G.

Each indoor unit B has an electric expansion valve 21 and an indoor heat exchanger 22, and one end side of the indoor heat exchanger 22 is connected to the liquid side pipe W via the electric expansion valve 21 so that the indoor heat The other end of the exchanger 22 is connected to the gas side pipe G. The electric expansion valve 21 is a pulse motor valve (PMV) whose opening continuously changes according to the number of input drive pulses.

By such pipe connection, the outdoor unit A and each indoor unit B constitute a heat pump type refrigeration cycle. At the time of cooling, the four-way valve 5 is set to a non-operating state, whereby the refrigerant discharged from the compressors 1 and 2 is caused to flow in the direction of the solid arrow to form a cooling cycle, and the outdoor heat exchanger 6 is connected to the condenser, The indoor heat exchanger 22 functions as an evaporator. During heating, the four-way valve 5 is switched and operated,
As a result, the refrigerant discharged from the compressors 1 and 2 is caused to flow in the direction of the broken line arrow to form a heating cycle, and each indoor heat exchanger 22 functions as a condenser and the outdoor heat exchanger 6 functions as an evaporator.

In the outdoor unit A, an outdoor blower 7 is provided near the outdoor heat exchanger 6. The refrigerant temperature sensor 12 and the refrigerant pressure sensor 1 are connected to the high pressure side pipe 3 on the side of the compressor 1.
Install 3. The refrigerant temperature sensor 14 and the refrigerant pressure sensor 15 are attached to the high pressure side pipe 3 on the compressor 2 side. A refrigerant pressure sensor 16 is attached to the low pressure side pipe 4. A high pressure switch 17 is attached to the connection portion of both high pressure side pipes 3. The high-pressure switch 17 operates when the high-pressure side pressure abnormally rises and reaches a predetermined value, and then returns when the high-pressure side pressure falls below a predetermined value. The heat exchanger temperature sensor 18 is attached to the outdoor heat exchanger 6.

In each indoor unit B, the indoor heat exchanger 22
An indoor blower 23 and an indoor temperature sensor 24 are provided in the vicinity of. The refrigerant temperature sensor 25 is attached to the liquid side pipe on one end side of the indoor heat exchanger 22. A refrigerant temperature sensor 26 and a refrigerant pressure sensor 27 are attached to the gas side pipe on the other end side of the indoor heat exchanger 22.

The control device is shown in FIG. Commercial AC power supply 30
The outdoor control unit 40 of the outdoor unit A is connected to, and the indoor control unit 50 of each indoor unit B is connected to the outdoor control unit 40 by a crossover connection.

In the outdoor control section 40, the four-way valve 5, the blower motor 7M, the refrigerant temperature sensors 12, 14, the heat exchanger temperature sensor 18, the refrigerant pressure sensors 13, 15, 16, the high pressure switch 17, the electromagnetic contactor 41, 42, an inverter circuit 43,
And the current sensors 44 and 45 are connected.

The inverter circuit 43 is connected to the commercial AC power source 30 via the contact (normally open type) 41a of the electromagnetic contactor 41.
Of the inverter circuit 43, and the compressor motor 1M is connected to the output terminal of the inverter circuit 43. The inverter circuit 43 rectifies the power supply voltage, converts it into a voltage of a predetermined frequency (and level) by switching according to a command from the outdoor control unit 40, and outputs the voltage.

A compressor motor 2M is connected to the commercial AC power source 30 via a contact (normally open type) 42a of the electromagnetic contactor 42. The current sensor 44 is attached to the connection line between the commercial AC power supply 30 and the contactor contact 41a. Commercial AC power supply 3
The current sensor 44 is attached to the connection line between 0 and the contactor contact 42a.

On the other hand, in the indoor control unit 50, the electric expansion valve 2
1, a blower motor 23M, an indoor temperature sensor 24, refrigerant temperature sensors 25 and 26, a refrigerant pressure sensor 27, and a remote control type operation device (hereinafter abbreviated as a remote controller) 60 are connected. The remote controller 60 has various key buttons (not shown) for setting operating conditions, and also has a display section 61.

The indoor control section 40 has the following [1] to [5] as main functional means. [1] Means for sending commands such as an operation mode, operation start, operation stop, etc., to the outdoor unit A based on the operation of the remote controller 60.

[2] The difference (air conditioning load) between the detected temperature (intake air temperature) Ta of the indoor temperature sensor 24 and the set indoor temperature Ts set by the remote controller 60 is obtained, and the required capacity corresponding to the temperature difference is obtained outdoors. Means to inform unit A.

[3] Means for controlling the opening degree of the electric expansion valve 21 according to the required capacity of the indoor unit and fully closing the electric expansion valve 21 when the operation of the indoor unit is stopped (or stopped).

[4] During cooling, the difference between the temperature Te ₂ detected by the refrigerant temperature sensor 26 on the outlet side of the indoor heat exchanger 22 and the temperature Te ₁ detected by the refrigerant temperature sensor 25 on the inlet side of the indoor heat exchanger 22 ( = Te ₂ −Te ₁ ) as the degree of superheat of the refrigerant in the indoor heat exchanger 22.

[5] A means for correcting the opening degree of the electric expansion valve 21 so that the detected superheat degree becomes a predetermined constant value. The outdoor control unit 50 includes the following [1] to [5] as main functional means.

[1] The operating capacities of the compressors 1 and 2 (the number of operating compressors 1 and 2 and the operating frequency F of the compressor 1) are
A means for controlling according to the total required capacity of each indoor unit B. [2] The four-way valve 5 is set to a non-operating state, and the refrigerant discharged from the compressors 1 and 2 is used as the four-way valve 5, the outdoor heat exchanger 6, and the electric expansion valve 2.
1, through the indoor heat exchanger 22, the four-way valve 5, the compressor 1,2
The means for performing the cooling operation.

[3] The four-way valve 5 is switched and operated, and the refrigerant discharged from the compressors 1 and 2 is passed through the four-way valve 5, the indoor heat exchanger 22, the flow rate adjusting valve 21, the outdoor heat exchanger 6, and the four-way valve 5. A means for returning to the compressors 1 and 2 and performing heating operation.

[4] Welding detection means for detecting contact welding of the electromagnetic contactors 41, 42. [5] A protection means for setting the refrigeration cycle to a predetermined operating state when the welding detection means detects contact welding when the compressor 1 or the compressor 2 needs to be stopped.

Next, the operation of the above configuration will be described with reference to the flowchart of FIG. When the operation start operation is performed by the remote controller 60 of any indoor unit B, the compressor 1,
First of all, the compressor 1 is started and the operation is started.

The indoor unit B obtains the difference between the detected temperature Ta of the indoor temperature sensor 24 and the set indoor temperature Ts by the remote controller 60, and informs the outdoor unit A of the required capacity corresponding to the temperature difference.

Further, the indoor unit B includes an electric expansion valve 21.
The opening degree of is adjusted according to the required capacity of the unit. For example, if the required capacity is zero (the operation is stopped or stopped), the electric expansion valve 21 is fully closed, and the opening degree of the electric expansion valve 21 is increased as the required capacity increases.

The outdoor unit A operates the operating capacities of the compressors 1 and 2 (the number of operating compressors 1 and 2 and the operating frequency F of the compressor 1) in accordance with the total required capacity from each indoor unit B. Set to capacity.

For example, if the total required capacity is small,
Only the electromagnetic contactor 41 is energized to operate the inverter circuit 43, the output frequency F of the inverter circuit 43 is controlled, and the capacity varying operation by the compressor 1 alone is executed. When the total required capacity increases, the electromagnetic contactor 41 is energized to perform variable capacity operation of the compressor 1 by the inverter circuit 43, and the electromagnetic contactor 42 is energized to add operation of the compressor 2.

When the total required capacity decreases as the number of operating indoor units B decreases, the electromagnetic contactor 42 is first deenergized and the operation of the compressor 2 is stopped. Finally, the electromagnetic contactor 41 is deenergized to stop the operation of the compressor 1.

However, even though the compressor 1 needs to be stopped, the contactor contact 41a may not be opened while being welded. If this happens, the operation of the compressor 1 will continue unnecessarily without being stopped. When the contactor contact 42a is welded, the operation of the compressor 2 will continue unnecessarily without being stopped.

In this case, while the operation of the compressor 1 or the compressor 2 is continued unnecessarily, the electric expansion valve 21 of the indoor unit B in which the operation is stopped (including suspension) is fully closed, and the refrigerant flow path. Is shut off, and the compressor 1 or the compressor 2 is in vacuum operation due to this effect.

When the compressor 1 is operated in vacuum, the internal temperature of the compressor 1 rises and the discharge refrigerant temperature Td ₁ rises. When the compressor 2 is in vacuum operation, the internal temperature of the compressor 2 rises and the discharge refrigerant temperature Td ₂ rises.

The discharged refrigerant temperatures Td ₁ and Td ₂ are detected by the refrigerant temperature sensors 12 and 14, and when at least one of the detected temperatures rises above a predetermined set value, the contactor contact 41a or 42a is opened. It is determined that welding has occurred. Then, based on this determination, the electrically-operated expansion valve 21 in the fully closed state is held at the predetermined opening state.

In this way, by keeping the electric expansion valve 21 in the fully closed state at the predetermined opening state, the refrigerant flow path is secured, and the vacuum operation of the compressor 1 or the compressor 2 is released. Therefore, it is possible to prevent the winding of the compressor motor 1M or the compressor motor 2M from being burnt out. Moreover, it is possible to suppress an abnormal rise in the high-pressure side pressure, and thus it is possible to avoid adverse effects on refrigeration cycle parts such as heat exchangers and piping.

When the contact welding is detected (determined), the fact is displayed on the display section 61 of the remote controller 60 in characters. This character display informs that the contact is welded and the operation is abnormal. At this time, various settings made by operating the remote controller 60 are ignored as an abnormal stop.

Next, a second embodiment of the present invention will be described (corresponding to claim 4). In the first embodiment described above, the electric expansion valve 21 in the fully closed state is held at the predetermined opening state as the "predetermined operating state" set when the contact welding is detected. Then, as the "predetermined operating state", the indoor unit B, which is stopped (including pause), is continuously restarted in the operating mode immediately before the stop. For example, if the immediately preceding operation is the cooling mode, the cooling operation is restarted, and if it is the heating mode, the heating operation is restarted. By restarting the operation, the electric expansion valve 21 is automatically opened to secure the refrigerant circulation path, and the vacuum operation of the compressor 1 or the compressor 2 is released.

A third embodiment of the present invention will be described (corresponding to claim 5). In the third embodiment, when the contact welding is detected in the electromagnetic contactor corresponding to the compressor that needs to be shut down, each indoor heat is ensured so that the refrigerant circulation amount according to the operating capacity of the compressor that needs to be shut down can be secured. The circulation of the refrigerant to the exchanger B is controlled.

For example, when the contact welding of the electromagnetic contactor 41 is detected when the operation of the compressor 1 needs to be stopped, the compressor 1 is selected from the indoor units B whose operation is stopped (including suspension).
The operation of the indoor unit B is restarted so that the refrigerant flows to the indoor unit B having the indoor heat exchanger 22 having the same capacity as the operating capacity. When the contact welding of the electromagnetic contactor 42 is detected when the operation of the compressor 2 needs to be stopped, the indoor heat exchange having the same capacity as the operation capacity of the compressor 2 in the indoor unit B that is in the operation stop (including the suspension). The operation of the indoor unit B is restarted so that the refrigerant flows to the indoor unit B having the container 22. The operation mode when restarting is the one immediately before the stop.

A fourth embodiment of the present invention will be described (corresponding to claim 6). In the second and third embodiments described above,
Although the operation is restarted in the operation mode immediately before the stop, the room temperature Ta gradually decreases when the cooling mode continues. If the operation is continued as it is, the refrigerant cannot be completely evaporated in the indoor heat exchanger 22, and liquid back to the compressor may occur, which may adversely affect the compressor. If the heating mode continues, the room temperature Ta rises and the high-pressure side pressure rises abnormally.
There is concern that it may adversely affect the refrigeration cycle parts.

Therefore, in the fourth embodiment, after restarting the operation in the immediately preceding operation mode, the difference between the detected temperature Ta of the indoor temperature sensor 24 and the set indoor temperature Ts is obtained, and when the difference exceeds a predetermined value, it is squared. Reverse valve 5.

When the four-way valve 5 is reversed, liquid back to the compressor or abnormal increase of the high pressure side pressure is suppressed. After that, the inversion of the four-way valve 5 is repeated every time the difference between the detected temperature Ta and the set room temperature Ts exceeds a predetermined value.

In each of the above embodiments, the discharge refrigerant temperature T
Although contact welding was detected using d ₁ and Td ₂ , the low pressure side pressure Ps (pressure sensor 16) is not limited to this, and attention is paid to the fact that the low pressure side pressure Ps decreases during vacuum operation of the compressor 1 or the compressor 2. It is possible to determine that the contact welding is present when the detected pressure Ps) Ps falls to a preset set value (corresponding to claim 7).

A current I flowing during the operation of the compressors 1 and 2 is detected by the current sensors 44 and 45, and an unnecessary continuation of the operation of the compressor 1 or the compressor 2 due to contact welding is detected from the presence or absence of the detected current I. You may do so (corresponding to claim 7).

During operation of the compressors 1 and 2, a difference between the high pressure side pressure Pd and the low pressure side pressure Ps occurs, and when the operation of the compressors 1 and 2 is stopped, the high pressure side pressure Pd and the low pressure side pressure Ps gradually. After a balance, Pd = Ps. However, if the compressor 1 or the compressor 2 continues to operate unnecessarily due to contact welding, vacuum operation may occur, and the high-pressure side pressure Pd and the low-pressure side pressure Ps are not balanced, but the high-pressure side pressure Pd rises. However, the low-pressure side pressure Ps drops, and the difference between the two pressures expands. Therefore, the high-pressure side pressure Pd and the low-pressure side pressure Pd after a certain time from the time when the operation is stopped
It is also possible to detect a difference from s and determine that the contact welding is present when the difference is equal to or larger than a predetermined value (corresponding to claim 7).

The contact welding detection means described above (detection means by increasing discharge refrigerant temperatures Td ₁ and Td ₂ , detection means by decreasing low pressure side pressure Ps, detection means by presence / absence of energizing current I, and high pressure side pressure) Regarding the detection means based on the difference between Pd and the low-pressure side pressure Ps), not only one means but a plurality of means are collectively provided to detect the contact welding from a plurality of directions, and any one of the means detects the contact welding. The protection control may be started when this occurs (corresponding to claim 7).

Based on the temperature of the outdoor heat exchanger 6 (the temperature detected by the heat exchanger temperature sensor 18) and the temperature of the indoor heat exchanger 22, instead of the discharge refrigerant temperatures Td ₁ and Td ₂ or the high pressure side pressure Pd. The contact welding may be detected.

Next explained is the fifth embodiment of the invention (corresponding to claim 3). Here, as shown in the flowchart of FIG. 4, contact welding is detected from the operation of the high-voltage switch 17 due to the increase in the high-pressure side pressure Pd. That is,
When the operation of the high-pressure switch 17 continues for x seconds, it is determined that the contact welding has occurred, and during cooling, the outdoor blower 7 is continuously operated. By this operation, the increase in the high pressure side pressure Pd is suppressed. After that, when the high pressure switch 17 returns, the operation of the outdoor blower 7 is stopped.

Thus, the outdoor blower 7 is operated each time the high pressure switch 17 is operated, and the operation of the outdoor blower 7 is stopped after the high pressure switch 17 is restored. However, when the outdoor blower 7 fails and does not move, it becomes impossible to suppress the rise of the high-pressure side pressure Pd.

Therefore, when the high-pressure switch 17 does not return for a predetermined time or longer, the outdoor blower 7 is determined to be out of order, and the four-way valve 5 is reversed. When the four-way valve 5 is reversed, the high pressure side and the low pressure side are pressure balanced, and as a result, the increase in the high pressure side pressure is suppressed.

Although the high-pressure switch 17 is restored by this suppression, if unnecessary operation of the compressor due to contact welding continues, the high-pressure side pressure starts increasing and the high-pressure switch 17 operates again and does not return. At this time, the four-way valve 5 is reversed again.

By repeating the reversal of the four-way valve 5 in this manner, it is possible to avoid an abnormal increase in the high pressure side pressure Pd. Note that, as shown by the chain double-dashed line in FIG. 4, when the four-way valve 5 is reversed after the failure of the outdoor blower 7 is determined, the operation of the indoor blower 23 is started at the same time, and the high-side pressure Pd rises. May be suppressed.

[0065]

As described above, according to the present invention, when the welding detection means for detecting the contact welding of the electromagnetic contactor is provided and the contact welding is detected when the operation of the compressor needs to be stopped,
Since the refrigeration cycle is set to a predetermined operating state, it is possible to provide an air conditioner that can sufficiently secure the safety of refrigeration cycle parts including the compressor even when the contacts of the electromagnetic contactor are welded.

[Brief description of drawings]

FIG. 1 is a block diagram of a control device according to each of the embodiments.

FIG. 2 is a configuration diagram of a refrigeration cycle of each example.

FIG. 3 is a flowchart for explaining the operation of the first embodiment.

FIG. 4 is a flowchart for explaining the operation of the fifth embodiment.

[Explanation of symbols]

A ... Outdoor unit, B ... Indoor unit, 1 ... Variable capacity compressor, 2 ... Fixed capacity compressor, 5 ... Four-way valve, 6 ... Outdoor heat exchanger, 7 ... Outdoor blower, 12, 14 ... Refrigerant temperature sensor,
13, 15, 16 ... Refrigerant pressure sensor, 17 ... High pressure switch, 18 ... Heat exchanger temperature sensor, 21 ... Electronic expansion valve, 2
2 ... Indoor heat exchanger, 23 ... Indoor blower, 24 ... Indoor temperature sensor, 25, 26 ... Refrigerant temperature sensor, 27 ... Refrigerant pressure sensor, 30 ... Commercial AC power supply, 40 ... Outdoor control unit, 4
1, 42 ... Electromagnetic contactor, 41a, 42a ... Contact, 43
... inverter circuit, 50 ... indoor control section, 60 ... remote control.

Claims (8)

[Claims] 1. A refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, an electric expansion valve, and an indoor heat exchanger are sequentially connected, an outdoor blower, an indoor blower, and the contacts for energizing the compressor are opened and closed. And an electromagnetic contactor controlled by the electromagnetic contactor to control the operation of the compressor with the electromagnetic contactor and the opening degree of the electric expansion valve,
In an air conditioner provided with a control device for controlling the operation of the outdoor blower and the operation of the indoor blower, the control device includes welding detection means for detecting contact welding of the electromagnetic contactor, and stopping operation of the compressor. An air conditioner comprising: a protection unit that sets the refrigeration cycle to a predetermined operating state when the welding detection unit detects contact welding when necessary. 2. The air conditioner according to claim 1, wherein the protection means includes means for holding the electric expansion valve at a predetermined opening state as a predetermined operating state. Harmony machine. 3. The air conditioner according to claim 1, wherein the control device further includes pressure detection means for detecting a high-pressure side pressure of the refrigeration cycle, and the protection means sets the predetermined operating state to the above-mentioned. The outdoor blower is continuously operated, and means for reversing the four-way valve when the pressure detected by the pressure detection means exceeds a predetermined value and the state continues for a certain period of time despite the operation of the outdoor blower An air conditioner characterized by 4. The air conditioner according to claim 1, wherein the protection unit includes a unit that continues the immediately previous operation mode as a predetermined operation state. 5. A plurality of compressors, a four-way valve, an outdoor heat exchanger,
An electric expansion valve, a refrigeration cycle in which a plurality of indoor heat exchangers in a parallel state are sequentially connected to circulate a refrigerant, and an outdoor blower,
A plurality of indoor blowers, a plurality of electromagnetic contactors that control the energization of each compressor by opening and closing contacts, the operation of each compressor with these electromagnetic contactors and the opening degree of the electric expansion valve, In an air conditioner provided with an operation of an outdoor blower and a control device for controlling the operation of each indoor blower, the control device is a welding detection means for detecting contact welding of each of the electromagnetic contactors, and each of the compressors. When it is necessary to stop the operation of any of the above, if the welding detection means detects the contact welding of the electromagnetic contactor corresponding to the compressor, it is possible to secure a refrigerant circulation amount according to the operating capacity of the compressor. An air conditioner comprising: a protection unit that controls the flow of the refrigerant to the heat exchanger. 6. The air conditioner according to claim 5, wherein the control device includes temperature detecting means for detecting an indoor temperature,
Means for reversing the four-way valve when the difference between the detected temperature of the temperature detecting means and the set room temperature exceeds a predetermined value,
An air conditioner characterized by further comprising. 7. The air conditioner according to claim 1 or 5, wherein the welding detection means includes a refrigerant discharge temperature of the compressor, a low-pressure side pressure of the refrigeration cycle, a current supplied to the compressor, and a refrigeration cycle. An air conditioner characterized by detecting using at least one of the difference between the high-pressure side pressure and the low-pressure side pressure. 8. The air conditioner according to claim 1 or 5, wherein the control device further includes a notifying unit for notifying that contact welding is detected by the welding detecting unit. And an air conditioner.