Air Conditioner

Abstract

An air conditioner of variable capacity type comprises a variable-capacity compressor capable of varying capacity in two levels by switching between FULL and SAVE. The variable-capacity compressor can start operation at SAVE so as to allow the air conditioner to start operation without causing a shutdown of the variable-capacity compressor in an overloaded condition or in a low power-supply voltage environment.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to an air conditioner of variable capacity type including a compressor capable of switching a compressor discharge volume between high and low levels.

BACKGROUND OF THE INVENTION

[0002] Conventional air conditioners comprise a compressor capable of varying capacity in two levels by switching the compressor discharge volume between full-power operation (hereinafter, FULL) of high level and power-saving operation (hereinafter, SAVE) of low level. These air conditioners start operation with the compressor at FULL. When such an air conditioner starts operation in an environment where both the indoor temperature and the outdoor temperature are high (that is, in an overloaded environment), too high a pressure of the compressor or a low power-supply voltage may cause an increase in the starting current value. The increase in the starting current value can extremely decrease the motor output in the compressor, causing the motor to make a forced stop or a so-called "breakdown", thereby interrupting the compression workings. To avoid this from happening, the air conditioner is structured as follows. When the starting current value is increased in an overloaded condition or in a low power-supply voltage environment, an overload relay (hereinafter, OLP) as a protection device is actuated to protect the compressor. As a result, the compressor energizing circuit is shut off to prevent the motor winding from burning or seizing.

[0003] When the OLP is naturally cooled, the compressor energizing circuit thus shut off is restored and supplied with a current, as shown in FIG. 20. This operation is repeated hereinafter.

[0004] The compressor protector with the conventional OLP has the following problem. When the power supply voltage is low, the refrigerating cycle is likely to be overloaded and the compressor is likely to be locked up. In these situations, the OLP is actuated repeatedly. To solve this problem, Japanese Patent Unexamined Publication No. H07-174392 discloses an air conditioner with an OLP actuating means for detecting OLP actuation and a restart-voltage changing means.

[0005] The aforementioned conventional structure, however, has the following problems. First, when an overload condition or a low power-supply voltage environment increases the starting current, the OLP is actuated to protect the compressor. This prevents the compressor from starting operation and therefore prevents the air conditioner from starting operation. Second, when the power supply voltage is extremely low, the low voltage protection means is actuated, and when the refrigerating cycle is overloaded, the OLP is actuated. These situations cause the compressor and the air conditioner main body to be started and stopped repeatedly, thereby damaging the compression mechanism part.

SUMMARY OF THE INVENTION

[0006] The present invention provides an air conditioner of variable capacity type which comprises a compressor capable of varying capacity in two levels by switching between full-power operation and power-saving operation and which is provided with a voltage detector, wherein when a supply voltage is below a predetermined value, the compressor is operated at the power-saving operation. With this structure, when the supply voltage is decreased and the operating current is increased, the compressor can be operated at the power-saving operation to reduce the compression load and hence the current value. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0007] The air conditioner of the present invention may be provided with a current detector, so that when an operating current exceeds a predetermined value, the compressor can be operated at the power-saving operation. As a result, when the supply voltage is reduced and the operating current is increased, the compressor can be operated at the power-saving operation to reduce the compression load and hence the current value. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0008] The air conditioner of the present invention may be provided with a discharge pressure detector for the compressor, so that when a discharge pressure exceeds a predetermined value, the compressor can be operated at the power-saving operation. When the discharge pressure is increased by an increase in outdoor temperature, the detection of a discharge pressure correlating to the current value makes the compressor operate at the power-saving operation, thereby suppressing an excessive increase in the discharge pressure and reducing the operating current. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0009] The air conditioner of the present invention may be provided with a temperature detector for an outdoor heat exchanger, so that when the temperature of the outdoor heat exchanger exceeds a predetermined value, the compressor can be operated at the power-saving operation. When the temperature of the outdoor heat exchanger is increased by an increase in outdoor temperature, the detection of the temperature of the outdoor heat exchanger correlating to the current value makes the compressor operate at the power-saving operation, thereby suppressing an increase in the temperature of the outdoor heat exchanger and reducing the operating current. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0010] The air conditioner of the present invention may comprise a compressor capable of varying capacity in two levels by switching between FULL and SAVE, and the compressor may start operation at SAVE. With this structure, in an overloaded condition or in a low power-supply voltage environment, the compressor can be operated at SAVE to reduce the compression load so as to have a low starting current value. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0011] The air conditioner of the present invention may be provided with a plurality of running capacitors connected to each other to increase a capacitor capacity when the compressor driven by a capacitor start and run induction motor starts operation at SAVE. With this structure, in an overloaded condition or in a low power-supply voltage environment, high starting performance allows the compressor to be started smoothly at SAVE, so that the air conditioner can start operation without causing a shutdown of the compressor.

[0012] The air conditioner of the present invention may be a variable capacity type which comprises a compressor capable of varying capacity in two levels by switching the compressor discharge volume between FULL of high level and SAVE of low level, and which is provided with a voltage detector. When the supply voltage is below a predetermined value, the compressor is operated at SAVE and at an increased capacitor capacity.

[0013] As a result, when the supply voltage is decreased and the operating current is increased, the compressor can be operated at SAVE to reduce the compression load and hence the current value. Furthermore, the capacitor capacity can be increased by providing a plurality of running capacitors for the compressor so as to increase the torque of the motor in the compressor, thereby reducing breakdown. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0014] The air conditioner of the present invention may be provided with a current detector, so that when the operating current exceeds a predetermined value, the compressor is operated at SAVE and at an increased capacitor capacity. As a result, when the supply voltage is decreased and the operating current is increased, the compressor can be operated at SAVE to reduce the compression load and hence the current value. Furthermore, the capacitor capacity can be increased by providing a plurality of running capacitors for the compressor so as to increase the torque of the motor in the compressor, thereby reducing breakdown. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0015] The air conditioner of the present invention may be provided with a discharge pressure detector for the compressor, so that when the discharge pressure exceeds a predetermined value, the compressor can be operated at SAVE and at an increased capacitor capacity.

[0016] When the discharge pressure is increased by an increase in outdoor temperature, the detection of a discharge pressure correlating to the current value makes the compressor operate at SAVE, thereby suppressing an excessive increase in the discharge pressure and reducing the operating current. Furthermore, the capacitor capacity can be increased by providing a plurality of running capacitors for the compressor so as to increase the torque of the motor in the compressor, thereby reducing breakdown. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0017] The air conditioner of the present invention may be provided with a temperature detector for the outdoor heat exchanger, so that when the temperature of the outdoor heat exchanger exceeds a predetermined value, the compressor can be operated at SAVE and at an increased capacitor capacity. When the temperature of the outdoor heat exchanger is increased by an increase in outdoor temperature, the detection of the temperature of the outdoor heat exchanger correlating to the current value makes the compressor operate at SAVE, thereby suppressing an increase in the temperature of the outdoor heat exchanger and reducing the operating current. Furthermore, the capacitor capacity can be increased by providing a plurality of running capacitors for the compressor so as to increase the torque of the motor in the compressor, thereby reducing breakdown. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a flowchart showing the operation of a compressor of a first embodiment of the present invention.

[0019] FIG. 2 is a block diagram relating to a controller of the first embodiment of the present invention.

[0020] FIG. 3 is a flowchart showing the operation of a compressor of a second embodiment of the present invention.

[0021] FIG. 4 is a block diagram relating to a controller of the second embodiment of the present invention.

[0022] FIG. 5 is a flowchart showing the operation of a compressor of a third embodiment of the present invention.

[0023] FIG. 6 is a block diagram relating to a controller of the third embodiment of the present invention.

[0024] FIG. 7 is a flowchart showing the operation of a compressor of a fourth embodiment of the present invention.

[0025] FIG. 8 is a block diagram relating to a controller of the fourth embodiment of the present invention.

[0026] FIG. 9 is a block diagram relating to a controller of a fifth embodiment of the present invention.

[0027] FIG. 10 is a flowchart showing the operation of a compressor of a sixth embodiment of the present invention.

[0028] FIG. 11 is a block diagram relating to a controller of the sixth embodiment of the present invention.

[0029] FIG. 12 is a flowchart showing the operation of a compressor of a seventh embodiment of the present invention.

[0030] FIG. 13 is a block diagram relating to a controller of the seventh embodiment of the present invention.

[0031] FIG. 14 is a flowchart showing the operation of a compressor of an eighth embodiment of the present invention.

[0032] FIG. 15 is a block diagram relating to a controller of the eighth embodiment of the present invention.

[0033] FIG. 16 is a flowchart showing the operation of a compressor of a ninth embodiment of the present invention.

[0034] FIG. 17 is a block diagram relating to a controller of the ninth embodiment of the present invention.

[0035] FIG. 18 is a flowchart showing the operation of a compressor of a tenth embodiment of the present invention.

[0036] FIG. 19 is a block diagram relating to a controller of the tenth embodiment of the present invention.

[0037] FIG. 20 is an operational block diagram showing a conventional overload protector.

REFERENCE MARKS IN THE DRAWINGS

[0038] 1, 11, 20 controller [0039] 2 compressor [0040] 3, 23 voltage detector [0041] 4, 24 current detector [0042] 5, 25 discharge pressure detector [0043] 6, 26 outdoor-heat-exchanger-temperature detector [0044] 10 operation switch [0045] 12 variable-capacity compressor [0046] 13, 22 FULL/SAVE selector [0047] 14 running-capacitor block [0048] 21 variable-volume compressor [0049] 27 compressor-running-capacitor block

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050] An air conditioner of the present invention comprises the following components: an indoor blower circuit, an outdoor blower circuit, a refrigerating cycle, and a controller. The indoor blower circuit comprises an indoor air inlet, an indoor heat exchanger, an indoor air fan, and indoor air outlet. The outdoor blower circuit comprises an outdoor air inlet, an outdoor heat exchanger, an outdoor air fan, and an outdoor air outlet. The refrigerating cycle comprises an indoor heat exchanger, an outdoor heat exchanger, a compressor, and a throttle, which are connected by piping. The air conditioner is a variable capacity type including a compressor capable of varying capacity in two levels by switching between full-power operation and power-saving operation. The air conditioner is provided with a voltage detector, so that when the supply voltage is below a predetermined value, the compressor can be operated at the power-saving operation. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor in a low voltage environment.

[0051] The air conditioner of the present invention may be provided with a current detector, so that when the operating current exceeds a predetermined value, the compressor can be operated at the power-saving operation. As a result, when the operating current is increased in a low voltage environment or in an overloaded condition, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0052] The air conditioner of the present invention may be provided with a discharge pressure detector for the compressor, so that when the discharge pressure exceeds a predetermined value, the compressor can be operated at the power-saving operation. As a result, even in an overloaded condition, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0053] The air conditioner of the present invention may be provided with a temperature detector for the outdoor heat exchanger, so that when the temperature of the outdoor heat exchanger exceeds a predetermined value, the compressor can be operated at the power-saving operation. As a result, even in an overloaded condition, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0054] The air conditioner of the present invention comprises the following components: an indoor blower circuit, an outdoor blower circuit, a refrigerating cycle, and a controller. The indoor blower circuit comprises an indoor air inlet, an indoor heat exchanger, an indoor air fan, and indoor air outlet. The outdoor blower circuit comprises an outdoor air inlet, an outdoor heat exchanger, an outdoor air fan, and an outdoor air outlet. The refrigerating cycle comprises an indoor heat exchanger, an outdoor heat exchanger, a compressor, and a throttle, which are connected by piping. The air conditioner is provided with a compressor which is capable of varying capacity in two levels by switching between full-power operation (FULL) and power-saving operation (SAVE) and which starts operation at SAVE. In an overloaded condition or in a low power-supply voltage environment, the compression load can be reduced to make the starting current value low. As a result, the air conditioning operation can be started without causing a shutdown of the compressor.

[0055] The air conditioner of the present invention may be provided with a plurality of running capacitors, so that the capacitor capacity can be increased by connecting the running capacitors to each other when the compressor starts operation. Thus, in an overloaded condition or in a low power-supply voltage environment, high starting performance allows the compressor to be started smoothly at SAVE, so that the air conditioner can start operation without causing a shutdown of the compressor.

[0056] The air conditioner of the present invention may comprise the following components: an indoor blower circuit, an outdoor blower circuit, a refrigerating cycle, and a controller. The indoor blower circuit comprises an indoor air inlet, an indoor heat exchanger, an indoor air fan, and indoor air outlet. The outdoor blower circuit comprises an outdoor air inlet, an outdoor heat exchanger, an outdoor air fan, and an outdoor air outlet. The refrigerating cycle comprises an indoor heat exchanger, an outdoor heat exchanger, a compressor, and a throttle, which are connected by piping. The air conditioner is a variable capacity type including a compressor capable of varying capacity in two levels by switching between FULL and SAVE. The air conditioner is provided with a voltage detector, so that when the supply voltage is below a predetermined value, the compressor can be operated at SAVE. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor in a low voltage environment. Furthermore, the capacitor capacity can be increased by providing a plurality of running capacitors for the compressor so as to increase the torque of the motor in the compressor. This can reduce the probability of breakdown and increase the number of revolutions of the compressor so as to maintain the air conditioning performance. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0057] The air conditioner of the present invention may be provided with a current detector, so that when the operating current exceeds a predetermined value, the compressor can be operated at SAVE. As a result, when the operating current is increased in a low voltage environment or in an overloaded condition, the air conditioning operation can be continued without causing a shutdown of the compressor. Furthermore, the capacitor capacity can be increased by providing a plurality of running capacitors for the compressor so as to increase the torque of the motor in the compressor. This can reduce the probability of breakdown and increase the number of revolutions of the compressor so as to maintain the air conditioning performance. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0058] The air conditioner of the present invention may be provided with a discharge pressure detector for the compressor, so that when the discharge pressure exceeds a predetermined value, the compressor can be operated at SAVE. Thus, in an overloaded condition, the air conditioning operation can be continued without causing a shutdown of the compressor. Furthermore, the capacitor capacity can be increased by providing a plurality of running capacitors for the compressor so as to increase the torque of the motor in the compressor. This can reduce the probability of breakdown and increase the number of revolutions of the compressor so as to maintain the air conditioning performance. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0059] The air conditioner of the present invention may be provided with a temperature detector for the outdoor heat exchanger, so that when the temperature of the outdoor heat exchanger exceeds a predetermined value, the compressor can be operated at SAVE. As a result, even in an overloaded condition, the air conditioning operation can be continued without causing a shutdown of the compressor. Furthermore, the capacitor capacity can be increased by providing a plurality of running capacitors for the compressor so as to increase the torque of the motor in the compressor. This can reduce the probability of breakdown and increase the number of revolutions of the compressor so as to maintain the air conditioning performance. As a result, the air conditioning operation can be continued without causing a shutdown of the compressor.

[0060] The following is a description of embodiments of the present invention with reference to drawings. Note that the present invention is not limited to the embodiments described below. There are two methods for increasing a capacitor in the present invention. The first one is to increase the number of capacitors connected in parallel to each other. The second one is to decrease the number of capacitors connected in series to each other.

First Embodiment

[0061] A first embodiment of the present invention will be described as follows with reference to FIGS. 1 and 2.

[0062] As shown in FIGS. 1 and 2, an air conditioner of the present embodiment comprises controller 1, compressor 2 capable of varying discharge volume in two levels between full-power operation (FULL) and power-saving operation (SAVE), and voltage detector 3 for detecting a power supply voltage and transmitting the detected value to controller 1. When the voltage detected by voltage detector 3 is below a predetermined power supply voltage set by controller 1, compressor 2 is operated at the power-saving operation. The air conditioner thus structured can perform air conditioning operation while reducing the load of the compressor and preventing the overload protector (OLP) from being actuated when the power supply voltage is low in unstable voltage areas.

Second Embodiment

[0063] A second embodiment of the present invention will be described as follows with reference to FIGS. 3 and 4.

[0064] As shown in FIGS. 3 and 4, an air conditioner of the present embodiment comprises controller 1, compressor 2 capable of varying discharge volume in two levels between full-power operation and power-saving operation, current detector 4 for detecting an operating current and transmitting the detected value to controller 1. When the current detected by current detector 4 exceeds a predetermined operating current set by controller 1, compressor 2 is operated at the power-saving operation.

[0065] The air conditioner thus structured can perform air conditioning operation while reducing the load of the compressor and preventing the OLP from being actuated when the operating current is high in unstable voltage areas.

Third Embodiment

[0066] A third embodiment of the present invention will be described as follows with reference to FIGS. 5 and 6.

[0067] As shown in FIGS. 5 and 6, an air conditioner of the present embodiment comprises controller 1, compressor 2 capable of varying discharge volume in two levels between full-power operation and power-saving operation, and discharge pressure detector 5 for detecting a discharge pressure and transmitting the detected value to controller 1. When the discharge pressure detected by discharge pressure detector 5 exceeds a predetermined discharge pressure set by controller 1, compressor 2 is operated at the power-saving operation.

[0068] The air conditioner thus structured can perform air conditioning operation while reducing the load of the compressor and preventing the OLP from being actuated when an increase in the outdoor temperature overloads the refrigerating cycle and hence increases the discharge pressure.

Fourth Embodiment

[0069] A fourth embodiment of the present invention will be described as follows with reference to FIGS. 7 and 8.

[0070] As shown in FIGS. 7 and 8, an air conditioner of the present embodiment comprises controller 1, compressor 2 capable of varying discharge volume in two levels between full-power operation and power-saving operation, and outdoor-heat-exchanger-temperature detector 6 for detecting the temperature of the outdoor heat exchanger and transmitting the detected value to controller 1. When the temperature detected by outdoor-heat-exchanger-temperature detector 6 exceeds a predetermined temperature of the outdoor heat exchanger set by controller 1, compressor 2 is operated at the power-saving operation.

[0071] The air conditioner thus structured can perform air conditioning operation while reducing the load of the compressor and preventing the OLP from being actuated when an increase in the outdoor temperature overloads the refrigerating cycle and hence increases the discharge pressure.

Fifth Embodiment

[0072] A fifth embodiment of the present invention will be described as follows with reference to FIG. 9.

[0073] As shown in FIG. 9, an air conditioner of the present embodiment comprises operation switch 10, controller 11, variable-capacity compressor 12 capable of varying capacity in two levels between FULL and SAVE, and FULL/SAVE selector 13 for detecting an operation start signal and transmitting the signal to variable-capacity compressor 12. When the operation start signal from operation switch 10 is detected, variable-capacity compressor 12 is operated at SAVE.

[0074] The air conditioner of variable capacity type thus structured can start operation at low current values while reducing the compression load even in an overloaded condition or in a low power-supply voltage environment.

Sixth Embodiment

[0075] A sixth embodiment of the present invention will be described as follows with reference to FIGS. 10 and 11.

[0076] Hereinafter the sixth embodiment a compressor is driven by a capacitor start and run single-phase induction motor(in the present embodiment variable-capacity compressor 12 corresponds). The motor is provided with running-capacitor block 14 including a plurality of running capacitors. As shown in FIGS. 10 and 11, an air conditioner of the present embodiment comprises operation switch 10, controller 11, variable-capacity compressor 12 capable of varying capacity in two levels between FULL and SAVE, and FULL/SAVE selector 13 for detecting an operation start signal and transmitting the signal to variable-capacity compressor 12. When the operation start signal from operation switch 10 is detected by running-capacitor block 14, the running capacitors are connected to each other to increase the capacitor capacity, so that variable-capacity compressor 12 is operated at SAVE.

[0077] The air conditioner of variable capacity type thus structured can achieve high starting performance even in an overloaded condition or in a low power-supply voltage environment, thereby successfully starting operation.

Seventh Embodiment

[0078] A seventh embodiment of the present invention will be described as follows with reference to FIGS. 12 and 13.

[0079] As shown in FIGS. 12 and 13, an air conditioner of the present embodiment comprises controller 20, variable-volume compressor 21 capable of varying compression discharge volume in two levels between FULL and SAVE, voltage detector 23 for detecting a power supply voltage and transmitting the detected value to controller 20, and FULL/SAVE selector 22 for transmitting the detected value to variable-volume compressor 21. When the voltage detected by voltage detector 23 is below a predetermined power-supply voltage set by controller 20, variable-volume compressor 21 is operated at SAVE. When variable-volume compressor 21 is operated at SAVE as a result of the detection of the low power-supply voltage by voltage detector 23, controller 20 transmits a signal to compressor-running-capacitor block 27 so as to connect compressor-running-capacitors to each other, thereby increasing the compressor-running-capacitor capacity.

[0080] The air conditioner thus structured can continue air conditioning operation while reducing the load of the compressor and preventing the OLP from being actuated when the power supply voltage is low in unstable voltage areas.

Eighth Embodiment

[0081] An eighth embodiment of the present invention will be described as follows with reference to FIGS. 14 and 15.

[0082] As shown in FIGS. 14 and 15, an air conditioner of the present embodiment comprises controller 20, variable-volume compressor 21 capable of varying compression discharge volume in two levels between FULL and SAVE, current detector 24 for detecting an operating current and transmitting the detected value to controller 20, and FULL/SAVE selector 22 for transmitting the detected value to variable-volume compressor 21. When the current detected by current detector 24 exceeds a predetermined operating current set by controller 20, variable-volume compressor 21 is operated at SAVE. When variable-volume compressor 21 is operated at SAVE as a result of the detection of the low operating current by current detector 24, controller 20 transmits a signal to compressor-running-capacitor block 27 so as to connect compressor running capacitors to each other, thereby increasing the compressor-running-capacitor capacity.

[0083] The air conditioner thus structured can perform air conditioning operation while reducing the load of the compressor and preventing the OLP from being actuated when the operating current of the compressor is high in unstable voltage areas.

Ninth Embodiment

[0084] A ninth embodiment of the present invention will be described as follows with reference to FIGS. 16 and 17.

[0085] FIG. 17 is a block diagram of the ninth embodiment of the present invention. As shown in FIG. 16 and 17, an air conditioner of the present embodiment comprises controller 20, variable-volume compressor 21 capable of varying compression discharge volume in two levels between FULL and SAVE, discharge pressure detector 25 for detecting a discharge pressure and transmitting the detected value to controller 20, and FULL/SAVE selector 22 for transmitting the detected value to variable-volume compressor 21. When the discharge pressure detected by discharge pressure detector 25 exceeds a predetermined discharge pressure set by controller 20, variable-volume compressor 21 is operated at SAVE. When variable-volume compressor 21 is operated at SAVE as a result of the detection of the overloaded refrigerating cycle by discharge pressure detector 25, controller 20 transmits a signal to compressor-running-capacitor block 27 so as to connect compressor running capacitors to each other, thereby increasing the compressor-running-capacitor capacity.

[0086] The air conditioner thus structured can perform air conditioning operation while reducing the load of the compressor and preventing the OLP from being actuated when an increase in the outdoor temperature overloads the refrigerating cycle and hence increases the discharge pressure.

Tenth Embodiment

[0087] A tenth embodiment of the present invention will be described as follows with reference to FIGS. 18 and 19.

[0088] As shown in FIGS. 18 and 19, an air conditioner of the present embodiment comprises controller 20, variable-volume compressor 21 capable of varying compression discharge volume in two levels between FULL and SAVE, outdoor-heat-exchanger-temperature detector 26 for detecting the temperature of the outdoor heat exchanger and transmitting the detected value to controller 20, and FULL/SAVE selector 22 for transmitting the detected value to variable-volume compressor 21. When the temperature detected by outdoor-heat-exchanger-temperature detector 26 exceeds a predetermined temperature of the outdoor heat exchanger set by controller 20, variable-volume compressor 21 is operated as SAVE. When variable-volume compressor 21 is operated at SAVE as a result of the detection of the high temperature of the outdoor heat exchanger by outdoor-heat-exchanger-temperature detector 26 controller 20 transmits a signal to compressor-running-capacitor block 27 so as to connect compressor running capacitors to each other, thereby increasing the compressor-running-capacitor capacity.

[0089] The air conditioner thus structured can perform air conditioning operation while reducing the load of the compressor and preventing the OLP from being actuated when an increase in the outdoor temperature overloads the refrigerating cycle and hence increases the discharge pressure.

[0090] The compressor can be started easily without being shut down, thereby allowing the air conditioner to start operation even in an overloaded condition or in a low power-supply voltage environment.

[0091] The air conditioner of the present invention comprises a variable-capacity compressor capable of varying capacity in two levels by switching between FULL and SAVE. Starting the air conditioner at SAVE enables the variable-capacity compressor to be started without being shut down in an overloaded condition or in a low power-supply voltage environment. Therefore, the air conditioner can be applied not only to an air conditioner of variable capacity type but also to a dehumidifier or a drier.

Claims

1. An air conditioner of variable capacity type which comprises a compressor capable of varying capacity in two levels by switching between full-power operation and power-saving operation and which is provided with a voltage detector, wherein when a supply voltage is below a predetermined value, the compressor is operated at the power-saving operation.

2. The air conditioner of claim 1, wherein the compressor is driven by a capacitor start and run single-phase induction motor, and when the compressor is operated at the power-saving operation, a plurality of running capacitors are connected to each other to increase a capacitor capacity.

3. An air conditioner of variable capacity type which comprises a compressor capable of varying capacity in two levels by switching between full-power operation and power-saving operation and which is provided with a current detector, wherein when an operating current exceeds a predetermined value, the compressor is operated at the power-saving operation.

4. The air conditioner of claim 3, wherein the compressor is driven by a capacitor start and run single-phase induction motor, and when the compressor is operated at the power-saving operation, a plurality of running capacitors are connected to each other to increase a capacitor capacity.

5. An air conditioner of variable capacity type which comprises a compressor capable of varying capacity in two levels by switching between full-power operation and power-saving operation and which is provided with a discharge pressure detector for the compressor, wherein when a discharge pressure exceeds a predetermined value, the compressor is operated at the power-saving operation.

6. The air conditioner of claim 5, wherein the compressor is driven by a capacitor start and run single-phase induction motor, and when the compressor is operated at the power-saving operation, a plurality of running capacitors are connected to each other to increase a capacitor capacity.

7. An air conditioner of variable capacity type which comprises a compressor capable of varying capacity in two levels by switching between full-power operation and power-saving operation and which is provided with a temperature detector for an outdoor heat exchanger, wherein when a temperature of the outdoor heat exchanger exceeds a predetermined value, the compressor is operated at the power-saving operation.

8. The air conditioner of claim 7, wherein the compressor is driven by a capacitor start and run single-phase induction motor, and when the compressor is operated at the power-saving operation, a plurality of running capacitors are connected to each other to increase a capacitor capacity.

9. An air conditioner of variable capacity type which comprises a compressor capable of varying capacity in two levels by switching between full-power operation and power-saving operation, wherein the compressor starts operation at the power-saving operation.

10. The air conditioner of claim 9, wherein the compressor is driven by a capacitor start and run single-phase induction motor, and the compressor starts operation at the power-saving operation, and at a same time, a plurality of running capacitors are connected to each other to increase a capacitor capacity.