Abstract: Disclosed is an air conditioner which can obtain an energy-saving effect without any change to the setting temperature set by a user and, accordingly, without causing discomfort to the user. If a capacity restriction mode is set to at least one of indoor units Y1 and Y2, the setting temperature Ts in the indoor units Y1 and Y2 is not changed and is maintained at a value set by the user and a compressor 1 is operated with the capacity less than the normal capacity.

Abstract: Disclosed is an air conditioner which can obtain an energy-saving effect without any change to the setting temperature set by a user and, accordingly, without causing discomfort to the user. If a capacity restriction mode is set to at least one of indoor units Y1 and Y2, the setting temperature Ts in the indoor units Y1 and Y2 is not changed and is maintained at a value set by the user and a compressor 1 is operated with the capacity less than the normal capacity.

Abstract: An air-conditioning apparatus includes a control circuit adapted to detect, from among first to third line voltages of a three-phase AC power supply, the second or third line voltage not synchronizing with a serial signal. The control circuit detects a difference between a phase angle of the detected line voltage and that of the serial signal, compares the difference with set values and determines, by that comparison, whether the three-phase AC power supply is in a positive-phase sequence or in a negative-phase sequence. The operation of a compressor is inhibited when the negative-phase sequence is determined by the control circuit.

Abstract: An outdoor unit includes at least two compressors and an outdoor heat exchanger commonly coupled thereto. An indoor unit is coupled to the outdoor unit to form a refrigeration cycle. The indoor unit includes at least an indoor heat exchanger and means for outputting required capacity data in accordance with an air-conditioning load with respect to the indoor heat exchanger. A pressure detector detects the high-pressure-side pressure of the refrigeration cycle. A first control section controls the number of compressors to be driven. The first control section sequentially starts the two compressors so as to control the compressors in a parallel operation state when the number of compressors to be driven is controlled to be two.

Abstract: A memory stores, in advance, at least a first V/F pattern corresponding to an air conditioning load and having reference voltage and frequency characteristics, and a second V/F pattern having voltage and frequency characteristics lower than those of the first V/F pattern in a starting region of a variable-capacity compressor for driving a refrigeration cycle. A detector detects an over current supplied to an inverter for driving the compressor. A controller stops the compressor through the inverter when the detector detects the over current, and restarts or holds the compressor through the inverter in accordance with the detection count of the over current. The compressor is restarted with the first V/F pattern from the memory when the detection count is smaller than a first predetermined count, and when the detection count reaches a second predetermined count larger than the first predetermined count.

Abstract: When the temperature of an internal heat-exchanger decreases below a first value in cooling mode, a normal operation, wherein a variable capacity compressor operates in response to the temperature in a space to be cooled, stops temporarily, and a defrost operation, in which the driving frequency of the compressor periodically decreases by a prescribed value until the temperature of the internal heat-exchanger increases above a second value greater than the first value, begins. When the temperature of the internal heat-exchanger increases above a second value greater than the first value, the compressor operates in response to the temperature in the space. When the compressor stops during the defrost operation, the temperature of the internal heat-exchanger is compared with a third value greater than the second value and the operation of the compressor responding to the temperature in the space is inhibited until the temperature of the internal heat-exchanger increases above the third value.