Abstract: A rectifier circuit (3) and a switching circuit (6) are mounted on a board (30). The board (30) is contained in a case (10) along with one or more capacitors (4, 5). In particular, the capacitors (4, 5) are laid sideways in the case (10).

Abstract: When an outdoor machine 2 includes a signal line connector 21 for receiving ON/OFF signals for a compressor, an outdoor machine drive control unit 30 of an air conditioner includes an inverter device 32 for supplying power variable in frequency to the compressor 22, and a control device 33 for controlling the inverter device 32 to gradually increase the number of revolutions of the compressor 22 when the ON/OFF signal for the compressor received through the signal line connector 21 changes from the OFF condition to the ON condition. The air conditioner outdoor machine drive control unit 30 enables to construct an inverter-type air conditioner by using a general heat-pump-type indoor machine and merely mounting it in an outdoor machine.

Abstract: A filter apparatus has a current-detecting coil. The coil detects a high-frequency leak current flowing from the phase-windings of a motor to the earth terminal through the closed case of a compressor. A current-canceling circuit generates a current similar in waveform to the high-frequency leak current detected by the coil. The current thus generated cancels out the high-frequency leak current.

Abstract: A power converter comprises: a rectifier composed of a plurality of bridge-connected diodes; reactors each connected in series in each power line of the rectifier; a chopper circuit having two switching elements connected in series between two DC output terminals of the rectifier; star connection capacitors, each of one end thereof being connected to the power source side of each reactor and each of the other end thereof being connected in common to a mutual connection point of the two switching elements of the chopper circuit; a smoothing capacitor for smoothing an output voltage of the rectifier; and ring connection capacitors each connected between two power lines and further between the AC power source and each of the reactors.

Abstract: This invention provides an inverter controlled air conditioner capable of employing a rush current preventing relay having a small capacitance, thereby decreasing the cost. An inverter circuit includes a rectifying circuit connected to an AC power supply, a smoothing capacitor connected to the output terminals of the rectifying circuit, and a switching circuit, connected to the two terminals of the capacitor, for outputting a voltage having a predetermined frequency upon performing switching. An auxiliary power supply circuit has a rectifying circuit connected to the AC power supply. A control section drives the switching circuit with an output from the rectifying circuit as the operation voltage. Relay drive circuits for receiving the output from the rectifying circuit as the operation voltage are connected to an electromagnetic contactor and a relay. When the air conditioner is started, the control section energizes the relay for a predetermined period of time t.sub.

Abstract: In an adjustable a.c. power supply for an air-conditioner system, comprising a first frequency converter for driving a compressor motor of a first air-conditioner, a second frequency converter for driving a compressor motor of a second air-conditioner, and a common a.c. power supply for delivering a.c. power to both frequency converters, a rectifier included in at least one frequency converter is constructed as a controllable rectifier and subjected to phase-control so that a synthetic higher harmonic current of the two frequency converters as viewed from the a.c. power supply is reduced. By conducting phase-control of plural controllable rectifiers in a manner that, e.g., one rectifier has a phase-control angle of zero degrees and the other rectifier has a phase-control angle of 30 degrees, load current from the a.c. power supply is permitted to have a waveform closer to a sine wave, i.e., a waveform in which higher harmonic components are further reduced.

Abstract: A control apparatus for a multi-air-conditioner system provided with a freezing cycle wherein refrigerant is supplied from a common outdoor unit to a plurality of indoor units via respective control valves. In order for a compressor to recover refrigerant and oil contained therein remaining in an indoor unit under interception, the control valve of the indoor unit under interception is opened cyclically to a degree of opening corresponding to the rated capacity of the indoor unit for the predetermined time while circulating the refrigerant cyclically for a predetermined time to the indoor unit.

Abstract: A first memory stores first PWM control signal pattern data being calculated in advance according to the sine-triangle wave comparison modulation system in the frequency region below a predetermined frequency, for each of predetermined frequency intervals. A second memory stores second PWM control signal pattern data being calculated in advance according to the harmonic removal pattern modulation system in the frequency region above the predetermined frequency for each of predetermined frequency intervals. A frequency designating section supplies frequency designating data. A controller reads out, when receiving the frequency designating data, either the first or second PWM control signal pattern data in accordance with the frequency designating data, from the first or second memory. An inverter outputs a predetermined AC power in accordance with the read-out first or second PWM control signal pattern data.

Abstract: An air conditioner having a heat exchange cycle which includes at least a compressor motor that is driven by an inverting apparatus at a variable speed, an indoor heat exchanger and an outdoor heat exchanger is provided.

Abstract: An air conditioner having a heat exchange cycle which includes at least a compressor motor that is driven by an inverting apparatus at a variable speed, an indoor heat exchanger and an outdoor heat exchanger is provided.