Abstract: It is judged whether the abnormal current is due to the electric leakage or not by a detection step detecting the abnormal current by the leakage current detection board and comparing a threshold value of predetermined items stored in a storing unit and actual values corresponding to the items at the time of when a compressor is stopped by detecting the abnormal current in the detection step. Specifically, the abnormal current is recognized as the electric leakage to be displayed on a display unit when at least one of the operating time at the time of detecting the abnormal current, the inner pressure of a motor, and a discharge pipe temperature is lower than the corresponding threshold value.

Abstract: A fan control system includes a first fan, a second fan that is adjacent to the first fan, a first motor that is configured to rotate the first fan, a second motor that is configured to rotate the second fan, and a control unit. The control unit is configured to control the rotational speeds of the first motor and the second motor, and to decrease the rotational speeds of both the first motor and the second motor when the rotational speed of the first motor must be decreased.

Abstract: A zero-phase current is outputted by detecting a ground-fault current with a zero-phase-sequence current transformer. A circuit having an open collector output operates when the voltage of the zero-phase current exceeds a positive side threshold value or it falls below a negative side threshold value to discharge a capacitor. When the inter-plate voltage of the capacitor falls below a threshold value voltage, a controlling means detects electric leakage to transmit that to a control unit of an air conditioner.

Abstract: A fan control system includes first and second adjacent fans, first and second motors configured to rotate the first and second fans, and a control unit configured to control rotational speeds of the first and second motors in order to control rotational speeds of the first and second fans. The first and second motors are energized such that the rotational speeds of the first and second fans reach target rotational speeds prior to increasing the rotational speeds of the first and second fans to required rotational speeds. The target rotational speeds are lower than the required rotational speeds. The first and second motors are energized such that the rotational speeds of the first and second fans reach the required rotational speeds after the rotational speeds of the first and second fans reach the target rotational speeds.

Abstract: An object of the present invention is to reduce electrical noise in accordance with the necessity of a countermeasure taken against electrical noise without changing a structure of an expansion valve. In a case where a judgment result as to whether or not the countermeasure against electrical noise is taken is affirmative, a drive timing (interval) of an expansion valve (107) is increased. Further, a driving amount is reduced. Accordingly, a flow of a refrigerant is made slow, whereby it is possible to reduce generated electrical noise while performing instructed temperature control.

Abstract: A plurality of air conditioning units (20, 20) are daisy-chain connected to each other by a switching hub (31) provided in an outdoor unit (30). An integrated transmission line (10A) and internal/external transmission lines (10B) are connected to each other by a gateway (32) connected to the switching hub (31) so as to be capable of separating data transmission.