Abstract: Air conditioning systems (1) may include an air conditioning circuit (2) and an electrically driven compressor (C). The compressor may have a motor (M) that includes a rotor (12) and a stator (14). The rotor may be rotated by a magnetic force generated when current is supplied to the stator. A temperature sensor (22) may detect the temperature of the rotor or the ambient temperature when the rotor is started to be rotated. A current calculator (26) may calculate a demagnetization limit current of the rotor at the detected temperature. The calculated demagnetization limit current may be used for determining a current that will be supplied to the stator for a predetermined period. In the alternative, the supplied current may increase as the rotor temperature increases during the initial operation. Preferably, the current may be less than the demagnetization limit current and may be greater than a minimum current that is required to rotate the rotor.

Abstract: A scroll-type compressor having a stationary scroll and a movable scroll is provided. A compression chamber is defined between a stationary scroll and a movable scroll. A refrigerant introducing passage formed in the movable scroll for introducing a refrigerant from the compression chamber to a driving mechanism. The compressed refrigerant including a lubricant introduced through the passage is affective to lubricate the driving mechanism. The compressor may also include a sump to collect the lubricant leaving the driving mechanism. Collected lubricant is reintroduced into the compression region via a suction region of the compressor.

Abstract: Vehicle air conditioning systems (2) may include an electrically driven compressor (4, 6) that is electrically connected to an alternator (16) driven by a vehicle engine (18). The compressor may be driven in a first drive mode, in which a normal drive control is performed. The compressor also may be driven in a second drive mode, in which the rotational speed of the compressor is increased, as compared to the normal drive control. The compressor may be driven in the second drive mode at least when vehicle running speed is being reduced.