Japan deeply depends on foreign energy source. After oil shock in 1970's, a lot of efforts have been made to save energy. A Government Regulation called top runner program enabled big progress in efficiency of air conditioners. Main factors are inverter control and high efficiency motors called interior permanent magnet motor (IPM motor).

IPM motor utilizes not only magnet torque but also reluctance torque. IPM motors contains thin NEOMAX^® deep in the rotor which is good for magnet cost and retention. Motor efficiency of an IPM motor is 10 to 20% higher than that of an induction motor.