Household air conditioner compressor motor, its rated power is generally 750 ~ 2 250W. Compressor is the heart of air conditioner, the motor stator windings are directly in a mixture of refrigerant and oil, so people often have a high motor requirements, such as high starting torque, high efficiency, low noise, vibration and shock resistance, insulation materials with good chemical stability (fluoride-resistant performance) and other things like that. For the current widely used fixed-frequency air conditioner, compressor uses single-phase asynchronous motors, 3P and over air conditioners use three-phase asynchronous motors. Such motor starting current is larger, less efficient, the biggest disadvantage is the speed cannot be adjusted, cannot achieve rapid cooling (or heating), the indoor temperature is kept constant that is dependent on frequent on-off motor. Inverter air conditioner can be divided into AC inverter air conditioners and DC inverter air conditioner, most of the products on markets are AC inverter air conditioner. AC variable frequency motor air conditioner compressor is a three-phase asynchronous motors, variable frequency control technology applies to control the motor speed, so that the cooling capacity of the compressor is continuously adjustable. Compared with the constant-speed air conditioner, various performance indexes of air conditioner is better than constant-speed air conditioner. For example, soft start, small starting current, can operate at a low voltage (such as 170V), quick cooling (or heating); compressor runs at night with a low speed, noise is greatly reduced, reducing the number of times the motor off.
AC inverter air conditioner can be divided into two structures, one is the same as a fixed-frequency air conditioner that throttling by capillary, the other is that throttling by electronic expansion valve controlled by stepper motor, and coordinate with the compressor and can accurately control refrigerant flow to achieve a high control accuracy of temperature. DC inverter air conditioner, the compressor and the fan apply brushless DC motors, and throttle by stepper motor control but also use electronic expansion valve to throttle. Compared with AC inverter air conditioner, it has lower noise, high electrical efficiency, more significant energy saving, faster cooling (or heating), is currently the best performance of the air conditioner.