1. Dunli YWF serialaxial fans with external rotor motor have been certified as compliant for CCC, CE, ROHS, ISO9001, ISO14001. It suits application with ventilation volume of 1,400 13,000m3/h, and can be widely used in refrigeration and warm ventilation industry. 2. Dunli axial fans with external rotor are featured with compact structure, small size, light weight, convenient installation, low noise, low start-up current, large torque and high efficiency. 3. The motors of Dunli axial fan can be divided into two types: Single-phase asynchronous capacitor-run motor, and three-phase asynchronous motor. The motors can work in environment with temperature from -30 to +50°. They are with protection class of IP54 and insulation class of B grade. With direct cooling, low temperature rise and thermal protector, the average service life of the motors is over 30,000 hours when working under condition of continuous rated load. 4. The rotor of dunli axial fan is balanced at two ends and the precision class is over G6.3. The rotor is featured with low vibration, smooth running and reliability.