This series of products is our newly developed series of products, the specifications cover the diameter range from A250 to A500, and the volume flow rate is up to 10000mˆ3/h; The series of external rotor fan products have the main features of compact structure, reliable operation, energy saving and high efficiency, low running noise, long design life and easy installation. The "forward-swept" wing blade of the product has obvious advantages in energy efficiency and noise performance compared with the sheet blade; In addition, the blades can be made of lightweight plastic or aluminum alloy materials according to different use environments, which has a wider environmental adaptability; The use of lightweight materials reduces the load on the bearing and the entire rotor power system, thereby further improving the reliability and service life of the product; The use of direct current motor (EC/DC) makes the fan have higher efficiency, more freely controlled, and can flexibly meet the needs of customers; Dunli DC motor can provide a variety of control schemes and protection functions to achieve intelligent control and energy saving and environmental protection.