The noise generated by motor operation is caused by electromagnetic noise generated during high-speed operation between the rotor and stator of the motor, and mechanical noise generated by the imbalance between the rotor and the stator. It also includes aerodynamic noise generated when the motor cooling fan is running. The noise is of intermediate frequency and the peak value is between 125 and 1000 Hz. Noise generated by the operation of the exhaust fan. When the fan runs at high speed, the mechanical components are rubbed together and the rotating parts of the fan are unbalanced, and the mechanical noise and aerodynamic noise generated by the friction between the blades and the air are composed of two parts. The peak frequency of the noise is 250-2000 Hz. between. Exhaust noise. When the powerful airflow generated when the fan runs at high speed moves forward, when it is rubbed against the air duct wall in the air duct and the airflow passes through the air outlet, the aerodynamic noise generated by the imbalance of internal and external pressures, the noise frequency is concentrated at 500-2000 H. Between z. Since the exhaust fan room has no special cooling holes, all of them are cooled by the open doors and windows. The inner wall of the machine room is not treated with sound absorption, and the noise generated by the motor cannot be effectively isolated. The fan does not have a special soundproof room, and is directly exposed to the outside world, and the generated noise is directly discharged. It is difficult to effectively reduce noise. Drone Controllers,Flight Control System,Obstacle Avoidance Radar,Automatic Flight Control System Dongying Tianqi Technology Co., Ltd. , https://www.uav5.com