Motor noise and its control

Thread Content

Motor noise and its control Motors (including generators and motors) are large-scale power equipment in industrial and agricultural production. According to surveys, the noise of domestically produced small and medium-sized motors is mostly between 90∽100dBA, and the noise of large motors is as high as more than 100dBA. The sound energy is distributed between 125∽500HZ (someone appears at 1000HZ). Its noise characteristics are low and medium frequency. The noise of the motor can be roughly divided into two parts: Part of it is caused by mechanical vibration, and its energy is directly related to the radiated sound power and electrical power. ； The other part is aerodynamic noise, which is directly related to the linear speed of the air flow, and the linear speed is related to the rotation speed of the motor. In addition, ventilation noise cannot be ignored. There are three main noise reduction measures for motors: 1． Install sound insulation hoods such as local sound insulation hoods, box sound insulation hoods, and assembled sound insulation hoods. 2. Changing the structure of the motor cooling fan changes the diameter of the blades and blades, and the number of blades changes from more to less. 3． Install the muffler motor inlet and outlet muffler and the rear axial air inlet muffler. At present, the most widely used noise reduction measure in China is to add a sound isolation cover or a sound isolation cover equipped with a muffler. Motors can be divided into three types: large, medium and small according to their power. Depending on their type and structure, the noise reduction measures adopted are also different.