HBzhan Content Introduction: The noise of centrifugal fans is mainly aerodynamic noise, which can be divided into discrete noise and broadband noise in nature. The aerodynamic noise is mainly generated by the interaction between gas, impeller blades, and volute shell, and propagated through the inlet and outlet channels. The three-dimensional unstable flow field inside the snail shell and the special shape of the shell make it difficult to conduct research on it.
　　
　　centrifugal fanIt is a mechanical device that relies on input mechanical energy to increase gas pressure and deliver gas. It is a passive fluid mechanical device. Centrifugal fans are widely used for ventilation, dust removal, and cooling in factories, mines, tunnels, cooling towers, vehicles, ships, and buildings; Ventilation and induced draft for boilers and industrial furnaces; Cooling and ventilation in air conditioning equipment and household appliances; Drying and selection of grains; Wind tunnel wind source and inflation and propulsion of hovercraft.
　　
The Lifengxin machine is a DC speed regulating motor, whose speed is controlled by changing the conduction angle of the thyristor through an adjustable resistor, and then the thyristor controls the rectification to reach the voltage at both ends of the motor to achieve the purpose of controlling speed. The motor speed is unstable, and theoretically, the following four situations are possible.
　　
(1) One of the four rectifier diodes has a problem
　　
(2) There may be carbon powder or carbon brush defects between the motor rotor and the rectifier. Following the principle of easy repair first and difficult repair later, the adjustable resistor was first measured, and the resistance value changed regularly with adjustment, proving that the potentiometer was good. Then, the thyristor was measured and no problems were found. As the diode is a high current metal sealed tube, one end is fastened to the circuit board with a screw, and the other end is soldered to the circuit board with a wire. When removed from the circuit board, it was found that the positive and negative poles were loose. The diode was then measured and shaken to confirm that it was sometimes good or bad.
　　
(3) There are also many problems with thyristors, usually caused by breakdown short circuits, open circuits, inability to trigger, or poor internal contacts.
　　
(4) Adjustable resistor, cabinet centrifugal fans have a very high frequency of use due to the installation of adjustable resistors on the control panel. Over time, poor contact is common.
　　
If you find that the fan has unstable speed during operation, you can use the four points mentioned above as a troubleshooting direction to quickly identify the cause and improve the efficiency of maintenance and repair.
　　
　　centrifugal fanWear of transmission parts is a common equipment problem, including wear of exhaust fan bearings, bearing chambers, and blower shaft bearings. For the above-mentioned faults of centrifugal fans, traditional maintenance methods include welding, thermal spraying, electric brush crossing, etc., but they all have certain drawbacks: the thermal stress generated by high temperature welding cannot be eliminated, which can easily cause material damage and lead to component bending or fracture; However, electric brush plating is limited by the thickness of the coating, and centrifugal fans are prone to peeling off. Both of the above methods use metal to repair the metal, which cannot change the "hard to hard" fit relationship. Under the combined action of various forces, it will still cause the rubber coated drum to wear again.