A centrifugal fan is a mechanical device that uses mechanical kinetic energy to increase air pressure and supply air. It is a passive power machine. Centrifugal fans are commonly used for natural ventilation, dust removal, and cooling in processing plants, coal mines, tunnel construction, fiberglass cooling towers, vehicles, ships, and buildings; Natural ventilation and induced draft fans for heating furnaces and kilns; Refrigeration and exhaust in air conditioning purification equipment and household appliances; Drying and selection of grains; Wind tunnel cleaning banquet and airship inflation and promotion, etc.
A centrifugal fan is a complex mechanical equipment, consisting of an air inlet, an electric air valve, a centrifugal impeller, a motor, and ventilation openings. The function of centrifugal fans varies in different situations. Therefore, different operating conditions may affect the efficiency of centrifugal fans. Adjusting the centrifugal fan to the optimal state can be approached from several aspects.
1. Centrifugal fans allow the motor to start at rated power or with a blood pressure lowering electric type, but it should be noted that the current required for starting at rated power is about 5-7 times the rated voltage. The torque of the blood pressure lowering motor is positively correlated with the square meter of current. When the power capacity is insufficient, blood pressure lowering starting should be used.
2. During the trial operation of the centrifugal fan, it is necessary to carefully read the product manual and check whether the wire connection method is consistent with the wiring method; Check whether the voltage of the fan switch power supply provided by the application center meets the standards, whether the switch power supply is out of phase or has a phase difference, and whether the volume of the distributed gas components meets the regulations.
3. During the trial operation, there should be no less than two people, one to control the power supply and one to observe the operation of the fan. If any abnormal situation is found, the machine should be shut down immediately for inspection; First check if the rotation direction is correct; After the centrifugal fan gradually runs, it should be checked immediately whether the current flow of each phase is balanced and whether the current flow exceeds the rated voltage; If there are any abnormal phenomena, the machine should be turned off for inspection. After running for five minutes, turn off the fan and check if there are any abnormal conditions before starting it again.
4. When testing a single speed centrifugal fan, first start the low-speed gear and check if the rotation direction is correct; When starting quickly, it is necessary to wait for the fan to come to a standstill before restarting to prevent rapid reverse rotation, triggering switch tripping, and motor damage.
5. When the centrifugal fan achieves a normal speed ratio, the input current of the fan should be accurately measured to ensure that it is normal. The operating current of the centrifugal fan should not exceed its rated voltage. If the operating current exceeds its rated voltage, the provided operating voltage should be checked for normality.
6. The motor power required for a centrifugal fan refers to the relatively high output power required for the centrifugal fan and fan case with the air inlet fully open and closed under certain conditions. If the air inlet is fully opened and operated, there is a risk of damage to the motor. During the trial operation of the fan, try to close the gate valves on the inlet or outlet pipelines of the fan as much as possible. After operation, gradually open the gate valves to achieve the required working conditions, and pay attention to whether the operating current of the fan exceeds the rated voltage.
