Centrifugal fan is a mechanical equipment that uses energy conversion to discharge gas, its main role is ventilation, dust removal and cooling, mainly used in mines, tunnels, cooling towers and buildings. Its working principle is similar to that of compressors, centrifugal fans are distinguished according to the type of motor, can be AC centrifugal fans (AC motor), DC centrifugal fans (DC motor), EC centrifugal fans (electronic commutation motor), each type of centrifugal fans have specific advantages and uses, making them suitable for different industries and application areas.
1. Debugging of centrifugal fan
1. The centrifugal fan allows full voltage starting or buck electric, but it should be noted that the current at full voltage starting is about 5 to 7 times the rated current, and the buck starting torque is proportional to the square of the voltage. When the power grid capacity is insufficient, the buck starting should be used.
2. When the centrifugal fan is on test run, it should carefully read the product manual and check whether the wiring method is consistent with the wiring diagram; It should be carefully checked whether the working voltage of the power supply to the fan meets the requirements, whether the power supply is in phase or in phase, and whether the capacity of the distributed electrical components meets the requirements.
3. The number of people in the test is not less than two, one person controls the power supply, one person observes the operation of the fan, and stops the machine immediately if any abnormal phenomenon is found; First check whether the rotation direction is correct; After the centrifugal fan starts to operate, it should be checked immediately whether the running current of each phase is balanced and whether the current exceeds the rated current. If there is an abnormal phenomenon, stop the machine for inspection. After five minutes of operation, stop the machine to check whether there is any abnormal phenomenon, confirm that there is no abnormal phenomenon and then start operation.
4. When the two-speed centrifugal fan is tested, the low speed should be started first to check whether the rotation direction is correct; When starting at high speed, the fan must be stationary before starting to prevent high-speed reverse rotation, causing switch trip and motor damage.
5. When the centrifugal fan reaches the normal speed, the input current of the fan should be measured whether it is normal, and the running current of the centrifugal fan should not exceed its rated current. If the running current exceeds its rated current, check whether the supply voltage is normal.
6. The motor power required by the centrifugal fan refers to the larger power required when the centrifugal fan and the air chassis are fully opened under certain working conditions. If the air inlet is fully open for operation, there is a risk of damage to the motor. When the fan is tested, the valve on the fan inlet or outlet pipe is closed, and the valve is gradually opened after operation until the required working condition is reached, and pay attention to whether the running current of the fan exceeds the rated current.
Second, the installation requirements of centrifugal fans
1. The installation of the whole unit of the centrifugal fan should be placed directly on the foundation with a pair of inclined pad iron leveling.
2. The cutting surface on the base of the centrifugal fan assembled on the site should be properly protected and should not be corroded or operated. When the base is placed on the foundation, a pair of inclined pad iron should be levelled.
3. The bearing seat and the base should be closely connected, the longitudinal non-levelness should not exceed 0.2/1000, measured with a level on the spindle, and the transverse non-levelness bottom should not exceed 0.3/1000, measured with a level in the horizontal middle plane of the bearing seat.
4. Before scraping the bearing shell, the rotor axis line and the housing axis line should be corrected, and the gap between the impeller and the air inlet and the gap between the spindle and the rear side plate of the housing should be adjusted to make it conform to the provisions of the equipment technical documents.
5. When assembling the spindle and bearing shell, it should be checked according to the technical documents of the equipment. The interference between the bearing cover and the bearing shell should be maintained at 0.03-0.04 mm.
6. When assembling the fan shell, the rotor axis line should be used as the reference to find the position of the shell and the axial and radial clearance between the impeller air inlet and the shell air inlet at high speed to the specified range, and check whether the anchor bolts are tightened. If the clearance value of the equipment is not specified in the technical document, the general axial clearance should be 1/100 of the outer diameter of the impeller, the radial clearance should be evenly distributed, and the value should be 1.5/1000-3/1000 of the outer diameter of the impeller. When adjusting, strive to reduce the gap value to improve the efficiency of the fan.
7. When the fan is timing, the different coaxiality of the fan shaft and the motor shaft: the radial positioning shift should not exceed 0.05 mm, and the tilt should not exceed 0.2/1000.
8. For the centrifugal fan assembled with rolling bearings, the different coaxiality of the bearing holes on the two bearing frames can be subject to flexible rotation after the rotor is installed.
By implementing these commissioning and installation requirements, centrifugal fans and their variations, including EC fans, AC fans, and DC fans, can be set up and operated effectively. If you have any further inquiries, please feel free to contact us, and we will provide you with professional assistance and service.
