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Eight precautions for debugging axial flow fans

Update:24-08-2019
Summary:

The axial fan allows full-voltage starting or step-down […]

The axial fan allows full-voltage starting or step-down starting, but it should be noted that the current at full-voltage starting is about 5-7 times the rated current. The axial-flow fan's step-down starting torque is proportional to the square of the voltage, when the grid capacity is insufficient. When using a step-down start. (When the power is greater than 11KW, it is recommended to use a step-down start).

1. The exhaust fan is faulty due to water in the axial fan oil. There is too much water in the oil. The soot contains water vapor. When the water vapor encounters a cold pipe, it condenses into water. The condensed water flows back to the fan through the outlet pipe when the exhaust pipe of the exhaust fan exhaust pipe is not well drained. Inside the casing, the motor enters the motor from the fan casing, causing the insulation of the coil to decrease and causing the motor to burn out.

2. Because the fan selection is too large during the transformation. In order to reduce the bearing housing negative pressure, the fan outlet damper is closed to 20% opening to ensure the negative pressure of the main tank -150 ~ -250Pa. In this way, the exhaust fan is pressed, and the opening of the outlet damper is too small, so that water and oil are not easily drained from the casing, and remain in the casing of the fan for a long time, thereby causing the motor to burn out after entering the motor.

3. The exhaust fan is faulty due to a problem with the axial fan motor seal. There is a problem with the motor seal, causing the water to burn out of the motor from the fan casing. When the fan outlet damper opening is adjusted to 20%, the fan casing is crushed, which makes it easier for water to enter the motor, which further exacerbates the frequency of motor burnout.

When testing the fan, carefully read the product manual and check whether the wiring method is consistent with the wiring diagram. Care should be taken to check whether the working voltage supplied to the fan power supply meets the requirements, whether the power supply is out of phase or in phase, and whether the capacity of the distributor component matches Claim.

When the test is carried out, there are less than two people. One person controls the power supply. One person observes the operation of the fan and immediately detects the abnormal phenomenon. First, check whether the rotation direction is correct. After the fan starts running, the current should be immediately balanced and the current exceeds the rated current. If there is any abnormality, stop the inspection. After five minutes of operation, check whether the fan is abnormal or not, and confirm that there is no abnormal phenomenon and then start up.

When testing the two-speed fan, start the low speed first and check whether the rotation direction is correct. When starting the high speed, it must be restarted after the fan is stationary to prevent the high speed reverse rotation, causing the switch to trip and the motor to be damaged.

When the fan reaches the normal speed, it should measure whether the fan running current is normal, and the operating current of the fan cannot exceed its rated current. If the operating current exceeds its rated current, check that the voltage supplied to the fan is normal.

The motor power required by the fan refers to the large power required for the centrifugal fan and the wind chassis when the air inlet is fully opened under certain working conditions. If the air inlet is fully open for operation, the motor may be damaged. When testing the fan, it is best to close the valve on the inlet or outlet of the fan. After the operation, the valve is gradually opened to reach the required working condition, and the operating current of the fan exceeds the rated current.

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