Centrifugal fans will switch between power frequency and variable frequency according to the needs in use, so how should it be operated?
1) The centrifugal fan power frequency is switched to variable frequency operation
1. The opposite side is in the power frequency mode
Step 1: When the unit load is reduced to about 50%, keep 3 coal mills running, and other coal mills stop ventilation.
Step 2: Gradually close the primary fan inlet adjustment baffle and open the opposite fan inlet adjustment baffle. Ensure the stability of the primary air pressure, then transfer the fan load to the opposite side, and stop the primary fan.
Step 3: Switch the frequency converter of the primary fan to the frequency conversion mode.
Step 4: Start the primary fan and adjust the fan speed to the power frequency speed.
Step 5: Open the primary fan outlet baffle.
Step 6: Gradually open the adjustment baffle for the inlet of the primary fan, and close the adjustment baffle for the inlet of the opposite primary fan until the currents of the two primary fans are balanced.
2. The opposite side is in the frequency conversion mode
Step 4: Steps 1-3 are the same as the above process, then start the primary fan, and adjust the speed of the fan and the primary fan on the opposite side to be similar.
Step 5: Open the primary fan outlet baffle.
Step 6: Gradually open the inlet adjustment baffle of the primary fan until it is fully open. At the same time, reduce the speed of the two primary fans until the currents of the two primary fans are balanced.
2) The centrifugal fan is switched from frequency conversion to power frequency operation
1. The opposite side is in the power frequency mode
The third step: The process of steps 1-2 is the same as the above, and the third step is to switch the inverter of the primary fan to the power frequency mode.
Step 4: Turn on the primary fan and check that the outlet baffle is connected.
Step 5: Gradually open the primary fan inlet adjustment baffle to full opening, and at the same time close the opposite primary fan inlet adjustment baffle until the currents of the two primary fans are balanced.
2. The opposite side is in the frequency conversion mode
Step 2: Step 1 is the same as the above. Step 2 is to gradually close the inlet adjustment baffle of the primary fan and increase the speed of the two primary fans to keep the primary air pressure stable, and then transfer the fan load to the opposite side. Stop the primary fan.
Step 3: Gradually increase the speed of the primary fan on the opposite side to the power frequency speed, and close the inlet adjustment baffle to keep the primary air pressure stable and the fan does not flow.
Step 4: Switch the inverter of the primary fan to the power frequency mode.
Step 5: Turn on the primary fan and check that the outlet baffle is connected.
Step 6: Gradually open the primary fan inlet adjustment baffle until it is fully closed, and at the same time close the opposite primary fan inlet adjustment baffle until the currents of the two primary fans are balanced.
The above is the answer to the switching operation of centrifugal fan, mainly for the steps of switching between power frequency and variable frequency of centrifugal fan.
