Issues regarding the startup of centrifugal fans and pumps
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The operating procedures for starting a centrifugal fan specify that the inlet should be opened to about 10%, while the vent should be fully open. A centrifugal water pump has the inlet open and the outlet closed. I can understand that if the inlet of a centrifugal water pump is not opened, it will not generate pressure. Why should the fan be run at 10% instead of being turned off completely? Additionally, some students have said that when a centrifugal fan is started, the outlet can be closed completely to enable start-up without any load. What is the difference in principle between closing the inlet and closing the outlet?
When all exports are blocked, it’s a cycle; thus, no option meets the requirements. Making it smaller means the same thing
The inlet of the centrifugal fan should be opened to 10%, and the vent valve should be fully open during startup in order to prevent surge due to too low flow rates after the fan starts up. The outlet of the centrifugal fan should be closed completely during startup; at this time, the return valve must be fully open to ensure an adequate flow rate at the fan’s inlet, thereby enabling the fan to start under its minimum load while also preventing surge after it starts operating.
There is no difference; it’s all done to reduce the starting current of the motor and protect the equipment.
The outlet is opened by about 10% – I don’t think I’ve heard of that. In centrifugal air compressors, the outlet is kept fully open while the inlet is opened gradually.