Problems with the motor
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The motor is operating under overload, and I want to reduce the motor current by lowering the flow rate. Should I reduce the flow at the pump’s inlet, or at the outlet? Or should I adjust the valve at the pump’s outlet? Which adjustment will result in a decrease in the current? Please share your opinions; thanks, bonus points available
Centrifugal pumps generally reduce flow by closing the outlet valve
As mentioned above, it is generally necessary to close the outlet valve of the pump to some extent, but exactly how much needs to be adjusted has to be determined by you yourself. I have a pump with an outlet butterfly valve; I ended up closing it until only one scale mark remained open, which seemed to be the right setting. Try a few more times
The flow rate of a centrifugal pump is related to the outlet pressure – higher pressure results in a lower flow rate, while lower pressure leads to a higher flow rate. If the inlet valve is closed, the flow rate remains almost unchanged if the outlet pressure stays the same. Closing the outlet valve increases the pressure and reduces the flow rate, thereby decreasing the load； For positive displacement pumps, the return valve is generally adjusted by reducing its setting.
Generally, the outlet valve is closed. If the pump is selected correctly, overcurrent generally does not occur. Check whether the viscosity and specific gravity of the material are compatible with the pump, or investigate possible mechanical faults in the pump
Reduce the pump flow rate, usually by closing the pump outlet valve. Closing the inlet valve of the pump can easily cause cavitation in the pump.