Variable-frequency centrifugal pump
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I would like to ask whether, when starting a variable-frequency centrifugal pump, the outlet valve should be opened fully right away, or wait until the appropriate speed is reached before opening it Also, there is a flow control valve at the outlet of the variable-frequency centrifugal pump in our setup. I would like to ask about the necessity of installing this flow control valve – isn’t flow control already achieved through variable frequency regulation? If flow is adjusted using variable frequency during production, then what should be the opening degree of the control valve in that case?
The original poster makes a valid point; it seems that one of these two should be sufficient, as their functions overlap. There might have been other intentions behind the design, and it’s important to understand those clearly. If the frequency is being changed, the inlet and outlet valves should be fully open!
Setting it to full open is sufficient; variable frequency can control the flow rate, but it cannot replace a flow meter in providing accurate readings
This is my first time dealing with variable-frequency centrifugal pumps. I would like to ask whether, after starting, the frequency of such pumps increases gradually from 0 to the desired value, or whether a frequency that is at least above a certain level must be set right after startup
It seems that the outlet is not a control valve, but merely a flow meter, which can be connected in cascade with the variable frequency control of the motor.
There should be relevant operation instructions; for our equipment’s variable-frequency motors, the value starts increasing in multiples of 5, and adjustments are made gradually as the flow rate approaches the target value
It depends on whether it starts with variable frequency or at fixed frequency; if it starts with variable frequency, there is no need to close the valve
:L industrial-frequency start means starting at full speed
For mechanical pumps, there is basically no impact, but it seems there are requirements regarding electrical equipment; you can ask about that.