Centrifugal Pump Loss of suction
Centrifugal Pump Loss of suction
(OP)
What happens if the centrifugal pump suddenly loss the suction due to some blockage in the suction pipe? I understand that impeller gets heated up and cavitation etc. What I would like to know is this sudden loss of load causes the shaft to rotate at a speed greater than the speed before the blockage? Because it can cause regeneration of power in the VFD.





RE: Centrifugal Pump Loss of suction
RE: Centrifugal Pump Loss of suction
Please explain this phrase.
Depends what the VFD.is controlling on but I would imagine the speed could increase.
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RE: Centrifugal Pump Loss of suction
Keith Cress
kcress - http://www.flaminsystems.com
RE: Centrifugal Pump Loss of suction
As the load reduces due to cavitation the slip may reduce slightly resulting in an increase in motor speed, but the speed will still be sub-synchronous. You can't get regeneration until the motor is at a super-synchronous speed.
The situation is slightly complicated in a VFD because synchronous speed itself is a variable, so depending on how the VFD control loop behaves it is possible that the motor could briefly go super-synchronous if the VFD demanded a forced deceleration, but this would only be a transient condition while the supply absorbed kinetic energy stored in the rotating masses of the pump and motor; it is unsustainable in steady-state unless the process is capable of driving the pump in reverse.
RE: Centrifugal Pump Loss of suction
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RE: Centrifugal Pump Loss of suction