Questions about centrifugal water pumps
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I have a question for everyone: Three centrifugal water pumps are connected in series, with a frequency converter used to control the system pressure. When the valves at the outlets of the water pumps are fully open, the system’s set pressure is 0.3 Mpa; in this condition, both Pump 1 and Pump 2 experience overcurrent (the pumps generate a lot of noise when operating at the standard frequency). Pump 3 also starts up, but it operates at variable frequency. When the valves at the outlets of Pump 1 and Pump 2 are closed by about 1/3, the system’s set pressure remains unchanged, and the operating conditions stay the same: Pump 1 operates at the standard frequency while Pump 2 operates at variable frequency (the noise disappears, and the overcurrent issue is resolved); Pump 3 does not start up； I would like to ask, what is the reason?
Linked together or side by side?
Is there an issue with the selection of pumps 1# and 2#? When the valves are fully open, they may operate at high flow rates, exceeding the optimal operating range
Speed: 2900； Flow rate: 46.8 m3/h ； Head: 44M ； Efficiency: 67% ； Power: 11kw
Considering the occurrence of a phenomenon similar to water hammer, the water flow cannot be effectively discharged.
Is this system pressure-retaining? Does this happen only during the first compression, or does it occur as well when there is pressure on the system? The flow rate of the pump should be set too low
The circulatory system, which is used to cool the equipment. Overcurrent has been occurring constantly; the load carriers have all burned out. The problem goes away once the water outlet is closed a little
Closed system or open system?