40ay 60*2 centrifugal pump overflow
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For a power frequency of 7.5, the rated current of the motor is 14.9. The current when the motor is running without a load is 5; when the pump is connected and the outlet valve is not opened, the current is 12.5. It rises to 17 when the valve is opened 4.5 turns. The bearings are new, so the motor rotates easily when turned by hand. The mouth ring gap is also normal. This pump has been in use for over 10 years, and the manufacturing process remains unchanged; the alignment is 0.05. The motor’s insulation is fine and there are no missing phases; replacing the motor didn’t solve the problem either – overflow still occurs. Today another pump suspension assembly was replaced, but the issue persists as well. If that doesn’t work, the pump body will need to be replaced. . Do you know anything about electricity? What other potential faults can there be with electricity?
Has the motor been repaired by a technician on-site?
Is the excessive current caused by damaged impellers and reduced efficiency of the pump?
If the impeller is damaged, closing the outlet shouldn’t cause a high current, right?
No, I suspected it was the motor, so I replaced it with another one, but that didn’t work either
Closing the valve should result in low current; even if the impeller is damaged, the current shouldn’t reach that of normal operating conditions. I plan to try using a different power supply today. At that time, I also wondered whether the reduced efficiency was caused by wear of that small metal piece used for guiding flow at the pump inlet, but if the outlet valve wouldn’t open, there shouldn’t be any overflow
What are the pump’s flow rate and head? What is the outlet pressure? Did the outlet pressure change during the periods before and after the overcurrent? Does the pressure change when the outlet valve is closed?
A high current indicates that more work is being done and the flow rate is high; first, determine whether the outlet pressure is too low； Also, has it been repaired recently, with the impeller replaced? Measure the outer diameter of the impeller to see if it is larger than before.