The strange phenomenon of pump overcurrent
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A centrifugal pump: the motor works fine when tested individually, and the pump also passes inspection after being disassembled. Once it starts up, it reaches its rated current almost immediately; at this point the pump’s outlet valve has not yet been opened. The pump is an old model that has been in use for over ten years. The outlet valve has no internal leakage (verified during pump repair). Could any expert help analyze this? Thank you!
When does the overcurrent start? Can the flow rate and head still meet the requirements? The old pump may have reduced efficiency and degraded performance, resulting in insufficient flow rate and thus higher overload.
Have there been any changes in the medium’s density and viscosity?
Wear in the impeller flow channels and whether the ring gap is appropriate can all lead to a decrease in pump efficiency. If an overcurrent occurs even when the valve is closed, that’s not right; what are the flow rate and head of the pump?
The gap of the mouth ring is normal; it’s difficult to determine the flow channel in the impeller. I don’t understand why there is still such a high current even when the valve is closed. Can overcurrent occur if the flow channel is damaged? What other reasons could there be (with the outlet valve closed)?
What are the pump’s flow rate, head, and speed?
5 cubic meters/60 meters/2900 rpm
The pump is of the 25-200 series; turning it manually poses no problem. Check whether there are any changes in the medium’s density and viscosity
Could the current also be high if the outlet valve of the pump is not opened due to medium-related reasons?
This is exactly where my disagreement with the engineering team lies; I think it might be a problem with the medium. Could you tell me the reason? I don’t quite understand.