In industrial fluid transfer applications, the stable operation of multistage pumps is of critical importance. However, in practical use, some users have observed abnormally low motor current during the operation of multistage pumps, which may indicate potential fault risks. Below, Zoomlian Pump Works analyzes the common causes of low current during multistage pump operation from a professional perspective, aiming to provide guidance for troubleshooting such current anomalies.
Malfunctions in the pump body components of a multistage pump will directly alter the motor load. For instance, worn, deformed, or impurity-clogged impellers—similar to a damaged "power core"—fail to drive the fluid efficiently, leading to reduced pump flow rate and head, lower motor load, and a consequent drop in current. In addition, seal failure inside the pump body increases leakage, reducing the actual liquid discharge rate; as a result, the motor does not need to operate at full load, which also causes a decrease in current. Cavitation is another critical factor: when cavitation occurs, the impeller surface is damaged, pump performance deteriorates, flow rate declines, and motor current decreases accordingly.
The normal operation of a multistage pump relies on the coordination of the entire system. Improper opening of inlet and outlet valves (e.g., the inlet valve is not fully open, or the outlet valve opening is too small), or pipeline blockages and leaks, will impede fluid flow, reduce flow rate, and cause a corresponding drop in motor current. Furthermore, when there is a mismatch between the pump head and actual requirements—if the actual head is much lower than the pump’s rated head—the pump operates under low load conditions, leading to decreased current. Changes in medium properties (such as reduced viscosity or lower density) can also lighten the pump load, resulting in lower motor current.
Motor malfunctions are one of the common causes of current anomalies. Short circuits, open circuits, or incorrect wiring in the motor windings, as well as severe wear of internal mechanical components (e.g., bearings), can all affect motor operation and lead to abnormally low current. Problems in the power supply system should not be overlooked either: low supply voltage, aging wires, or poor electrical connections can hinder current transmission, resulting in insufficient input power to the motor and a natural decrease in current.
When dealing with the issue of low motor current in multistage pumps, a step-by-step troubleshooting approach is recommended: first inspect the pump body components (impellers, seals, etc.), then check the status of the system pipelines and valves, and finally test the motor and power supply lines. With decades of experience in the pump industry, Changsha Pump Works boasts a professional technical team that provides services such as equipment testing and fault analysis, helping users ensure the efficient operation of multistage pumps. Follow Changsha Pump Works for more updates. For product solutions or technical support, feel free to contact our online customer service to access practical industrial pump guides and ensure stable production!