We recently installed a new pump, and when we commissioned it, the motor amps were above full load. What could be the cause?
Motor amps (current) is an electrical parameter representing the flow of electricity. If the current is above the full load, it means that more power is going into the motor than it is continuously designed for and it should be investigated.
The following are some common items to consider in a pumping system.
- Examine the flow rate and differential pressure to determine if the pump operating point could be the cause. There are instances where the pump operating region will need to be limited to not overload the motor.
- Review if the flow rate and differential pressure match the pump curve. Deviation could be due to internal clearances or fluid properties.
- If the system is operated at variable speeds, check that the rotational speed is not too high.
- Verify the fluid properties. If the density or viscosity are higher than expected, the power draw will increase.
- Evaluate if the efficiency of the pump and drive system could be reduced. Some causes could be grit or other foreign material that is causing friction, other mechanical binding or electrical motor defect.
Some of these items will take experience to evaluate properly. If you do not have in-house expertise troubleshooting rotating equipment and pumping systems, you should reach out to the manufacturer’s representative as a starting point. For more complex pump system issues, a certified pump system assessment professional (PSAP) may be necessary to determine the best path forward.
For more information on pump system analysis and troubleshooting, refer to the Hydraulic Institute’s “Pump System Assessment Body of Knowledge” at pumps.org.
