The difference between the power induced to the pump and the hydraulic power indicates the efficiency of the pump.
P1 is the total induced power to the pump system.
P2 is the power coming from the motor (shaft effect). P2 is the nominal power of the motor.
The difference between P1 and P2 indicates either:
• The efficiency of the motor (ηmot.)
• The efficiency of the motor (ηmot.) + the efficiency of the built-in frequency converter (ηreg.)
P3 is the effect induced to the pump. P3 is mostly equal to P2, because the pump is coupled directly to the motor (no gear or V-belt drive)
P4 is the hydraulic power (Q x H).
The difference between P2 (or P3) and P4 indicates the efficiency of the pump (ηpu).
Use the Grundfos sizing tool to ensure the correct efficiency for the pump installation or pumping station.