Centrifugal Pumps - Speed Torque Curve
The characteristic speed torque curves for centrifugal pumps. Calculate theoretical torque based on pump speed or full load torque based on power and speed.
Speed Torque Curve
The speed torque curve characterizes a centrifugal pump. The theoretical characteristic is a parabola starting from the origin and proportional to the square of the speed.
Formula (1): Theoretical Torque
T = k × n²
Where:
- T = torque (Nm)
- k = constant
- n = pump speed (rpm)
With the discharge valve closed, the torque amounts to 30-50% of the nominal torque at full speed.
Formula (2): Full Load Torque
T = 30 × P / (π × n)
Where:
- T = torque (kN m)
- P = power (kW)
- n = pump speed (rpm)