Centrifugal pumps are usually driven by electric motors. Piston engines (e. g. diesel engines) and gas and steam turbines also provide drive power, however. Hydraulic engines are rarely used. Electric motors and turbines generate uniform torque, whereas piston engines produce non-uniform torque. This irregularity is largely compensated by implementing appropriate design measures (e. g. flywheels, changing the number of cylinders and their arrangement).
The medium to high power range (up to 8000 kW) is dominated by three-phase motors (e. g. asynchronous motors) with squirrel-cage rotors.
Another option in the top power range are synchronous motors due to their relatively high level of efficiency and ability to compensate reactive power. In storage power stations, they operate as generators in turbine mode.