Abstract: An immersion pump assembly comprises a pump and a wet-rotor motor driving the pump and having a common hollow spindle for the motor and the pump. Liquid in the wet-rotor compartment of the motor can be introduced into the spindle and conveyed within the spindle into the pump casing in heat exchange relationship with the liquid conveyed by the pump, by way of the wall of the spindle. The liquid is returned from the spindle into the rotor compartment by a pumping action. The exit and return openings for the liquid in the rotor compartment are spaced from each other axially of the pump assembly.

Abstract: An immersion pump assembly comprises a wet-rotor motor of which the rotational speed and/or the torque can be varied by means of a frequency changer, and a pump unit. The frequency changer, the wet-rotor motor and the pump unit are arranged one above another within a tubular jacket. The motor comprises a split tube formed as a closed pot which is connected to the jacket and which separates the stator compartment from the pump unit in liquid-tight and pressure-tight fashion. The frequency changer is so installed in the stator compartment that its operating electronic system is disposed on the bottom of the split tube pot in the stator compartment.