Wet rotor motor
A wet rotor motor is typically an asynchronous squirrel-cage motor (see Asynchronous motor) whose rotors and bearings are operated in the fluid handled. These motors require special attention during the design, assembly and commissioning stages to ensure that they are reliably filled and vented and that solids in the fluid handled do not reach the fluid-lubricated plain bearings.
The wet motor is completely filled with fluid (preferably water). Together with the rotor and bearing, the stator and winding are also submerged along with the supply line connections. All live parts must be protected by water-proof and pressure-tight insulation, however.
The power range is approximately 1 kW to 2500 kW (glandless circulating pump) or 3500 kW (submersible motor) for operating voltages that normally peak at 6.6 kV or 10 kV in special cases.