Submersible pump sets are Single stage or multi-stage single entry centrifugal pumps of ring section type with radial or mixed flow impellers connected by means of a sleeve coupling to a water filled, rewindable type AC induction motor. Pumps with radial flow impellers have renewable diffusers. Pumps with mixed flow impellers have guide vanes cast in the bowls. The different stages are connected by hook bolts in the case of radial flow pumps and bolted together in case of mixed flow pumps. The plain bearings are water lubricated. Suction casing between the pump and the motor is fitted with a suction strainer to prevent the ingress of coarse impurities. The motors are of water filled, rewindable type. The inside of the motor is sealed against the external medium by double oil seals (in back to back arrangement). The design is such as to facilitate easy dismantling and cleaning of parts.