Method of fabrication of an induction motor driven seal-less pump

A method of fabricating a motor-pump combination with the motor thereof comprising a stator, the stator comprising a pair of opposite end faces, a plurality of teeth extending between the opposite end faces, and a plurality of tooth tips on the teeth defining in part a generally axial bore between the opposite end faces and having axially extending rounded portions, the method comprising:

• (a) forming a magnetic portion of a generally annular sleeve by using a plastic binder for compression molding a plurality of axially extending ferromagnetic strips each comprising an inner annular sleeve surface which is wider than an outer annular sleeve surface and includes an axially extending rounded portion corresponding to an axially extending rounded portion of a respective one of the tooth tips;
• (b) forming a non magnetic portion of the annular sleeve by injection molding plastic material between adjacent ferromagnetic strips to form a plurality of resin material strips;
• (c) molding a resin material casing member for the pump of the motor pump combination with the casing member having a generally annular cylindrical section and including the annular sleeve in part in the annular cylindrical section;
• and
• (d) inserting the annular cylindrical section into the bore of the stator and aligning the ferromagnetic strips of the annular sleeve in abutting engagement with the tooth tips on the teeth of the stator.