Method of manufacturing a copper bar induction rotor

DETAILED DESCRIPTION OF THE INVENTION The method of manufacture of this invention is applied to an induction motor rotor of conventional construction, as seen in the drawing.
The left-hand end of the rotor, as viewed in the drawing, is depicted in a state of partial completion, while the right-hand end is depicted as fully completed.
The conventional steps of the manufacture include stacking a number of slotted steel laminations 10 onto a solid rotor shaft 12 to form a base core assembly, and inserting an elongate copper conductor bar 14 into each slot of the core.
The bottom of the core slots, and thus, the radial depth of the inserted conductor bars 14 is designated by the broken line 16.
The conductor bars 14 are longer than the lamination stack, and the tapered portions 18 which extend beyond each end of the lamination stack are referred to as end turn portions.
Following completion of the conventional subassembly described above, aluminum spool elements 20 are positioned in abutment with the axial ends of the lamination stack, as seen in the left-hand portion of the drawing.
The spool elements 20 have a diameter which matches that of the lamination stack and define annular cavities 22 into which the conductor bar end turns 18 extend.
To this end, the inboard wall 24 of each spool 20 is slotted to generally match the profile of the lamination stack.
The spool elements 20 need not be physically attached to the lamination stack so long as they are maintained in abutment therewith.
In an actual mechanization of the subject method, a removable spacer (not shown) was inserted in the space 26 between the shaft 12 and spool element 20 to maintain concentricity.
The cavities 22 defined by spools 20 have a continuous opening in the radial direction which permits access to the exposed end turn portions 18, as shown.
Once assembled, as shown in the left-hand portion of the drawing, the rotor is positioned in a fixture (not shown) in relation the nozzle 30 of a conventional copper plasma spray apparatus