Arrangement for locking slot wedges retaining electric windings

Claim 1

In an magnetic core of an electric machine, having longitudinal slots arranged around the periphery thereof and provided with longitudinal grooves on the side walls near the top of the slots, said slots including a winding disposed therein, a plurality of radial ventilating ducts extending across said longitudinal slots, a plurality of slot wedges located end-to-end in the top portions of said longitudinal slots above said winding to retain said winding from displacement within said slots, and an arrangement for locking said slots wedges, disposed in the end portions of each of said longitudinal slots; said arrangement comprising: locking wedges disposed in said longitudinal slot and contacting the extreme slot wedges and having lugs on the side portions thereof, engaging said grooves of said longitudinal slot, and teeth on the surfaces parallel to the bottom of said longitudinal slots, defined by an inclined plane facing the central portion of said longitudinal slot from the ends thereof, and a plane perpendicular to the axis of said core; stop collars, disposed at the points of the intersection of said longitudinal slots and the extreme radial ventilating ducts, embracing said locking wedges, said stop collars shaped congruent to said locking wedge within a tooth portion thereof, the portions of said stop collars facing the winding being in tight contact with the mating portions of said locking wedge and the inner side portions of said stop collar being spaced from the lateral sides of said locking wedge with side clearances formed therebetween, said side clearances enabling said locking wedge to be urged in said longitudinal slot along said grooves toward the central portion of said longitudinal slot from the ends thereof, one end face of said stop collar contacting the surface of said tooth of said locking wedge, defined by the plane perpendicular to the axis of said core, and the other end face of said stop collar bearing against the surface of said extreme radial ventilating ducts; whereby said slot wedges are prevented from any axial displacement in said longitudinal slots.