a 51 b 51 d 51 i the third support block 51 c is preferably formed by a g11 or similar epoxy glass the third support block 51 c is engaged at one end in a notch of the lamination 30 a and contacts the outer support ring 20 a at the other end i e the end radially closest to the longitudinal axis 3 another slot 70 b is thus formed between the second and third support blocks 51 b 51 c in the circumferential direction and between the outer support ring 20 a and the lamination 30 a in the radial direction the another slot 70 b encloses another six bars of the winding 40 a as those skilled in the art will appreciate additional slots can be formed in a similar manner again similar comments of the foregoing description apply to all other laminations inner and outer support rings and support blocks slots etc forming the support structure as noted above clearance space is formed in the slot 70 a of the lamination 30 a between the support blocks 51 a 51 b this clearance space exists for example between the bars of the winding 40 between each support block 51 a 51.