Rotor disc

摘要

A rotor disc (14) for use in an electrical machine (10) has circumferential rotcr rims (16) mounted thereon. The rotor rim (16) comprises a row of alternate magnets (20) and laminated pole pieces (18). Each laminated pole piece (18) is supported on two electrically insulated through bolts (22). A compressive force is applied to the stack of laminations via two rings (24 and 26). The outer ring (26) is tightened down by nuts (28) and washers (30). The washers (30) are resilient so that the correct compressive force is maintained regardless of relaxation in the lamination stack and differential expansion of the rotor components. <IMAGE>