MAGNETIC ROTOR HAVING INSET BRIDGES TO PROMOTE COOLING

A rotor arrangement with decreased fluid flow impedance and improved rotary motor cooling is mountable on a shaft for rotation relative to the stator of a rotary motor arrangement The rotor arrangement has a plurality of laminations joined together to form a multilayer laminated rotor with a plurality of magnet receptacles. Each of the laminations has a solid central section surrounding an opening within which the shaft is receivable, spokes extending substantially radially outwardly from said solid central section, ribs interposed between adjacent spokes, and bridges interconnecting the spokes and ribs. At least some of the bridges are inset from an outer diameter of the lamination toward the solid central section to decrease fluid flow impedance and improve rotary motor cooling.