Flywheel permanent magnet machine

A flywheel energy storage device comprising a sealed housing containing:

• a central shaft;
• a flywheel having a flywheel rotor supported by and mounted for rotation around said shaft;
• and
• a motor/generator having a stator and a motor rotor, the motor rotor being formed integrally with said flywheel rotor;
• wherein the stator comprises (i) a cylindrical hub having an outer surface and longitudinal channels formed therein, (ii) a cylinder surrounding said cylindrical hub thereby providing passages through the channels, and (iii) end caps sealing the passages and providing a distribution channel for distributing fluid to said passages, thereby providing fluid cooling passages for said stator;
• and
• wherein said rotor of the motor/generator is formed by positioning permanent magnet pieces in an array around an inner cylindrical surface of the rotor and separated from the stator by a gap, the permanent magnet pieces being magnetized radially with adjacent magnet pieces having opposite polarity,
• further comprising a radial vibration dampener positioned at one end of the shaft, said dampener comprising a plurality of spring members positioned between two cylindrical surfaces, one end of each spring member being attached to each cylindrical surface.