Patent ID: 7365461

Claim:
A flywheel energy storage system that is resistant to catastrophic failure comprising: (a) a housing defining an interior having support members; (b) a flywheel assembly operatively disposed in the interior of the housing between the support members, the flywheel assembly including: (i) upper and lower bearings; (ii) an elongated shaft coupled between the upper and lower bearings for rotation about an axis; (iii) at least one rotor coupled to the shaft for rotation therewith; and (iv) a flywheel coupled to the at least one rotor for rotation therewith, the at least one rotor being sized and configured to form a first annular gap and a second annular gap in opposing end portions of the at least one rotor; (c) a first plate inserted in the first gap to hinder radial movement of the at least one rotor such that if the at least one rotor fails, the at least one rotor is inhibited from releasing energy to threaten a structural integrity of the flywheel; and (d) a second plate inserted in the second gap to hinder radial movement of the at least one rotor such that if the at least one rotor fails, the at least one rotor is inhibited from releasing energy to threaten a structural integrity of the flywheel.