Patent ID: 8319380

Claim:
A method for tuning the structural stiffness of the rotor of an induction motor for achieving rotordynamic stability objectives, comprising: providing a rotor having: a rotatable shaft, a rotor core of stacked rotor laminas radially projecting from the shaft and defining a generally cylindrical outer circumference that is generally concentrically aligned with the shaft and axial ends, and a plurality of bores defined in the rotor core through both ends thereof that are radially symmetrical with and generally parallel to the shaft; inserting a dynamically balanced array pattern of tie rods into at least a portion of the rotor core bores; compressing the rotor core axially by selectively tensioning the tie rods to create a first rotor stiffness characteristic; determining whether the first rotor stiffness characteristic resulting from the tie rod insertion and compressing steps achieves motor rotordynamic stability objectives; and adjusting at least one tie rod in the array pattern of tie rods in order to selectively tune a second rotor stiffness characteristic for achieving the rotordynamic stability objectives, if the first rotor stiffness characteristic does not achieve rotordynamic stability objectives.