Abstract: An integrated gas compressor is disclosed herein. The integrated gas compressor includes an integrated motor with a stator, centrifugal impellers, and a shaft assembly with a rotor and conical transition. The integrated motor can produce an electromotive force that is imparted by the stator to rotate the rotor and components coupled to the rotor, such as the conical transition and the centrifugal impellers. At least one of the rotor and conical transition have a cavity.