Rapid developments in rotor dynamics have made it easier to design high-speed rotating systems. Highspeed rotor systems are subjected to high rotational stress and therefore to ensure the safety of the rotor it becomes essential to evaluate the operating stress condition. Spin test of critical rotating components is a common method to simulate the rotational stress in the rotor. In the present paper, the design and development of high-speed spin test facility for testing disc type rotors is being presented. The high-speed spinning disc is mounted vertically on a flexible shaft connected to an electric drive on the other end. A high-speed induction motor with variable frequency supply has been used to drive the system to high speed. The challenges include development of high-speed drive, flexible shaft design and containment design. In this paper, dynamic analysis of motor shaft and flexible shaft with disc are presented. Flexible shaft is made in such a way that the first and second critical speeds are low and third critical speed is very high in relation to the operating speed. The flexible shaft is designed, so that unbalance force of the disc and impact loads in case of rotor crash, do not appear on the motor bearings. Entire system runs in vacuum in order to reduce aerodynamic drag force, impact induced fire during rotor disc failure. The mathematical model takes into account the gyroscopic moments, rotary inertia, shear deformation, internal viscous damping, hysteretic damping, linear stiffness, damping of bearings and the support conditions. In-house code was developed using Thimoshenko-beam theory to find the mode shapes, critical speeds and unbalance response of motor shaft and flexible shaft-disc. Viscous and hysteric damping model is incorporated to find the stability of the system through logarithmic decrement.