The problem of vibration and noise is a challenge for high-speed motors. Compared to ordinary motors, there are vibration problems caused by rotor dynamics, such as critical speed problems of the rotor and shaft deflection vibration problems. There is also a whistling problem caused by high-frequency electromagnetic force. The electromagnetic force of high-speed motors has a higher frequency and a wider distribution range, which easily triggers resonance in the stator system.

In order to avoid critical speed vibration, the rotor design of high-speed motors is crucial and requires rigorous modal analysis and testing. When designing, it is necessary to use the aspect ratio as an optimization variable: if the rotor design is too coarse or short, it can increase the upper limit of the critical speed and is not prone to resonance, but the difficulty of overcoming centrifugal stress on the rotor will increase. Conversely, the slender design of the rotor improves the centrifugal strength issue, but the critical speed shifts downwards, increasing the probability of resonance and resulting in a decrease in electromagnetic power. Therefore, the design of the rotor requires repeated balancing, which is of utmost importance in the design of high-speed motors.