Disturbance resistance is a key factor in a system’s ability to resist disturbances arising from vibrations or milling forces. The larger the motor is relative to its load, the higher the system’s disturbance resistance is to fluctuating milling forces or vibrations. But if the inertia ratio between the motor and its load is high, then the loop gain must be reduced, thereby also lowering the disturbance resistance.
Motors specifically designed for machine tools enable a more balanced transmission ratio between the motor and its load. In this case, outside influences on the load have no effect on the machining results, and a high loop gain can be employed.