Using a single small motor to spin multiple devices can be achieved through a belt system, which is a common mechanical solution. This method allows for the distribution of power from one motor to several devices effectively. However, for optimal airflow and performance, it's often recommended to use one motor per device, especially for fans. Electrical power transfer is generally more efficient than mechanical systems like belts or gears. Overall, the choice between a single motor with a belt system or multiple motors depends on the specific application and desired performance.