Direct-drive mechanism in the context of Drive wheel

A unicycle, also monocycle is a vehicle that touches the ground with only one wheel. The most common variation has a frame with a saddle, and has a pedal-driven direct-drive. A two speed hub is commercially available for faster unicycling. Unicycling is practiced professionally in circuses, by street performers, in festivals, and as a hobby. Unicycles have also been used to create new sports such as unicycle basketball and unicycle hockey. In recent years, unicycles have also been used in mountain unicycling, an activity similar to mountain biking or trials.

Small wind turbines, also known as micro wind turbines or urban wind turbines, are wind turbines that generate electricity for small-scale use. These turbines are typically smaller than those found in wind farms. Small wind turbines often have passive yaw systems as opposed to active ones. They use a direct drive generator and use a tail fin to point into the wind, whereas larger turbines have geared powertrains that are actively pointed into the wind.

They usually produce between 500 W and 10 kW, with some as small as 50 W. The Canadian Wind Energy Association considers small wind turbines to be up to 300 kW, while the IEC 61400 standard defines them as having a rotor area smaller than 200 m and generating voltage below 1000 Va.c. or 1500 Vd.c.