8483.40.50.20 - Gear boxes and speed changers for wind turbines, as described in statistical note 6 to this chapter

This HTS category, 8483.40.50.20, specifically covers gear boxes and speed changers designed for use in wind turbines. These units are integral components of wind energy systems, responsible for transmitting and modifying the rotational speed and torque generated by the turbine rotor to a generator. The "statistical note 6 to this chapter" provides further defining characteristics and specific criteria for goods to be classified under this heading, which customs officers and importers should consult for precise classification.

Distinguishing this category from its sibling, 8483.40.50.10 (Fixed ratio speed changers), is crucial. While both fall under "Gear boxes and other speed changers," this specific subcategory is for those explicitly intended for wind turbine applications, often implying more complex designs, specific power handling capabilities, and specialized environmental resistances that differentiate them from general-purpose fixed-ratio gearboxes. The sibling category 8483.40.50.80 encompasses other speed changers not fitting the defined wind turbine application or the "fixed ratio" designation.

As this classification node is a leaf node, there are no further subcategories. Therefore, the classification hinges on meeting the definition of a gear box or speed changer for wind turbines, as further elaborated by statistical note 6. Examples within this category would include the main gearbox that connects the wind turbine rotor shaft to the generator, facilitating the necessary speed increase to enable efficient electricity generation.