Manufacturer
Enercon Series
Enercon's design signature is that it uses no gearbox. The rotor drives an annular generator directly. That removes the single largest failure category in the industry; in exchange it brings a very heavy generator and a sensitivity to thermal management.
The field consequence of the gearless design is plain: there is no oil change, no gear pitting and no reduction-stage failure on the maintenance list. What replaces them is the generator cooling ducts — a blocked duct comes straight back as a temperature alarm.
2.3 MWEnercon E7071 m rotor, direct-drive annular (synchronous) generator, no gearbox. From 2013 to 2016 I worked on hybrid tower assembly on Enercon sites.
2.0–3.0 MWEnercon E8282 m rotor, direct-drive. E2 and E4 variants, storm control, annular generator maintenance.
2.35 MWEnercon E9292 m rotor, low-wind design (IEC IIA). A large rotor with a moderate rating for early power in light wind.