Model guide
Enercon E92
2.35 MW rated power, 92 metre rotor. The sibling of the E82 with a larger rotor and — deliberately — a lower rated power. That apparently backwards choice explains the whole character of the machine: it was built to stay in production for far more hours of the year on low and medium wind sites.
Why a bigger rotor and less power?
Put side by side with the E82 it looks wrong at first: the rotor grows from 82 m to 92 m while rated power falls from 3.0 MW to 2.35 MW. In fact this is the classic signature of a low-wind design.
Rated power is a ceiling, and you only reach a ceiling when the wind is strong enough. On a weak site the turbine spends most of its time far below that ceiling. What helps there is not a high ceiling but the ability to make meaningful power in light wind. A larger rotor sweeps more area and therefore harvests more energy from the same weak wind; the deliberately lower rated power keeps the generator and power electronics smaller, cheaper and saturating earlier.
On site this shows up as: the E92 starts earlier, approaches rated output at lower wind speeds, and returns a high capacity factor. Put the same machine on a windy ridge and it becomes the wrong choice, because it wastes the resource — there the E82's higher ceiling wins.
E82 vs E92 — same family, different site
| Feature | E82 | E92 |
|---|---|---|
| Rated power | 3.0 MW (E4) | 2.35 MW |
| Rotor diameter | 82 m | 92 m |
| Swept area | 5,281 m² | 6,648 m² (+26%) |
| Blade length | ~40 m | ~45 m |
| Rotor speed | 6–18 rpm | 5–16 rpm (slower) |
| Drivetrain | Direct-drive | Direct-drive (same) |
| Hub height | 78 / 85 / 98 / 108 / 138 m | 84 / 98 / 104 / 138 m |
| Target wind class | IEC IIA | IEC IIA / IIIA (low–medium) |
| Power per swept area | ~568 W/m² | ~353 W/m² (low-wind signature) |
The last row summarises the design: the lower the power per square metre, the more the turbine is built for weak wind.
Specifications
| Parameter | Value |
|---|---|
| Rated power | 2350 kW |
| Rotor diameter | 92 m |
| Swept area | 6,648 m² |
| Blade length | ~45 m |
| Hub height (typical) | 84 / 98 / 104 / 138 m |
| Rotor speed | 5–16 rpm (variable) |
| Cut-in | 2 m/s |
| Rated wind speed | ~11–12 m/s |
| High wind behaviour | Storm control — graded power reduction |
| Generator | Many-poled annular generator, gearless |
| Gearbox | None |
| Wind class | IEC IIA / IIIA |
Model-specific systems
Low speed, high torque
- Speed range: 5–16 rpm, markedly slower than the E82. A rotor turning five times a minute must carry very high torque to make rated power.
- Consequence: the main bearing and generator rotor work under high torque, so bearing condition monitoring carries more weight on this model.
- Benefit: a slow rotor is quieter. Near settlements that means running without noise-related curtailment.
Long blade, low tip speed
- Blade: ~45 m. Longer than the E82 but, thanks to the modest rated power, structurally manageable.
- Tip speed: limited by the low rotational speed. That reduces noise emission, but it also makes surface contamination and icing relatively more costly in efficiency terms.
- Field consequence: blade cleaning makes a measurable contribution on this model. It is easy to skip and pays well.
Annular generator and thermal management
- Rotor drives the generator directly; there is no gearbox.
- Oil sampling, filter changes and gear pitting do not exist as maintenance items here.
- In exchange, keeping the cooling ducts clear is the primary periodic task; a blocked duct returns as a temperature alarm.
Yaw
- A 92 m rotor generates a larger yaw moment than the E82.
- Typical issue: when lubrication falls behind, drag rises and the nacelle starts to oscillate. That is precisely the mechanism in Case 03, which happened on an E92, and the wear pattern in Case 06.
Assembly stages (15–17 days)
- Days 1–2: crane pad, ground bearing capacity, dedicated lift plan for the annular generator, safety briefing.
- Days 3–8: tower erection; the 138 m hub option adds a section and noticeably extends this stage.
- Days 9–11: generator and hub — heavy, large-diameter, needs a narrow wind window.
- Days 12–15: blade installation, ~45 m blades. Access road and turning radius should be verified in advance.
- Day 16: electrical and control — converter connections, SCADA, backup supply tests.
- Day 17: commissioning — grid synchronisation, pitch calibration, storm control verification.
Maintenance schedule
| Task | Interval | Note |
|---|---|---|
| Visual inspection | Monthly | Blades, nacelle, tower, leak traces |
| Generator cooling duct cleaning | 6 months | Primary job on this design |
| Yaw bearing greasing | 12 months | Large rotor, high yaw moment — not to be skipped |
| Automatic lubrication line check | 12 months | A blocked line starves one sector; wear starts there |
| Blade cleaning and surface check | 12 months | Efficiency effect is more pronounced at low tip speed |
| Main bearing condition monitoring | 12 months | Comes to the front because of the high torque |
| Pitch drive and backup supply test | 12 months | Safety function |
| Generator insulation (megohm) test | 24 months | Target above 10 MΩ |
| Bolt torque check | 12–24 months | Tower flange and blade root, star pattern |
Faults seen most
- Yaw bearing drag and oscillation: when lubrication falls behind, the nacelle starts chasing the wind. Full case: Case 03.
- Generator temperature alarm: usually a blocked cooling duct. Sensor calibration drift produces the same picture, so take a physical IR reading first — Case 04.
- Storm control mistaken for a fault: low output in high wind is often normal behaviour.
- Blade contamination: efficiency loss is felt sooner on this model because of the low tip speed.
- Gearbox failure: none, by design.