Model guide
Vestas V126/3.3M
3.3 MW rated power, 126 metre rotor. One of the more efficient designs of its generation and widely used on medium-to-high performance sites. The step to a planetary gearbox is what most distinguishes it from the V110 in daily service.
V110 vs V126
| Feature | V110 | V126 |
|---|---|---|
| Rated power | 3.0 MW | 3.3 MW (+10%) |
| Rotor diameter | 110 m | 126 m (+15%) |
| Swept area | 9,503 m² | 12,469 m² (+31%) |
| Blade length | 53.5 m | 61.5 m |
| Hub height | 80/100/120 m | 90/105/120 m |
| Gearbox type | Parallel-axis | Planetary (compact) |
| Gearbox oil volume | 700–750 L | 850+ L |
| Assembly time | 16–17 days | 18–20 days |
The swept area gain of 31% against a power gain of only 10% is the important line: the V126 is tuned to produce more of the time, not to produce a higher peak.
Specifications
| Parameter | Value |
|---|---|
| Rated power | 3300 kW |
| Rotor diameter | 126 m |
| Swept area | 12,469 m² |
| Blade length | 61.5 m |
| Hub height (typical) | 90 / 105 / 120 m |
| Rotor speed | 6.9–12.1 rpm (variable) |
| Cut-in | 3.5 m/s |
| Rated wind speed | ~11.5 m/s |
| Cut-out | 25 m/s |
| Gearbox | Planetary (epicyclic), ratio ~1:81 |
| Generator | DFIG with converter |
| Cooling | Active liquid cooling |
Model-specific systems
Planetary gearbox
- Advantages: smaller, lighter and quieter than a parallel-axis box of the same rating, because load is shared across several meshes.
- The catch: each mesh is highly stressed, which makes surface pitting the characteristic failure mode.
- Oil: 850+ L; nominal 45–65 °C, alarm above 80 °C, shutdown above 95 °C.
- The decisive maintenance item: oil sampling every six months. Pitting shows up in metal concentration long before it shows up in temperature or noise.
Advanced pitch control
- Pitch motors: 22–25 kW, driving heavier blades.
- Maximum pitch rate: 8–10 °/s, faster than the V110.
- Individual blade pitch: lets the controller reduce asymmetric rotor loading as well as regulate power.
Yaw
- Motors: 10–15 kW; slewing bearing 4500+ mm.
- Vane sensor: hybrid magnetic and analogue for redundancy.
- Alignment tolerance: ±1°, tighter than the V110.
Assembly stages (18–20 days)
- Days 1–2: site preparation, tooling and safety briefing.
- Days 3–10: tower erection to 90–120 m, sectional.
- Days 11–12: nacelle lift, 600+ t, high precision required.
- Days 13–16: blade installation — 61.5 m blades at roughly 22 t each, root flange bolting.
- Days 17–19: electrical and cooling — converter cabling, liquid cooling lines, SCADA setup.
- Day 20: commissioning — grid synchronisation, pitch calibration, performance test.
Maintenance schedule
| Task | Interval | Note |
|---|---|---|
| Visual inspection | Monthly | Blades, nacelle, tower |
| Gearbox oil sampling | 6 months | Metal concentration — critical on planetary sets |
| Oil and hydraulic filter change | 12 months | |
| Cooling system check | 6 months | Coolant level, fan test |
| Blade cleaning | 12 months | Can recover 2–4% in efficiency |
| Converter capacitor check | 12 months | Power electronics health |
| Pitch sensor calibration | 24 months | Asymmetry check — see Case 07 |
| Yaw bearing greasing | 12 months | Dedicated slewing bearing greaser |
Faults seen most
- Planetary gear pitting: from sustained overload and marginal oil management. First evidence is in metal analysis, not temperature.
- Converter thermal management: a blocked cooling path raises converter temperature and triggers derating.
- Pitch asymmetry: a couple of degrees of calibration drift causes 1P vibration and lost production — see Case 07.
- Generator temperature alarms: often a drifted RTD rather than a hot machine — see Case 04.
- Grid interaction: harmonics and resonance on weak grids.