TerraScan Rotor-Imbalance-Diagnosis

Identify critical conditions and propose solutions

Rotor Imbalance – the underestimated danger for your wind turbine generators

TerraScan WKA Bending


TerraScan WKA Torsion


TerraScan WKA Tilting


How does rotor imbalance evolve?

There are two reasons for rotor imbalance:

  • Aerodynamic imbalance, caused by deviations in blade angles and blade twists as well as blade damages
  • Mass imbalance, caused by different weight distributions within the rotor

Consequences of rotor imbalance

Rotor imbalance causes vibrations in axial and lateral directions, which result in enhanced tower and nacelle movements (graphics above).

Long-term consequences of rotor imbalance:

  • Lifetime reduction of major components
  • Energy yield reduction caused by decreased efficiency
  • Down times due to repair or replacement of damaged components

Frequency of rotor imbalance

Findings of a case study on 240 wind turbine generators

Häufigkeit von Rotorunwuchten, Grafik: TerraScab


45% of wind turbines show inadmissible
rotor imbalance


30% of wind turbines show a level below the limit, but increasing vibrations
and small energy yield loss


Low rotor imbalance:
25% of wind turbines show a well balanced rotor with minimized vibrations

Rotor imbalance can be corrected by TerraScan

Overview of the TerraScan principle:

TerraScan Blattwinkelanalyse; Foto: Terrawatt Planungsgesellshaft mbH
TerraScan Datenerfassung Rotorunwucht

1. Data collection and analysis

Turbine type, blade type, error log, site conditions

TerraScan Inspektion Rotorunwucht

2. Turbine inspection and blade angle analysis

Turbine inspection and blade angle analysis, Turbine inspection, condition evaluation, optical blade angle analysis (accuracy: 0,1°)

TerraScan Auswertung Rotorunwucht

3. Evaluation and recommendation of action plan

Evaluation and recommendation, Inspection report including recommendations for blade angle corrections
and vibration analysis

TerraScan Behebung Rotorunwucht

4. Imbalance correction

Supervision of blade angle corrections, performance of vibration analysis with subcontractors

Overview TerraScan-benefits for your wind farm

TerraScan Diagramme Elektrische Leistungskurve bei Rotor-Fehljustage und Kosten einer Rotorunwucht

Reduction of vibrations

Increased energy yield

Reduction of maintenance and repair costs

Life time extension

Optimize your wind farm or your single WEA now!