Major forces test wind turbine drivetrains, the long-term reliability of which requires special materials meant for significant wear. Case carburizing ensures a competitive solution for lifetime costs of gearboxes’ planetary stages. Jari Toikkanen, Manager of Moventas’ Conceptual Design & Analysis team, explains more…
In a wind turbine gearbox, the greatest torque goes through the planetary stage’s toothed parts; the sun, the planets and the ring gear. Gearbox expert Moventas measures new gearbox concepts with a torque density performance indicator, Nm/kg. The trend is clear.
The importance of torque density
In gearboxes made in 2005, a typical torque density was on a level of 60 Nm/kg. The gearboxes in Moventas’ production now are on the level of 125-150 Nm/kg and before 2020 Moventas is certain it will surpass the 200 Nm/kglimit. In wind power, torque density partly correlates with the amount and cost of energy produced. Hence, material technology must evolve, as the production ability of the turbine is the most significant design parameter for new power plants. Yields have come a long way from the 1990’s 1MW turbines to the current 10MW turbines.
