Wind Turbine Actuators from Trelleborg Sealing Solutions


Trelleborg Sealing Solutions supplies a specially engineered sealing configuration to AVN Energy A/S, a leading hydraulic actuator manufacturer for wind turbines. Meeting the dynamic criteria due to constant movement of the actuator, the sealing system offers maximized seal life, contributing to minimal turbine maintenance requirements.

Stall machine turbines being replaced by continuous pitch systems has put extreme demands on hydraulic actuators. The position of stall machines would shift only once every 10 minutes, but in continuous pitch wind turbine systems the nacelle and angles of the blades constantly change in small amounts once every rotation, 15 times per minute on average. This means that instead of producing six long strokes per hour, the turbine’s hydraulic actuator must now initiate 900 short strokes in the same period, 24 hours a day and seven days a week, for a targeted 20-year period.

“Customers have high expectations from our products, and the number-one requirement of the wind turbine manufacturers is reliability,” says Poul Kristensen, export sales manager at Denmark-based AVN Energy A/S, one of the world’s leading suppliers of actuators for wind turbines. “Maintenance of turbines is difficult and costly. On land it is hard enough, but offshore it is really tough. And when the windmill is switched off for maintenance, it is not producing energy and losing income. On top of that, operators are often penalized if supply targets are not met. So a primary objective for them is to minimize routine downtime, while stoppages due to component failure have to be avoided at all costs.”

Having worked with Trelleborg Sealing Solutions on stall machines, AVN approached it to jointly develop a sealing system to meet the challenging requirements of continuous pitch systems. The specified solution is a complex arrangement of seals ranging from O-Rings to specialist Turcon® PTFE based geometries and Slydring® in Orkot®. The unique configuration is specially engineered to enhance lubrication and optimize friction characteristics, while preventing any external leakage. For more information contact Donna Guinivan at +44 121 746 3621 or Visit online at