Table of Contents

Yaw Bearing Load Outputs

The yaw bearing loads are reported to the user, when using a YawSystem. The loads are output in the local frame from the "YB" node side of the "Yaw Gearbox" component. See the yaw bearing model article for more details.

  • Yaw bearing Mx - Bending moment about local x coordinate. If there is no tower deflection then x will be parallel to the straight (without tilt) drivetrain axis.
  • Yaw bearing Mx - Bending moment about local y coordinate. The y-axis will form a right handed coordinate system with the x and z axes.
  • Yaw bearing Mz - Bending moment about local z coordinate. If there is no tower deflection then z will be in the vertical direction.
  • Yaw bearing Mxy - The resultant bending moment of \(M_x\) and \(M_y\).
  • Yaw bearing Fx - Force along local x coordinate. If there is no tower deflection then x will be parallel to the straight drivetrain axis.
  • Yaw bearing Fx - Force along local y coordinate. The y-axis will form a right handed coordinate system with the x and z axes.
  • Yaw bearing Fz - Force along local z coordinate. If there is no tower deflection then z will be in the vertical direction.
  • Yaw bearing Fxy - The resultant force of \(F_x\) and \(F_y\).

Yaw Actuation

A Yaw Actuation logging group is created for the yaw actuation kinematics. It contains the following series:

  • Gearbox position – Yaw gearbox rotation angle wrapped to \([-\pi, \pi)\). Angle of 0 deg means the rotor is pointing Northwards/Southwards in upwind/downwind turbine configurations respectively. Angle is measured anticlockwise (looking down onto the turbine) relative to North.
  • Gearbox rate – Yaw gearbox rotation angle rate.
  • Motor position - The gearbox position multiplied by the gearbox ratio. If HSS flexible component is included then the motor position of each load bank is the sum of the gearbox position multiplied by the gear ratio and HSS flexible hinge position of the corresponding load bank. Angle wrapped to \([-\pi, \pi)\).
  • Motor rate - The gearbox rate multiplied by the gearbox ratio. If HSS flexible component is included then the motor rate of each load bank is summation of the gearbox rate multiplied by the gear ratio and the HSS flexible hinge rate of the corresponding load bank.
  • HSS flexible hinge position – Angular deflection of high-speed shaft. Output depends on inclusion of high-speed shaft flexibility. Angle wrapped to \([-\pi, \pi)\). Will be numbered if more than one high-speed shaft is included.
  • HSS flexible hinge rate – Angular deflection rate of high-speed shaft. Output depends on inclusion of high-speed shaft flexibility. Will be numbered if more than one high-speed shaft is included.

The positions and rates are reported relative to the tower top coordinate system where the yaw bearing attaches to the structure.

Note

For dual load banks, the load bank number will be appended to the output name, such as Motor position : load bank 1.