sin αst

LIST OF ATTACHMENTSBASIS FOR CALCULATIONS
Variable Symbol Numerical value Reference
Design wind speed Vdesign 8.4 m/s IEC 61400-2
Design torque Qdesign 32.5 Nm Rotor design tool
Design thrust Tdesign 276 N Rotor design tool
Design tip-speed ratio �design 5.6 Rotor design tool
Design rotational speed �design 35.1 rad/s Rotor design tool
Mass of blade mB 2.61 kg 3D model
Mass of rotor mr 45.2 kg a 3D model
Blade moment of inertia
about rotational axis
124
IB 0.317 kg m 2 3D model
Number of blades B 3 3D model
Projected blade area Aproj.B 0.230 m 2 3D model
Distance between COG of a
blade and rotor centre
Distance between rotor
centre and the first bearing
Distance between blade root
centre and the yaw axis
Rcog 434 mm 3D model / Figure A.2
Lrb 77.7 mm 3D model / Figure A.2
Lrt 217 mm 3D model / Figure A.2
a) Mass includes generator, blades, bolts, washers, bearings etc. in the rotor
Table A.3: Key variables used in load cases
Load case A: Normal operation
Load case A defines loads for the wind turbine blades and shaft. The load case is a fatigue
load case with constant range. The basic idea behind the range is that the turbine speed
cycles between 0.5 and 1.5 of the design value.
By varying �design from 0.5�design to 1.5�design the following centrifugal load range is achieved
for the blades
�F zB
� �2 mB Rcog �0.5�design �2 � mB Rcog 1.5�design The edgewise bending moment range consists of a term due to torque variation (from
0.5Qdesign to 1.5Qdesign equally divided among B blades) and a term due to the moment
caused by the pure alternating load of the blade weight:
� � 2.79 kN
Qdesign �M xB �
� 2mB g Rcog � 33.1 N m
B
(A.2)
(A.3)