Specifications

30
BASIC TOWER REQUIREMENTS
For the BWC XL.1 Wind Turbine
Customer supplied towers for the BWC XL.1 Wind Turbine should meet the fol-
lowing minimum requirements:
Tower Height: 9 m (30 ft) minimum, though we recommend 18 m (60 ft) or higher
Design Wind Speed: 54 m/s (120 mph)
Turbine Weight: 34 kgs (75 lbs)
Maximum Turbine Thrust Load: 890 N (200 lbs) @ 54 m/s (120 mph)
Blade Clearance: Top 1.1 m (44 in) of the tower must not exceed 12.7 cm (5 in)
radius from the tower center line
Dynamics: Not considered due to variable rotor speed
Stiffness: Tower top should not deflect more than 15 cm (6 in) @ 54 m/s (120 mph)
Turbine Mounting: Cylindrical, 108 mm (4.25 in) Outside Dia. See attached drawing
Tower Climbing: On non-tilting towers, provisions must be made to allow the tower to
be climbed for inspections and possible maintenance. Climbing pegs should be remov-
able if they do not meet the blade clearance requirement. On lattice-type towers, we
recommend the use of horizontal laterals to facilitate climbing. We recommend the use
of anti-fall devices for towers requiring climbing.
Materials: We recommend low-carbon steel towers, with careful attention given to weld
quality. Stress risers and brittle materials must be avoided because of the possibility of
fatigue and cracking. We do not recommend aluminum be used due to the risk of
cracking. Fasteners should be U.S. Grade 2 or Grade 5 or equivalent.
Finish: We recommend hot-dip galvanizing after fabrication
Pipe / Tubing Sizes: The following standard steel tubing sections have ID and OD
dimensions that are compatible with the BWC XL.1 (shipped after Sept. 2003):
4.5 in. OD, 0.095 in. wall thickness
4 in. pipe, 0.120 in. wall thickness
120 mm OD, 5.0 mm wall thickness
120 mm OD, 2.5 mm wall thickness
Appendix 3