WES30 Rotor
The rotor of the WES30 has two blades. With a length
of 14.25 meters for each blade, the overall rotor diameter is 30 meters.
For this reason the wind turbine is called WES30. The blades are made
of carbon- and glass fiber reinforced epoxy. They are light, strong and
flexible and are well protected against erosion by a shock absorbing
coating on the leading edge. A WES30 blade weighs 315
kilogram. Initially designed over 25 years ago, the blades have been
thoroughly tested and optimized over the years.
The blades are
connected to the rotor with a hinge. In stand still position the blades
are hanging a bit backward. When the wind comes up the blades will come
forward (flapping). This hinged connection results in a reduced load
on the construction. This allows for a lighter construction and less
maintenance and makes that the WES30 has less wear and a longer life
expectancy compared to other turbines.
The way this flapping
works: In stand still position the wind will push the blades in the
direction of the tower. The hinged connection of the blades make that
the position of the blades is then slightly backward. Starting to
rotate the blades will come forward due to the centrifugal forces on
the blades. In final position the blades will form a “flat” circle.
Changing wind (and therefore RPM and thus centrifugal forces) and
changing pressure due to the blade passing the tower will make the
blades to flap.
The right blade-angle is important for the
efficiency of the rotor. The balance of the blades together with the
springs in the rotor will set the angle of the blades (pitching). A
synchronization mechanism in the centre of rotor makes that the angle
of both blades is always the same. Wind speeds less than 13 m/s will
not affect the blade-angle, the blades remain in their maximum
position. When the wind speed gets above 13 m/s, the increased rotor
speed will activate the passive blade-angle adjustment. The blades
become less efficient, the rotor speed will maximize to about 85 rpm
and the result is that power output of the turbine is limited to a
nominal value of 250 kW. This mechanism is the first safety system of
the WES30 wind turbine.
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WES30 rotor ready to go up.
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Passive pitch mechanism. |
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