Mk1 is equipped with two blades and is characterised by the flexible (hinged) way of mounting the blades and the passive blade angle adjustment.
GENERAL SPECIFICATIONS 80 kW 250 kW
Supplier / manufacturer WES BV
Life expectancy minimum 20 years
Service maintenance twice a year
Nominal Power 80 kW 250 kW
Cut in wind speed < 3 m/s - 6,7 mph
Cut out wind speed 25 m/s - 56 mph
Nominal wind speed 12 m/s - 27 mph
Survival wind speed 60 m/s - 134 mph
Yawing active yawing
Passive power regulation blade angle adjustment
Active power regulation fully variable
back-to-back system
Hub height 18–40 m 31–51 m
Number of blades 2
Rotor diameter 18 m 30 m
Noise emission at 8 m/s 95 dB(a) at source
104 dB(a) at source
Noise emission at distance WES18 45 dB(a) at 100 m
WES30 45 dB(a) at 300 m
ELECTRICAL SPECIFICATIONS 80 kW 250 kW
Power 80 kW 250 kW
Voltage 400V/50Hz 3 phase or
400V/60Hz 3 phase
Connection grid connected
Converter back-to-back inverter
(IGBT)
APPLIED STANDARDS 80 kW 250 kW
Degree of Protection IP55 IP54
According NEN1010 & NEN6096
First safety passive blade pitch
Second safety yawing out of the wind
GENERATOR 80 kW 250 kW
Type a-synchronous
Number of poles 4
Frequency variable 40–80 Hz 25–75 Hz
WEIGHTS 80 kW
Blade 80 kW 86 kg 250 kW327 kg
Rotor 80 kW 900 kg 250 kW 2.500 kg
Nacelle incl. rotor 80 kW 3.000 kg 250 kW 7.500 kg
Tower: 30 m. 80 kW 8.020 kg 250 kW 13.300 kg
Tower: 50 m. 80 kW 9.400 kg 250 kW 24.400 kg
MATERIAL SPECIFICATIONS 80 kW 250 kW
Blades carbon fibre
reinforced epoxy
Blade length 80 kw 7.8 m / 250 kw 13.4 m
Weight of single blade 80 kw 86 kg / 250 kw 327 kg
Tower steel: tubular or lattice
Foundation concrete block with
anchor or tube
ROTOR
The rotor of the WES
The possibility for the blades to hinge over a small angle has the advantage that the loads on the construction will be less. This way of mounting the blades is similar to the teetering hub construction but has the additional advantage that the blades can hinge independently. This allows for a lighter construction. The operating principle is described as follows:
The pressure of the wind pushes the blades in the direction of the main shaft. Due to the hinges in the rotor hub, the actual position of the blades will be slightly backward. Instead of a disc perpendicular to the main shaft, the rotating blades will form a cone with the hub being top. The rotation of the rotor causes centrifugal forces on the blades, forcing the blades to stretch out and come forwards to a position more perpendicular to the main shaft. Mentioned opposite forces will come to an equilibrium. Bending moments and forces on the rotor hub and main shaft are being reduced considerably by this design.
The passive blade angle adjustment affects the blade angle. The blade angle is a major aspect with regard to the efficiency of the rotor and consequently for the generated power. The pitch can be altered by rotating the blades around a pitch shaft. The blade angles of both blades are always kept equal by means of a synchronisation mechanism located in the rotor hub.
The pressure on the blades causes a force which intends to reduce the projected area: increasing the blade angle. A spring is installed to withstand this force. Wind speeds less than 13 m/s will not affect the blade angle: it will remain in its most favourable position. The nominal power output of the turbine is limited to 250 kW by means of the back-to-back converter system. Wind speeds above 13 m/s will increase the rotor speed since the extra power produced by the rotor is not absorbed by the generator.
The blades are manufactured from carbon fibre reinforced epoxy. Due to the properties of this material the blades are light, strong and flexible. The shape of the blades is based on the NLF 416 airfoil and has a tapered form and a slightly twisted chord. The length is 13,4 metre. The blades are mounted by means of an insert and bolted to the pitch shafts. This design has been tested thoroughly both under static and dynamic loading.
HUB FRAME
The rotor speed is increased by the gearbox. In two stages a ratio of 1:26.6 is obtained. Therefore the outgoing shaft, and consequently the generator, will have an effective working range between approximately 1050 and 2250 rotations per minute. A built-in radial bearing and an attached radial/axial bearing allow the rotor to be mounted directly to the gearbox.
The high speed shaft is connected to the generator by means of a flexible coupling. Furthermore the gearbox is equipped with a brake which prevents the rotor of turning backwards. When the turbine is shut down and yawed 120 degrees out of the wind, the rotor could rotate backwards. The above mentioned brake will be activated and the rotor will be stopped. With this procedure the turbine is being shut down.
For maintenance reasons it is required that the rotor can be locked. Therefore the high speed shaft of the gearbox is provided with a disc brake which can be activated manually. After having yawed the turbine out of the wind, the high speed shaft can be locked.
YAW SYSTEM
The yaw system controls the position of the nacelle in order to place the rotor in the required position. The system is driven by two electric motors, each provided with its own reduction. The yaw bearing is externally geared.
GEARBOX
The hub frame is the connection point of the blades to the main shaft. In the frame the synchronisation mechanism and the blade hinges for flexible mounting of the blades are located. The blade hinges are provided with maintenance-free bearings.
By means of a flanged connection the hub frame is mounted to the main shaft, being the low speed shaft of the gearbox.
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