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GENERATOR AND ELECTRICAL SYSTEM
Figure 7.4: Schematic overview of the electrical system. Three connecting lines between the
components indicate AC and two connecting lines indicate DC.
Shutdown switch
In case of an emergency, a shutdown switch is used to brake the wind turbine. It works by
short-circuiting the 3 phases of the generator, hence creating a high current load which
effectively stops the rotor. A further advantage of the shutdown switch is that it is possible
to manually park the wind turbine during maintenance and installation. For the present
wind turbine a shutdown switch is not required, but recommended by IEC 61400-2 [5, p.
93].
Slip ring
Since the wind turbine is able to yaw freely about its yaw axis, there would normally be a
risk of twisting the wires of the electrical system, which eventually would cause failure. A
slip ring, also known as a rotating electrical connector, prevents this problem from occur-
ring.
Rectifier
A rectifier is an electrical device used to convert the wild alternating current from the
generator, which periodically reverses direction, into direct current, which is in only one
direction. This is necessary to charge the battery bank that the wind turbine is assumed to
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