Patent ID: 8643997

Claim:
A lightning current transfer assembly for a wind turbine comprising at least a first part and a second part rotatable relative to each other, the lightning current transfer assembly being arranged to transfer lightning current from the first part to the second part, comprising: at least one electric contact arrangement comprising complementary contact members which provide electric connection by mechanically contacting each other while being movable relative to each other; a spark gap connected in series with the at least one electric contact arrangement, wherein the spark gap comprises spark-gap electrodes, the spark-gap electrodes being stationary relative to each other; and a spark-gap-bridging resistance connected parallel to the spark gap, the lightning current transfer assembly thereby providing at least two alternative current paths from the first part to the second part: (i) a lightning current path across the at least one electric contact arrangement and the spark gap, and (ii) a permanent-discharge current path across the at least one electric contact arrangement and through the spark-gap-bridging resistance.