ISO 10816-21:2015

ISO 10816-21:2015 specifies the measurement and evaluation of mechanical vibration of wind turbines and their components by taking measurements on non-rotating parts. It applies to horizontal axis wind turbines with mechanical gearbox and rated generator output exceeding 200 kW and the following design and operational characteristics:
a)    installation on supporting systems (tower and foundation) made of steel and/or concrete;
b)    horizontal axis rotor with several rotor blades;
c)    rotor bearing separate from or integrated into the gearbox;
d)    generators driven via gearbox;
e)    generators of the synchronous or asynchronous type (mostly equipped with 4-pole generator);
f)     generators with only a fixed pole number or which are pole-changeable for speed adjustment;
g)    output control by rotor blades (pitch or stall wind turbines);
h)    generator coupled to the power grid via converter or directly.