US Patent 10927819 Monitoring a blade bearing

A method of monitoring a blade pitch bearing of a rotor blade of a wind turbine is provided, the method including: pitching the rotor blade; measuring an amount of a vibration of the blade pitch bearing during the pitching; estimating a condition of the blade pitch bearing based on the measured amount of vibration. Also disclosed is an arrangement for monitoring a blade pitch bearing, a rotor blade bearing and a wind turbine.