China
Africa
Explore chapters and articles related to this topic
Wind Energy Equipment
Published in Bella H. Chudnovsky, Transmission, Distribution, and Renewable Energy Generation Power Equipment, 2017
Rotor: The rotor is three-bladed and each blade has independent pitch. The pitch bearings are the rolling-element type, and are periodically lubricated with grease. The pitch mechanism may be one of two types. Hydraulic pitch system includes a pitch cylinder, proportional valve, crank arm mechanism, accumulator, and displacement transducer for each blade. Electric pitch system includes a motor with a position encoder, gear reducer, electronic drive, and backup battery bank for each blade. The pump and position controller are common for all three mechanisms (i.e., one per blade).
Pitch bearing case study with supervisory control data of 7MW wind turbine
Published in C. Guedes Soares, Developments in Renewable Energies Offshore, 2020
W. Song, K.A. Karikari-Boateng, H. Lee
The blade rotation is achieved by a pitch bearing (also called blade bearing), which is located in between the blade root and the hub of the wind turbine. The main role of the pitch bearing within the system is to allow the blade rotation while accommodating all the dynamic loads imparted by wind through the blade. Typically, bending moment which increases with blade length (also called flap-wise and edge-wise moment) is most critical load component among other load components.
Lifetime prediction of bonded structural patch repairs for wind turbine pitch bearing strengthening
Published in The Journal of Adhesion, 2022
J. Manterola, I. Leciñana, J. Zurbitu, H. Zabala, I. Urresti, M. Olave
Pitch bearings connect the rotor hub and rotor blade of a wind turbine, allowing for the rotation of the blade to maximise the power of the wind turbine (Figure 1(a)). Attached to the blade, the inner ring is subjected to tilting moments because of wind action. Cyclic loads vary in magnitude with wind loads and blade positions, and they are transmitted by the rolling elements through angular contact from the inner to outer ring. Bolted joints are used to connect the outer ring to the hub, and significant hoop stresses are generated, with a critical point being the outer edge of the holes drilled for bolt mounting (Figure 1(b)).[3] At this point, a crack may initiate because of fatigue loads, causing the failure of the component (Figure 1(c)); this is known as ring structural failure (RSF).