Slew Ring Bearings for Wind Turbines – Yaw Bearings & Pitch Bearings Explained

Wind turbines are among the most demanding environments for rotational bearings in the world. They must operate for 20–25 years with minimal maintenance, in exposed outdoor locations, under enormous and constantly changing loads. At the heart of every wind turbine's rotation control system are two critical slew ring bearings — the yaw bearing and the pitch bearing.

Kavitsu Robotronix, a slew ring bearing manufacturer with 30+ years of experience based in Satara, India, supplies precision wind turbine slewing bearings to OEMs and wind farm operators across Europe, the USA, the Middle East, and Southeast Asia. This article explains exactly how slew ring bearings function in wind turbines and what specifications matter when sourcing them.

The Yaw Bearing – Rotating the Nacelle

The yaw bearing is the large slew ring bearing mounted between the top of the wind turbine tower and the nacelle (the housing that contains the generator and gearbox). Its job is to rotate the entire nacelle to face the wind direction — a process called yaw control.

• The yaw bearing must support the full weight of the nacelle plus all internal components
• It carries enormous moment loads from the asymmetric forces of the rotating blades
• Typical yaw bearing diameters range from 2,000mm to over 4,000mm depending on turbine capacity
• Yaw bearings typically use a four-point contact ball design or a three-row roller design for very large turbines
• The gear is usually an internal gear driven by multiple yaw drive motors positioned around the tower

The Pitch Bearing – Adjusting Blade Angle

Each blade of a wind turbine is attached to the hub through a pitch bearing — another large slew ring bearing. The pitch bearing allows the blade to rotate about its own axis to control the angle (pitch) of the blade relative to the wind. This is how modern turbines control power output and protect themselves in high winds.

• Pitch bearings are typically 1,000mm to 2,500mm in bore diameter depending on blade size
• They experience very high combined radial and moment loads from the blade weight and aerodynamic forces
• Pitch bearings often use a four-point contact single-row ball design for lighter blades, or a double-row ball design for larger blades
• The gear is usually an external gear driven by an electric or hydraulic pitch drive motor
• Because each blade has its own pitch bearing, a 3-blade turbine needs 3 pitch bearings

Critical Requirements for Wind Turbine Slewing Bearings

Why Source Wind Turbine Slewing Bearings from India?

India has become a globally significant source for precision slew ring bearings, offering European and American buyers a compelling combination of quality and cost:

• Cost advantage: Indian-manufactured slew ring bearings typically offer 25–40% cost savings compared to European-produced equivalents at the same quality level
• Engineering capability: Manufacturers like Kavitsu have 30+ years of experience and full engineering design capability for custom specifications
• Export infrastructure: Direct sea freight from JNPT (Mumbai) to major European and US ports is well-established and cost-effective
• Compliance: Indian manufacturers increasingly meet ISO 9001, CE, and other international quality standards
• Customisation: Full bespoke design service — share your drawing, we manufacture to your exact specification

Kavitsu's Wind Energy Bearing Supply Capability

Kavitsu Robotronix manufactures and exports slew ring bearings to wind energy OEMs and aftermarket suppliers across Europe (Germany, Netherlands, Spain, Finland), the USA, Australia, and the Middle East. Our wind turbine bearing supply includes:

• Yaw slew ring bearings — four-point contact and three-row roller types up to 4,500mm bore
• Pitch slew ring bearings — single-row and double-row ball types
• Replacement/aftermarket bearings matching existing turbine drawings
• Custom-designed bearings for new turbine platforms

Frequently Asked Questions