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CNC Onsite to present its yaw ring repair at WindEurope 2023

Using the company’s patented, portable and compact tool onsite and uptower, the yaw ring is repaired, not replaced, resulting in cost reduction, both offshore and onshore, while eliminating the CO2 emissions from crane and transport needed for replacement

Vejle, Denmark, 5 April, 2023 – At its stand E-D54 at WindEurope 2023, 25-27 in Copenhagen, Denmark, CNC Onsite, a mobile machining expert, will be demonstrating its patented yaw ring repair method that eliminates the costly, time-consuming and potentially risky disassembly of the rotor and nacelle. When applying CNC Onsite’s patented custom-built tool and method, the yaw ring does not need to be replaced.

Complex to replace yaw ring

A crucial component in securing maximum power production from a wind turbine, the yaw ring, also called a “yaw gear rim”, is complex to replace and the costs are so high that damage to the teeth can leave operators of older wind turbines with little choice other than scrapping them.

Keeping turbines operating longer

CNC Onsite offers the repair service for both onshore and offshore wind turbines at a fraction of the cost of replacing the entire yaw ring, and that makes it viable to keep perfectly good turbines operating for longer. Launched in 2019, the machine has repaired yaw rings in several countries across Europe on both onshore and offshore wind farms.

At WindEurope, CNC Onsite will use graphics and live commentary to demonstrate how its portable precision machine repairs the yaw ring, removing damaged areas and reinserting prefabricated teeth.

Disassembly feature of machine

CNC Onsite designed the machine to be disassembled into manageable components to allow lifting and handling. After reassembly in the nacelle, the compact machine can be operated in the confined working space around the yaw ring.

The repairs, which are carried out inside the turbine, can be completed in most weather conditions, ideal for both work schedules and costings.

What is a yaw ring on wind turbine?

The toothed yaw ring is a gear that engages with motors mounted on the nacelle to align the rotor blades with the wind. CNC Onsite estimates that turbines on some 5 to 10 percent of wind farms will experience damage to their yaw ring teeth during their service life. Typical causes include unpredictable wind events or uneven loads sustained over time.

Replacing the yaw ring requires the entire nacelle to be detached using a crane and specialist resources – a process that is expensive, labor intensive and time consuming and, whenever a nacelle is taken down, there is a potential risk of damage, especially to the blades. CNC Onsite repairs are completed within days – minimizing downtime – and contributing to significantly reduced CO2 emissions as no cranes and trucks are needed.

For further technical information and illustrations, please contact:

Søren Schmidt Kellenberger
+45 25 53 76 50

Note to editors

WindEurope estimates that turbines that are at least 20 years old are responsible for generating 14 GW of renewable electricity in Europe and, within the next four years, that figure will increase to 52 GW.

CNC Onsite’s patent: Method for repairing a gear and processing machine for carrying out the method

The patent for the system covers the milling process by which the damaged teeth are excised, and the bed created for the new part, as well as its particular insertion method. Also covered under the same patent, the machining tool was designed to be attached to the yaw ring so that it can work automatically. The in-house machine is a full CNC (Computer Numerical Control) machine, producing the required very precise milling in the limited space.

Milling process and pocket design

The machining tool is mounted to and aligned with the wind turbine’s yaw ring and is pre-programmed with all relevant parameters like dimensions of yaw ring and teeth. 

Once mounted to the yaw ring, the milling machine automatically identifies and cuts out the damaged area precisely, creating a pocket for the replacement teeth. The milling machine is designed to work sideways – part of the patent – on either inward or outward-facing yaw teeth, not from above due to the tight nacelle area.