Yaw Ring Teeth Repair
Damaged yaw ring teeth are precisely machined out, creating a pocket with extremely fine tolerances for a replacement segment that are fitted to exact dimensions.
Uptower Solution
3000+ Repairs completed
0.05mm OEM tolerance
80%+ Cost reduction vs. replacement
No hot work Required
How It Works On site precision machining.
On site precision machining.
Directly inside the nacelle.
Using our patented up-tower repair method, damaged yaw ring teeth are repaired directly inside the turbine. By eliminating the need to remove the nacelle, we significantly reduce downtime, costs, and logistical complexity while restoring full yaw ring functionality.
Our repair process uses a portable precision machining system specifically developed for confined nacelle environments. Damaged yaw ring teeth are precisely machined out, creating a pocket with extremely fine tolerances. New replacement segments are then installed and fitted to exact dimensions, restoring the geometry and functionality of the yaw ring without disturbing the surrounding structure. The process is comparable to replacing a dental crown: only the damaged section is removed and replaced, while the healthy structure remains intact. Designed specifically for up-tower work, the equipment can be transported in sections and reassembled inside the nacelle, allowing repairs to be performed even in restricted working areas.
Since introducing the technology, CNC Onsite has continuously expanded its repair capabilities to support a growing range of wind turbine platforms. Our portable machining systems have been used to install more than 100 replacement yaw ring segments, corresponding to approximately 600 repaired teeth on both onshore and offshore wind turbines across three continents. Backed by extensive testing, engineering development, and years of operational experience, the solution has become a proven alternative to complete yaw ring replacement.
Operated by our trained technicians, the patented CNC machine applies the proprietary repair method, working at extremely fine tolerances, to remove and reinsert machined yaw ring teeth precisely. Because the repairs take place inside the wind turbine tower/nacelle, our method is less dependent on weather, potentially reducing downtime. The yaw ring repairs eliminate the costly, time-consuming and potentially detrimental disassembly of the rotor and nacelle – a requirement when replacing the entire yaw ring gear.
Technical Specifications
Typical duration 3–7 days on site
Positioning tolerance 0.05 mm
Surface roughness Ra 0.8 μm or better
Certification ISO 9001 | OEM-spec
Equipment Mobile CNC milling system
Turbine types Vestas, SGRE, GE
Expected lifetime Similar to original
ISO 9001GWO CertifiedPatented ProcessOffshore Ready
Reduced Downtime Onsite repair and the elimination of crane mobilization and component transportation reduces downtime from weeks to days.
Resources No new components, no cranes, minimal logistics. Significantly lower carbon footprint and manpower requirements.
Total Economy Repair instead of replacement. No cranes, no component exchange. No transportation. Fewer ressources. 80% lower total project cost.
Reliable Results Precision machining performed to OEM tolerances of 0.05 mm and surface finishes of Ra 0.8 μm or better.
Our Process
From call to commission
01
Commissioning
The wind park reports damage to the yaw ring and turbine type. Within 24 hours, our repair technician calls to discuss the damage and assess repair options. Quote issued the same working day.
02
Planning
Repairs planned in detail to exact specification with minimal disruption. Yaw ring type and number of damaged teeth determine the pre-manufactured replacement segments. CNC machine programmed for the exact turbine type.
03
Implementation
Technicians arrive at dawn with portable CNC machine. Equipment assembled in the nacelle. Pre-programmed milling machine excises damaged segments, leaving precisely measured pockets. New segments inserted mechanically and fixed robustly.
04
Handover
Repair results discussed with customer. Turbine tested and started up. Job signed off by customer. Full repair report issued. Turbine back in production.
05
Follow-up
As part of our quality standards, we follow up on each job individually. Experience is documented for future cases. We trace each repair and follow up with the client to ensure continued satisfaction and longevity.
We can now offer a repair service for both onshore and offshore at a fraction of the cost of replacing the entire yaw ring — and that makes it viable to keep perfectly good wind turbines operating for longer.
Søren Kellenberger CEO, CNC Onsite
FAQ
Frequently asked questions
Can a yaw ring be repaired on a wind turbine?
Yes. A wind turbine yaw ring with damaged teeth can be repaired directly in the nacelle by technicians equipped with the right precision machine — without removing the whole yaw ring or nacelle.
How is the yaw ring repaired?
The repair is performed uptower without disassembling any wind turbine parts. The patented precision machine is programmed for the exact turbine type, mills away the damaged yaw teeth automatically, and leaves a precision-shaped pocket. Pre-fabricated replacement segments are inserted and fixed mechanically.
How many yaw ring teeth can be repaired?
In principle, all teeth on a yaw ring can be replaced using this method. Consecutive repairs are possible — there is no inherent limit to the number of teeth that can be addressed.
How common is yaw ring damage?
It is estimated that 5 to 10 percent of all turbines will experience yaw ring damage during their operational lifetime. Damage is not evenly distributed — some sites are more exposed, and multiple turbines within the same park are often affected.
How quickly can technicians be on site?
Technicians can be on site within days of a received purchase order, depending on location. The service is offered worldwide, 24/7.
Can repairs be performed offshore?
Yes. We offer repair services for both onshore and offshore turbines. Our method eliminates the need for offshore crane deployment, making the economics of offshore yaw ring repair viable for the first time.
Contact our team Let us find
Let us find
the right solution
Whether it's a repair, machining project, or custom machine solution, our engineers are ready to help you find the most efficient way forward.
