I’ve spent a lot of time with wind turbine technicians the last 6-month and generally enjoy asking questions about day-to-day work that’s done up-tower. One of the least-celebrated jobs to do? Swapping out yaw pucks – especially if they have the 18 puck system with the side pucks.
Listen to what a wind technician in Wisconsin had to say.
“Yeah, I’d rather walk to work in the snow – uphill both ways – than have to change those puppies out every year.”
Over the last decade, Federal Mogul has flipped traditional Yaw Puck technology upside-down and developed a lead-free metal alloy yaw puck that can last 7 or more years. Here we will cover everything you need to know about finally solving your yaw puck headaches.
As always, we’re here if you want more product info or to request a quote.
What are Yaw Pucks?
Yaw pucks (or friction pads) assist in the active braking system as the nacelle ‘yaws’ in and out of the Wind. Without the yaw system, the wind turbine couldn’t align with the changing direction of the wind or produce maximal power.
Watch this video for a comprehensive look at the yaw system of a wind turbine:
Deva Pucks Eliminate Foghorning
One of the crucial features of the Deva Puck is its ability to eliminate the rattling noise called foghorning – think of the sound when moving a table on hardwood floors – that occurs when the nacelle yaws around the tower.
What causes the horrible rattling sound?
The difference between static and dynamic coefficient of friction being too excessive. I had Kumar Nainani of Federal Mogul help me break down what this meant in a podcast (coming soon!).
What the Heck is Coefficient of Friction?
To understand foghorning from an engineering perspective, we first must understand static and dynamic coefficient of friction.
In simplest terms, static coefficient of friction is when two objects are not moving relative to one another. Think of a parked vehicle. The car is static because the force on the brake is greater than stored kinetic energy. Hence, the car stays still.
Dynamic coefficient of friction is the force that objects place on one another when moving. Think of skates on an ice rink. Therefore, there is less friction and low dynamic coefficient of friction between the skate and the ice to allow the skater to glide across the rink.
Since the Deva Pucks need to both allow the nacelle to move and hold it in place, you must find the sweet spot with your coefficient of friction metrics. If the nacelle moves over the yaw pucks like a skater on ice, that would lead to a lot of issues. Conversely, if there is excess much force on the pucks that won’t allow the turbine to move, you’re going to experience a different set of problems.
Federal Mogul has determined the best coefficient of friction range for a wind turbine to be 0.3 to 0.4 – exactly in line with the data on the Deva Pucks.
Deva Pucks are Self-Lubricating and Maintenance Free
There aren’t many people that enjoy greasing yaw pucks. Besides being extremely hard to reach, the job itself can be tedious and dirty.
Deva Pucks are self-lubricating. If you were to run your finger over the surface, there would be a slight film of a graphite-resembling material on your fingertips.
This homogenous dispersion of solid lubricants like graphite throughout the metallic matrix eliminate the need for maintenance of the pucks. It’ll also ensure your coefficient of friction stays in the perfect range.
Some ask – “What if I grease my yaw pucks?”
That’s completely fine, too. There are many end-users that grease their Deva Pucks. While it is not necessary, they can operate with or without grease.
Why is the Deva Puck a Metallic Alloy and not Composite?
Metallic pucks are dimensionally more stable and circumvent cracking issues that a lot of composite pucks experience. Metal pucks also carry the advantage of lasting longer because of their ability to operate with or without grease.
The consensus in the field and with end-user testing is the movement away from composite materials and fully adopting the Deva Metal technology.
Am I A Good Candidate for the Deva Pucks?
Simply put – it’s probably time to switch if you check any of these boxes:
- Deal with excess foghorning.
- Seeing 3-4 years of life, or less, with your current pucks.
- Find your puck maintenance to be a headache each time you’re up-tower.
- Seeking to eliminate excess climbs due to puck damage.
- Want to invest in the long-term health of your turbines and quickly gain a return on your investment.
The Deva Puck comes in both the 7 mm and 9 mm version – both are the same composition with different thicknesses – and Federal Mogul sees ~1 year of life per puck millimeter.
The Deva Puck is an Excellent Solution for Your Site
Deva Pucks extend the life of your yaw pucks and get rid of pesky issues stemming from poor wear rates and unsuitable coefficient of friction for your wind turbines.
If you think this technology is a potentially good fit for your site, feel free to reach out to any one of the Kurz Wind Team members below. We would be thrilled to determine if it’s a viable solution for your site.
Kurz Industrial Solutions carries both the 7 mm and 9 mm Deva Pucks today. Fill out a quote here.