In no slip ring application is reliability more important than in wind turbines. Recently I had the opportunity to make the climb up a Megawatt wind turbine in order to diagnose a slip ring assembly. The experience reinforced, first hand, the value of reducing maintenance costs in our slip ring assemblies.
I've been onsite with several customers looking at applications a few feet off the ground and that is much simpler to work with when compared to 80 meters in the air. Before the climb even begins, the journey starts with getting to the site. Most wind farms are in remote locations over an hour away from a town large enough to host an airport. Being from Iowa, this wasn't a new experience.
However, what I did underestimate was the size of the farms. Even when you get to the main buildings there is an additional ride to the specific tower, which can take up to 20 minutes in and of itself. Once at the tower the real fun can begin.
Naturally there are some safety precautions to keep in mind. First, a full body harness is worn with a one way latching mechanism. This latch hooks over a cable that runs parallel with the single ladder that will be climbed to the top of the roughly 80 meter tall tower. Similar to a seatbelt stopping mechanism, it allows for flow in both directions; however, when a sudden force is applied in a certain direction it will lock up. Other safety precautions include a hard hat, as any falling object becomes dangerous, steel toe boots with a heel to prevent slipping on the ladder, abrasion resistant gloves and of course safety glasses.
One foot after another, over and over. A technician went first and he made the climb look effortless, experience helps quite a bit. As a first timer I noticed my grip was much tighter and my pace was much slower than others. While I feel confident on a ladder cleaning leaves out of the gutter, this is a whole different type of climb. Slowly but surely I made my way up.
Some turbines, like the one I climbed, have platforms that allow the climbers to take a break, those are very helpful. The climb time for the group of 5 was about 25 minutes. Once up tower, we spent a few hours mostly letting the technicians do their other maintenance and then about half an hour looking at the slip ring assembly. The value of fully understanding the slip ring assembly location can't be understated. Being able to see the product actually mounted and hooked up helps quite a bit with understanding the current design and provoking ideas for future improvements.
The climb down was much easier, considering gravity is now working in my favor. At times you can even lean against the tower wall and sort of slide down, slow enough to prevent the harness from latching but quick enough to keep pace and not slow down the crew. The overall experience requires great physical effort, but the opportunity to help our customers makes it completely worth it. The view at the top doesn't hurt either.