When wind turbine couplings fail, it’s a long way up to get a replacement coupling installed. When wind turbine couplings fail and the coupling OEM is on a different continent, it can mean many months of downtime. This is precisely what happened to a wind turbine fleet owner in West Texas. They experienced a rash of coupling failures in a short amount of time, and had a very short supply of replacement couplings. The coupling OEM in Europe gave a lead time of 12 weeks, which amounted to a large amount of lost MWh.
The turbines were Vestas V-47 machines, and they had been recently repowered to 735 kW. The existing disc couplings were having problems cracking with the new setup. It was likely that there was some change in the alignment that increased the bending stress in the discs. Unfortunately, there was not enough time to analyze the problem and make the necessary alignment corrections on all units, so additional couplings were needed to keep the units running. For an in-depth look at wind turbine misalignment, check out this paper: The detection of wind turbine shaft misalignment using temperature monitoring – ScienceDirect
Luckily, CouplingCorp was ready to help. Our engineers analyzed the situation, and examined the broken elements of the original coupling. Within a couple days, they designed a replacement unit that could be dropped into place.
Using the same technology principles from the FLEXXOR coupling, the same torque capacity was achieved without having to change any dimensions – even the thickness. The design called for a higher quantity of thinner membranes which had the effect of making the coupling more compliant to angular movements. In other words, as the misalignment occurs, there is less force created by the coupling, so the bearings can operate with less side load. Overall, the new coupling elements worked extremely well. CouplingCorp was able to produce 40 units in a couple weeks to allow the fleet to keep making MWh’s.