Maintenance crews acknowledge that frequent lubrications with small amounts of grease extend the working life of bearings and seals. But long hours of hub crawling is physically and mentally demanding work. To minimize that work, centralized and automated lubrication systems are useful. One version for lubrication tasks in a nacelle can also handle main-shaft bearings. The equipment also reduces lubricant consumption. Most equipment of this sort makes refilling the grease pump simple and quick. Centralized lubrication systems are said to reduce turbine operating costs, increase operational reliability, and extend service intervals.
There is more than lubrication in turbine maintenance. Some cost-saving options are available for wind-farm operators in the form of turbine component repair. Component repair from a qualified service provider can slice 30 to 70% off the cost of new OEM components, says a spokesman for a repair facility. He says repair depots offer repair services for electronic, hydraulic, and precision mechanical components from all the major manufacturers that drive wind turbines’ pitch and yaw system, as well as downtower electronics.
Trends: Hydraulic-component companies are designing more complete lubrication-oil systems for wind-turbine gearboxes. These systems would come with filters, pumps, valves, coolers, and heaters as well as manifolds and piping to connect components. The advantage here is that the assemblies are probably more thoroughly tested and proven and carry the assurance of reliability from a qualified supplier.
Tools: The equipment used to maintain the machinery in a nacelle are much like those used by other technicians except they are fitted with tethers to prevent them from falling many feet to the ground. See the safety and bolting sections for additional discussions.
Cold weather filters: A recent element intended for wind turbines is said to ensure sufficient and effective filtration levels and prevent the filter from going into bypass mode, an event common to cold starts. Also, offline filters can remove water from oil. Existing systems on turbines can be upgraded with these capabilities.
Oil filters: Conventional oil filters are limited to removing dust and debris above a certain size, 2 to 20 microns, for example. But lubricant contain a variety of contaminants, varnish in particular. Adsorption is one way to remove varnish from oil and cellulose is effective in doing so. The adsorption characteristics of cellulose are inherent so it needs no voltage or control systems. Filter stacks of cellulose are effective and a few psi are needed to push oil through the filters to remove varnish and other contaminants. One expert claimed that with proper filtration, oil changes can be spaced as much as two and three years apart.