ZF
Great expectations: the growth in capacity in the 10 leading wind power nations in megawatts
the wind blows most reliably. So wind turbine gearboxes must be particularly robust and durable. They are often sited at high altitudes and in air that can be wet and salty (at sea, for instance) and the temperature ranges we need to design for vary from -40C to 60C. While the turbine is designed not to operate in extreme wind speeds (it is shut down to prevent overloading), normal operation should occur for wind speeds up to 25 m/sec (90 km/h or 55.9 mi/h). In the area of product validation, ZF is even planning new standards for wind turbine gearboxes. This is necessary because conventional product testing has its limits when dealing with products that must run nonstop for 175,000 operating hours. The ‘dedicated process management’ is another one of ZF’s strong points. We can offer the wind industry decades of process management experience gained in the automotive sector, as well as the quality assurance know-how that we have collected building industrial, marine, and rail gearboxes. Please describe the testing process. Who does it? Where is it done? What criteria are measured or evaluated? In the development 2010 | WIND TUNNEL INTERNATIONAL
phase, we conduct functional tests with and without load applied, lubrication tests, and system integration tests. Finally the gearboxes are also installed up in a tower for field testing. We are conducting the tests together with Vestas at our facilities, and at their test facility in Denmark. Are there any new technologies in the new design? The gearbox that ZF has developed for wind turbines is a new design. Our material specifications are different and we believe our design will allow for more maintenance while the gearbox is still installed in the nacelle. There are different types of gearboxes, depending on the needs of the customer. The most common design is a planetary stage combined with two spur gear stages. Will this arrangement produce cheaper electricity, more reliable electricity or both? Reliability is definitely linked to cost, so we believe both will be affected. CONTACT Bryan Johnson, ZF Group North American Operations Email: bryan.johnson@zf.com 51