The use of PTFE-faced pads in large vertical axis hydro-generators was pioneered in Russia in the 1970s, prompted by a series of failures of conventional babbitt-faced bearings. Some advantages claimed include higher specific loading, lower power loss and the omission of oil-lift facilities. There is strong interest in the Industry concerning this material, but limited data are available on actual performance. Some results from extensive testing of PTFE-faced pads are given, for two sizes of pad. These are compared directly size-for-size with results for babbitt bearings of nominally the same area. The power losses for the two types of bearing were found to be almost identical. Some of the effects observed during testing are described and discussed, including the effect of creep. The test results are compared with predictions using the GENMAT analysis software. A method of allowing for creep in numerical modeling is discussed.

Polytetrafluoroethylene (PTFE)-faced hydrodynamic thrust bearings have been used for many years in the former Soviet Union and in the People's Republic of China for large hydrogenerator applications. Although there has been some recent interest in other countries, few installations of this sort have previously been reported in Europe or the USA. This paper describes the state of the art and the development and laboratory testing of a prototype set of PTFE pads. Following these trials, a second larger set of thrust pads was designed for use in the pumped-storage hydroelectric power station at Ffestiniog in North Wales. The pads were installed in September 1996 and inspected in May 1997. After nearly 3000 h of operation including 900 separate occasions when the system was started up under load, the pads were found to be in excellent condition. Further hydrogenerator installations of PTFE-faced pads are planned as a result of this successful development.

This paper aims at the completion of a CAM process for 2D and 3D woven fabrics by proposing a new approach for generating weaves. Unlike the other methods used in some of the textile CAD packages, the method suggested in this paper enables the automatic generation of 2D and 3D weaves represented by 2D-weave matrices. The 2D weaves are re-grouped into regular and irregular weaves, and all the regular weaves can be treated as one whereas the irregular 2D weaves and the 3D weaves are treated as individual types. When the parameters of a type of weave are specified, a 2D binary weave matrix will be generated automatically, which can be directly used as or be easily converted into a lifting plan. Such a lifting plan can then be loaded to a loom with an electronic shedding system for the CAM of woven fabrics.

PTFE faced bearing technology, already established for hydro generator use, has been further developed for civil and military marine applications. The paper describes this type of bearing and the advantages compared with conventional babbitt. Details of testing and a description of a PTFE-faced thrust bearing supplied for the Japanese Techno Super Liner project are also presented.