The Use of Preferreed Orientation Strip Steel in Turbine-Generator Stators

Strip steel with preferred grain orientation has been applied successfully to stator punchings of 2-pole turbine generators. Tests on 16 generators ranging from 1,000-kw to 20,000-kw rating indicate a reduction of 25 to 30 per cent in core losses and 50 per cent in required magnetomotive force in the stator punchings, compared with generators built with present nonoriented hotrolled sheet steels. Use of oriented strip steel permits design of generators of greater efficiency, greater rating for a given size, or both. Effective use is being made of this material in the design of certain 2-pole generators ranging in rating from 1,000 kw, 0.8 power factor, to 125,000 kw, 0.85 power factor.¹ This paper describes the specific application of oriented strip steel to turbine generators in the range of 1,000 kw to 20,000 kw. The advantages of the oriented strip material over the former nonoriented materials are discussed. Test results on 16 generators using oriented strip are presented. The material itself is described, and a brief history of its development given. Special generator manufacturing processes required when using the oriented strip, as well as some of the equipment used, are described. Possible further developments are touched upon.