Iron Losses in Turbine Generators

In large turbine generators there is no convenient method for determining the iron losses under load. It is the purpose of this paper to show, analytically, the factors influencing the change in iron loss with load. While very definite results are given for a simplified machine, it is not recommnended at this time that any change be made in the A. I. E. E. Standards for computing load loss, because there is miuch to be done before the work can be considered complete. This particular problem is typical of many which are entirely suitable for purely analytical study, and should furnish very desirable able work for investigators who do not have access to large machines for extensive tests, but who desire to carry on studies related to this type of apparatus. This, as well as similar loss problems, can be studied much more readily by theoretical work and model tests, than from measuring the total losses of an entire machine, because the value sought is never a predominant proportion of the total value measured; and even if satisfactory results be obtained on a particular machine, they are not generally applicable to all such apparatus. In this article, it is shown that on the basis of the flux distributions, the machines can be most conveniently divided into end zones, which present three dimensional problems and a large central zone, which presents only two dimensional problems.