Probable values of conventional allowance for A-C. generator stator windings

THE principle employed in the A. I. E. E. Standards for determining the limiting temperature rises as a basis for rating is the so-called hottest-spot principle. The hottest-spot temperature is the bench mark or original point of reference and the limiting observable temperature is derived from it by subtracting a temperature that represents the difference between this temperature and the highest temperature that it is possible to measure by commercial methods. This difference is known in the A. I. E. E. Standards, as the “conventional allowance.”