Induction motor load losses

On account of uncertainties and irregularities, methods of measuring losses are more desirable than those involving the entire energy. The usual losses, viz. core, loss, friction, and I²r are mentioned and conditions shown under which so-called load losses appear; these are largely in the form of excess core loss, due to saturation of the teeth. Excess copper loss may also appear and be corrected for, both in primary and secondary. Test results are given showing the effect of saturation in the teeth, and excess copper losses; also from 29 input output tests, showing the efficiency by direct measurements in comparison with the method of losses, showing an average of about ¾ of 1 per cent lower by direct measurement. Results of two tests are shown where load losses were excessive, due to peculiar construction. The conclusion is that where no saturation exists there will be no load losses, and no excess copper losses in wire wound stators.