Abstract :
Quentin Graham (Westinghouse Electric and Manufacturing Company, East Pittsburgh, Pa.): This paper deals with aspects of induction-motor operation which usually have been omitted from elementary textbooks and have had rather infrequent attention in the technical journals. For that reason the authors probably are justified in their references to what they have considered as the conventional methods. I believe, however, that the paper may give a false idea of the actual methods of practicing engineers. In particular the following items may be noted as representative of present-day design practice: 1. The rotor resistance is treated as a variable and appropriate values are taken depending on the slip. 2. The rotor reactance is varied with the slip. 3. The effect of saturation of the leakage paths is calculated so that the correct values are used for locked current and for full-load current. 4. The effects of flux harmonics on losses and torques are considered. 5. When motors are tested actual speed-torque curves are measured over the complete range of positive and negative speeds and at oversynchronous speeds rather than being constructed from no-load and locked-rotor test data.
