A new parameters determination method forsquirrel-cage induction motors is presented. As a main contribution,the method uses the instantaneous electrical power andthe mechanical speed measured in a free acceleration test toestimate the double-cage model parameters. The parameters areestimated from the machine impedance calculated at severalpoints: (1) at speed points where the double-cage effect is significant,i.e., between the zero speed point and the maximumtorque point, the machine impedance is evaluated by the instantaneouspower method and (2) at speed points where the doublecageeffect is not significant, i.e., between the maximum torquepoint and synchronism, the machine impedance is evaluated bya dynamic model based linear least square method. The proposedmethod has been applied to obtain the parameters ofthree motors tested in the laboratory. To check the method accuracy,the steady-state torque- and current-slip curves predictedby the estimated parameters are successfully compared withthose measured in the laboratory.
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