I always had this question that I never really found written anywhere and I have the good or bad habit of not believing my teachers when answering this kind of odd questions.
Whenever I read about the induction motor equivalent circuit R1 is always the resistance of the stator winding. Great! I have a stator, how do I get R1?
My first guess is to measure the resistance value between one phase and neutral in Y (star) connection. That or take the resistance value between phases in Delta connection and divide it by 1.5 to get the resistance of only the winding that connects them directly.
To extract the parameters of the equivalent circuit, I tested the motor in Delta connection, with the rotor blocked and in free running mode. Is V1 the phase to phase voltage? What about Is? Should I test it in Y instead? I have V(t) (phase to phase) and I(t) that I got using an oscilloscope and a current probe.
Equivalent circuit with variable names: