AC single phase induction motor - phase difference problem
If you know the resistance and inductance of the windings, you can calculate the impedance angles from Zm = Rm + jXm and Za = Ra + jXa - jXc. Main winding angle = arctan (Xm/Rm) and aux winding angle = arctan (Ra/(Xa-Xc)). These angles will only be true for the instant the motor is energized. Once the rotor begins to rotate, the rotor characteristics and load must be taken into account.