Single phase ind. motor with external inductor

To the person who replied: Thank you. I finally found my way into your reference. However, the resistance split phase motor does not seem to explain the motor I have. In the book there is no external inductor. The two shown are stator windings, if the same symbolism is followed as for the other motors. So, my questions remains: what is the external inductor for? Was there such a thing as an inductor start motor? Thanks, CP