It should be noted that in split-phase motors, the auxiliary circuit is properly deactivated at the moment the motor is capable of reaching approximately 70% of the synchronous speed. In this range of speeds, the main winding alone will develop practically the same torque as the combined windings. In the case of higher speeds between 80% and 90% of the synchronous speed X033, the torque curve with the combined windings will cross the torque curve of the main winding so that at higher speeds of this point the motor will be able to develop torque lower for any slip, with the auxiliary circuit connected than without it.
Due to the fact that the cross curves have the possibility of not always occurring at the same point, and the centrifugal circuit breaker does not open frequently at the same speed, it is a common practice to make the opening take place instant before the curves intersect. The main difference between them is the inclusion of an electrolytic capacitor in series with auxiliary starter winding. The capacitor can provide a greater angle of lag between the main and auxiliary winding currents, thereby allowing high starting torques.