The symmetrical components method was used to obtain the Resistance- Capacitance parameters formula of the SemihexTM-connection single phase motors on the basis of the static equivalent circuit of the three-phase generator, and then the optimization calculation was carried out. The instant mathematic model of the motors under the α-β coordinate system was established, and the correspondent program was written to simulate the motor' Resistance- Capacitance breaking process with a ventilator load. The result has shown that this breaking method suits various types of load, especially those with a feature of friction damp or light and permanent torque.