In start-up control of a motor in which currents are caused to flow through any two of three phase coils to detect the polarity of a voltage induced in each de-energized phase, thereby determining the corresponding energized phase at start-up thereof, based on the polarity of the detected induced voltage,...http://www.google.ca/patents/US7071640?utm_source=gb-gplus-sharePatent US7071640 - Rotation drive control circuit of multiphases direct current motor and the start-up method thereof
