Abstract: A reduced voltage starter for gradually starting a polyphase motor having an acceleration control circuit for gradually applying power to the motor and detector circuits for detecting various fault conditions for terminating power to the motor. A shorted solid state switch detector senses when one of the semiconductor switches applying power to the motor is shorted to terminate the application of power from the remaining phases. A phase angle control circuit insures a uniform application of power to the motor. A phase rotation detection circuit detects when the three phases are in other than their correct sequence and terminates power in the event of such detection. An underload detection circuit senses when the current drops beneath a preselected reference after the motor has reached its full speed and terminates power in response to such detection. A line-to-line to line-to-neutral convertor produces signals representative of the line-to-neutral voltages which are necessary for other circuit functions.