A method and apparatus for controlling commutation of a motor. A voltage is measured at each of a plurality of windings of a motor using an electric circuit. A controller computes an overall back electromotive force for the motor using the voltage measured at each winding in the plurality of windings. The controller generates a result having either a first value or a second value based on the overall back electromotive force. The controller adjusts the commutation phase and the commutation period of the motor using the result.