 The motor voltage was 1,800V at a continuous current rating of 980A, 1,030A (one hour) and 1,580A peak for starting.Control of power was by controlling the excitation of the alternator, although there was also a single step of field weakening for the motors.The Alsthom ATD2 alternator was itself an innovative design in which two diesel engines drove a common alternator sited between them.