An apparatus (80) controls a synchronous machine (20) used to start an engine (300) during an engine start operation. The apparatus comprises: an exciter current control unit (84) for controlling exciter current output to the synchronous machine (20) during the engine start operation; and a main current control unit (82) for controlling main current output to the synchronous machine (20) during the engine start operation as a function of machine speed. In one implementation, the main current control unit (82) controls main current output to the synchronous machine (20) so that the synchronous machine (20) exhibits a reduced output torque during an initial torque application stage. The reduced viscous drag effects and reduced impact torque are beneficial to the engine system (100).