A diesel-electric drive system includes a generator having two multi-phase winding systems, a diesel engine, and a DC-link converter. Two self-commuted pulse power converters on the generator side are linked to the windings systems and to each other by a brake resistor on the alternating voltage side. The brake resistor is split into two series-connected resistors, each having half the resistance value of the brake resistor. An input of a bipolar switching device is connected to a connecting point of two series-connected resistors. The capacity of the diesel motor can then be checked in a self-load test with a controllable load torque of the diesel-electric drive system, while eliminating overloads of the power semiconductors of the self-commuted pulse power converters on the generator side.