A two-speed drive for a generator of an internal combustion engine includes two belt pulleys and centrifugal type friction-clutch coupling. The coupling has an actuating lever formed as a flyweight and pivotally supported against the force of a spring on a pin connected either to the belt pulley of a smaller diameter or to the generator or to the generator fan. The coupling can be mounted either to the driven side of the generator or to its driving side. A coupling jaw pivotally supported on the actuating lever cooperates with a friction surface provided on the housing of the coupling. An angle formed between the direction of action of the resulting normal force acting on the coupling jaw and the line between the pivot point of the lever and the pivot point of the coupling jaw corresponds to a friction angle at static friction.