A drive unit for an endless conveyor, comprising a magnetic transmission and an electric motor connected to an input shaft of the magnetic transmission, where the magnetic transmission comprises a rotatable outer cylinder comprising a plurality of permanent magnets arranged as magnetic poles at the inner side of the outer cylinder, an intermediate cylindrical element comprising a plurality of ferromagnetic pole pieces, an inner cylinder comprising a plurality of permanent magnets arranged as magnetic poles at the outer side of the inner cylinder, where the outer side of the outer cylinder is configured with a drive surface adapted to interact with a conveyor belt or conveyor chain. The advantage of the invention is that a compact and efficient drive unit for a conveyor system is provided, which is provided with a contactless predefined slip.