To reduce mechanical loading due to guidance of the transport unit of a conveyor installation in the form of a long stator linear motor and nevertheless ensure safe retention of the transport unit on the conveyor track of the conveyor installation in all operating conditions, the normal force (FNn) is controlled with a controller (Rk) for controlling the normal force (FNn). The controller (Rk) determines a normal-force-forming current component (iAnd) of the drive current (iAn) of the drive coils interacting with the transport unit (Tn) so that a resulting normal force (FΣNn) acting on the transport unit (Tn) as the sum of the normal force (FNn), a magnetic force (FMn) in the normal direction (N) caused by the drive magnets, and an external force (FEn) in the normal direction (N) acting on the transport unit (Tn) corresponds at least to a specified retaining force (FNnmin) in the normal direction (N).