Abstract: A linear motor of the type having an elongated stator contained in a U-shaped channel includes a linearly moving element connected to its load by a connecting beam which passes out of the U-shaped channel. A flexible seal on each arm of the U-shaped channel seals against the sides of the beam where it passes out of the U-shaped channel and opposed elements of the seal abut each other to provide a barrier in other areas. In one embodiment of the invention, a positive pressure of a clean gas is maintained within the sealed U-shaped channel to prevent entry of atmospheric contaminants. In another embodiment of the invention, the seal in the vicinity of the beam is purposely made less than perfect so that the cooling gas is encouraged to flow toward, and exit in the vicinity of, the region where maximum cooling is required.