A control system for a controlled atmosphere room for storing perishable commodities, such as fruits and vegetables. In order to compensate self-induced eddy currents in the gradient coils it is proposed according to the invention to provide a conductive element in close proximity to at least one of the gradient coils in order to compensate self- induced eddy currents in the gradient coil assembly. Furthermore, stable high-speed rotation is assured. The lower heel plate is associated with a cantilever portion that supports the upper heel plate laterally.