A description is given of theoretical and experimental research into the possibility of using, an automatically regulated transverse field to increase the gas-kinetic pressure limit of the plasma in an ℓ = 3 stellarator. In terms of a simplified theoretical model the various laws governing the control of a transverse field by means of feedback are analysed. It is shown that a control system based on magnetic measurements can provide the accuracy required for maintaining an equilibrium close to optimum. Experimental data relating to equilibrium effects obtained on the Uragan stellarator are in close agreement with theory.