  The paper deals with basic designs of a fault current limiter of the
transformer type which differ each other by the mutual location of a primary
winding and a superconducting short-circuited cylinder. Theoretical study of
the main parameters of the different designs is performed in the framework of
the critical state model and shows that the most effective is a design in which
the primary winding is divided to two sections with equal turn numbers. The
sections are placed inside and outside of the cylinder and connected in series.
Such arrangement of the windings leads to a substantial reduction of AC losses
in the superconducting cylinder, an increase of the activation current and a
decrease of the inductive reactance in the normal regime of a protected
circuit. The experimental results obtained on the laboratory model with a BSSCO
cylinder confirm the theoretical predictions.
