Supply chain of a synchronous electric machine, electric traction system including such a chain and method for controlling such a chain

The chain (16) has a converter (22) for converting direct input current into polyphase alternating output current. An insulation device (26) is placed between the converter and feed outputs (31), and comprises a set of branches (50). Each branch includes an electric switch (52) for disconnecting a considered phase and arranged between the converter and one of the outputs. A controller (28) controls the converter and the device. A short-circuit setting unit (27) connects the outputs with each other. The controller controls the setting unit for realization of short-circuiting operation. Independent claims are also included for the following: (1) an electric traction system (2) a method for controlling a feed chain.