When a brushless exciter is used what converts the AC producing in the armature winding into DC before it is supplied to the field winding?

In a brushless exciter system, the AC produced in the armature winding is converted to DC by a set of diodes, typically arranged in a rectifier configuration. This rectifier is often mounted on the rotor of the synchronous machine, allowing for efficient conversion of the generated AC voltage into DC. The resulting DC is then supplied to the field winding, enabling the excitation of the main generator without the need for brushes.