A rotary transformer has a bus duct assembly that extends through the hollow shaft of a rotary transformer from collector or slip rings positioned above a drive motor for the rotary transformer to end windings of the rotor positioned most remote from the drive motor. By positioning the leads of the bus duct connection with the rotor end windings on the rotor end windings most remote form the drive motor, the shaft strength and integrity is not reduced due to the torque applied by the drive motor. Further, the shaft is formed from two coupled shaft sections and the bus duct assembly comprises two L shaped sections each positioned substantially within a corresponding shaft section. The bus duct sections are interconnected to complete the bus duct assembly making it simpler to remove the first or upper shaft section from the second or lower shaft section during field servicing. Further, the use of the two bus duct sections within the shaft coupled together simplifies assembly of each bus duct section within its corresponding shaft section.