Voltage-regulating commutating transformer with 12 phase and No.3 coiling

Provided is a twelve phases third winding voltage regulation and rectification transformer which comprises a major varying and two serial varyings and two loaded voltage regulation switchs, the transformer is characterized in that each serial varying makes a six-phase, the major varying high voltage and voltage regulation winding and the serial varying high voltage winding are arranged at the inner side and close to the iron core, the low voltage winding is arranged at the external side, the major varying low voltage winding and the serial varying low voltage winding cascade to comprise a twelve phases double '8' shape winding structure. The utility model has the advantages as follow: (1) the utility model realizes the homophony unification, decreases the land occupation area, improves the operation efficiency; (2) the utility model decreases the harmonic influence to the power network and the operation cost; (3) the utility model improves the operation safety and reliability.