This can be achieved easily by phase shifting the Ac sources using two three-pulse transformers, one of which is Y-connected and the other -connected on the secondary side. On the primary side, both transformers are connected in Y to the same three-pulse source. With this connection, the secondary side phase voltages of the - transformer are shifted in phase by 30° ,so all the secondary phase voltages of one transformer will be shifted in phase by the same 30° with respect to the corresponding phases in the other. There will also be a difference in the magnitude of the secondary phase voltage.The secondary voltage of the - transformer will be less by a factor of 3 than that of the Y transformer. However, this can be taken care of by having a different turn's ratio