There are two (1) (发动机驱动发电机). Each generator supplies (2) (交流电) to its (3) (交流电汇流条). Each AC bus supplies it's own (4) (变压整流器). The TR converts alternating current into (5) (直流电) to supply their associated (6) (直流电汇流条). The DC bus can charge (7) (蓄电瓶).