某些铁路正在試驗以三相同步发电机和半导体整流器作为列車照明系統的基础。由于半导体整流器輸入电源的不拘极性,所以这种列車照明发电机无需极性变換装置。半导体整流器具有高度的閉塞能力,因而不需用切断开关来防止蓄电池电流經发电机而放电。三相同步发电机較直流列車照明发电机能在更高的轉速下运行,这是因为它既没有中間极也不受換向条件的限制。因而同容量的发电机交流的体积和重量 Some railroads are experimenting with three-phase synchronous generators and semiconductor rectifiers as the basis for train lighting systems. Due to the unregulated nature of the input power of semiconductor rectifiers, this train lighting generator does not require a polarity changer. Semiconductor rectifiers are highly blocking and therefore do not require a cut-off switch to prevent battery current from discharging through the generator. Three-phase synchronous generator The DC train lighting generator can operate at a higher speed because it has neither the middle pole nor the commutation conditions. Thus the volume and weight of the generator with the capacity exchange