2、50Hz就是1秒钟发生上述变化50个周期，这是发电机每秒钟转50转得来的。我国交流发电机采用的就是每分钟转速3000转，每秒转速50转，这样频率就是 ...

Czech operator Leo Express has awarded Stadler a contract to install 25kV 50Hz ac traction equipment in its fleet of five ...