Why do we need 25Hz Frequency Converter Systems?

25Hz frequency converter systems were put in place after the decline of the hydro power stations.  At the turn of the century, hydro power plants produced electricity at 25Hz.  25Hz power has very limited use in the United Stated.  These are the railroad industry and power grids supplied by Hydro power plants.  The first 25Hz generator was built in 1895, by Westinghouse for the Niagra Falls project. This project produced power by using energy from the waterfall, to rotate a water turbine, that subsequently produced 25Hz. 

The First step in the process is the water falls by means of gravity.  The next step is the water is forced through turbine blades, which spins them.  After that step, this force of energy causes the blades to rotate as the blades are curved.  The rotating blades are mechanically coupled to a synchronous generator, therefore the generator spins.  With the generator field is excited, it produces electricity.

The Niagra project was not only important, but influential on electrical power system design.  Due to the success of this project, the 25Hz power became the standard low frequency AC in North American.  However, 25Hz power would be phased out and replaced by 60Hz power.  Similar to the this change, 50Hz power became the standard, outside the United States.  As a result, 50Hz and 60Hz became more accepted and incorporated globally.

Who uses 25Hz electrical systems?

Currently, 25Hz power is used to support the railroad industry and limited factories that still use it.  The majority of urban subway systems use 25Hz power to supply their lineside rotary converters used to generate the DC voltage supplied to the trains. Since rotary converters work more efficiently with low frequency supplies, 25Hz was a common frequency.  Amtrak, Southeastern Pennsylvania Transport Authority (SEPTA), and Long Island Railroad (LIRR) are some of companies that still use 25Hz power.

25Hz Frequency Converters for Rail System: