Reestablishing service in a D-C. Edison system after an interruption

Most of the large central station companies have certain areas to which 125–250-volt d-c. energy is supplied. In the days gone by, this direct current was generated in a number of stations having d-c. engine-driven generators. These generating stations were tied in by means of feeders with the “mains” which were laid in the streets and connected together to form an extensive network; the entire combination being known universally as an Edison system.