Introductory, Direct-current generators, Synchronous converters, Mercury rectiflers, Storage batteries, Three-wire system, Feeder panels, Direct-current motors, Direct-current circuit breakers, Direct current stations, Typical electric power stations, Low-tensio alternating current, High tension switching arrangements and methods of connection, Circuit-interrupting devices, Oil switches, Relays, Potential regulators, constant-current systems, Starting compensators, Lightning arresters, High-tension switchboards and wiring diagrams, Cells and compartments, Wall outlets, Central stations, Typical central stations,