New mercury-gap ring-collector system for double-armature generators

A mercury-gap ring collector (MGRC) for supplying current to the rotating armature of the double-armature synchronous generator is presented. The MGRC can be considered as a valid alternative to conventional collector rings with solid brushes. It offers several advantages over sliding contacts with carbon brushes, especially when the machine has high rating currents and high rotating speed. The design of a prototype is presented; the experimental tests are reported, and the MGRC is compared with a conventional carbon brush collector