An Edison Z-type generator of bi-polar construction, rated for 60 sixteen-candlepower incandescent lamps (52 amps at 110 volts), made about 1881. Markings: "D18" on top block; metal tag: "4E-107"; "No ...

A small bi-polar direct current machine of Edison's design, with an armature rotating in a magnetic field from pole pieces energized by two field magnets set above the armature. A pulley wheel is on ...