Zénobe Théophile Gramme was a Belgian electrical engineer best known for the invention of Gramme dynamo, a continuous-current electrical generator .
In 1856, Gramme began working in a Paris factory that fabricated apparatus for the infant electrical industry. In 1870, he invented a continuous-current dynamo with a ring armature (a ring of soft iron around which were placed insulated copper coils). This produced much higher voltages than other dynamos of the time and was the first high-voltage direct-current generator practical for mass production and distribution. Being driven by steam-engines, they were immediately successful and were used for a variety of purposes such as factory lighting, electroplating, and lighthouses. The era of large-scale electrical engineering began with these dynamos.
In 1871, the Academy of Sciences was shown a working model that produced much higher voltages than did previous dynamos. He began manufacturing his dynamo in partnership with Hippolyte Fontaine, also an inventor. In 1873, a Gramme dynamo was exhibited at the Vienna exhibition, where it was demonstrated that the device was reversible and could be used as an electric motor. Before Gramme’s inventions, electric motors attained only low power and were mainly used as toys or laboratory curiosities.
Gramme died at Bois-Colombes on 20 January 1901.