A: Belgian Znobe Theophile Gramme stumbled across the invention of the first direct-current motor by accident at the 1873 expo in Vienna.

He had already created a direct-current dynamo, a primitive type of generator, but it was not until the wires were mistakenly connected to the output terminal of a direct-current dynamo at the expo that he realized his device could serve as a power source to any direct-current power supply.

He applied this knowledge to his dynamo and successfully created direct-current motors.

Prior to this discovery, electric motors had only low-power voltages, not enough to supply power to other generators. Thus, his invention was the first to be further developed by the industry and produced for commercial use.