From the Series-Dynamo Machine to the Singing Arc: Gérard-Lescuyer, Blondel, Poincaré

Abstract

At the end of the nineteenth century, magneto- or dynamo-electricmachines were used in order to turn mechanical work into electrical work and vice versa. With the former type of machine, the magnetic field is induced by a permanent magnet, whereas the latter uses an electromagnet. These machines produced either alternatingor direct currentindifferently. They were therefore the most economical of all appliances where powerful currents are required, such as supplying lighthouses with power using electrical arcs.A dynamo-electric machinewhere the electromagnet is integrated into the circuit is called a series dynamo machine, or self-exciting dynamo.