A current produced in solid conductors, and which is converted into heat
(Ganot). These currents are produced by moving the conductors through a
field, or by altering the strength of a field in which they are
contained. They are the source of much loss of energy and other
derangement in dynamos and motors, and to avoid them the armature cores
are laminated, the plane of the laminations being parallel to the lines
of force.

The presence of Foucault currents, if of long duration, is shown by the
heating of the metal in which they are produced. In dynamo armatures
they are produced sometimes in the metal of the windings, especially if
the latter are of large diameter.