ABSTRACT
An electrical heating element is normally a detachable part of a furnace, an appliance, or a heater consisting of one or more electric circuits. In electrical heating elements for appliances the assembly of resistor and terminals is often mechanically supported by electric insulation that is part of the element. Some elements of the supported type involve the heat exchange between three bodies: the resistance wire, a ceramic body supporting the wire, and the environment. The heat is normally transferred from the wire to the ceramic body mainly by radiation and conduction. The mandrel should be cleaned before changing wire type or used only for the same wire type. This is more important for coils intended for a high temperature than for coils having a low operating temperature. The heat transfer is effected by radiation and convection, not by conduction. Mica for heating elements consists of phlogopite or muscovite together with a binder.
