Abridgment of calculation of induced voltages in metallic conductors

A review is given of the rules and procedure used in electrical engineering for the calculation of induced voltages in metallic conductors, not including radiation effects. For the e. m. f. in a closed circuit e = — d ϕ/dt, the restriction is slated that the circuit is a closed loop of infinitesimal cross-section and without parallel branches. More complicated circuits are to be calculated by replacing them by a number of elementary circuits. Where there are moving contacts and conductors of finite cross-section, the rule e = B l v should be used. A discussion is given of calculations by considering magnetic fields to have velocities and the restriction is slated that in general, the resultant magnetic field should not be used with the B l v rule, when it is made up of component fields having velocities which differ in magnitude or direction.