Methods of energy input In a general electromagnetic system we can identify the following methods of exchanging
energy between that system and its environment.
• Moving charged bodies in an electric field. The forces on the charged bodies result
in the performance of mechanical work.
• Injecting currents from voltage sources into terminals of a network. It is usual to
regard this as an example of the delivery of electrical power.
• Moving polarised dielectrics in electric fields. The forces and torques on the polarised
bodies result in the performance of mechanical work.
• Moving current carrying wires in a magnetic flux density. The forces on the wires
require the performance of mechanical work. It is also true that the movement of
the wires may cause changing magnetic fields which induce voltages in the circuits
in which the currents flow, causing an exchange of electric energy of a type described
• Moving magnetised media in a magnetic field. The forces and torques exerted by
the field on the poles of the media involve the performance of mechanical work. It
is also true that changing fluxes caused by the movement may induce voltages in
circuits which may be carrying currents to produce the magnetic field in which the
motion is taking place.
... zobacz całą notatkę