Lexicon DIY-Knowledge

Permanent magnets


Imanes permanentes

Aimants permanents

The principle of the electric motor is based on the fact that a current-carrying conductor in a magnetic field is exposed to a force which can provide motion to the freely suspended conductor. On the other hand, every current-carrying conductor generates a magnetic field whose strength can be increased by increasing the number of conductors or the intensity of the current. The strength of the magnetic field depends on the number of windings and the current intensity; it is measured by the number of ampere turns. Electromagnets lose their magnetic force once the current flow is stopped; only a low-level remanence stays behind which initiates self-excitation in generators. On the other hand there are permanent magnets which generate a constant magnetic field. Certain alloys are regarded as magnetically hard, i.e. they retain their magnetic flux after being initially charged. Cordless power tools are equipped with motors containing permanent magnets which do not require additional energy.