Suggest methods to make electromagnet permanent.?
It is not possible to make an electromagnet permanent.Because a ferromagnetic material will behave like a magnet(electromagnet) until a electric field (which is produced by a current carrying coil wound on the material) is provided.It will lose its magnetic property as soon as the field is withdrawn.Although a residual magnetism will remain in the material due to hysteresis loss.This will maintain its magnetic property even after the field is withdrawn or current is made to stop flowing.But the strength will be too weak to consider it as a magnet
If you have a soft magnetic material it will retain some residual flux after the coil is deenergized. The amount depends on the core dimensions, the material and how many amp turns were applied.
