What type of cores do most Exciters use that retain residual magnetism?

Most Exciters utilize soft iron cores that retain residual magnetism. Soft iron has unique magnetic properties that allow it to become magnetized easily when an external magnetic field is applied but lose that magnetism more readily when the field is removed. This characteristic is essential for exciters, as they often need to quickly establish and break down magnetic fields to generate the necessary electrical power. The ability to retain some magnetism, even after the external field is gone, ensures that the exciter can rapidly respond to changing demands without needing to fully remagnetize after each cycle.

In contrast, hard steel, while good for applications where long-term magnetism is beneficial, does not have the same quick response and ease of demagnetization. Copper and aluminum are not magnetic materials in the context of magnetic cores and do not retain residual magnetism, thus making them unsuitable for exciters that require effective and reliable operation through magnetism.