Why do most exciters utilize soft iron cores?

Soft iron cores are utilized in most exciters primarily because they retain residual magnetism, which is crucial for their functionality in electrical production systems. Residual magnetism refers to the ability of a magnetic material to maintain some level of magnetization even after the external magnetizing force is removed. This characteristic is particularly beneficial in applications involving electromagnetic induction, as it helps in quickly establishing the magnetic field necessary for generating voltage in alternators and generators.

When the excitation system is turned on, the residual magnetism allows for immediate generation of the magnetic field, which enhances the efficiency of voltage build-up during startup. Over time, once the required field current is applied, the system can quickly reach stable operating conditions. The ability to quickly respond and establish a magnetic field while maintaining robustness in operation makes soft iron an ideal choice for exciters.

In contrast, while options regarding weight, manufacturing ease, and energy conversion performance might hold some relevance in different contexts, they do not directly address the fundamental importance of residual magnetism in achieving reliable and efficient operation within exciters used in electrical power production.