General information on current transformers

Current transformers are primarily used in situations where direct current measurement is not possible. They are a special type of transformer with a defined degree of precision (class) that converts the primary current into a smaller, standardized secondary current while also providing galvanic isolation between primary and secondary circuits. The physical saturation of the core material, particularly in monitoring current transformers, offers additional protection to the secondary circuit from higher currents.

There are two main types of current transformers: single-phase current transformers and winding current transformers. The most common type of single-phase current transformer is the molded case feed-through current transformer. This transformer is installed onto the current-carrying phase, forming a transformer with primary winding (and secondary windings according to the transformation ratio). This setup allows for the conversion of the primary current into a smaller, standardized secondary current for measurement purposes.