Low Tension Current Transformers

Current transformers convert an alternating current usually high in to a proportional lower one,
depending on their use. Measurement type CTs are required to transform the primary current, at various classes of
accuracy, as specified by the class designation, over a current range from 1 to 120 percent of its rated primary ratio.
The design of this type of transformer requires the inclusion of a core and winding which will when connected to its
rated burden; perform within the limits of error as indicated by the standard’s specification. It is an advantage for a
measurement type transformer to saturate above this range, which provides a protection against damage to
instruments by limiting the secondary current when surge currents or faults appear in the primary circuit.