Current transformer

A current transformer (CT) is a type of <a href="/facts/Transformer/EYYfXWrF">transformer</a> that reduces or multiplies <a href="/facts/Alternating_current/qxICS3xa">alternating current</a> (AC), producing a current in its secondary which is proportional to the current in its primary.
Current transformers, along with <a href="/facts/Voltage_transformer/QIMoV35s">voltage or potential transformers</a>, are <a href="/facts/Instrument_transformer/h0slFl4y">instrument transformers</a>, which scale the large values of voltage or current to small, standardized values that are easy to handle for measuring instruments and <a href="/facts/Protective_relay/UluJBy4S">protective relays</a>. Instrument transformers isolate measurement or protection circuits from the high voltage of the primary system. A current transformer presents a negligible load to the primary circuit.
Current transformers are the current-sensing units of the power system and are used at generating stations, electrical substations, and in industrial and commercial electric power distribution.

Current transformer open-in-new

Current transformer