{"schemaVersion":1,"slug":"low-power-current-transformer","name":"Low-power current transformer","kind":"symbol","abbreviation":"LPCT","aliases":["LPCT","current sensor with voltage output"],"category":"measurement-protection","drawingTypes":["SLD","Schematic"],"referenceFamilies":["IEC","Manufacturer"],"summary":"Small iron-core CT with an integral shunt that delivers a low-level voltage signal instead of a standard secondary current.","description":["A low-power CT uses a small magnetic core and an integral burden resistor, so its output is a low-level voltage proportional to primary current. It suits digital relays and compact switchgear, and a single LPCT can often replace several conventional CT ratios.","Because the burden is built in, the output must not be shorted or loaded like a conventional CT, and it cannot feed electromechanical relays or ordinary meters. The symbol shows the sensor but the reader must confirm the relay input type and the sensor's rated output."],"readingNotes":["Check the receiving input is an LPCT input.","Do not short the output as for a conventional CT."],"drawingChecklist":["State rated output","Reference relay input type","Show sensor cable"],"distinction":"An LPCT has an iron core with integral burden; a Rogowski coil has no iron core and gives a di/dt output.","facts":[{"label":"Output","value":"Low-level voltage proportional to current"},{"label":"Burden","value":"Integral to the sensor"},{"label":"Preview","value":"Functional illustration of the device role; not a product footprint or certified standard graphic"}],"references":[{"sourceId":"s28-abb-advasense-sensors","relevance":"Public manufacturer page describing low-power instrument transformers based on Rogowski coils and voltage dividers."},{"sourceId":"instrument-transformers","relevance":"Public manufacturer overview of indoor current and voltage instrument transformers."}],"related":["rogowski-coil","current-transformer","resistive-voltage-divider-sensor"],"artwork":"s28-low-power-current-transformer","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","plainEnglish":{"title":"What does Low-power current transformer mean?","introduction":"A low-power CT uses a small magnetic core and an integral burden resistor, so its output is a low-level voltage proportional to primary current. It suits digital relays and compact switchgear, and a single LPCT can often replace several conventional CT ratios.","example":"Because the burden is built in, the output must not be shorted or loaded like a conventional CT, and it cannot feed electromechanical relays or ordinary meters. The symbol shows the sensor but the reader must confirm the relay input type and the sensor's rated output.","drawings":"Check the receiving input is an LPCT input. Do not short the output as for a conventional CT. An LPCT has an iron core with integral burden; a Rogowski coil has no iron core and gives a di/dt output.","terms":[{"name":"Winding","meaning":"A coil of conductor inside an electrical machine or transformer."},{"name":"Coil","meaning":"A wound conductor that can produce a magnetic field when energised."},{"name":"Signal","meaning":"Electrical information passed between devices, rather than necessarily the main power supply."}],"diagram":"flow","steps":["Identify the device and form","Read the connections and state","Check the equipment reference"],"caption":"A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.","sources":[{"label":"Medium-voltage indoor sensors: Rogowski coil and voltage divider low-power instrument transformers","url":"https://www.abb.com/global/en/areas/electrification/medium-voltage/grid-components/core-components/indoor-sensors"},{"label":"Indoor current and voltage transformers","url":"https://www.abb.com/gb/en/areas/electrification/medium-voltage/grid-components/core-components/indoor-instrument-transformers"}],"detail":"Small iron-core CT with an integral shunt that delivers a low-level voltage signal instead of a standard secondary current. An LPCT has an iron core with integral burden; a Rogowski coil has no iron core and gives a di/dt output.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/low-power-current-transformer","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/low-power-current-transformer.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"s28-abb-advasense-sensors","title":"Medium-voltage indoor sensors: Rogowski coil and voltage divider low-power instrument transformers","publisher":"ABB","url":"https://www.abb.com/global/en/areas/electrification/medium-voltage/grid-components/core-components/indoor-sensors","type":"manufacturer","scope":"Public product overview describing low-power instrument transformers based on Rogowski coils and voltage dividers for MV switchgear.","checkedOn":"2026-10-28","reuse":"link-only","relevance":"Public manufacturer page describing low-power instrument transformers based on Rogowski coils and voltage dividers."},{"id":"instrument-transformers","title":"Indoor current and voltage transformers","publisher":"ABB","url":"https://www.abb.com/gb/en/areas/electrification/medium-voltage/grid-components/core-components/indoor-instrument-transformers","type":"manufacturer","scope":"Public current- and voltage-transformer product families. Ratings, terminals and dimensions depend on the model.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Public manufacturer overview of indoor current and voltage instrument transformers."}]}