AiVibeCurrent Transformer (CT)
A current transformer is an instrument transformer that produces a secondary current proportional to the alternating current flowing in a conductor, allowing meters, relays and IIoT sensors to measure high currents safely.
The conductor carrying the measured current acts as the primary, passing through a magnetic core wound with a secondary coil. The secondary current is the primary current divided by the turns ratio, commonly scaled to standard outputs such as 1 A or 5 A for metering and protection, while many low-voltage monitoring sensors provide millivolt or milliamp outputs instead. Split-core CTs open to clamp around an existing conductor, which makes them popular for retrofitting measurement without disconnecting cables.
CTs are used in energy metering, power monitoring, protective relays and motor monitoring. In IIoT applications, they measure motor and machine current to track running status, load, energy consumption and anomalies, and current signature analysis can reveal electrical and mechanical faults. IEC 61869-2 specifies requirements, including accuracy classes, for metering and protection current transformers.
CTs measure alternating current only; direct current requires Hall-effect or other sensor types. Accuracy depends on operating within the rated current range and burden, and the core can saturate under overcurrent. The secondary of a conventional current-output CT must never be open-circuited while the primary carries current, as dangerously high voltages can develop, so installation must follow the manufacturer's documentation and be carried out by qualified electrical personnel.
Key points
- Produces a secondary current proportional to the primary current
- Split-core CTs clamp around existing conductors for retrofits
- IEC 61869-2 specifies requirements for current transformers
- Measures AC only; DC needs Hall-effect or similar sensors
- An open secondary on a conventional CT can develop dangerous voltages
Where AiVibe comes in
AiAmbA IoT is AiVibe's edge protocol layer: it discovers devices and normalises industrial signals, with supported protocols including Siemens S7, Mitsubishi MC, Delta Modbus, OPC UA and MQTT, and driver availability confirmed per installation. Writes to machines are deny-by-default.