Aim Dynamics offers Rogowski coils (also called rope CTs or flexible current transformers) from several manufacturers. Rogowski coils are more versatile than other types of current transformers. They don’t have a core that saturates like a standard solid or split-core CT. The lack of core allows them to be used in a much wider range of amperages. Additionally they are flexible and generally thinner than traditional CTs, allowing them to be installed in some places where a regular solid or split-core CT wouldn’t fit. Often Rogowski coils are sold in sets of three with one integrator that magnifies and adjusts the signal. Without the integrator, the output of Rogowski coils is a very low AC voltage signal. An output signal of 333mV, 4-20mA, 0-5Vdc, 0-10Vdc, 100mA, 1A or 5A can be achieved with the actively-powered integrator. Some power meter manufacturers can accept the native output of the Rogowski coil (without the powered integrator), whereas less flexible meters require the signal to be amplified and the phase corrected via the use of an integrator.
They can also be used in short-circuit testing of electric generators, motor protection systems, measuring harmonic current content, and as sensors in protection systems of electrical plants.
The Rogowski coil is a useful alternative because it: