Rogowski Sensors/CTs

Over the years, Amran has produced custom Rogowski sensors/CTs for various applications. Rogowski sensor is an air-core – usually toroidal or rectangle coil placed around the conductor. Rogowski sensors do not use magnetically permeable core. Since there is no magnetic core to saturate, one of the most important properties of these coils is that they produce extremely linear output. Rogowsi sensors are very popular for the application requiring excellent linearity for very high current range.

Amran also manufactures combination of Rogowski CTs and CTs with magnetic core. Both these are combined into one construction. These combination CTs are typically used for protection application where magnetic core CT can operate for low current range and then, once it saturates, Rogowski CT picks up signal and provides appropriate output.

It is not easy to wind Rogowski sensors. Over the years, Amran has developed equipment and expertise to wind these products uniformly so that the coil does not pick up any magnetic signals from adjacent circuitry. Special machines are used for accurate winding. Amran has state of the art in-house test facilities to test Rogowski sensors for required parameters. Picture below shows typical secondary output for Rogowski sensors.

Coils

Amran manufactures custom design coils for many OEMs. These coils are usually wound on bobbin made out of engineering plastic material. The coils can be precision wound on multi spindle machines with wire diameter from 0.05mm up to 3.5 mm for turns ranging from 50 to 50,000. Typical application for such coils are LV and MV motor controls, relays, contactors, power control equipment etc. Amran can integrate further assembly of these coils with other components. Resin molding, vacuum varnishing, impregnation etc. procedures are performed to ensure excellent environmental protections.