Radio Frequency Current Transducer Rogowski Coil

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A number of designs of radio frequency current transducers based on the Rogowski Coil principle are available. These are primarily designed for use inmeasuring high frequency current pulses such as those generated by electrical discharge processes. As the transducers are based on an air cored principle, they are not subject to the usual limitations of saturation and non-linearity if the wide band ferrite current transformers. This they can be used to measure rf current signals and reject low frequency currents when installed on cables and bus bar carrying large poer frequency currents.

Two preferred designs are provided. One being a closed ring (type 991/021/R/xx) that is installed in systems where it is possible to break the circuit to install the tranducer. The second is a splir ring type (type 991/021/S/xx) which is hinged and has a clasp. It is designed to permit the transducer to be installed without breaking the circuit. The additions of the splitting mechanism incrases costs and reduces the specifications, so should only be consider for installation where the option of splitting the cable ends is not available.

The standard transducers are made available in four sizes with 200mm, 160mm, 100mm and 70mm diameter hols.

For sitution where the standard shape and size transducers are unsuitable, special transducer can be designed.

Electrical Specifications

Physical Dimensions

The devices are assembled in an aluminium case which should be earth to the plant at the point of installation. It is the installers responsibility to provide the insulation necessary for the operating voltage of the sustem on which it is installed. In many applications it is possible to install the transducers in terminal boxes of the plant under test. Then the insulation on the cable ends can be used to provide this insulation, the transducer being installed symmetrically around the cable with a small clearaance to the cable outer surface, so not to affect the crapage distance.

There is a wide range of other transducers and instrumentation available to assist organisations interested in condition monitoring of electrical plant. A number of application notes are also available.