Many electricians and contractors are moving towards using Rogowski Coils because of the time saved during installation and the reduced shipping costs for high amperage requirements. Because of the size, weight and flexibility of a Rogowski Coil, installers can save significant time and labor because of the ease of surrounding conductors of all sizes. However, what most people don’t realize is that Rogowski Coils have many technical advantages over standard split-core or “donut” CT’s which can help improve monitoring energy in different applications.
WIDE CURRENT RANGE
The Patrol Flex has a current range of 5-4000A and up, yet weights less than .5lbs, drastically reducing shipping costs. A typical 100A CT weighs 2lbs, however as the current range expands to 3000A, the average weight can increase from 2lbs to 20lbs. Considering three CT's are required to monitor a 3-phase motor, certain applications could require up to 65lbs or shipping weight per metering point; a serious waste of shipping dollars.
BEST IN CLASS LINEARITY
Conventional CT's are wound over a magnetic iron core, which makes them more susceptible to saturation leading to linearity error. Engineers and contractors must adjust the phase shift of the meter to compensate in order to achieve an accurate reading. Rogowski Coils are wound over a non-magnetic core, giving them perfect linearity and improved accuracy over wide current ranges.
FASTER RESPONSE TIME
Because of the low inductance of Rogowski Coils, it is able to respond to currents much quicker than conventional current transformers.
Understanding specific job requirements, such as performance, installation, amperage load and environmental factors are critical to selecting the proper current transformer for an application. Conventional CT's do come with their limitations in that they are difficult to install and are lacking in performance and measurement range. It is imperative examine the application requirements and challenges before selecting a CT in order to ensure that you have the right tool for the job.
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