Thinking of people has come to change, and most engineers consider the Rogowski coil a valid alternative for any current measurement application where flexibility, accuracy, or both are required in almost every case. But, just as any technology will do, they are beings with limitations that users need to be aware of to use them effectively.
Here at Aim Dynamics, we take the time to give you all of our best tips and tricks for your current sensing needs. What you need to know about the accuracy & limitations of Rogowski coils.
Rogowski Coils
Rogowski coils sense current flow using electromagnetic induction, creating a voltage output that scales with the rate of change in current inside a conductor. They are uniquely designed to allow measurements without intrusiveness, making them perfect for monitoring AC currents in various environments.
Key Advantages
Bendable: They can be bent to stretch around conductors in small spaces and weigh very little.
Extensive Measurement Range: Rogowski coils will not saturate at current amplitudes from milliamperes to thousands of amperes.
Non-interfering: They can be mounted without a physical change in the circuit, so safety and security continuance
Accuracy Factors
Though Rogowski coils provide many advantages, there are a few reasons that can interfere with their accuracy:
Positioning and Alignment: One factor is the relative placement of the Rogowski coil to a conductor. Incorrect alignment, like promoting the coil lay flat and perpendicular to the current flow, must occur, or accuracy will not be achieved. This positioning sensitivity causes inaccuracies of up to 3%, quickly increasing the overall inaccuracy of a CT measurement by more than a fold.
Conductor Size and Proximity: The horizontal size of the conductor being measured relative to the Rogowski coil will affect measurement accuracy. A coil too small to capture all of the field lines (left) leads to underestimation.
External interference: Nearby devices emitting electromagnetic interference (EMI) can affect the sensor results. Best practices for shielding and installation are a must
Temperature Variations: Temperature changes can affect the electrical characteristics of the coil and the conductor, potentially leading to measurement inaccuracies.
Integrator Requirement: The output from a Rogowski coil must be processed through an integrator circuit to obtain a usable current waveform. This additional component introduces complexity and potential points of failure that can affect overall accuracy.
Limitations of Rogowski Coils
Despite their advantages, Rogowski coils have limitations that users should consider:
AC Only: Rogowski coils are designed primarily for alternating (AC) measurements and cannot accurately measure constant direct current (DC). This limitation makes them less suitable for applications where Rogowski coils DC measurement is necessary.
Sensitivity: Compared to traditional current transformers, Rogowski coils may exhibit lower sensitivity due to their lack of a high-permeability core. This can lead to challenges in applications requiring precise low-current measurements.
Calibration Requirements: Regular calibration is critical to maintaining measurement accuracy over time. Users must ensure that their Rogowski coils are calibrated according to manufacturer specifications.
Why Choose Aim Dynamics?
At Aim Dynamics, we understand that accurate, current measurement is essential for your operations. Our range of high-quality Rogowski coils is designed with precision in mind, ensuring reliable performance across various applications. By addressing common pitfalls and providing expert guidance on installation and calibration, we help you achieve optimal results.
Conclusion
Ready to enhance your current measurement capabilities? Explore our selection of advanced Rogowski coils at Aim Dynamics today! Contact us for expert advice tailored to your specific needs and discover how our solutions can drive efficiency and accuracy in your operations.
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