Transformers for AC current measurement offer unique advantages over other current measurement solutions: galvanic isolation, low losses, high noise immunity, and simple design. Selecting the right current sensor can be challenging, depending on the application. With the Current Sensor Transformer Selector, Würth Elektronik offers a unique design tool that has never before been available on the market in this format.
After entering the required parameters for current, frequency, signal type, and desired maximum error rate, the Selector finds all available options in the Würth Elektronik product catalog that meet these criteria. The tool provides a list of components with their corresponding parameters and simulates the temperature rise and error as a function of frequency and current. Furthermore, the tool displays a comparison of the different options and provides a summary page with all relevant information for the selected component. These simulations, based on series of measurements, save designers from having to perform their own tests for CST selection.
The selection process without the REDEXPERT Current Sensor Transformer Selector module is as follows: First, the current measuring transformer must be selected with a suitable ET constant to prevent saturation, even under unfavorable conditions, such as low frequencies and high currents. It is also important to ensure that the CST does not overheat at maximum current. Finally, and equally important, the failure characteristics required for the specific application must also be considered when selecting the component. Since current measuring transformer datasheets do not cover all application-relevant parameters—and in practice, cannot—it is often necessary to test several components to optimize the selection.
Applications
Typical applications of current measuring transformers include AC current measurements, switched-mode power supplies, overload detection, load disconnection/release detection, metering, load measurement, and high-frequency current detection.
