Due to their ability to make high-voltage and high-amperage inputs measurable without significantly affecting the circuit being measured, AC current sensors are commonly used in power monitoring systems. When incorporating these sensors into a monitoring setup, it’s important to take their design specifications into account. Below are some of the key specifications that need to be considered when choosing a sensor for a particular situation:
- Transformer or transducer: There are generally two types of AC current sensors available. In design, these two types are basically the same, the only difference being the additional circuitry in a transducer to convert the current output from the coil into a DC signal.
- Output type: Originally, other than transducers, current sensors would output a rated current from their secondary winding. However, with the development of wideband transformers, it is now also possible for current sensors to output a rated voltage at the secondary.
- Output rating: There are a wide range of output ratings available for current sensors. For use with digital networked power meters, the most common output ratings are 4-20 mA or 5A.
- Input rating: Input rating is usually less important than output rating because if the input to be measured is too small, adding additional windings to the primary can make even lower input levels measureable.