Split Core Current Transformers Key Specifications
Current Sensor Requirements and specifications you must know before selecting one for your application
In most applications, measurement accuracy directly affects the efficiency of an overall system. The accuracy of the power calculation depends on the accuracy of the current sensors. A class 1 power meter requires current sensors with accuracy much better than 1%.
The drift of a sensor is related to the sustainability of a reading over time. Some variations of its characteristics may be caused by changes in the ambient humidity and temperature, component aging, and so on.
The linearity of the sensor refers to the stability of its characteristics within the full operating mode. A high linearity of the analog-sensing part is essential to measure a wide range of primary currents accurately, especially at low current levels.
The accuracy of the true active power or energy calculation is not only related to the accuracy and linearity of the AC current and voltage sensors in terms of amplitude, but also to the phase shift that may occur between the measurement of these correlated values. The phase shift should be as low as possible.
Being self-powered, the CTs do not require any other wiring than a 2-wire output connection to the main power monitor unit. The typical 1-A and 5-A or 333-mV outputs are compatible with most standard power meters on the market. Current outputs are also almost insensitive to interferences and are preferable to voltage outputs when long cables are required to connect the sensors to the power meter.
The price of the sensors is important when accurate current sensors are required for 3-phase power measurement.
Types of split core CT
Depends on core material there are several different types of split core current transformer are available in the market that can be used in different applications.
1. FeSi split core CT
FeSi split core current transformer is the most affordable option. but, it have poor linearity, especially at lower currents.It is better suited for high current measurements only where precision is not as important as getting a rough figure for electricity consumption. Such CT are also large and weighty, so it has specific physical limits for use.
2. FeNi split core CT
If you’re searching for something more precise,a FeNi split core CT does a great job. Those provide a better measuring performance, including low current conditions. They’re also more expensive though. FeNi split core CT struggle with linearity and take up more space in your panel.
3. Ferrite split core CT
The modern ferrite core transformers have increased permeability and can be used in a wide variety of power monitoring applications, replacing both FeSi and FeNi transformers, even with low magnetic saturation. It provides an affordable alternative to transformers from FeSi and FeNi.