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What are they? What are they used for?
Why is it important to choose the right version for energy consumption measurement installations?
An current transformer consists mainly of two conducting wires wound to form a coil around two pieces of ferromagnetic material, typically called a core; each winding is called a loop.
Current transformers are accessories that are used to be integrated into Energy Meters or applications where a current needs to be measured, with secondary manageable by the instrument, while maintaining the same waveform as the primary.
To measure power and energy, in addition to the voltage measurement, we must also read the current measurement. Circuits can be single-phase or three-phase: a single phase with a the use of only one CT or a three-phase circuit with three CTs installed.
Choosing the correct for current transformer determines the good execution of our installation. But how can we choose the right current transformer?
Simple, by starting and analyzing the application on which we want to go and use them.
We divide into two macrocategories: closed-loop current transformers (solid core) and openable versions (split-core). The two uses are distinct.
In the construction of a switchboard by a manufacturer/electrician, there is no need to use an openable current transformer, but closed-loop ones are used, which are cheaper and perform better.i.
On the other hand, for monitoring and retrofit installation activities of Network Analyzers and Energy Meters, it is advisable to use an openable current transformer, as there is no need to intervene in the wiring by going to unplug or disconnect the load.
Openable Current Transformers are less performing because of their construction and more expensive precisely because there is more processing to be done.
In the next video we are going to look in detail at the features of these current transformers.