Two factors to consider when choosing a Miniature Current Transformer

Miniature Current Transformer works based on the principle of electromagnetic induction. The so-called current transformer is usually composed of a closed iron core and windings. Similar to the transformer, the current transformer also works according to the principle of electromagnetic induction. The transformer transforms the voltage, but the difference is that the Miniature Current Transformer transforms the current.

Usually there are different situations in the application. Generally, we connect the Miniature Current Transformer to the winding of the measured current (the number of turns is N1), which is called the primary winding (or the primary winding, the primary winding); the winding of the measuring instrument ( The number of turns is N2) is called the secondary winding (or secondary winding, secondary winding). The more common transformers used for precision measurement, different types of precision current transformers can be selected according to different needs, but in order to improve the measurement accuracy, the following two aspects should be considered in the selection process of current transformers:

The first is to consider the influence of primary current. This is because when the Miniature Current Transformer is working and its primary current is relatively small, the error caused will be relatively large; and when the primary current is larger than the rated current for a long time, the error will also increase. Therefore, generally The primary measured current should be greater than 25% of the rated current of the transformer and less than 120%.

In view of this situation, during the selection of Miniature Current Transformer, we need to select the primary side current of the transformer in combination with the rated range of the product. The second is to take into account the impact of secondary loads. When the secondary load of the current transformer increases, the error (ratio difference and angle difference) also increases. Therefore, the secondary load should not exceed its rated value (volt-ampere or ohm) in use.

In fact, the secondary load capacity of Miniature Current Transformer mainly depends on the rated capacity of the current transformer. The rated capacity of the current transformer is the apparent power consumed when the rated secondary current I2e passes through the rated load Z2e, that is, S2e=I2e² ×Z2e. In the production process of the transformer, the core and cross-sectional area of the transformer can affect the rated capacity of the current transformer.