Why does the transformer output current increase and the input current increase?

When the transformer output current increases, the input current also increases, which is mainly based on the principle of electromagnetic induction and the law of conservation of energy. The following is a detailed explanation of this phenomenon:

Principle of electromagnetic induction

A transformer is a static electrical appliance made of the principle of electromagnetic induction. When the primary coil (primary coil) of the transformer is connected to the AC power supply, alternating magnetic flux is generated in the core. This alternating flux passes through both the primary and secondary coils (secondary coils), causing a voltage (or current) to be induced in the secondary coils. Since the magnetic flux in the primary and secondary coils is the same, the voltage and current between them have a fixed relationship.

Conservation of energy law

In the process of energy conversion, the transformer follows the law of conservation of energy. This means that the power at the input end of the transformer (that is, the product of the input voltage and the input current) is equal to the power at the output end (that is, the product of the output voltage and the output current). Therefore, when the output current increases, in order to maintain power balance, the input current must also increase accordingly.

Relation between turns ratio and current

In a transformer, the ratio of turns between the primary coil and the secondary coil determines the voltage ratio and current ratio. Specifically, the voltage ratio is equal to the turns ratio, i.e. U1/U2=N1/N2 (U1 is the voltage of the primary coil, U2 is the voltage of the secondary coil, N1 is the number of turns of the primary coil, N2 is the number of turns of the secondary coil). The current ratio is inversely proportional to the turn ratio, that is, I1/I2=N2/N1 (I1 is the primary coil current, I2 is the secondary coil current). Therefore, when the current I2 of the secondary coil increases, the current I1 of the primary coil will also increase correspondingly in the inverse ratio of the number of turns.

In summary, when the output current of the transformer increases, the input current also increases, which is an inevitable result based on the principle of electromagnetic induction and the law of conservation of energy. In practical applications, we need to reasonably select and adjust the parameters and operation state of the transformer according to the changes of the load and the needs of the power grid.