Why should the transformer be oiled, and why should the magnetic core inside be covered with oil?

- Feb 25, 2020-

The magnetic core inside the transformer is covered with oil, because the transformer works in AC, and the current passes through the coil to generate a magnetic field. In the case of mutual inductance, noise will be generated. The oil can reduce noise, and at the same time, it can also serve as insulation and cooling Role.


 Transformer oil has the following main functions:

1. Insulation: Transformer oil has much higher insulation strength than air. Immersion of the insulating material in oil not only improves the insulation strength, but also protects against moisture.


2. Cooling effect: The specific heat of transformer oil is large, and it is often used as a coolant. The heat generated during the operation of the transformer causes the oil near the iron core and windings to expand due to heating. Through the up and down convection of the oil, the heat is dissipated through the radiator to ensure the normal operation of the transformer.


3. Arc extinguishing effect: On the on-load voltage regulating switch of the oil circuit breaker and the transformer, an arc occurs when the contacts are switched. Because the transformer oil has good thermal conductivity, and can contact a large amount of gas under the high temperature of the arc, generating a large pressure, thereby improving the arc extinguishing performance of the medium and causing the arc to extinguish quickly.