Here are several common methods for handling multi-point grounding faults in transformer cores: (1) For cores with external grounding leads, a resistor can be connected in series within the core grounding circuit to limit the grounding current. This method should only be used as an emergency measure. (2) For grounding faults caused by metallic foreign objects, the problem can usually be identified by performing a tank removal inspection (uncovering the core). (3) For grounding faults caused by burrs on the core or the accumulation of metal powder, the following methods have proven to be quite effective: Read More

The two key conditions for demagnetization are: alternating magnetic poles and decreasing magnetic field strength. To demagnetize a ferromagnetic material, the uniformity of its magnetic domain alignment must be disrupted, making the arrangement of the magnetic domains completely random so that no magnetism is exhibited externally. Read More

The primary source of transformer noise is the core. Core noise is caused by core vibration resulting from the magnetostriction of silicon steel sheets and magnetic attractive forces. The magnitude of magnetostriction is related to the material of the silicon steel sheets and the tightness of the core; the higher the magnetic flux density of the core, the greater the magnetostriction of the silicon steel sheets. The condition of the stacking joints in the transformer core affects the flow of magnetic flux, causing the core to generate noise of varying degrees and magnitudes. If the AC power supply contains harmonic components, it will lead to increased noise. The fundamental frequency of core noise is twice the power supply frequency, along with noise at various integer multiples of that frequency. Additionally, electromagnetic forces between winding conductors or between coils can also cause vibration and lead to noise. The following are several countermeasures for suppressing noise: Read More