Three-phase transformers (including 33kv to 400v transformer, transformer oil immersed type, oil immersed type transformer) are like three closely connected 'energy portals', and one of their core components is the magnetic circuit system. One of the core components is the magnetic circuit system. The three 'portals', i.e. the three-phase coils, rely on a special channel between them for the transfer of energy, and this channel is the magnetic circuit. The magnetic circuit is usually made up of an iron core, which is made of ferromagnetic material because iron has a high permeability and is able to direct the magnetic field extremely efficiently. From the principle of physics, the magnetic permeability characterises the ability of the material to conduct the magnetic field, the high permeability of ferromagnetic materials is like a highway for the vehicle to provide a smooth and high-speed conditions, greatly reducing the magnetic resistance, so that the magnetic field can be a very small loss through the guarantee of the high efficiency of the energy transfer.
One of the group transformers has a structure similar to three '⊏' shaped doors arranged side by side. In this structure, each 'gate' has its own magnetic path, which is independent of each other and does not interfere with each other. Core transformers, on the other hand, are constructed more like a 'cloverleaf' shape. In this design, three coils are co-wound on top of the same core, and they share the main magnetic circuit in the middle, just as three roads intersect on a single main road, which reduces the amount of material used and, in turn, achieves miniaturisation of the size.
The magnetic circuit system of the three-phase transformer is essentially the use of the iron core to build a 'magnetic highway' serving the three coils, enabling energy to be efficiently transferred between the three phases in the form of a relay race, ensuring the stable operation of the power system and the effective transmission of electric energy. The main reason for choosing iron core instead of air as the magnetically conductive medium in the magnetic circuit system is that the magnetic permeability of air is extremely low, compared with its poor magnetic conductivity, just like a vehicle travelling on a rugged dirt road, it will encounter a large resistance, which will make it difficult for the magnetic field to pass through smoothly, resulting in a large amount of energy loss. And the iron core with its good magnetic conductivity, just like vehicles driving in the flat and wide tarmac, magnetic field can easily in which 'shuttle', greatly reducing the hysteresis loss and eddy current loss, improve the operating efficiency of the transformer, to protect the energy utilisation in the process of power transmission!