Transformer cores
The three-phase transformer uses the principle of electromagnetic induction to exchange electricity and magnetism. Its main structure is a coil and an iron core. Generally, the high and low voltage windings of each phase are wound on the same iron core column and pass through the same magnetic flux.The high and low voltage windings of the three-phase transformer have star and delta connections, which can be combined with each other to obtain 12 groups of more than 48 different connection methods, and three of the most commonly used are: Yyn0; Yd11 and YNd11.
1. The connection method of Yyn0 means that the high and low voltage windings are all star-connected and have a neutral wire.
2. The connection method of Yd11 is that the high-voltage winding is star-shaped, and the low-voltage winding is delta.
3. The connection method of YNd11 is that the high-voltage winding is star-shaped with neutral wire, and the low-voltage winding is delta.