In power transformers, the high-voltage (HV) winding is typically placed over the low-voltage (LV) winding machine. This is because the HV winding has a higher voltage potential than the LV winding, and placing it on top helps to reduce the risk of electrical breakdown between the windings.
When the transformer is energized, the HV winding produces a strong electric field, which can ionize the surrounding air and create corona discharge. This corona discharge can lead to an electrical breakdown between the windings if the HV winding is placed below the LV winding. By placing the HV winding on top, the distance between the windings is increased, which reduces the risk of electrical breakdown.
Additionally, placing the HV winding on top can help to improve the cooling of the transformer. Since the HV winding generates more heat than the LV winding due to the higher current density, placing it on top allows for better heat dissipation, as the heat rises naturally towards the top of the transformer.
Overall, placing the HV coil winding machine on top of the LV winding is a common practice in a power transformer design to reduce the risk of electrical breakdown and improve cooling efficiency.
