Based on the principle of electromagnetic induction. When high-voltage electrical energy flows through the high-voltage coil, the generated magnetic field will generate magnetic flux in the iron core. This magnetic flux will further induce the electromotive force in the low-voltage coil, thereby converting high-voltage electrical energy into low-voltage electrical energy. Specifically, when a pole mounted transformer is connected to a power source, magnetic flux is generated in the coil due to the flow of current. This flux passes through the magnetic circuits inside and outside the coil, ultimately forming a magnetic flux. Due to the fact that the magnetic flux inside the coil is generated by current, it is called self induced magnetic flux or inductive magnetic flux. When the number of turns of two coils in a transformer is different, the voltage in the transformer will change. This is because when the magnetic flux passes through coils with different numbers of turns, different voltages will be generated inside and outside the coils.