1 "First winding primary or secondary coil can be, usually choose to wind the primary coil after winding secondary coil, because secondary coil wire diameter is relatively large, wound in the outer layer to make mechanical properties more reliable.
2 "primary coil load voltage is high, as far as possible to row winding direction, small wire diameter is difficult to row winding should try not to overlap the winding turns, so as to avoid the voltage difference between the front and back winding is too large, easy breakdown short circuit.
Can be wound in multiple layers, between layers should be old-style wax paper as the insulation between windings.
3 "Between the primary and secondary application of green shell paper or single-sided thin film insulating paper around 2 or 3 layers to strengthen insulation.
The most basic form of a 220v transformer consists of two sets of coils with wires wound around them and weighed together with each other in an inductive manner.
When an AC current (with a given frequency) flows through one set of coils, an AC voltage of the same frequency will be induced in the other set of coils. The induced voltage depends on the degree of coupling and magnetic cross-linking between the two coils.