The main magnetic flux in the transformer core, the induced potential in the primary and secondary windings is alternating potential, there is no fixed polarity. The transformer winding polarity here refers to the relative polarity of the primary and secondary windings, that is, when one end of the primary winding is positive at a certain instantaneous potential, the secondary winding is also positive at the same moment for the corresponding end of the potential, then the two corresponding ends are called the same polarity end of the transformer.
 
The polarity of the transformer winding is determined by the winding direction of the transformer winding, when the winding direction changes the polarity will also change. Polarity is one of the main conditions for transformer parallel operation, if the polarity is reversed, it will cause a short circuit and burn the transformer. This is the same as two batteries used in parallel, should be connected to the positive terminal and the positive terminal, the negative terminal and the negative terminal, if the positive terminal and the negative terminal are connected at the same time, the battery will be short-circuited, and the battery will soon be burned up.
 
The winding is usually divided into two types of layer and pie type.
 
The winding of the wire turns along its axial arrangement of continuous winding, known as layer winding. General layer winding each layer such as a cylinder, so the winding composed of two layers called double cylinder type; composed of multiple layers called multi-layer cylinder type.
 
The winding of the wire turns along its radial continuous winding made of a pie (segment), and then by many pie along the axial arrangement of the winding is called pie winding. It includes continuous type, insert capacitor type and kink type.
 
Between the layer and pie type winding are foil winding and spiral winding. The foil winding is also in the form of a tube, and the wire turns are wound continuously in the axial direction, generally one turn is a layer, so it can be a layer winding. Spiral winding is generally one turn per pie, or two pies, four pies a turn, and each turn is wound continuously along the axial direction, but the form is composed of each pie, so it can belong to the pie winding.
 
The winding is the circuit part of the transformer, is made of copper or aluminum wire winding with insulation on the surface, and set on the core column of the transformer. The winding has primary winding and secondary winding, primary winding for power input, secondary winding for output. When the primary winding passes alternating current, alternating flux is generated in the core accordingly. According to the principle of electromagnetic induction, the energy input from the primary winding is transferred to the secondary (output) winding through the core. Line loss in the process of transmission. The winding should have sufficient insulation strength, mechanical strength and heat resistance.
 

Previous：Quels sont les types de matériaux de bobinage utilisés dans les transformateurs ?
Next：Electromagnetic wire industry news