Now let’s talk about the transformer winding. The main part of the winding is a coil that once wraps around the magnetic circuit and in which a magnetic field is induced. Under the winding understand the sum of the turns, the EMF of the entire winding is equal to the sum of the EMF in each turn.
In power transformers, the winding usually consists of conductors having a square cross section. Such a conductor is also called a residential conductor in another way. A square conductor is used to make better use of the space inside the core. As insulation of each core, either paper or enamel varnish can be used. Two cores can be interconnected and have one insulation this design is called a cable. For the high voltage transformers and switchgears a proper repair source is important.
The windings are of the following types: main, regulatory and auxiliary. The main one is called the winding to which current is supplied or from which (primary and secondary windings) are drawn. A winding with terminals for regulating the voltage transformation coefficient is called regulating.
From the course of school physics it is known that the power loss in the wires is directly proportional to the square of the current strength. Therefore, to transmit current over long distances, the voltage is increased, but before being fed to the consumer, on the contrary, it is lowered. In the first case, step-up transformers are needed, and in the second, step-down transformers. This is the main application of transformers.
Transformers are also used in power supply circuits for household appliances. For example, in televisions, transformers are used that have several windings (for powering circuits, transistors, a kinescope, etc.).
The transformer insulation is based on matrixless vacuum impregnation and works in an environment with high humidity and in a chemically aggressive atmosphere.
Minimum combustion energy (for example, 43 kg for a 1600 kVA transformer corresponds to 1.1% of the weight). Other insulation materials are practically non-combustible, self-extinguishing and do not contain any toxic additives.
- Transformer resistance to pollution due to convection self-cleaning winding disks.
- Large leakage lengths on the surface of the winding discs, which create the effect of insulating barriers.
- Transformer resistance to temperature shock even at extremely low temperatures (-50 ° С).
- Ceramic laying blocks (without the possibility of fire) between the winding disks.
Insulation of glass-silk conductors
- Safe operation of the transformer due to the special structure of the winding. The influence of voltage on the insulation never exceeds the insulation voltage (no more than 10 V). Partial discharges in isolation are physically impossible.
- The transformer is cooled by vertical and horizontal cooling channels, and the minimum insulation thickness allows the transformer to operate during large short-term overloads in the IP 45 protective housing without forced cooling.
- The insulating cylinder is made of a practically non-combustible and self-extinguishing material reinforced with fiberglass.
- Low voltage winding from standard wire or foil; Copper is used as winding material.
- The dynamic resistance of the transformer to short circuits is provided by ceramic insulators.