Transformer working principle
Transformer is the exchange of AC voltage, alternating current and impedance of the device, when the primary coil with AC current, the core (or core) will produce AC flux, the secondary coil induced voltage (or current) The
Transformer consists of iron core (or core) and coil, the coil has two or more than the winding, which connected to the power supply winding called the primary coil, the rest of the winding called secondary coil.
Commonly used transformer classification can be summarized as follows:
1, according to the number of points:
1) single-phase transformer: for single-phase load and three-phase transformer group.
2) three-phase transformer: for three-phase system of the rise and fall voltage.
2, according to the cooling method points:
1) Dry-type transformers: rely on air convection for natural cooling or increase fan cooling, and more for high-rise buildings, high-speed toll stations and local lighting, electronic circuits and other small-capacity transformers.
2) oil-immersed transformers: rely on oil as a cooling medium, such as oil from the cold, oil-cooled air-cooled, oil-water cooling, forced oil circulation.
3, according to the use of points:
1) power transformer: for the transmission and distribution system of the rise and fall voltage.
2) instrument with transformers: such as voltage transformers, current transformers, for measuring instruments and relay protection devices.
3) test transformer: to produce high pressure, the electrical equipment for high pressure test.
4) special transformers: such as electric furnace transformers, rectifier transformers, adjust the transformer, capacitive transformers, phase-shifting transformers.
4, according to the winding form points:
1) Double winding transformer: Used to connect two voltage levels in the power system.
2) Three-winding transformer: generally used in power system area substation, connect three voltage levels.
3) Autotransformer: Power system for connecting different voltages. Can also be used as a normal step-up or down transformer.
5, according to the core form points:
1) core transformer: for high voltage power transformers.
2) amorphous alloy transformer: amorphous alloy core transformer is a new type of magnetic materials, no-load current drop of about 80%, is the energy-saving effect of the ideal distribution transformer, especially for rural power grids and developing areas such as load Rate lower place.
3) Shell transformers: special transformers for high current, such as electric furnace transformers, welding transformers; or power transformers for electronic instruments and televisions, radios, etc.
Transformer components include body (core, winding, insulation, lead), transformer oil, fuel tank and cooling device, pressure regulator, protection device (dehumidifier, airway, gas relay, oil conservator and temperature measurement device ) And outlet bushings.
1, iron core
The core is the main magnetic part of the transformer. Usually by the high silicon content, the thickness of 0.35 mm \ 0.3mm \ 0.27 mm, by the surface coated with insulating paint hot rolled or cold rolled silicon steel sheet stacked from.
The core is divided into two parts: the core column and the horizontal piece, the core column has the winding; the horizontal piece is the closed magnetic circuit.
Core structure of the basic form of heart and shell type two.
Winding is the circuit part of the transformer, it is double wire package insulated flat wire or enamel round wire wound into.