Classification of transformers

Time:2023-06-17   Visits:1083

A transformer is a device that uses electromagnetic mutual induction to transform voltage, current, and impedance. It has functions such as voltage transformation, current transformation, and impedance transformation. Frequency transformers, high frequency transformers, power transformers, adjustable transformers, electronic transformers (silicon controlled voltage regulators), etc., and many others are not listed one by one. It has a very wide range of applications in daily life. Next, I will briefly introduce the family of transformers.

1) Classified by cooling method: dry type (white cold) transformer, oil immersed (white cold) transformer, fluoride (evaporative cooling) transformer.

2), according to the moisture-proof classification: open transformers, potted transformers, sealed transformers.

3), according to the core or coil structure classification: core transformer (insert core, C-type core, ferrite core), shell-type transformer (insert core, C-type core, ferrite iron core) core), toroidal transformers, metal foil transformers.

4) Classification according to the number of power supply phases 1. Single-phase transformer: used for single-phase load or three-phase transformer group. 2. Two-phase transformer, also known as dual live wire transformer. 3. Three-phase transformer: used for raising and lowering the voltage of the three-phase system. 4. Multi-phase transformer

5) According to the cooling method

1. Dry-type transformer: rely on air convection for natural cooling or increase fan cooling, mostly used in small-capacity transformers such as high-rise buildings, high-speed toll stations, local lighting, and electronic circuits.

  2. Oil-immersed transformer: rely on oil as cooling medium, such as oil-immersed self-cooling, oil-immersed air-cooled, oil-immersed water-cooled, forced oil circulation, etc.

6) According to the purpose

1. Power transformer: used for raising and lowering the voltage of the power transmission and distribution system.

2. Instrument transformers: such as voltage transformers, current transformers, used for measuring instruments and relay protection devices.

3. Test transformer: It can generate high voltage and conduct high voltage test on electrical equipment.

4. Special transformers: such as electric furnace transformers, rectifier transformers, voltage regulating transformers, capacitive transformers, phase-shifting transformers, etc.

7) According to frequency: audio transformer, intermediate frequency transformer, high frequency transformer, pulse transformer.

8), according to the winding form

1. Double winding transformer: used to connect two voltage levels in the power system.

2. Three-winding transformer: generally used in substations in power system areas to connect three voltage levels.

3. Autotransformer: used to connect power systems with different voltages. It can also be used as an ordinary step-up or step-down transformer.

9) 、Extended information

10) Cooling method of transformer

1. Oil immersion natural cooling method

2. Oil-immersed air-cooled

3. Forced oil circulation water cooling

4. Forced oil circulation air cooling

5. Forced oil circulation guide cooling

11), other transformers

The electronic voltage regulator is also called the thyristor voltage regulator, and the output voltage is changed by changing the conduction angle through the principle of phase shifting. There are also sine wave voltage regulators, DC voltage regulators, etc.

12) Conditions for Parallel Transformers

1. The voltage ratio is the same, allowing a difference of ±0.5%;

2. The percentage impedance is equal, and the difference is allowed to be ±10%;

3. The wiring group is the same.


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