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3 phase to single phase transformer

Three-phase transformer: In order to input different voltages, the input winding can also use multiple windings to accommodate different input voltages. At the same time, multiple windings can be used in order to output different voltages. Three independent windings are connected to the three-phase AC power supply through different connections (eg, star, triangle), and the output is also the same. This is a three-phase transformer.

Single-phase transformer: A device that uses the principle of electromagnetic induction to change the AC voltage. The main components are the primary coil, the secondary coil, and the core (core). In electrical equipment and wireless circuits, it is often used as lifting voltage, matching impedance, and safety isolation.

A three-phase variable single-phase transformer is a transformer that turns a three-phase input into a single-phase output. The transformer input maximum phase current is twice the current of one of the other phases. It can reduce the single-phase 220V load current by 40%; the single-phase 380V load current has the same maximum phase current, while the other two phases are 50% of the maximum one-phase current. It is more expensive than an isolation transformer. It is widely used in the occasion of specific load of industrial and mining enterprises to solve the problem of serious imbalance of three-phase current. Three-phase to single-phase transformer This series of products is suitable for AC 50/60Hz working voltage below 600V. This series of transformer insulation heat resistance grade is F grade. The three-phase variable single-phase transformer core is formed by stacking cold-rolled oriented high-quality silicon steel sheets, and the coil structure adopts a cylinder, an elliptical cylinder and a rectangular cylinder. Small size, excellent performance, safe and reliable.

3 phase to single phase transformer

Few people know what is the working principle of a three-phase transformer single-phase transformer? Because buyers basically do not pay attention to what works, functions, materials, etc., only pay attention to the price, which leads to few people understand the working principle of three-phase transformer single-phase transformer.
Generally speaking, three cores of a three-phase transformer are wound around three windings, and the three-phase power source can be simultaneously transformed to the secondary side winding, and the output thereof is also a three-phase power source. The single-phase transformer has only one winding on the core, and can only transform one-phase power to the secondary output. In large substations and power plants, three single-phase transformers are also combined into one three-phase transformer, called “combined three-phase transformers.” Generally, three-phase power supplies are used for power grid transmission and industrial use, so three-phase transformers are used. The single-phase transformer is generally used in places where the single-phase power supply is required for civilian use, such as household appliances, etc., and its capacity is relatively small. Generally speaking, three cores of a three-phase transformer are wound around three windings, and the three-phase power supply can be simultaneously changed. Pressed to the secondary winding, the output is also a three-phase power supply. The single-phase transformer has only one winding on the core, and can only transform one-phase power to the secondary output. In large substations and power plants, three single-phase transformers are also combined into one three-phase transformer, called “combined three-phase transformers.” Generally, three-phase power supplies are used for power grid transmission and industrial use, so three-phase transformers are used. Single-phase transformers are generally used in places where single-phase power is required for civilian use, such as household appliances, etc., and their capacity is relatively small.

3 phase to single phase transformer

The difference between single-phase transformer and three-phase transformer
1, the definition is different
Single-phase transformer: A device that uses the principle of electromagnetic induction to change the AC voltage. The main components are the primary coil, the secondary coil, and the core (core). In electrical equipment and wireless circuits, it is often used as lifting voltage, matching impedance, and safety isolation.
Three-phase transformer: In order to input different voltages, the input winding can also use multiple windings to accommodate different input voltages. At the same time, multiple windings can be used in order to output different voltages. Three independent windings are connected to the three-phase AC power supply through different connections (eg, star, triangle), and the output is also the same. This is a three-phase transformer.

2, the application is different

Single-phase transformer: suitable for application and promotion in low-voltage distribution networks with low load density.

Three-phase transformer: Three-phase transformer is widely used in circuits with AC 50Hz to 60Hz and voltage below 660V. It is widely used in importing important equipment, precision machine tools, mechanical and electronic equipment, medical equipment, rectifiers, lighting, etc.

The various input and output voltages of the product, the connection group, the number and position of the adjustment taps (generally ± 5%), the distribution of the winding capacity, the configuration of the secondary single-phase winding, the operation of the rectifier circuit, whether it is required The outer casing and the like can be carefully designed and manufactured according to the requirements of the user.

3, different characteristics
Single-phase transformer: Single-phase transformer has a simple structure, small volume and low loss, mainly due to small iron loss.
Three-phase transformer: The new neutral-grounding of the three-phase transformer can remove the common mode interference and other mid-line problems in the power grid. The three-phase transformer converts the three-wire △ wiring into a four-wire Y0 system.
The addition of shielding further eliminates the high-frequency pulse interference and noise coupled by the transformer. Although the shielded three-phase transformer can effectively prevent the interference from various NGs (pulse and high-frequency noise), the transformer must be properly grounded otherwise. Anti-common mode interference will have no effect.

Application limitations
Limitations of single-phase transformer applications First, single-phase transformers can only be used in lighting or small motors due to their single voltage. The application range has limitations. However, due to the sideline business and workshops in China's rural areas, it cannot be widely promoted, that is, used, and it is only used as a supplement to the three-phase power supply system. Single-phase transformers have been applied. First, they are applied in the deep mountainous areas. The residents are scattered, the electricity load is small, and there is basically no power application, which can greatly reduce the line investment. Second, it is applied to street lamps. Secondly, the high-voltage input load center caused by the single-phase transformer is easily resisted by people. People's legal concept is improved, and the concern for the living environment is also very important. No owner wants the electric industry department to root the "flag pole" in front of the door, with transformers on it, high voltage power, and noise. At the same time, real estate merchants only require electricity, but they are reluctant to appear in the blueprint of their own power facilities. One is afraid of electromagnetic radiation, the other is fear of danger, and the third is afraid of affecting the landscape. The power sector charges to the household, and the loss of the line is a matter of the power sector. The owner and the developer are not obliged to provide convenience to the power sector.

3 phase to single phase transformer

Generally speaking, three cores of a three-phase transformer are wound around three windings, and the three-phase power source can be simultaneously transformed to the secondary side winding, and the output thereof is also a three-phase power source.
The single-phase transformer has only one winding on the core, and can only transform one-phase power to the secondary output.
In large substations and power plants, three single-phase transformers are also combined into one three-phase transformer, called a “combined three-phase transformer”.
In the general grid transmission and industrial use of three-phase power, so three-phase transformers are used. Single-phase transformers are generally used in places where single-phase power is required for civilian use, such as household appliances, etc., and their capacity is relatively small.

The transformer uses the principle of electromagnetic induction to change the AC voltage. The main components are the primary coil, the secondary coil and the core (core). In electrical equipment and wireless circuits, it is often used as lifting voltage, matching impedance, and safety isolation. The functions of the transformer mainly include: voltage conversion; current conversion, impedance transformation; isolation; voltage regulation (magnetic saturation transformer); autotransformer; high voltage transformer (dry and oil immersed), etc. Type and C type core, XED type, ED type CD type.

significance:
Less material
Single-phase transformers of the same capacity are reduced by 20% compared to three-phase transformers and 10% by copper. Especially when the coil core structure is adopted, the no-load loss of the transformer can be reduced by more than 15%, which will reduce the manufacturing cost and the use cost of the single-phase transformer at the same time, thereby obtaining the optimum life cycle cost.
Low line investment
The use of a single-phase power supply system in the power grid can save 33% to 63% of the wire. According to the economic current density calculation, the wire weight can be saved by 42%. According to the mechanical strength calculation, the wire consumption can be reduced by 66%. Therefore, the construction investment of the entire transmission line can be reduced. This is very meaningful in the lighting of rural areas and towns in China and the electricity consumption of residents.

Conducive to modern production
Due to its simple structure, single-phase transformers are suitable for large-scale modern production, which is conducive to improving product quality and efficiency. Fourth, it is suitable for introducing new technologies, new materials, new processes, and gaining technical points. The Fifth Plenary Session of the 16th CPC Central Committee proposed to save resources as a basic national policy, and the "Eleventh Five-Year Plan" of the "Outline" further In the five-year period, the energy consumption per unit of GDP was reduced by about 20% as a binding indicator. In this context, new products with high added value will be greatly reduced. When calculating the online loss theory, it can be found that 80% of the line loss occurs on the 20% main line. Therefore, shortening the low-voltage main line distance can greatly reduce the low-voltage line loss. Because the single-phase transformer is light in weight, it can be flexibly installed on the pole. It can be used in the center of the load, and it can reduce the power supply and improve the quality of power supply. Generally, the single-phase transformer is powered in a small range, and the fault has a small surface, which is beneficial to improve the reliability of the power supply. At the same time, because the single-phase transformer is light in weight, easy to install and maintain, flexible to use, it can be used in single-phase or three-phase three-phase transformers.

Less investment in construction
The cost of transformers is reduced. The construction of single-phase power supply systems in light-load areas can reduce construction investment. The transformation of single-phase power supply systems in heavy-duty areas requires a large economic investment. The author has seen that some single-phase transformers are piloted in residential areas, and the implementation of large transformers into multiple small transformers, installed near the load, shortens the distance of the low-voltage main line, because the distance from the power point to the load is certain, shortening the low voltage The power supply distance will inevitably extend the high-voltage transmission distance. This kind of transformation requires a lot of investment. For example, 30 households in the original three units use one 160 kVA three-phase transformer, and three sets of 50 kVA single-phase transformers are used for power supply. Table 2 lists The changes in materials and losses of the two retrofit schemes have significantly increased construction investment. First, in order to reduce the line loss of the low-voltage main line, the high-voltage line should be introduced into the load center to increase the investment in the construction of the high-voltage line. Second, the no-load loss and load loss after using multiple small-capacity transformers are more than the original single-capacity transformers. Third, the purchase of multiple small-capacity transformers is also greater than the purchase of a single large-capacity transformer. Because of the large amount of electricity used by residents in foreign countries, several or each household uses a single-phase transformer because of the country's wealth and the large capital investment in the power sector. Although the investment is large, it is still cost-effective for them in general.

 

3 phase to single phase transformer

A single-phase transformer is a transformer in which the primary winding and the secondary winding are single-phase windings.
The unipolar switching power supply means that the output is unipolar, that is, only the positive and negative outputs. Compared with the bipolar switching power supply, the bipolar switching power supply has three outputs, which are divided into positive power supply, negative power supply and ground. .
The single-phase transformer has a simple structure, small volume and low loss, and is mainly small in iron loss, and is suitable for application and promotion in a low-voltage distribution network with a small load density. Suzhou City has used more than 1,000 units and saved 45GWh of electricity. The experience is worth promoting. Some data show that single-phase transformers are widely used in developed countries, such as the United States and Japan. Single-phase power supply is the main way to supply electricity to residents. Under this propaganda, some people think that single-phase power supply has "falling loss". Magic, think that single-phase transformer is more energy-efficient than three-phase transformer, and that single-phase power supply system is superior to three-phase power supply system. In fact, single-phase transformers and single-phase power supply systems are only complementary forms of the current three-phase power supply system. Due to their own characteristics, they can only be applied to certain specific fields.

effect:
More energy efficient
Is the loss of single-phase transformer low? In the previous papers on single-phase transformers and single-phase power supply technology, it is considered that single-phase transformers have lower no-load losses, lower energy consumption, and lower loss than three-phase transformers of the same capacity. Some papers cite examples of applications, mentioning the economic benefits of retrofitting, using D10, D11 or even D12 series transformers and S9 series transformers of the same capacity, for example, mentioning the same capacity D11 single-phase transformer than S9 three Phase transformers have much lower no-load losses, so it is a misunderstanding that single-phase transformers are more economical than three-phase transformers. For example, the technical level difference between the two is neglected. According to JB/T3837-1996 "Modulation Method for Transformer Product Models", the performance level of the transformer model is specified, and the performance parameters of the No. 1 To be raised to a new level. For example, the D10 series transformer is designed according to the S10 transformer parameters. When demonstrating the effect of reducing the loss of series transformers such as D10 or D11, the S10 or S11 transformer of the same type should be selected for comparison. It is unfair to select the S9 series transformer as the reference object. .
In addition, ordinary S9 series transformers use a stacked iron core structure, while D10, D11 and so on mostly use a wound core structure: the stacked iron core and the wound iron core have different technical differences, and the wound core structure overcomes The insurmountable disadvantages of the conventional stacked core structure, for example, in a core lamination, the lengths of the magnetic paths along the outer side and the inner side are relatively large, so that the magnetic flux is not evenly distributed in the iron piece, and high harmonics are generated. The wave results in an increase in loss. In the three-phase iron core, in the intersection area of ​​the iron yoke and the B-phase core column, a rotating magnetic field is generated due to the three-phase magnetomotive force to increase the loss, and there is a seam at the butt joint between the iron core laminations. Within the seam area, there is a magnetic flux that traverses the laminations laterally to increase losses. Therefore, the wound core transformer has less no-load loss and less no-load current than the stacked iron core transformer. In addition to the weight difference of the 11-model 100 kVA capacity three-phase coil core sealed transformer and single-phase coil core transformer, the technical indicators are not obvious. Therefore, the conclusion that single-phase transformers have always been less damaged and energy-saving than three-phase transformers is unfounded.

Low line loss
Is the single-phase power supply mode low? According to the circuit principle, the same distance is transmitted by the same power P, the power factor is 1, and the line loss of the three-phase power supply mode and the single-phase power supply mode is as follows. Assume that a wire of the same cross section is used and the wire resistance is R. The single-phase transformer is powered by two-wire mode. When the power P is delivered, the current in the phase and neutral lines is I, and the resulting line loss is P single loss = 2I^2R. The three-phase transformer is powered by three-phase four-wire mode. When the power P is delivered, the phase current in the line is I /3. In the ideal state, there is no current in the neutral line, and the phase-phase P-phase loss = (I/3) 2R = I2R/9.
In this mode, the line loss is P three losses = 3 × (I / 3) 2R = I2R / 3. It can be seen from the calculation that the line loss of the three-phase power supply mode is the lowest, and the single-phase power supply mode is six times higher than the three-wire power system. It can be seen that the single-phase power supply mode has no advantage in reducing the line loss in the three-phase power supply mode.

3 phase to single phase transformer

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