Tips of single phase transformer

Tips of single phase transformer (1)

A single-phase transformer is a distribution transformer that we often see. It is a cylindrical electrical equipment, not very large, generally installed on the poles. When you are walking on the outskirts of the country and on both sides of the road, you may look up and see a single-phase transformer.

DAELIM is a Chinese transformer manufacturer integrating design, production and sales, with a 15-year history in the transformer field. Daelim builds the brand with the concept of DAELIM EDGE+ADVANTAGE. The story of DAELIM BELEFIC is about a brand that cares about achieving the best for its customers. We are becoming the world’s leading power transformer manufacturer, and achieving a win-win situation with customers is Daelim’s corporate purpose and philosophy. With this philosophy, Daelim offer you a variety of standards, cutting-edge service/speed and expert-level customization skills.

Pad-mounted Transformer

We can provide you single phase and three phase pad mounted transformer

Dry-type Transformer

Type:Cast resin; Rated Capacity: Up to 25MVA; Rated Voltage: Up to 36KV;

Pole Transformer

TypeCSP type Frequency: 50/60Hz; Rated Power: 5~167kva

Oil immersed transformer

Frequency: 50/60Hz Rated voltage:10kv, 20kv,30kv Rated Power: 400~2500kva

Table of Content

What is single-phase transformer?

Single-phase transformer is a transformer whose primary and secondary windings are single-phase windings.Single-phase transformers are generally used in places where single-phase power is required for civil use, such as household appliances, etc., and their capacity is relatively small.

How does a single phase transformer work?

Use electromagnetic induction or mutual inductance principle. A primary current generates a magnetic field, and a secondary current under the action of the magnetic field.

What are the main components of a single-phase transformer?

Porcelain high-voltage bushings, cover band, lifting lugs, low-voltage bushings, copper ground strap, low-voltage circuit breaker, ground connector, high-voltage lighting arrester, oil fill plug, welded hanger brackets, De-energized operation tap changer, nameplate.

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Types of single phase transformer

Tips of single phase transformer (2)

Conventional type: (Single hanger bracket two high voltage bushing self protected unit & Single hanger bracket one high voltage bushing self protected unit). The transformer is sealed with an oil tank inside. Our ANSI single-phase transformer from Daelim has a grounding device, hook, support lug as the fixation, and one or two high voltage bushings will be installed on the box cover, and low voltage bushings will be installed on the tank wall.

The lifting ring bolts will be matched with the connecting terminals.

Tips of single phase transformer (3)

CSP type : CSP transformer is a transformer with lightning protection and short circuit protection function. It can protect transition lines and distribution lines from current failure due to their own faults. For example, oil cylinder, hook, lug, earthing device, nameplate, iron core, winding and other ordinary types are different. Our Daelim single phase transformer has certificate of ANSIIEC/IEEEC57. 12. 20, CSA C2. 1-06, CSA C2. 2-06 and etc.

Tips of single phase transformer (4)

Single-phase transformers are designed for distributed distribution networks and are suitable for urban and rural residents. The single phase distribution transformer may be used alone or as three units in a bank to use. Our single-phase transformers can be mounted directly on wooden or concrete poles, or for the convenience of three-phase use in clusters mounted directly on the pole.

Our single phase transformers serve residential overhead distribution loads, light commercial loads, light industrial lighting and other power applications. Overhead distribution load for village residents.

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Single phase transformer working principle

Tips of single phase transformer (5)

In general, the mutual inductance between the secondary winding and the primary winding is the reason why the transformer works in a power transformer. When the primary side of the AC voltage transformer is U1, the current in the transformer flows through a winding I1. At this time, the alternating magnetic flux generated by the current in the iron core will cause magnetic contact between the primary and secondary windings. According to the known electromagnetic induction principle, the induced electro motive force generated by alternating magnetic flux through two windings is proportional to the maximum number of turns of the windings and the main magnetic flux.The voltage of the side with more turns of the winding is high, and the side with less turns of the winding is low. When the transformer is open on the second side, that is, when the transformer is empty, the voltage of the one and two ends is proportional to the number of turns of the one and two winding. The transformer plays the purpose of changing the voltage.

When the load is connected to the secondary side of the transformer, a secondary current will pass through under the action of THE electromotive force E2, and the electromotive force generated by the current will also act on the same iron core and play a reverse demagnetization role. However, because the main magnetic flux depends on the power supply voltage, while U1 basically remains unchanged. Therefore, the primary winding current will automatically increase a component to generate the magneto motive force F1 to offset the magneto motive force F2 generated by the secondary winding current. Under the action of the primary and secondary winding currents L1 and L2, The total magnetic force acting on the iron core (excluding no-load current I0) is F1+F2=0. Since F1=I1N1 and F2=I2N2, I1N1+I2N2=0. According to the formula, I1 and I2 are in phase, so I1/I2=N2/N1=1/K

By type, a secondary current ratio and a secondary voltage ratio are reciprocal, transformer power basically remain unchanged, a secondary winding (due to loss of transformer itself from its transmission power is relatively small), the size of the secondary winding current I2 depending on the needs of the load, so the size of the primary winding current I1 also depends on the need of load, the transformer have played an important role in power transmission.

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Single phase transformer advantages and disadvantages


Adopt new materials. According to the analysis, when the urban and rural power network is reformed to a certain extent, the share of line loss in network loss will be greatly reduced, and the no-load loss of distribution transformer will occupy the main position in network loss. Only by greatly reducing the loss of iron core can the power loss of power grid be further reduced. Therefore, coil core and amorphous core single-phase transformers have great development potential.The application of coil core and amorphous core technology in single-phase transformer can greatly reduce the loss of transformer core. Conducive to modern production. Single-phase transformer is suitable for mass production because of its simple structure, which is beneficial to improve product quality and benefit.


First of all, there is only one winding on the iron core of the single-phase transformer, which can only change the voltage of the one-phase power supply to the secondary output side. Due to single voltage and small capacity, it can only be used for lighting or small power stations, rural sidings, workshops and other places, which cannot be widely promoted, resulting in limited application scope. Only used as a supplement to the three-phase power supply system. Using single-phase transformer, one is used in mountainous areas, residents scattered, power load is small, basic no electricity application, can greatly reduce line investment.

Secondly, it is suitable for the power supply system of street lamps. The electric power department charges to the household, the line loss is the matter of the electric power department, the owner and the developer have no obligation to provide convenience for the electric power department.

What are single-phase transformers used for?

Single phase is used for changing the AC voltage, that’s how it got its name, the transformer changes the voltage at the same time do not change the power (not considering the loss), so when the voltage changes the current will change, that is, change the impedance. So in electronic technology, transformers are used for impedance matching.

What is difference between single and three-phase transformer?

Different definitions

Single-phase transformer: Single-phase transformer uses the principle of electromagnetic induction to work, it is a device that can change the AC voltage, the main components are primary coil, secondary coil and magnetic core. In electrical equipment and wireless circuit, commonly used for lifting voltage, matching impedance, safety isolation, etc.

Three-phase transformer: In order to input different voltages, the input windings can also be used to adapt to different input voltages. Multiple windings can also be used to output different voltages. Three independent windings, through different connections (such as: star, triangle), so that its input three-phase AC power supply, its output is the same, this is the three-phase transformer.

Different applications

Single-phase transformer: suitable for low voltage distribution network with low load density.

Three-phase transformer: three phases transformer is suitable for the frequency of 50Hz to 60Hz, voltage 660V below circuit, it can be used in imported important equipment, precision machine tools, mechanical and electrical equipment, medical equipment, rectifier, lighting, etc.

We produce Daelim three-phase transformer are suitable for all kinds of input and output voltage, the number and location of wiring group, adjusting tap, the distribution of the winding capacity, equipment of secondary phase winding, such as the use of the rectifier circuit, if you need shell requirement, the design team in our company can design and manufacture according to user requirements carefully.

Which is best single phase or three phases?

Single-phase transformer is simple in structure, small in volume, low in loss, mainly small in iron loss, and suitable for application and promotion in low-voltage distribution network with low load density. Three-phase transformer with the same capacity is smaller than the single-phase transformer, saving materials and lower loss. In fact, not only transformers, including electric motors. So usually the distribution transformer will use three-phase transformer. Single phase and three phase are suitable for different voltages and places, and can be selected according to demand.

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Why to choose us?

We are an products design, electric product and equipment manufacturer in China, we leverage our DAELIM EDGE+ Advantage to win our clients commitments. We have multiple standards ability, speed execution ability, and product line customization ability. Welcome to discuss any possible business cooperation.

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Hello, I am Bin, General manager of Daelim which is a leading transformer manufacturer. If you have problems when you are looking for the equipment, what you need to do is tell us.