How Much You Know For The Different Types Of Transformers?

In the operation of power transformation and distribution, transformers play an important role in the transmission, distribution and use of electric energy, and are indispensable in the power system. 


There are mainly the following types of transformer designs:

Based on the number of phases, transformers include single-phase and three-phase transformers.

According to the purpose, it is divided into power transformers, distribution transformers, instrument transformers, test transformers and special transformers, special power transformers, voltage regulating transformers, measuring transformers (voltage transformers, current transformers), small power transformers (for low-power equipment ), and safety transformer.

Based on the structure, transformers can be core type or shell type.

Coils have double windings and multi-windings, autotransformers.

According to the cooling method, it is divided into dry-type transformers and oil-immersed transformers.


As a professional manufacturer of transformers, Daelim mainly focus on power transformers and single-phase three-phase distribution transformers.

It has been exporting for more than 16 years, serving customers on 5 continents.

With excellent customized production capacity and delivery advantages, it can be produced according to a variety of standards.
Our main transformers include:
1, Main Power Transformers to 220kv
2, Distribution Transformers to 35kv;
3, Pad Mounted Transformers to 34.5kv;
4, Pole Mounted Single Phase Transformers to 34.5kv;
5, Dry Type Transformers to 35kv


Contents Of Table:
1.What's The Transformer?
2.What Are The Functions Of Three Phase Transformers?
3.How Does A Three Phase Transformer Convert Voltage?
4.What Different Dypes Of Transformers From Daelim Belefic?
5.What Accessories Of Daelim Pad Mounted Transformer Include? 
6.How To Choose The Three Phase Transformer's Capacity?
7.The Difference Between A Step-up Transformer And A Step-down Transformer
8.Could A Transformer Convert AC To DC?
9.What Kind Of Technical Data The Pad Mounted Transformer's Nameplate Include?
10.Why The Three-phase Pad Mounted Transformer's Tap Changer So Important?
11.Why The Three-phase Transformer Can't Be Overloaded?
12.What Kinds Of Optional Items For Three Phase Pad Mounted? 


What's The Transformer?

In the AC circuit, the device that increases or decreases the voltage is called a transformer.


The transformer can convert any value of voltage into the voltage value we need with the same frequency to meet the electricity requirements.



For example, the electricity from a power plant has a low voltage level, and the voltage must be increased before it can be transported to a distant power consumption area.


The power consumption area must be reduced to a suitable voltage level to supply power equipment and daily electricity Equipment.


What Are The Functions Of Three Phase Transformers?

The functions of the three phase transformer mainly include: voltage transformation; impedance transformation; isolation; voltage regulation (magnetic saturation transformer), etc.


How Does A Three Phase Transformer Convert Voltage?

The principle of the transformer is electromagnetic induction.


It is composed of an iron core of silicon steel sheet and windings on the iron core.

Coils contain primary and secondary, also called primary and secondary coils.


When the primary coil of the transformer is connected to a power source, which is usually an AC power source, magnetic lines of force are generated in the iron core.


Since the secondary coil and the primary coil are wound on the same iron core, at this time, the magnetic line of force cuts the secondary coil, and a voltage will appear at both ends of the coil.


The voltage ratio of the primary and secondary coils is related to and proportional to the turns ratio of the coil.


It can also be judged whether the transformer is a step-up transformer or a step-down transformer.


If the first time is greater than the second time, it is a step-down transformer; if the second time is greater than one time, it is a step-up transformer.


What Different Dypes Of Transformers From Daelim Belefic?

Daelim can design and produce transformers according to ANSI/IEEE/CSA/NEMA/UL/GS/NZ/AS/IEC and other standards.


The most popular products are 66KV-230KV power transformers, single and three phase pad mounted with voltages below 35KV transfomer and pole mounted transformer, etc.


What Accessories Of Daelim Pad Mounted Transformer Include? 
Transformer components are mainly composed of iron core, coil, in addition to oil tank, insulating sleeve and so on.


Accessories Of Padmounted transformer

The IEEE standard pad mounted transformer is made of a steel barrier that divides the transformer into a high voltage chamber and a low voltage chamber, and accessories are mainly distributed in the two high and low voltage chambers.

Load break switch and tap changer are fixed on the high voltage side;

There are high-voltage bushings in the high-voltage chamber.


If it is a dead front type, there will be bushings, elbow joints and hangers; sometimes there will be grounded bushings;

3 bayonet fuses and drip tray are also in the high pressure chamber;

The low pressure chamber is different.

The oil temperature gauge, oil level gauge, vacuum pressure gauge and pressure relief valve, which are often called "three gauges and one valve" in the industry, are all fixed on the low pressure side;

The nameplate and drain valve are usually on the low pressure side;

The low-voltage spades are also on the low-voltage side.

According to different requirements of customers, they can be made into 6 holes to 16 holes. Different from the high-voltage side, the grounding terminal X0 on the low-voltage side is a conventional configuration, so the transformer has 4 low-voltage terminals.


The H0 on the high pressure side is extra bushing.


How To Choose The Three Phase Transformer's Capacity?

Dalin's professional engineer team has summarized the following steps for your reference:

First, determine the power supply voltage and power load.

Second, pay attention to the technical information on the transformer nameplate.

The transformer capacity, voltage, current and its environmental conditions need to be comprehensively considered.

To determine the required load, the capacity, nature and use time of the electrical equipment should be fully considered, so as to select the transformer capacity.


The Difference Between A Step-up Transformer And A Step-down Transformer

The basic principles of step-up transformers and step-down transformers are the same. 

The main difference is the number of turns of the primary and secondary windings: the number of turns of the main winding of the step-up transformer is less, and the number of turns of the main winding of the step-down transformer is more.

The so-called step-up transformer naturally refers to increasing the value of the instantaneous voltage supply, while the step-down transformer converts the higher voltage at the input end of the power supply into a lower ideal voltage output for the normal use of our home appliances to achieve step-down purpose. 

So can step-up transformers and step-down transformers be used interchangeably?

Regarding this issue, it is not possible in principle, because the loss element needs to be considered in the design and packaging process of the equipment.

When the primary coil is responsible for transferring the power to the secondary, it is also responsible for providing losses such as iron loss, while the secondary coil needs to increase the coil to offset the voltage loss, so the two cannot be used in reverse.


Could A Transformer Convert AC To DC?



Inverting is the process of converting DC voltage into AC voltage.


This process gets the AC voltage we want.


After passing through the rectifier circuit, we get the DC voltage we need, realizing the change of DC-AC-DC, as shown in the figure below shown:


What Kind Of Technical Data The Pad Mounted Transformer's Nameplate Include?


Pad Mounted Transformer's Nameplate

The following information shall be shown on the combination nameplate: 
(a) PADMOUNT TYPE ONAN 60 Hz, 65 °C; 
(b) number of phases: 3; 
(c) rating in kilovolt amperes; 
(d) identification number (e.g., serial number); 
(e) per cent impedance at 85 °C (one decimal minimum); 
(f) oil volume in litres; 
(g) BIL (basic impulse level); 
(h) total mass (including liquid);
(i) rated high and low voltage; 
(j) < 2 ppm PCB; 
(k) bayonet fuse and CLF fuse identification; 
(l) tap voltages as a per cent of rated voltage and corresponding position of tap switch; 
(m) terminal markings, including physical identification, diagram of connections, and vector diagram; 
(n) year and month of manufacture; 
(o) CSA Standard number; 
(p) manufacturer reference number; 
(q) name of manufacturer and address; 
(r) energy efficiency in accordance with CAN/CSA-C802.1; and 
(s) if the option specified is selected by the purchaser, a warning in accordance with. 
The lettering or numbering required in Items (c), (d), (e), (i), (k), and (l) shall be 4 mm high and shall be legible from outside the cable entrance compartment. 
Note: Where applicable, “ONAN”, as specified in Item (a), may be replaced with “KNAN” or “LNAN”


Why The Three-phase Pad Mounted Transformer's Tap Changer So Important?

TToo high or too low voltage will affect the normal operation and service life of the transformer, which is the meaning of the existence of the voltage regulating switch.

The voltage regulating switch is connected to the coil of the primary voltage.

The number of turns of the coil is changed by rotating the contacts at the start of a tap-change.

By turning the position of the tap changer, the desired rated voltage value is obtained.

Daelim can provide customers with 5-speed pressure regulating switch and J tap pressure regulating switch according to the different needs of customers.


Why The Three-phase Transformer Can't Be Overloaded?



Three-phase transformer overload operation means that the transformer operates at a current value exceeding the value specified on the nameplate.

Overload increases the temperature of the three-phase transformer, promotes the aging of the three-phase transformer insulation, and reduces the service life of the three-phase transformer.

Therefore, overload operation of the transformer is not allowed.

Under special circumstances, the transformer can be allowed to operate with overload for a short time within a certain range.

It is stipulated that the rated load shall not exceed 30% in winter and 15% in summer.


What Kinds Of Optional Items For Three Phase Pad Mounted? 


Transformers may be provided with the following optional items if specified by the purchaser: 
(a) load-break switches; 
(b) provision for padlocking load-break switches; 
(c) mechanical interlock of the transformer winding switch and bayonet fuses to prevent removal while 
the transformer is energized; 
(d) load-break inserts complete with dust cap; 
(e) customer stock code number stencilled on the door as shown in Figure 15; 
(f) dual-voltage selector switch; 
(g) high-voltage off-circuit taps; 
(h) under-oil surge arresters; 
(i) cores capable of being energized by two phases on all three phases while supplying rated load (i.e., 
AAC, BBC, ABB, ACC), with maximum temperature rise of 65 °C; 
(j) thermometer of the maximum indicating type; 
(k) impulse test may be requested as a routine test by the purchaser. The test shall be performed 
according to ANSI/IEEE C57.12.90, Clause 10.4; 
(l) permanent and/or temporary bar coding label according to ANSI/IEEE C57.12.35; 
(m) purchaser-specified impedance limits; 
(n) load-break switch nameplate (content to be specified by purchaser); 
(o) internally connected H0 and X0, brought out through an external bushing marked H0X0;
(p) fire-resistant fluid in place of oil. Transformers with fire-resistant fluid shall be designated KNAN or 
(q) alternative protection devices, specified by the purchaser, that provide equivalent protection; 
(r) no fusing. If no fusing or bayonet only is specified by the purchaser, then the nameplate shall include 
a warning that an external current-limiting device shall be provided
(s) a barrier between the high-voltage and low-voltage compartments.


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