Dry Type Distribution Transformer

Dalin three-phase epoxy resin Dry Type Distribution Transformer conforms to IEC726, GB/T10228-1997 standards, and has the characteristics of low loss, compactness, lightness, low noise, moisture resistance, high mechanical strength, and flame retardancy. , Strong overload capacity, low partial discharge quality. It is suitable for power transmission and distribution systems, especially for heavy load centers and places with special fire protection requirements.

10KV Class Three Phase Epoxy-resin Dry-type Transformer

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20KV Class Three Phase Epoxy-resin Dry-type Transformer

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35KV Class Three Phase Epoxy-resin Dry-type Transformer

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Dry Type Distribution Transformer: The Ultimate FAQ Guide

Nowadays, companies and industries are starting to reconsider their purchase decision towards oil type transformers because of the better alternative which are dry-type distribution transformers.


How are dry-type transformers the superior choice? Everything you need to know will be in this article with the help of DAELIM’s team of professionals.


Nevertheless, both types of transformers are available at DAELIM if you find that dry-type transformers are not suitable for your use.

What are Transformers for?

Tachnical Data for Dry Type Distribution Transformer
Tachnical Data for Dry Type Distribution Transformer

Transformers regulate the electricity of buildings to prevent electrical disruptions for security.


It can be both used to increase and decrease the voltage at the power generating station. This is to mitigate the transmission losses during the transmission.


The increase in voltage is called step up while the decrease in voltage is called step down. With both purposes to supply power to the building.


In other forms of application that consist of different voltages, transformers are of great help because they can adjust the voltage to a compatible level for the appliance to work.


An example of this is that when a specific appliance requires a specific amount of voltage, and when the voltage is not at the right level, it will simply not operate. With the use of a transformer, adjusting the voltage can be easily done. Resulting in a fully functional appliance with the right amount of voltage.

Why is a Transformer Important?

Transformers are responsible for the basic components of both transmission and distribution of electricity in a power system. Without a transformer, the absence of it would pose a risk of electrical disruption or uncontrollable voltage that could cause an explosion and fire.


One of the main functions of a transformer is to regulate the voltage, this is why it is necessary to have one in your building (depending on the size).

Different Types of Transformers

There are other types of Transformers as well that serve their unique purposes. Should you require more information after this section, we can get you professional help here.

Core Type Transformer

Core type transformers are usually used as energy transformation, transfer cores, and power grids.


It still serves its main function when it comes to electrical transformer applications, which is to step up transmission and step down transmission.


For its components, the core type transformer has two limbs, and the windings are contracted on two limbs of the core material.

Shell Type Transformer

Shell type transformers are commonly used for low voltage applications and in low voltage power circuits including electrical circuits.


For the components of the shell-type transformer, its core has three limbs and two windows. Both windings are contracted on the central limb specifically, one over the other.


The arrangements of these windings can also be done with one limb.

Spiral Core Transformer

The spiral core transformer employs the latest development in core construction.


Its components consist of the following: its core has three limbs and two windows. Both windings are contracted on the central limb specifically, one over the other.

What are Dry Type Distribution Transformers?

A dry type distribution transformer is a type of transformer that does not depend on any insulating liquid. Unlike other transformers, its core and windings are sealed in a tank with pressurized or forced air inside.

What does Dry Type Mean?

Tachnical Data for 10KV Class Three Phase Epoxy-resin Dry-type Transformer
Tachnical Data for 10KV Class Three Phase Epoxy-resin Dry-type Transformer
Tachnical Data for 35KV Class Three Phase Epoxy-resin Dry-type Transformer
Tachnical Data for 35KV Class Three Phase Epoxy-resin Dry-type Transformer
Tachnical Data for 20KV Class Three Phase Epoxy-resin Dry-type Transformer
Tachnical Data for 20KV Class Three Phase Epoxy-resin Dry-type Transformer

The term “Dry Type” means that the cooling medium for this type of transformer is normal air ventilation. As aforementioned, dry type transformers do not require insulating liquid, oil, or silicone unlike other types of transformers.


This is because dry type transformers are designed to withstand its purposes with only air as its cooling medium.

What is Dry Distribution?

Dry Type Distribution Transformer shipping
Dry Type Distribution Transformer shipping

The term “Dry-Type” is also a reference to its insulation medium which is dry air. The core, windings, and coil are all regulated or insulated by air as opposed to oil or liquid immersion.

Different Types of Dry Type Transformers

There are plenty of Dry Types Transformers out there, and to check which one is best for your project, you can scroll through DAELIM’s list of products.


Here are widely used dry type transformers that can be found normally in commercials and industries.

Vacuum Pressure Impregnated (V.P.I) Transformers

Vacuum Pressure Impregnated transformers or V.P.I transformers serve a purpose that is self-explanatory due to its name. This type of transformer is vacuum pressure impregnated with high-temperature varnish to protect its environment and surroundings.

Vacuum Pressure Encapsulated (V.P.E) Transformers

In the construction process, there are a few dip processes that are added to encapsulate the coil. Coatings are cured in the oven shortly after. This transformer was designed to withstand harsh and high moisture or wet environments.

Cast Coil Transformers

Cast coil transformers are transformers that have their windings cast in resin.


The cast coil transformer is also known to be the alternative to medium-voltage and liquid-filled transformers such as oil type transformers.


Cast coil transformers are more environmentally friendly compared

Mechanical Properties of Dry Type Distribution Transformers:

One of the key advantages of dry-type distribution transformers is that they require little to almost no maintenance at all of its mechanical components.


This is because it was specifically designed to be low-upkeep compared to other transformers.

Static Device

A static device is a device that converts one form of energy to another without physical movement. Meaning there are no moving parts in dry-type distribution transformers, which is one of the contributors to its low maintenance.

Laminated Core

Dry-type distribution transformers contain a rectangular-shaped soft magnetic laminated core, which is designed to carry both large input and output power transmission.


The windings in dry-type distribution transformers are usually made up of copper or aluminum with a coating of thin insulation that contains higher temperature class and insulation class.


The conservator’s purpose is to store additional cooling oil that can be used or recycled after a short period of time.


For the dry type distribution transformer, the cooling medium is air, pressurized air, or forced air only. There is no liquid insulation involved in its cooling.


The breather in dry-type distribution transformers absorbs moisture content from the air which sucks in while the oil gets expanded or contracted.


Since there is no oil in dry-type distribution transformers, air is sufficient for the job.
Electronic Relay

The electronic relay or also known as the Buchholz relay secures the winding by protecting the winding from overheating that might burst into flames or even explode.

Cooling Medium

The cooling medium for dry-type transformers is only air, which is why its maintenance costs much less than oil type transformers.

Applications for Dry Type Transformers

Dry Type Distribution Transformer
Dry Type Distribution Transformer

These are the common applications for Dry-type distribution transformers:

Chemical Industries

It is very common for chemical industries to use dry type distribution transformers as their choice of transformers, because its design is built to be environmentally-friendly and less flammable compared to oil type transformers.


As you know, chemical industries are exposed to dangerous elements and fire hazards, which is why the best choice for them are dry type distribution transformers.


Forests are highly risky because they are prone to fire, which can easily spread out at a very fast rate. For industries that are near forests or high-risk fire areas, they use dry type distribution transformers in order to prevent fire.


Dry-type distribution transformers are commonly used substations as well as this is more suited for the area because of its safer mechanical components.
Residential Complexes
Since there are a lot of buildings in residential complexes, the risk of using oil-type transformers is just too high to be applied in residential complexes. A fire could easily start and could spread easily.


The same goes with villages, as this can also be dangerous for the people living in close distances.

Large Buildings

Large buildings are known to always choose dry distribution areas because they prefer an environmentally-friendly transformer around.


When it comes to apartments, dry-type distribution transformers do an excellent job at regulating the circuits in apartments, and it is simply more reliable than oil type transformers.

What’s the Difference between Oil Type Transformers and Dry Type Transformers?

Now that oil type transformers are often mentioned, the question that is probably on your mind is: what is it?


There are two types of transformers commonly used in industries which are either oil type transformers or dry-type transformers.


Each transformer has its pros and cons, and you will get to know of each thoroughly.


The main difference of both is that dry type distribution transformers have a natural cooling medium which is air.


On the other hand, oil type uses oil and other insulating liquids.


It is important to keep this in mind if you are looking for a transformer with good longevity: Oil filled transformers have a higher energy efficiency which results in higher lifespan than dry type transformers.

Which oil is used in oil type transformers?

Mineral oil
Specifically naphthenic, silicone, and bio-based oil. These three transformer oils are commonly used in oil type transformers. Mineral oil does a much better job compared to the other oil as it has better electrical and cooling properties.

Advantages and Disadvantages

Advantages and Disadvantages

In this section, you will learn the key advantages and drawbacks of using dry type distribution transformers.


This section will also provide you with more information that can help you make your purchase decision.


Below are the key advantages of using dry type distribution transformers

Environmentally Friendly

They are less flammable, and they do not contain any oil. This advantage right here is already a purchasing consideration because mineral oil can be expensive.

Low Cost Installation

DAELIM offers low cost installation to their dry type distribution transformers for your convenience. It is known that installation costs for oil type transformers can be more expensive but you can contact DAELIM for a better offer.

Low Maintenance

There is absolutely little to no maintenance for dry type distribution transformers because of their mechanical properties that makes them almost independent of care.

Low Fire Hazard

The oil in oil type transformers are highly flammable. Whereas, in dry type distribution transformers there is oil involved.

No Oil Usage

As you know by now, there is no oil in dry type distribution transformers, this is because its cooling medium is using only pressurized air or forced air.


There is without a doubt that dry type distributions transformers are durable. In fact they are very adaptable to certain environments that oil type transformers cannot withstand.


Below are the drawbacks of dry-type distribution transformers that consumers point out.

Only Needs Air to Cool

So what does this have to do with being a disadvantage? Well, this makes liquid testing unneeded. You will need a technical personnel to clean and regularly check up on it. Or you can do it yourself but you need to learn it first.

Electric Breakdowns

When it comes to the transformer’s windings, there are electric breakdowns between the turns or parts of the windings which is a major issue because chances are, this leads to partial discharges before an electric breakdown.


Yes, dry type distribution transformers are known to be more loud than oil type transformers. This is because of the air disturbing the sheets of metal within the transformer, which makes a metal-banging sound.


1000KVA Dry Type Distribution Transformer
1000KVA Dry Type Distribution Transformer

In conclusion, if you are looking for a transformer that does well in high moisture areas and chemically-exposed environments, then the dry type distribution transformer is for you. Dry type distribution transformers are incredibly versatile and easy to maintain.


You do not have to worry about public danger as well since it is environmentally-friendly.


So, if this is the type of transformer you are looking for, DAELIM offers premium-quality dry type transformers with the best services for your convenience.


DAELIM: An Electric Product & Equipment Manufacturer.