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Oil Type Transformer vs Dry Type Transformer: Understanding the Differences


Transformers are used in many settings and are very useful pieces of equipment. The primary function of a transformer is to take high voltage electricity directly or indirectly from the power station and convert it to low voltage electricity for use. This allows electricity to be used safely and efficiently by machinery and appliances that can only handle the low voltage.

Examples of this are offices, transportation hubs, schools, and factories. Currently, there are two different types of transformers being used in industries. They are dry type transformer and oil type transformer. This blog will cover the basic difference between the two and outline some of the main benefits of using both transformers.  

What Does a Transformer Do?

A transformer is a piece of electrical equipment that increases or decreases the voltage as it transmits electric energy from one alternating-current circuit to another. Transformers are used for many functions, including raising the voltage from electric generators to enable long-distance electricity transmission and lowering the voltage of traditional power circuits to run low-voltage devices like doorbells and toy electric trains. 

Transformers work by inducing current in a second coil known as the secondary coil as the magnetic lines of force (flux lines) build up and contract in response to variations in current flowing through the primary coil. 

Oil Type Transformer and Dry Type Transformer

Dry-type transformer: There are two types of transformers most commonly used; oil type transformer and dry type transformer. A dry-type transformer employs insulating techniques with ecologically friendly temperature ranges. The term’ cast resin type transformers’ is another name for them. The transformer is kept in a casing with sufficient ventilation, which causes the air within the case to cool the coils. They also have windings made of aluminum or copper that have been lacquered.

Due to cooling restrictions, the maximum voltage of dry-type transformers is limited to 35kV. A dry transformer has many uses in industrial, commercial, and utility applications. This type of transformer uses air as a cooling medium. 

Oil-type transformer: As implied by the name, the coils of an oil-type transformer are submerged in oil, typically mineral oil, which aids in regulating the transformer’s temperature. The radiators are equipped with fans to lower the temperature and further enhance the transformer’s cooling. 

In some circumstances, this kind of transformer has a high voltage capacity—up to 1000kV. The heat produced by the iron core and coil in an oil-type transformer is first transported to the insulating oil, then to the cooling fluid. Due to the liquid’s inflammability, oil-type transformers are typically employed in outdoor installations. Now that we understand what each of these transformers does let us look at the major differences between the two. 


Cooling medium


The major area where oil type transformer differs from a dry-type transformer is its cooling medium. The cooling medium of a dry-type transformer is air, whereas in the case of oil type transformer is oil. 




Another aspect that differentiates a dry-type transformer from an oil-type transformer is its maintenance cost. Dry-type transformer requires more maintenance and is more expensive than an oil-type transformer. 




Since a dry-type transformer has a low voltage bearing capacity, it is less efficient than an oil-type transformer. Dry types are also more prone to overheating during overload, leading to higher loss. 

Utilize the Expertise of a Top Electrical Supplier

Our comparison of oil-filled vs dry-type transformers shows that oil-filled transformers provide better energy, financial, and recyclable alternatives. On the other hand, dry-type transformers are safer for use inside. Whether you choose a dry-type or oil-filled transformer, you should only work with a reputable supplier who sells the best products available. The best electrical supplier will provide top-notch quality equipment and around-the-clock customer services to cater to your needs. 

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