Electrical Transformers: Dry Type vs. Oil Type

Electrical Transformers

Electrical transformers are useful technical devices that take high voltage electricity from power stations and convert it to a lower voltage, for usage. This permits the energy to be efficiently and carefully used by appliances and machinery in spaces that can only handle low voltages like schools, apartment complexes, transportation hubs, offices, and factories. 

Such utilisation in the aforementioned spaces generates large amounts of heat in the electrical transformers, which have to be dispelled to keep them functioning safely. There aretwo types ofelectrical transformers, both with different cooling systems. Let’s take a look at them:

  • Oil-Filled Transformer

As the name suggests, the coils and the tank in this type of electrical transformer are immersed in oil, which helps in controlling and managing the heat. The oil also adds a layer of insulation that helps in increasing the safety factor of the transformer. 

  • Dry Type Transformer

In this type of transformer, the air is used as the cooling medium instead of oil. These electrical transformers usually have aluminium or copper windings that are sealed in varnish, which are contained within polyester or silicon varnish using vacuum pressure impregnation. 

This covering makes the transformers suitable for tougher environmental conditions. Due to the limitation in the cooling aspect, the maximum voltage in dry type transformers are limited up to 35kV. 

Dry Type Transformers vs. Oil Type Transformers

  • Maintenance

Oil typeelectrical transformers require greater maintenance processes as compared to dry type transformers. The mineral oil present has to be sampled and tested for contaminants annually as part of preventive maintenance procedures. 

Apart from this, oil filtration should also be done at least once a year. On the other hand, dry type transformers are resistant to chemical contaminants, thus reducing the need for carrying out maintenance procedures.

  • Operating Costs

Oil type transformers have higher energy efficiency that helps in increasing their lifespan, thus resulting in limited operational costs. Compared to oil type transformers, dry type transformers are less efficient due to their restricted cooling capacity, leading to higher operating costs. 

  • Efficiency

As mentioned earlier, dry type electrical transformers are less efficient when compared to oil type transformers. This is because they are larger units and limited in voltage, making them more prone to overheating. 

Hence, they have higher electrical losses, which is expensive to maintain over time. Oil type transformers are smaller and more efficient and create a minor environmental footprint. 

  • Recyclability

The scope of recycling dry type transformers is limited. On the other hand, oil-filled electrical transformers can be recycled properly due to easy reclamation of the coils. Furthermore, oil type transformers have a better operating life, require fewer replacements and labour, and they produce less wastage. 

  • Noise Level

Electrical Transformers are known to be noisy when they are running. However, the noise levels of dry type and oil type transformers differ. Oil-filled transformers have a lower operating sound level as compared to dry type transformers, thus resulting in lower noise pollution. 

  • Location of the Electrical Transformer

This is considered to be the key determinant while deciding which transformer to opt for. Since dry type transformers are less flammable, they are ideal for hospitals, residential complexes, shopping malls, and other commercial indoor locations. 

Due to the possibility of fire hazard, oil leaks and spillage, oil type transformers are preferred for outdoor installations. However, these electrical transformers are more environment friendly. 

Which Electrical Transformer to Opt for?

Both the aforementioned types of electrical transformers have their own sets of benefits and limitations. The suitability of the transformer ultimately depends on your business requirements. 

If you are looking to purchase an electrical transformer for your business, make sure to consult experienced professionals who will understand your requirements and guide you throughout the process of purchasing a suitable transformer. 

Since electrical transformers are technical products, purchasing them without consulting the experts might result in you purchasing a transformer that does not meet your business requirements. This mistake could lead to a decrease in efficiency and a loss of capital. 

So, conduct in-depth research, take advice from the professionals and purchase your electrical transformer!

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