5 Things to Know Before you Buy a Power Transformer

Jun 8, 2021 | Power Transformers | 0 comments

Introduction of Power Transformers

Everyone hates the 9-hour shutdown at homes because life is too uncomfortable without Television, mobile phones (no charger to keep it on), refrigerators, and air conditioners. Admit it! Electricity has become indispensable in this modern era and one cannot think of a world without it. Well, not anymore. We would never want to go back to the old days. We are happy with our new lives filled with modern inventions. However, electricity is not that modern but it has been 2000 years.

Talking about electricity in our everyday life, Transformers play a significant role in the transmission of electrical energy from the power plants (generation) to our doorstep (distribution). Transformers regulate electricity by either increasing or decreasing the alternating current within the electrical system.

Why Power transformer?

With a wide variety of transformers available in the market, it is crucial to analyze and choose the right one that suits your requirements. The most widespread and commonly used transformers are Power transformers and Distribution transformers and they both have different applications and purposes.

Unlike distribution transformers where the transformers are always in energizing conditions, Power transformers are put into operation only when the load connected to it is to be operated. They are designed to handle high voltage inputs and can operate at more than 95% efficiency on full load whereas Distribution transformers will have high efficiency when operated at 50% to 70% load.

Power transformers have greater insulation property which results in increased cooling and also functions at low noise levels when compared to other transformers.

The expected life of power transformers is considered to be between 20 to 40 years.

When you have high voltage applications that require 100% efficiency at full loads and a constant power supply with the least fluctuations, it is the Power transformer you are looking for.

Where Power transformers are used?

Power transformers have a wide range of applications across a multitude of residences, industries, power generation, and distribution stations, commercial spaces, reactors, auxiliary plants – to modify and regulate the power to a specific voltage level that is suitable for the given application.

Now that we know the features and applications of a Power transformer, let’s dive into our guide that states 5 things that you need to know before buying a power transformer.

Things to know before you buy a Power transformer

Small Power Transformers

First things First, before we look into our list, it is important to first gather some information about your voltage and power requirements. This can help you avoid mistakes related to voltage compatibility and wrong purchases.

There are several transformer manufacturing companies out there with a wide range of product options for different applications. Choosing the right one that matches your requirements can be a little daunting task. Here are few factors that will help you in the quest for your power transformer.

1. Power Rating of a transformer

Transformers are rated according to the level of power that they can safely handle without overheating causing damage. It is simply the maximum power that the transformer can deliver. The power transformer rating is usually in kilovolt amperes (kVA) or megavolt amperes (MVA) which is stamped on the transformer nameplate.

Since a Power transformer can operate close to the maximum capacity, it is important to ensure that the power rating is high enough. If the transformer has to handle higher power than its actual power rating, it can produce overheating and damage. So, it is essential to calculate the maximum power that the transformer may have to handle after installing it and then getting the transformer with the next higher rating.

2. Efficiency and Performance

An ideal transformer will have no losses and therefore be 100% efficient. As we know, power transformers are expected to operate at more than 95% efficiency. This means that the losses from the transformers should be minimized as much as possible. Two major causes of losses are the iron core (iron loss) and the copper winding (copper loss). The maximum efficient point is where both the losses match.

Before making the purchase, ensure whether

  • The iron core is made out of high-grade, laser-cut, colled rolled sheets that have been assembled properly to prevent iron core losses; and whether
  • The copper winding of the transformer is of high quality to prevent copper losses.

3. The Durability of the Tank

The transformer tank provides the containment for the core and windings and the dielectric fluid or insulation oil. It must withstand the forces imposed on it during transport and operation. Power transformers are usually heavy and huge equipment, occupying a lot of space. They are also in constant exposure to the external surroundings and elements of nature.

The more durable and robust the tank is, the better the performance of the transformer is. You need to confirm beforehand that the tank is so manufactured with strong, corrosion-resistant, and leak-proof arrangements.

4. Determine the Vector Group

The Vector Group is a notation that provides details on the winding configurations (star/delta configurations) and the phase angle difference between the windings. Each group comprises of three methods of connection of high voltage and low voltage windings. Therefore, determining the vector group of the Power transformer before buying it is the key for the successful parallel operation of transformers in your network. Otherwise, it can cause circulating currents and other disturbances leading to unnecessary losses and decreased efficiency.

5. Quality of the Product

Last but not least, the quality of the transformer plays a vital role. Power transformers are expected to run incessantly 24*7 at their maximum load capacity and the components of the transformer are subject to heavy mechanical and electrical loads.

Thus, before making a transaction to buy a power transformer, you must communicate your needs clearly to the manufacturer and ensure that the transformer can endure heavy-load conditions without breaking down. Also, check if best designing solutions such as making use of continuous windings with minimal joints, better insulation, and other standard quality assurance practices were followed while manufacturing the transformer.

Keeping these points and your requirements in mind, you should pose the right questions to the power transformer manufacturer and see if the product really matches your needs before making the purchase. Other key specifications to look out for are – Input and load voltage, phase requirements, size/capacity, frequency of operations, impedance, protection, mount/spacing, and location requirements.


By choosing the right power transformer, you can increase the efficiency and the life of your application. Having a better understanding of your requirements with a little bit of accurate research to realize the complete monetary value of the product can help you make worthy purchase decisions.

Besides this, purchasing from a credible and reputed power transformer manufacturer like EVR Power guarantees a quality product that will last longer and will be reliable. You can also seek advice from the supplier to pick the right one to suit your application. A good manufacturer will also help you with installation and regular maintenance.

EVR Power is the leading power transformer manufacturers in Tamil Nadu. They build transformers using high-end technology, top-quality components, and trailblazing latest processes. Their sophisticated design of the products ensures sustainability and longevity without any service. The company also manufactures distribution transformers, Isolation transformers, Convertor/Invertor Transformers, Automatic voltage regulators, industrial refrigerators, etc.

Do you have any other points to add to help the readers understand better? Feel free to comment with your thoughts! Have a great day!



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