What is a Transformer?

A transformer is an electrical device that is used to transfer electrical energy from one circuit to another either by Electro-magnetic induction or through capacitive coupling. It has the capability to increase or decrease the alternating voltages of electrical power in electrical devices. Transformers are widely used in the power industry and in everyday life.

Transformers range in size from less than a cubic centimetre in volume to units interconnecting the power grid which weighs hundreds of tons.

How Transformers are Manufactured?

The manufacturing process of transformers can be divided into 3 major phases.

The process of manufacturing a transformer begins with the construction of a core. The core is made up of a stack of thin metal sheets, called laminations, that have been punched to create a series of slits. The laminations are stacked so that the slits line up, and the stack is held together with clamps or bolts. The core limits the transformer’s magnetic field to the area inside the slits.

First phase comprises winding of the transformer’s coils or arms:
The 1st phase involves the winding of the transformer’s coils or arms around the core. In order to wind the transformer, the coil should be an exact size. Then, aluminum is used to form the conductor core. This core is heated and then cold poured, to be converted into a solid winding. The wires are then wound around the transformer to create the arms or coils. The width and length of the wire used for winding is a critical factor, as its dimensions strongly affect the electrical properties of the transformer.The number of turns in the primary winding determines the ratio of primary to secondary voltage. More turns in the primary winding produces a higher primary voltage.

Secondly, coating of the winding:

The 2nd phase is the coating of the winding. Once the windings are in place, the transformer core and windings are placed in a transformer tank. The tank is filled with a dielectric liquid, such as transformer oil, to insulate the windings and prevent arcing between the windings and the transformer’s metal casing. The transformer is then sealed and pressurized. This process involves the use of insulating materials like glass, paper, or other varnish proving the waterproof and insulation of the windings. Usually, the insulating material is hot varnished.

Assembly of the transformer:

The 3rd phase is the assembly of the transformer. This involves all the other components such as the tap changer, cooling fans, and bushings.
After the transformer is assembled, it undergoes a series of tests to ensure that it meets all performance specifications. These tests include measuring the transformer’s voltage and current ratios, impedance, and losses. Then all these components are assembled in a protective enclosure and tested for quality assurance.

Zastata also performs premium quality testing procedures such as Non-destructive testing like fluorescent penetration, magnetic particle, radiographic, or other inspections may also be performed. Final dimensional inspections, alloy test results, and NDT are validated authentically with expertise prior to shipment.

Materials Used

The primary materials used in the construction of a transformer are often referred to as the core and winding materials. The core material is a ferromagnetic metal alloy that serves as the primary energy transfer mechanism of the transformer.

There are several materials used in transformer such as copper, aluminum, iron, and silicon. Each material has its own unique properties that make it suitable for transformer application. It depends on the transformer’s application and size.

  • Copper is an excellent conductor of electricity and highly corrosion resistant. It is also a relatively low cost material, making it a popular choice for transformer manufacturing.
  • Aluminum is another good conductor of electricity and has a higher resistance to corrosion than copper. However, it is more expensive than copper and is not as widely used in transformer manufacturing.
  • Iron is a magnetic material and is used in transformer cores to create the magnetic field.
  • Silicon is used in the transformer windings to improve the electrical properties of the transformer. Its Silicon Iron is a ferrite core which is used in transformers. Ferrite cores are used because they are cheaper than laminated cores, but are just as strong.
Difference between Transformers And Induction Motor:
 This is an electrical device that transfers energy between two or more circuits through electromagnetic induction
Transformers are designed to operate at the same frequency as their input voltage
The operation of a transformer is mainly dependent on the frequency of its input AC voltage
Transformers are easily installed due to their small size and light weight.
 Typical applications include electrical power distribution, voltage/current measurement
 It is an AC electric motor in which the electric current in the rotor is required to produce torque.
 The speed of an induction motor is determined by the frequency and voltage of the applied alternating current.
The operation of an induction motor is mainly dependent on the input voltage
The size and weight of an induction motor is typically higher than transformers
Induction motors are used in a variety of industries including the mining industry, industrial processing, and the manufacturing of pumps and blowers.

Transformer manufacturing is a complex and highly precise process that involves a great degree of inspection to ensure product safety and quality.

Zastata provides various Inspection Processes and testing procedures like

  • Visual Inspection : visual tests, during which an assembler carefully assesses the component parts for any visible blemishes, deformations, or contaminants. Visual inspections can also confirm basic measurements to ensure the transformer components meet the provided specifications
  • Mechanical testing may be employed to ensure the transformer is correctly aligned and meets the desired connections of the metal frame or core.
  • NDTs are used to further assess the transformer’s performance and detect any potential issues. This includes windings resistance tests which measure the resistance signature of the transformer and AC voltage test which measures the induced voltage at various positions.
  • Other types of tests also include high-frequency test which in intended for small sizes, low power transformers, as well as resistance leakage tests used to identify any current leakage from the windings to the remaining components.
  • Oil testing procedures are implemented to check for the purity, conductivity, and viscosity of the transformer’s oil
  • Vibrations tests can also be performed to evaluate the integrity of the transformer components while under various operating loads.

Manufacturing Documentation

The parts manufactured in our plants are based on the quality certifications and International Standards as,

Certified in ISO 9001:2015, ISO 14001:2015, ISO 45001:2018,
IEC 60076-1, IEC 60076-3:2013.

Also, expertise in utilizing assessment tools like


There Are Other Types of Transformer

  • Step-up Transformers – capable of increasing the voltage of the power source while lowering its current level.
  • Step-down Transformers – Used to reduce the voltage of an electrical system while increasing the current level.
  • Isolation Transformers – commonly used in electrical systems to separate two portions of a circuit that must not be directly connected. This prevents overloading and short – circuiting
  • Auto-transformers – used to adjust the voltage level of a system and mainly used in telecommunications.


Whilst Pressure die casting is widely used casting method for high volume production, there are other casting methods which have their merits





Over the years, Zastata has audited and worked with various die casting manufacturer across India for various casting types. Our pressure die casting company are selected and retained based on their quarterly quality performance on Cost, Delivery, Quality, Communication, Innovation and flexibility.


Over the years, Zastata has audited and worked with various die casting manufacturer across India for various casting types. Our pressure die casting company are selected and retained based on their quarterly quality performance on Cost, Delivery, Quality, Communication, Innovation and flexibility.










Advantages of buying Transformers from India:

Zastata is well placed as one of the top sourcing companies for buying transformers. India has become a major supplier of transformer parts due to low cost, and ease of material availability. These are some of the reasons why transformer manufacturing in India is becoming increasingly popular among businesses and individuals.

  • Larger workforce
  • Availability of raw materials and minerals
  • Strong infrastructure with large number of ports and airports along with well developed railway networks
  • Increased investment in the transformer manufacturing industry in India, due to economic growth
  • wider selection of transformers available.

The most common application of transformers is to provide isolation between circuits and to step up or step down voltages. Some other applications are

  • Prevents undesirable electrical interference between components
  • Offers protection to human operators.
  • Prevents overheating
  • They can be used in parallel to increase capacity.
  • used in various power converters, such as rectifiers, AC/DC converters, inverters, and converters between different AC frequencies
  • Different AC frequencies can be converted between for applications such as providing power to industrial machines.

Transformer is a vital device for the transmission of power. The manufacturing process of transformer is complex and requires the use of specialized and precise equipments. Overall, careful consideration should be given while manufacturing a transformer and Zastata ensures the safety and performance of the device.




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