Transformers Manufacturing Process

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We at Royal transformers, an eminent transformers manufacturing firm, follow systematic frameworks and methodology in the process of transformer manufacturing. We believe in step by step development with qualitative progress but in a faster approach.

We plan, design and then create exclusive products that are in par with the specified quality standards with no scope for flaws. Royal transformers, is well known for its state-of-the-art transformer services inclusive of transformer overhauling at site, repairing and also supplying of transformer spares.

Starting off with the Core Assembly step where we carefully assemble cores to lessen the scope for energy loses, we then wind coils followed by Coil Assembly. Once we complete winding arrangement in a customized manner, matching specific client requirements, we then set the product for drying.

Further, during the tank fabrication and fittings stage, we make the transformer leak-proof and make it strength-full mechanically. Finally we pass the product through tanking process and ultimately test it for quality through our 3-tier quality assurance protocol. We specialize in transformer overhauling at site and in transformer spares. We understand and specify customers about some exclusive parts inside the transformers that need to be given importance and special care in order to keep the transformer working smoothly without any discrepancies.

Our expert teams of well-qualified engineers make sure the transformer overhauling at site is done instantly with efficiency coupled with eminence. We perform overhauling and repairing of transformers and we also offer gasket sealing, insulation, windings and moisture removal. We hold an expertise in supplying all sorts of accessories pertaining to any make of transformers and also relative apparatus. We offer transformer spares inclusive of cooling radiators, Buchholz,assemblies, indicator for oil temperature and windings, oil seal, Oil Surge relay, gasket, OLTC Spares, Flow indicators, valves for pressure management and Silica gel Breather.

We can proudly say that our products have made their way to various industries and their success rate has pushed our growth trajectory towards the higher end.

Core Assembly

Here we assemble cores together to minimize energy loses and magnetizing currents.
core assembly repairing of transformer repairing of distribution transformer transformer testing transformers fitting

Coil Winding

Winding arrangements mat vary depends on clients’ requirements and usage. It is further divided into two popular categories – Low Voltage (L.V.) Coil, and High Voltage (H.V.) Coil

1.  L. V. Coil :
2.  H. V. Coil :


The Low Voltage coil is designed to approximately match the current rating of the available low-voltage (LV). The L.V. coil is normally wound on robust tube of insulation material and this is almost invariably of synthetic resin-bonded paper. This material has high mechanical strength and is capable of withstanding the high loading. Electrically it will probably have sufficient dielectric strength to withstand the relatively modest test voltage applied to the L.V. winding during the repairing without any additional insulation.


The second process is H.V. Coil Winding, which are wound with strip conductor and it usually consists of continuous disc type. The coils are usually created in layers and ideally all the joints are extremely well brazen and insulated in order to withstand difficult service conditions and tests.

transformer l. v. coil winding transformer h. v. coil winding transformer coil winding in india
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Core And Coil Assembly

This is an important part of transformer manufacturing process where core assembly is placed vertical.

transformer coil assembly transformer coil assembly transformer assembly transformer core and coil assembly
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Drying Out Process


During this stage, we assure reliable power supply through transformer. Moisture content is minimized to reduce noise and also increases overall life of a transformer.

transformer drying out process transformer process

Tank Fabrication And fittings


At this stage, we make our transformer free from leakage to give maximum mechanical strength.

The Pressed steel radiators are used to dissipate heat generated at rated load. The fin height and length are calculated according to the rating of transformers as well as customers' specifications. The fins can be plain or embossed. The radiators are fitted variably according to the rating of transformer. For smaller rating radiators are directed welded to the main tank while for higher rating detachable type radiators are provided with valves to facilitate during transportation and handling at site.

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After vaccum drying process the active part is removed from the Oven and all components subject to the shrinkage are tightened again. The core & coil assembly is then placed into the tank and properly lacked up during the transformer manufacturing process. The temperature and exposure time is monitored during this time to ensure that the transformer is not too cool by the time it is get off from the oven. While in higher rating transformer, the vacuum is drawn for a period of time dependent on the voltage of the unit and time for which the active part was exposed to the atmosphere and the humidity at the time. The vacuum period is between 12 to 35 hours. Meanwhile the external wiring and termination work to be completed as per customer requirements.

transformer tanking transformer tanking in india
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The outside surface of tank including all fittings and accessories are cleaned properly. Necessary chipping and grinding applied for smooth surface and finishing. After cleaning of the tank, one coat of hoi oil resistance pint is applied on the internal surface of the tank during the transformer manufacturing process. The outside surface is painted with one coat of Red Oxide Primer and subsequently one coat of enamel paint as per customer's requirement.

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The stringent test are carried out at each and every stage/intervals are carried out as well as on finished transformer confirming to IS:1180 amd IS-2026 by qualified and experienced engineers with precision grade testing equipments.

Transformer Overhauling at Site


We provide various transformer services that include - Transformer Overhauling at site and repairing. There are certain parts inside transformer that needs special attention. We have appointed a team of qualified engineers for Transformer Overhauling at site and repairing. They are checking transformer on different parameters before it is handled back to the end user.

Our overhauling and repairing services include transformer gasket sealing, windings, insulation, and moisture removal etc. Our transformer overhauling services are carried at site having adequate handling and lifting facility for different parts. Our modern handling and lifting equipments assure enhanced speed for vital operations and transformer overhauling.

Transformer Spares


We supply all kind of transformer accessories and protection apparatus for any make of transformers and critical spares of On Load Tap Changers.

We supply plenty of accessories and spare parts for different type of transformers available in market. Our list includes cooling radiators, indicator for oil temperature and windings, assemblies, oil seal, gasket, Oil Surge relay, Buchholz, OLTC Spares, valves for pressure management, Flow indicators, Silica gel Breather, etc.

Other than these processes defined earlier, custom fittings can be provided based on clients’ needs and requirements. The best part is that we have completed many successful projects in last few years. Our products are working amazingly in various industrial sectors like chemical factories, casting industries and steel industries.

transformer testing transformer testing in india electrical transformer
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