Constructional Features

Welcome to TRANSTRON Electricals

CORE BUILDING

The core of a Transformer is, in real terms the very soul of the Machine. The process of making it requires careful planning and the whole process is out of the scope of this page. But the process is given as simply and as briefly as possible under:-

Magnetic circuit of the Transformer is built by assembling high grade Cold Rolled Grain Oriented, non aging Silicon electrical steel lamination having high permeability and the low hystersis loss. Laminations are melted out, cut, free from burrs, fully annealed to minimize the stresses, developed during slitting, cutting and punching. The lamination of different size are assembled to different step- thickness as per design and firmly secured by M.S. clamps and Bolts, so that the core remains free of any strain during lifting and handling operations.

WINDINGS & COILS

If the core is the soul, the coils are the lungs that breathe life into the transformer. This next part is as complicated as the first one and requires much skill and labour too.

The High Voltage and Low Voltage windings are fabricated in the shape of Coils, perfectly circular in section, with high conductivity Copper /Aluminium conductor. Spiral, cross-over or continous disc coils are used depending on the Voltage class and rating of the Transformer. These coils are dried and pressed to predetermined stack heights and are assembled concentrically on the core.

Both types of windings are magnetically balanced with respect to each other, thus minimizing the mechanical stresses, that arise under short-circuit conditions.
Tappings are normally provided on HV coils, at the electrical centre of the windings and are so spaced to provide ampere turn balance.

TANKING & BOXING

The "Coil and the Core Assembly" is put inside the heating chamber, under controlled temperature to drive out the moisture from the insulating material.

Coil clamping and Megger Testing is done at this stage in steps to ensure desired value of insulation resistance and stack height of Windings. Once the drying and tightening process is complete, the "Core & Coil" Assembly is put inside the pre-fabricated and painted M.S. Tank, clamped, and filled with dehydrated and filtered Transformer Oil. All electrical connections are made to H.T. & L.T. Rods, complete set of accessories is fitted and the Transformer is ready for testing.

TESTING & QUALITY CONTROL

Apart from the stage-wise testing of every single component and sub-assembly, the fully manufactured Transformer is subjected to all routine tests using high precision measuring instruments as per I.S. 2026 (1987) or any other applicable standard, such as Insulation Test, Voltage Ratio, Polarity, Excitation Current and No Load Loss, Winding Resistance, Load Loss, Impedance, Vector Group, Induced over Voltage Test, Separate Source Voltage Withstand Test, Temperature Rise test, Impulse Test., Dynamic Short Circuit Test, can also be conducted on any Transformer, as a type test at any Govt. approved Testing Lab, if desired by the customer

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