DESIGN

QTC is a leader in the manufacturing of Hermetically Sealed Type Transformers fully filled with oil. This particular design defends against the build up of humidity and gas inside transformer tank. However, silica gel and oil checks are unnecessary for many years to come. Our purpose is to minimize maintenance expense for our customers. QTC Transformer are designed, mass -produced and tested by an engineers team who have a wide range of experience in developing and manufacturing transformers. QTC transformer can guarantee its operational safety, reliability and maintenance free.
Computers are used to calculate all transformer data as well as to prevent the electrical and thermal stress that may arise during operation.

TRANSFORMER CORE
The iron cores are assembled from high QTC cold-rolled, grain-oriented magnetic sheets by the use of step lap method. The machine can cut steel sheet precisely and instantly to receive greater accuracy. In addition, it gives an even QTC. The minimum of values of no load loss, magnetizing current, vibration, and noise are a result of these mechanical solidity increased. However, the maintenance expense can simply and automatically reduces.


Nevertheless, QTC uses an identical procedure in punching hole onto the iron core and core cutting. Since the beginning of core cutting to core punching, an operation error can arise in one place or another. Therefore, the stacking table is an essential. It has a controlled key punch where it protects a misstep. This shows a proper QTC of stacking table.

STACKING TABLE stacks the core in the correct layout precisely and instantly on the table. It stacks the 0.23-0.30 mm. Sheets. The core limb and laminations are mitered at the joints with the yoke. The limb and yoke have exactly the same cross-section in which are spread out step by step achieve the circular-like shape. An adequate number of core bandages make certain uniform compression of the limbs.


TRANSFORMER WINDING

COPPER FOIL
COPPER FOIL is used to produce the low voltage winding for QTC transformer. This technique is to reduce the axial short-circuit forces. The conductor and insulation material are bonded with thermo pox that can safety withstand radial forces.


FOIL WINDING MACHINE
QTC transformers use a modern foil-winding machine to wind the low voltage coils by aiming at high QTC, safety and long life warranty.



HIGH VOLTAGE WINDING
Winding technology of QTC transformer is the last improvement of long layer winding to decrease interlayer voltage. An automatic winding machine is controlled by the computer system. The winding is more of homogeneous and less sensitive of high frequency resonance due to current harmonics.

HIGH VOLTAGE WINDING MACHINE can control strength of copper wire and winding layer, winding sequence which is computerize control to prevent human error and keep the similarity of QTC for every coils.



TRANSFORMER TANK
CORRUGATED TANK is a part of QTC Hermetically sealed transformer, which has the advantage of being maintenance free.

  • Fin of tank is made from a single piece of stretched metal to minimize the amount of welding. Therefore these are lesser of chance of leakage.
  • The corrugated tank has been designed to transfer heat better than conventional tank. This prevents the coil winding from heating up.
  • The dimension of tank is much smaller and lighter, which requires less space for installation.
  • Most importantly, the corrugated tank has also been designed to be elastic tank with high volumetric efficiency. The volume will increase at the fin when there is any fault within the tank.

 

VACUUM DRYING AND FILLING PLANT

With electric low-frequency heating, the first and only one in Thailand, is used in QTC. The uniform, modern, and economical processes by injection of low frequency heating current, desired to transformer winding then vacuum and oil filling. The computerize controller ensure the highest QTC insulation system in QTC transformer for longer life.


Typical Process Sequence During Drying and Filling of Distribution Transformers.





TESTING

Tests performed by several test institutes were according to the latest international transformer standards for instance.
  • IEC 76
  • TIS 384-2543
  • VDE 0532 and DIN4290
  • JIS
  • NEMA
  • ANSI C57.12


ROUTINE TESTS
As an integrated part of our production process, and also on the completely assemble transformer which consist of
  • Ratio test
  • Resistant measurement
  • Polarity and Phase relation test
  • No-load loss test
  • Exciting current measurement
  • Impedance and load loss test
  • Applied potential test
  • Induced voltage test
  • Insulation resistance test
  • Oil test
  • Oil leakage test


    • TYPE TESTS
    Type test has been performed on customers request and on our own initiative. These have enabled us to prove the constant QTC and reliability of our transformer range. The details of type test as follow.

    • Impulse voltage test
    • Temperature rise measurement.

    		 
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    Design by Systop Co.,Ltd.