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Quality Testing

          Every Ekarat Transformer will go through a Test called “Routine Test” according to agreeable standard.  The Routine Test items are as follow:

♥ Measurement of Winding Resistance

          This is to measure the resistance of the Windings and compare between phases to see any abnormality.  The measured values will be recorded as the test temperature for transferring to the new reference temperature of 75 deg C.

♥ Measurement of Voltage Ratio and Phase Displacement 

          This is to measure the Voltage Ratio of the transformer compare with standard value. Also measure the Vector Group

♥ Measurement of Short-Circuit Impedance and Load Loss

          This is to measure the Load Loss or the Copper Loss, and measure the Impedance Voltage by short circuit method

♥ Measurement of No-Load Loss and Current

         This is to measure the No-Load Loss or the Core loss, and measure the No-Load Current

♥ Separate Source AC Withstand Voltage Test 

          This is to check the internal insulation between the HV coils and Ground, and LV coils and Ground.  By energize high voltage AC 50Hz between the measure points according to the standard.

♥ Induced AC Voltage Test 

          This is to check the insulation of each wire in the coils.  By energize twice of voltage according to the standard.

♥ Measurement of Insulation Resistance 

           This is to measure the insulation overall of the transformer, or sometime called “Megger Test”.

Other than the above Routine Tests, there are other tests called, “Type Test” or “Special Test”, that tested on Prototype transformer or certain transformer (to be agreed with customer).  Such tests are as follow:


This is to measure the temperature of the transformer at Full Load condition. If a transformer does not pass this test, that transformer is not “Full Capacity” as declared in the nameplate.


This is to measure the Dielectric Loss of the insulation, in order to know the condition of the insulation.


This is to test for the determination of moisture in the oil


This is to test the strength of the insulation to Standard Lightning simulation.


This is to find the leakage spot of the tank when pressure is high.


This is to test for the acidity in the oil


This is to measure the level of sound during normal energize.


This is to test of the insulation value of transformer oil


This is a test to analyze the mixture of dissolved gas or Dissolve Gas Analysis (DGA)

During Production Process, there are some tests called, “In-process Tests”,  that we performs regularly.   These tests are as follow:

♥ 100% testing of leakage of the welding seam of the tank

♥ 100% testing of the thickness of each layers of paint. 

♥ Operation test of each devices installed on the transformer, such as, Thermometer, Pressure Relief Device, Buchholz Relay, Integrated Safety Detector, Pressure Gauge, etc