Testing A Transformer The Right Way


Lighting surges, short circuits, overloading, loose connections are just some of the most common failures seen occurring in transformers; you may experience a lot more if your transformers aren’t built right; and to avoid such catastrophes, it is crucial that the transformers are thoroughly tested before being used.

While there are a variety of different types of transformers available, the basic construction of any kind of transformer involves two coils wound together on a core made of either iron or ferrite; with the main function being to alter the AC current and voltage. Because of such an intricate purpose being solved with a transformer, you would certainly approach a reliable and trusted transformer manufacturer in India to have your transformer build. But, you should be certain that the transformers are not only built, but also tested before being delivered to you.

How are transformers tested?

Winding breakdown test – If a very high voltage or current passes through the coil, the circuit may break down due to the heating up of the winding. To check for such winding breakdowns, AC voltage is first applied to the primary winding. In case of low or zero voltage from the secondary, an opening of the winding is indicated.

Ringer test – To check for any shorts, a ringer test is performed. The most cost-effective ringer test is the LOPT or FBT tester, which can instantly tell the results on the bar graph by connecting its probes to the primary winding. A 4-8 reading indicated full winding, while a 1-3 reading signifies partial shortening. A complete switch off means heavy shortening in the coil.

Megger test – This test is used to determine the quality of insulation within the transformer, which is performed with the help of a megohmmeter. The insulation of the transformer must be determined to have a greater resistance than defined by international standards. Any lower than the required measurement signifies an issue with the insulation, which then requires replacement.

Power factor test – This process involves the testing of the power loss of the insulation system, which is done by measuring the power angle between an applied AC voltage and the resultant current. The angle of the current should measure 90 degrees; the closer to 90 that the current is, the better the insulation is. Using a power factor test kit to regularly test the transformer from time to time can help detect deteriorating or malfunctioning insulation, giving you an idea of when the transformer will need to be replaced.

Resistance test – This test checks for any differences between the opens and windings within the transformer with the help of an ohmmeter, ensuring that all the circuits are still wired and connected correctly.

Repairing a transformer is not easy, and requires a good amount of knowledge and skill, which is why you need to approach a reliable and professional transformer manufacturer in India like Miracle Electronics, to have your transformers built, wherein the equipment is not only built, but also thoroughly tested.

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