How To Accurately Test A Transformer ?

Category : Transformer Testing | Posted on 2021-08-18 20:11:23

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There are two main types of transformers available in the market: the linear transformer and power transformer, which differ in their design and application.  Thought, they both have coils wounded together on the iron (ferrite) core.

In real world application, transformer failures occurs in case of a too high voltage or current passing through the coil leading to the circuit breakdown by heating of the windings. Linear transformer can be tested in the absence of load. The breakdown of the windings (primary / secondary) can be checked by the signs of overheating. It is done by applying ac voltage to the primary winding and checking the very low or negligible voltage from the secondary winding of the transformer.

On the other hand, the power transformer works on load. Thus, a power transformer is tested by firstly disconnecting it from the board and then investigating the primary winding and the secondary windings for failures. The ringer test and/or the resistance checks method is applied to check the coil winding failures. The ringer tester is performed by connecting its probes to the primary winding and instantly shows the results in the form of bar graph.  A reading of 4-8 means good winding, while 1-2 bar signifies partial shortening and switching off of the represents heavy damage in the coils.

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