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Winding Resistance Test Of Transformer

The measurement for the temperature of winding

The temperature in the channel between the high and low pressure winding passages which is measured by dry type transformer is seen as the temperature of winding;

The average temperature between the top and the bottom oil measured by the oil—immersed transformer is seen as the temperature of winding.

The selection of measuring current

The measuring current can not be over 15% of the rated current of the tested winding;

The measuring current should be selected within the range of the testing resistance as stipulated by instrument;

The tester for the DCR of transformer:

5A       1mΩ—4Ω

10A       0.2mΩ—2Ω

20A       0.1mΩ—1Ω

The measurement of winding resistance

According to the point 7 to connect the test line, when we use the magnetic circuit method, the current direction of magnetic winding should be in accordance with that of the same end of the tested winding. On the basis of the point 9.2 of technical conditions of products, when it comes to the power switch of instrument, we should select the measuring current by pressing the mode button and press the start key to measure the winding resistance. After the result becomes stable, record the value. Then press the reset key to discharge off and the measurement ends.