Method of Testing the Temperature Rise in the Windings of OD-Cooled Transformers.

For output-limit transformers the principle of controlled cooling is being adopted more and more widely. The present article describes the basic differences in the cases of natural and controlled flow of the cooling medium. On the basis of these considerations a criterion is given for the checking of controlled cooled together with a method of testing temprature rise of windings. Test results and estimates of errors prove the efficiency of the proposed method.