Exam Question

(a) Explain the potential hazards if liquid-cooled transformers are used. (6)

(b) What are the losses in transformers? Mention the various factors which affect these losses. In a 25 KVA, 3300/233 V, single phase transformer, the iron and full-load Cu losses are respectively 350 and 400 w. Calculate the efficiency at half-full load 0.8 power factor. (10)