Q4
(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 watts. Calculate the efficiency at half-full load, 0.8 power factor.
(7)
Reference Answer
### Part (a): Potential Hazards of Liquid-Cooled Transformers Liquid-cooled transformers, typically using mineral oil as a coolant and insulator, present several significant hazards onboard a vessel. These must be managed through proper design, installation, maintenance, and emergency procedures. 1. **Fire Hazard**: * **Cause**: The mineral oil used as a coolant is combustible. An internal fault, such as a short circuit between windings or a core fault, can cause severe arcing. This arc has a very high temperature, which can vaporize and ignite the oil.
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