| 摘要 |
PURPOSE:To make preventive against a nearby fire by housing an insulating tank filled with a mineral insulating oil, an internal pressure discharger, etc. in a main tank and by dipping in a noncombustible insulating liquid. CONSTITUTION:A main tank 1 is provided with a pressure discharger 14, a conservator 11b, an external radiator 25, etc. and is filled with a noncombustible insulating liquid 6. An insulating tank 4 housing a winding 3 and a mineral insulating oil 5 forms a closed system 20 connected to a liquid-cooling heat exchanger 21 via upper and lower pipings 23a, 23b and an oil pump 22. When a fire breaks out near by, the noncombustible insulating oil 6 is locally boiled, noncombustible vapor is discharged via a pressure discharger 14 and the temperature of the insulating liquid 6 is kept below a boiling point temperature. Accordingly, the insulating oil 5 in the closed system 20 can be prevented to be heated to the boiling point temperature and sufficient prevention capability can be obtained against a nearby fire.
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