. Electrical world. mto contact with air, there is^no danger of oxidation. This is apomt which does not seem to b*e sufficiently appreciated by electricalengineers in general. In a Franklin Institute paper of Mr. C. E. FIG. I.—PARTS OF TRANSFORMER. the latest types of oil-cooled, three-phase transformers built by thiscompany will, therefore, be of interest. All these transformers of capacities between i and 50 kw areoil-cooled, since it has been found that a much more compact con-struction can thus be obtained than with air cooling; other thingsbeing equal, an oil-cooled transformer has a high
. Electrical world. mto contact with air, there is^no danger of oxidation. This is apomt which does not seem to b*e sufficiently appreciated by electricalengineers in general. In a Franklin Institute paper of Mr. C. E. FIG. I.—PARTS OF TRANSFORMER. the latest types of oil-cooled, three-phase transformers built by thiscompany will, therefore, be of interest. All these transformers of capacities between i and 50 kw areoil-cooled, since it has been found that a much more compact con-struction can thus be obtained than with air cooling; other thingsbeing equal, an oil-cooled transformer has a higher efiiciency and asmaller voltage drop than an air-cooled transformer of the samedimensions. Moreover, since oil prevents the windings from coming. FIG. 2.—EFFICIENCY CURVES. Farrington on the chemical problems involved in the production of a perfect insulating material for electric machinery, the authorpoints out that while electricians like to claim that their apparatusis well ventilated, they forget that well-ventilated also meanswell oxidized. All these transformers are built as core transformers with thethree cores in one plane. The cores are made up of thin iron sheetscovered with paper. As few bolts as possible are used passingthrough the laminations, and the number of accessory cast-iron partsis restricted as far as possible in order to reduce the losses due toeddy currents, etc., to a minimum. Fig. i shows the method ofbuilding up the transformer. The smaller sizes (up to 7 or 12 kilovolt-amperes) and for voltagesup to 6,000 on the high-tension side, have concentric windings, thehigh-voltage winding being at the outside. In the larger sizes thewindings are subdivided into smaller coils, the high-tension andlow-tension
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectelectri, bookyear1883
