Nikola Tesla Books
Books written by or about Nikola Tesla
Taking one wire in each groove (No. 10 B. & S.) we have for 48 turns 10.380 mills being the section of wire No. 10 total section reduced to one turn
| 10380 x 48 41520 83040 498240 | } | = 498,240 c. mills or |
| 498,240 x 0.0005067 2491200 2989440 3487680 2524582080 | } | = 252.46 mm. square. That is very nearly the section of primary cables. |
Therefore, if two primary cables are used there should be two wires in each groove of the secondary as provided for. The total section of primary will then be 490.82 sq. mm. and of secondary reduced to one turn: 504.92 sq. mm., but as the wire is slightly stretched the sections or masses respectively will be more equal.
Colorado Springs
Sept. 24, 1899
Note relative to Westinghouse Transformer.
The iron core is of dimensions indicated in sketch. The insulation from core 1" thick blocks of wood. Insulation between fibre paper about 1/2" thick.
There are three primary coils and 4 secondary coils. For a transformation to 60,000 volts a part of primary is left out. Best way of working is to use smaller transformation ratio to 45,000 approx.
The secondary coils are connected up alternatively, that is, beginning with the first on the left, then to third, then to second and from there to the fourth coil.
The transformer gives every evidence of having a high efficiency. The leakage current is remarkably small for so large a machine. The alternate connection and disposition of coils is evidently to reduce stray field and also for convenience to enable use of similarly wound coils, that is, coils wound on one form.
The tests of mineral seal oil 300° show it to be oil of excellent quality penetrative, of high flashing point and good insulating properties.
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