Publication: The Electrician
New York, NY, United States
THE LAUFFEN-FRANKFORT TRANSMISSION
The Frankfurter Zeitung, in expressing the general wish for the speedy publication of the report on the Lauffen-Frankfort transmission experiments, remarks that the long silence of the Commission has been commented upon by adversaries of the system adopted. In the meantime, therefore, the following particulars, which have been obtained by the Schweizerisch Bruze tung, from Herr Emil Huber, of the Oerlikon Works, will be read with interest.
The transmission, says the latter paper, was effected for the most part at a pressure of 16,000 volts, which was only raised towards the close of the tests to 30,000 volts. The early apprehensions that the insulators would not be able to stand this pressure have turned out to be perfectly groundless, as only one insulator, and that at the maximum pressure, was perforated by the stress. Slight breakdowns occurred also in two other instances, on one occasion through the failure of a wire, and on the other owing to the breaking of an insulator. From an examination of the broken surface of this insulator it was clear that the accident was due to a defect in manufacture, which was further corroborated by the fracture of several of them whilst they were being put up.
It is noteworthy that these defective insulators were all of the large type, with the triple oil groove, whilst not one of the small ones with the single groove (which were only used as a makeshift) was found to fail. The larger ones were made in great haste, so that slight faults might easily have escaped notice. It follows accordingly that adequate insulation for such an undertaking can be obtained by simple means and at a reasonable cost. The actual capital outlay per effective horse-power amount to £60, of which £50 had to be devoted to the conductor.
The question is what proportion of the work absorbed at Lauffen was recovered at Frankfort. Observations were taken simultaneously at Lauffen and Frankfort. AT Lauffen currents of 500, 490, and 500 amperes in the three branches were observed, whilst there were 54 volts between each of the leads and the neutral point. Leaving out of the question the phase difference between volts and current, the energy supplied amounted to 80,500 watts. At the same instant 1,060 glow lamps of 16 c.p., or their equivalent, requiring 58,000 watts, were being run off the transformers at Frankfort. This gives an efficiency of 72 per cent. Practically the efficiency must have exceeded this value, probably by about 5 per cent.
The damp weather did not seem to do any harm; no direct leakage to earth could be observed.
The static charge effects occasioned only the smallest loss. In fact, the whole undertaking showed nothing abnormal.