Nikola Tesla - Free-Energy Devices

HIGH FREQUENCY AND HIGH POTENTIAL CURRENTS. 223be most carefully expelled, for in it the charged surfaces are neareach other, and if the potentials are high, just assure as a weightwill fall if let go, so the insulation will give way if a singlegaseous bubble of some size be present, whereas, if all gaseousmatter were carefully excluded, the condenser would safelywithstand a much higher difference of potential. A main conveyingalternating currents of very high tension may be injuredmerely by a blow hole or small crack in the insulation, the moreso as a blowhole is apt to contain gas at low pressure and as it;appears almost impossible to completely obviate such little imperfections,I am led to believe that in our future distribution ofelectrical energy by currents of very high tension, liquid insulationwill be used. The cost is a great drawback, but if we employan oil as an insulator the distribution of electrical energywith something like 100,000 volts, and even more, becomes, atleast with higher frequencies, so easy that it could be hardlycalled an engineering feat. With oil insulation and alternate currentmotors, transmissions of power can be affected with safetyand upon an industrial basis at distances of as much as a thousandmiles.A peculiar property of oils, and liquid insulation in general,when subjected to rapidly changing electric stresses, is to disperseany gaseous bubbles which may be present, and diffuse themthrough its mass, generally long before any injurious break canoccur. This feature may be easily observed with an ordinary inductioncoil by taking the primary out, plugging up the end ofthe tube upon which the secondary is wound, and itfilling withsome fairly transparent insulator, such as paraffme A oil. primaryof a diameter something like six millimetres smaller than theinside of the tube may be inserted in the oil. When the coil isset to work one may see, looking from the top through the oil,many luminous points air bubbles which are caught by insertingthe primary, and which are rendered luminous in consequenceof the violent bombardment. The occluded air, by its impactagainst the oil, heats it the oil ; begins to circulate, carrying someof the air along with it, until the bubbles are dispersed and theluminous points disappear. In this manner, unless large bubblesare occluded in such way that circulation is rendered impossible,a damaging break is averted, the only effect being a moderatewarming up of the oil. If, instead of the liquid, a solid insulation,no matter how thick, were used, a breaking through and injuryof the apparatus would be inevitable.