Nikola Tesla - Free-Energy Devices

HIGH FREQUENCY AND HIGH POTENTIAL CURRENTS. 381the annular groove are brought together, while the inner flangesare serrated, as in the previous case, and form the polar faces.The two parts H H are formed with a base E, upon which themachine rests, s s are non-magnetic bushings secured or set inthe central opening of the cores. The conductor D is cut entirelythrough at one point to form terminals, from which insulatedconductors T are led through the shaft to collecting-rings v.In one type of machine of this kind constructed by Mr. Tesla,the field had 480 polar projections on each side, and from thismachine it was possible to obtain 30,000 alternations per second.As the polar projections must necessarily be very narrow, verythin wires or sheets must be used to avoid the eddy currenteffects.Mr. Tesla has thus constructed machines with a stationaryarmature and rotating field, in which case also the field-coilwas supported so that the revolving part consisted only of awrought iron body devoid of any wire and also machines with arotating armature and stationary field. The machines may heeither drum or disc, but Mr. Tesla's experience shows the latterto be preferable.In the course of a very interesting article contributed to theElectrical World in February, 1891, Mr. Tesla makes some suggestiveremarks on these high frequency machines and his experienceswith them, as well as with other parts of the highfrequency apparatus. Part of it isquoted here and is asfollows :The writer will incidentally mention that any one who attemptsfor the first time to construct such a machine will have atale of woe to tell. He will first start out, as a matter of course,by making an armature with the required number of polar projections.He will then get the satisfaction of having producedan apparatus which is fit to accompany a thoroughly Wagnerianopera. It may besides possess the virtue of converting mechanicalenergy into heat in a nearly perfect manner. If there is areversal in the polarity of the projections, he will get heat out ofthe machine ;if there is no reversal, the heating will be less, butthe output will be next to nothing.He will then abandon theiron in the armature, and he will get from the Scylla to theCharybdis. He will look for one difficulty and will find another,but, after a few trials, he may get nearly what he wanted.