Nikola Tesla Books
146 HIGH FREQUENCY APPARATUS former shed and a switch is conveniently placed both at the shed and at the point where the wires leave the house or pole. Caution Must be Observed.-The utmost care must be used to prevent the possibility of persons coming in contact with the span of wire over the bed, or, indeed with either wire leaving the transformer secondary, as the voltage delivered at this point would produce a dangerous shock. To afford a safeguard in this particular, a fence should surround the plot and a contact be arranged at the gate in such manner that when the gate is opened a bell will be caused to ring and this will remind one to turn the current off from the transformer before entering the gate. This device is not difficult to design and in fact it may consist of one of the familiar release pushes such as are used on door jambs. The transformer used by the author delivered a potential of 10,000 volts and was rated at ½ kw. The construction was of the closed core variety and the instrument was immersed in oil to assist in cooling as the runs were from 8 to 12 hours daily. Such an instrument can be purchased for a small sum from manufacturers of wireless telegraph apparatus and the experimenter is advised to buy one outright. The necessary details are given, however, so that the ambitious worker may try his hand at the job if his courage is good. Construction of the Apparatus.-The transformer to be described is generously proportioned in order to provide ample insulation and radiation surface. The constructional details for a transformer to operate on the usual 60-cycle, 110-volt supply are given herewith and in the full-page plate the worker will note that data for 25-cycle and 125cycle instruments are given also. The windings for 70, 110 and 220 volts are appended as well.
