. Journal of electricity, power, and gas . ngles to the flow ofcurrent. The coils can be plainly seen and the polesproject through the other sides of the chamber. Thesmall motor revolves the cathode very slowly and prevents a deposit of carbon taking place and so short-ening the arc gap, which is maintained at from 3 to5 mm. in length. The chamber is equipped with inletand outlet for supplying the arc with a hydrogen-containing gas. On the generator shown there is asight feed oil cup in which alcohol is placed. Drops ofalcohol on being introduced into the chamber are im-mediately vaporized and
. Journal of electricity, power, and gas . ngles to the flow ofcurrent. The coils can be plainly seen and the polesproject through the other sides of the chamber. Thesmall motor revolves the cathode very slowly and prevents a deposit of carbon taking place and so short-ening the arc gap, which is maintained at from 3 to5 mm. in length. The chamber is equipped with inletand outlet for supplying the arc with a hydrogen-containing gas. On the generator shown there is asight feed oil cup in which alcohol is placed. Drops ofalcohol on being introduced into the chamber are im-mediately vaporized and this method of gas supply isin use on ship board. The mechanism seen to the frontof the generator, is for striking and adjusting thelength of the arc by hand. In the chamber there is ayoke which is attracted by the magnetic field when thecurrent is switched on and a small copper tip serves tostrike the arc. This automatic arc striking feature wasdevised for wireless telephoning, so that talking andlistening could be carried on with Fig. 1. Poulsen Arc Generator. A large amount of heat is produced in the water-cooled chamber which is removed by means of thecooling water. A certain amount of power is absorbedin the regulating resistance in series with the arc. Ofthe power which is converted into high frequencyoscillations, part is dissipated as heat in the capacityand inductance and part is radiated b} the antenna. A wattmeter may be used to measure this radiatedenergy by using a direct coupled antenna and measur-ing the watts at some point in the condenser circuitwith and without the antenna. The difference will bethe watts radiated. Fleming has shown that if W represents theenergy in ergs radiated per second, whstn the oscilla-tions are persistent, W = 128 A^ where A is the cur-rent read on a hot wire ammeter. Thus a current of2 amperes would give a radiation of 512 watts, show-ing that when working with persistent oscillations and April 2, 1910] JOURNAL OF ELECTRICITY,
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Keywords: ., bookcentury1800, bookdecade1890, bookidjo, booksubjectelectricity
