The Design of Poulsen Arc Converters for Radio Telegraphy

The Poulsen arc converter cycle is studied in detail, and the various relations between direct and alternating arc currents and voltages obtained and discussed. The possible production of harmonics is considered. The effect of arc field strength on the arc phenomena is then taken up. The efficiency of the Poulsen arc cycle is obtained and checked experimentally. The theoretical relation between best field strength and wave length, arc current and voltage, and nature of atmosphere surrounding the arc, is deduced, and shown to be correct by elaborate experimental data. In this connection, ethyl alcohol and kerosene atmospheres are compared. The design of the magnetic circuit is then handled in detail. The most economical pole shape is given, the tip being a triple tapered conical frustrum. The tip-gap ratio and the pole-gap ratio are also experimentally obtained. Open and closed magnetic circuits are compared. The design of these large electromagnets is facilitated by the use of small models, the results thus obtained being reliable. Data are given for desirable chamber surface for various arc inputs, and for the design of arc electrodes.