Design of Wave Filter for Absorption of Irregularities of Direct Current Pressure Wave and Applieation of Aluminium Cell Condense

Abstract

It is well known that the irregularities of amplitude which exist in the pressure cud current wave of direct current generators, rotary converers and mercury are rectifiers often give disturbances to acoustic instcuments conneeted to the communication circuits. The most conspicuous i regularities of ampliftude are due to (i) slot and commutator harmonies direct current generators and rotary converters, (ii) higher harmonics of 6 times the frequency of the supply alternating current of motary couverters and (iii) higher harmonics of n, 2n, 3n & c times the frequency of the supply alternating current in mercury are rectifiers where n is the number of anodes. In order to absorb such higher harmonics, the use of the resonant shunt wave filter which consists of a static capacity and an inductance connected in series to the terminals of direct current machines has often been proposed by many authors. Although this wave filter is effective for the suppression of inductive disturbances due to higher harmonics in the communication circuits, yet it is not sufficient to protect the direct disturbances to acoustic instruments from irregularities of pressure waves of direct current generators to be used for the plate or filament circuit of vacuum tubes in the wireless communication and for the power source of automatic or common battery telephone systems. The author has analytically investigated the properties of wave filters of different kind and the method of preliminary design of the wave filter which is effective in protecting the direct disturbances Consequently he has found that an aluminium cell condenser can best be applied as a shunt condenser for such wave filters. Also be has deduced the simple formula for the determination of the above wave filters and explained the test results of so designed wave filters with oscillograms.