Method of rapidly reversing large currents in highly inductive loads

The paper describes a method of rapidly reversing a large current in a highly inductive load, which has been satisfactorily applied to the paralleled field windings of a pair of 2MW d.c. generators. The technique discussed avoids disconnection of the inductive load whilst current is still flowing, and hence the problem of dissipating the stored energy. The power unit evolved consists of two 3-phase fully controlled thyristor bridges arranged in a figure-of-eight formation. The means of avoiding large circulating currents by controlled methods is discussed in detail.