An Analytical Investigation of the Causes of Flashing of Synchronous Converters

The object of this paper is to show on what factors the flashing tendency of synchronous converters depends, and how, on the broadest considerations, an improvement of their momentary overload characteristics can be obtained. From the interpretation of a number of oscillograms, and other experimental data, it is shown that a heavy load surge produces unbalanced armature reactions, resulting in abnormal voltage conditions on the commutation, which are in turn largely responsible for the flash. Synchronous stability, stability of commutating conditions, and means of choking down the flash, are the means enumerated by which the momentary overload capacity may be increased.