Flashing of 60-cycle synchronous converters and some suggested remedies

WITH the increasing application of 60-cycle synchronous converters to railway service, the question of flashing is receiving considerable attention. A series of tests has recently been made, and others are still in progress, with a view to determining the possibilities of protection from flashing by various methods, including the “quick-acting breaker,” “flash suppressor,” “flash guards” and various modifications and combinations of these. The converter that has been used for these tests is a standard 500-kw., 600-volt, six-phase, 60-cycle, 1200-rev. per min. machine. It was supplied with power from a 5000-kv-a. generator through three standard high-reactance transformers. These transformers had a reactance of approximately 17 per cent at normal load and 10 per cent on short circuit.