Suddenly applied loads carried by a variable-ratio synchronous-induction frequency changer

The induction machine of this frequency changer has demonstrated its ability to start and carry rotating machine induction loads requiring 140 per cent of the kilovolt-amperes of the induction machine to start them without benefit of capacitive excitation. A-c amplidynes are used for automatic voltage regulation of the induction machine. D-c amplidynes are used for regulating the load through the frequency changer. So far as the authors are aware, this is the first commercial installation of this type to incorporate these features.