Wide-range reversible voltage controllers for polyphase induction motors

The many static, magnetic voltage controllers reported in the literature are shown to be combinations of four basic saturable reactor and saturable transformer connections. It is found that the replacement of series-connected saturable reactors by pairs of back-to-back connected silicon-controlled rectifiers is feasible in some control applications, thus providing opportunities for more compact, more economical drives with faster transient response. Several new controllers of wide voltage range are described.