Self Excitation of a Frequency Converter

After a general discussion of the phenomenon of self excitation of a-c machines, a specific case of 3 phase self excitation of a Scherbius machine is treated. Such a machine is used in the regulating set of a variable-ratio frequency converter for inherently constant power transfer, the operating features of which are described. Under certain conditions this converter may be subject to the danger of self excitation. These conditions are discussed in detail and means are indicated to prevent self excitation during the normal operation of this converter.