The thyristor commutatorless motor

The commutatorless motor (CLM) is a type of a dc motor whose commutator is replaced by the thyristor power converter. The thyristors are switched by the signals from a position sensor connected to the rotating shaft of the synchronous motor. Therefore, the CLM never loses synchronism and has the good speed characteristics of a dc motor. The current type CLM, having a current smoothing reactor, was studied and found to have better characteristics than the voltage type. In this paper two kinds of the current type CLMs are described; one is the dc CLM using an inverter, the other the ac CLM using a cycloconverter.