Polyphase Commutator Machines

In a certain type of frequency-changer which consists of an armature similar to that of a synchronous converter, viz., a type of direct-current armature with slip rings on one side and a commutator on the other, the energy loss due to the currents flowing in these conductors is here analyzed. The energy loss appearing as heat depends upon the degree to which the currents which flow in or out at the commutator end or the slip rings compensate one another. In the case of the synchronous converter the former are direct currents while the latter are alternating currents. In the case of the frequency-changer, they are alternating currents of different frequency. This paper analyzes the losses taking account of the time and space overlapping of the currents and gives the results for different numbers of phases and for different power factors.