Disc geometry single-phase alternator with slotless stator and AC-side excitation

The paper presents an investigation of an unusual form of solid-pole brushless alternator as a single-phase machine. Its behaviour with pulsating single-phase fields is of particular interest. The design of the prototype alternator is discussed, with special attention being given to the design considerations of this class of machines. An analysis is presented of the nonsynchronous fields in the airgap of a salient-pole single-phase alternator. From this the fields contributing to energy conversion are identified and expressions are developed for the machine reactances. A method of calculating the leakage inductances follows from this and the additional component of leakage inductance in a single-phase machine is identified. Experimental results are presented for the machine, which include reactance measurements, a load test, heat run and voltage waveforms.