The current locus of the single-phase induction motor

The theory of the single-phase induction motor has, until recently, been complicated by the general use of Ferrari´s expedient of resolving the impressed alternating magnetic field into forwardly and backwardly rotating components; this conception, though it leads to correct results if consistently handled, is open to the objection that it departs unnecessarily from the physical facts, and gives rise to the notion that the ordinary laws of electromagnetic induction are not immediately applicable, as in the direct-current machine. Within the last few years, however, the tendency in treating this problem has been to go back to first principles, and several valuable contributions have appeared, notably those of Fynn and McAllister. The following treatment has been based largely on the theory advanced by Fynn in his several publications.