Synchronous-motor pulling-into-step phenomena

INVESTIGATIONS of synchronous motor phenomena during transient conditions have been made, using a mechanical calculating machine called the “differential analyzer” to solve the non-linear differential equations involved. Previous investigations have been made on a preliminary calculating machine called the “product integraph.” The extent and accuracy of the solutions, however, were limited on this preliminary machine, and the work was confined principally to determining whether or not a synchronous motor would synchronize for the worst switching conditions. The curves presented in the present paper and obtained by use of the differential analyzer make it possible to calculate quantitatively the additional load that may be synchronized if the field switch is closed at the most favorable switching angle.