Discussion at Pacific Coast convention: Synchronizing power in synchronous machines

Abstract

F. E. Terman: The results of Mr. Putman's carefully made calculations will be partially upset if the motor is fed by lines and transformers that have considerable impedance. This is because Mr. Putman's derivation assumes a constant voltage at the motor terminals, and this constant terminal voltage is not obtained if the supply lines and transformers have much impedance. In such a case the surging line current causes a varying voltage drop in the line. The effect of the line impedance can be taken into account in Mr. Putman's result by interpreting the motor terminal voltage to be the voltage nearest the motor that is substantially constant during the surging, and interpreting the so-called “real armature impedance” as the actual armature impedance plus the line and transformer impedance between the motor and the point of constant voltage.