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.
