Linearised analysis of induction-motor transients

The effect of supply frequency on the speed transients of an induction motor due to small voltage and torque disturbances is discussed. The transients which depend on four nondimensional parameters are obtained by a graphical (root-locus) method which could well be followed at the design stage. The transfer functions between speed and small changes in input voltage and torque are given. It is shown that in low-frequency motors a lightly damped transient speed oscillation will occur at a frequency just below the supply frequency, which is influenced only slightly by the machine parameters.