The paper analyses the behaviour of induction motors under transient conditions of changing the supply frequency. This is necessary owing to the possibility of utilising induction motors in position-control servomechanisms in which the control signal determines the frequency of supply to the stator. The analysis achieves a torque differential equation and frequency-response loci. The analytical results are compared with experimental results obtained on an induction motor and from an analogue simulator. The effects of rotor inertia and rotor (electrical) time constant are studied using the simulator.