The phase co-ordinate method is applied to the study of some dynamic characteristics of single-cage deep-bar and double-cage induction motors. Particular attention is given to the dynamic run-up characteristics and how they are modified by the effects of saturation, inertia or load, and, for synchronous motors, by field connection. Induction motors are studied further in the complex transient situations arising owing to nonsimultaneous breaker operation, system fault condition, reswitching and plugging operation.