The paper describes an investigation into the contribution that a conventional velocity governor controlling the input power to a synchronous generator makes to the transient stability of a typical power-system configuration. It seeks to ascertain the corresponding transient-stability effect using an alternative operating signal, derived from rotor acceleration, for the control of input power. A governor actuated from a compound of velocity and acceleration signals is described, and its effect on transient stability is compared. The effects on this stability of varying some of the parameters of the system, the machine and the governor are described. The paper concludes with a brief study of the effect of various governors on the transient stability of a synchronous generator connected to a large system by a single faulted transmission line that is fitted with autoreclosing circuit breakers.