In order to make further progress with the solution of multimachine transient problems, it is necessary to augment the facilities of network analysers, the most convenient of the analytical tools available to the power-system engineer. The paper describes a new simulator which enables the symmetrical a.c. transient component of current or voltage of a synchronous machine, subsequent to any 3-phase disturbance, to be obtained. The simulator is based on the duals of equivalent circuits for the direct and quadrature axes of synchronous machines, and is entirely electronic in its operation.Experimental results are given and a comparison is drawn between these and the results obtained by calculation. It is concluded that such a simulator is an essential preliminary step towards a more accurate representation of machines and their associated apparatus, either individually or when interconnected in a power system.