The digital transient torque measuring device presented in this paper is able to make a "real time" calculation in steady-state and transient conditions of the electromagnetic torque or force of an extremely wide range of ac electrical machines supplied with sinusoidal voltages or through frequency converters with frequencies up to 30 kHz. The device needs no shaft position or speed sensors, it uses exclusively the acquisition of the stator currents and voltages. The main fields of applications are: test shop, control, measurement, integration in a control or regulation unit, element of a monitoring system.