Abstract: This invention describes a control mechanism for an electric main drive of a printing machine, whereby the electric main drive operates with a motor, a brake and a tachometer generator. The machine control of the control mechanism is connected to a multiplicity of signal transmitters (pushbuttons). The signal transmitters detect the machine state to ensure that the printing machine does not run at an excessively high speed. For this purpose, the invention outlines, in addition to the machine control, a monitoring device which detects the switching states of the signal transmitters, forms a highest possible permitted speed therefrom and compares this value with the actual speed value delivered by the tachometer generator. The electric main drive is shut down as soon as the actual speed value overshoots this upper limit.