The invention relates to a drive unit for switching circuit breakers, especially disconnecting and/or grounding switches of medium-voltage switchgear, on and off. Said unit comprises a reversible d.c. motor and a switching device which contains two reversing switches which can be driven separately and mutually interlocked and which are each assigned to one direction of rotation of the d.c. motor. The contacts of said reversing switches carry out the current polarity reversal at the d.c. motor windings which is necessary for reversing the direction of rotation and, for the purpose of load switching, have power contactors with contacts having the required switching capacity. The all-or-nothing relays and safety switches are embodied as uniform, low-power relays (KL, KR) representing the direction of rotation, which each have at least two electrically decoupled relay contacts (RK) connected in parallel and to each of which a power factor capacitor is connected in parallel. Drive units of this kind are used in connection with switchgear for energy transmission and distribution.