Abstract: An activation circuit and a method for operating an activation circuit for a DC motor having an electrically actuated stopping brake, in particular for adjusting a rotor blade of a wind or water power facility. The activation circuit includes an emergency operation supply unit and a three-phase bridge inverter. The emergency operation supply unit is connected so it is disconnectable via an emergency operation network switching element to the intermediate circuit of the three-phase bridge inverter, the DC motor is connected via an emergency operation motor changeover element either to the three-phase bridge inverter or to the emergency operation supply unit, and the stopping brake is connected via an emergency operation brake changeover element either to the three-phase bridge inverter or to the emergency operation supply unit.

Abstract: The present invention relates to an activation circuit and a method for operating such an activation circuit for a DC motor (04) having electrically actuated stopping brake (07), in particular for adjusting a rotor blade of a wind or water power facility. The activation circuit comprises an emergency operation supply unit (03) and a three-phase bridge inverter (01). The emergency operation supply unit (03) is connected so it is disconnectable via an emergency operation network switching element (12) to the intermediate circuit (16, 17) of the three-phase bridge inverter (01), the DC motor (04) is connected via an emergency operation motor changeover element (13) either to the three-phase bridge inverter (01) or to the emergency operation supply unit (03), and the stopping brake (07) is connected via an emergency operation brake changeover element (14) either to the three-phase bridge inverter (01) or to the emergency operation supply unit (03).