Abstract: A power-operated chuck, for turning machines, having at least one jaw which is radially movably guided in a chuck body and which is actuated by a pressure medium piston which is movably guided in the chuck body and the working chamber of which is connected to a source of pressure medium via a releasable check valve. The working chamber of the pressure medium cylinder is connected with the pressure chamber of a centrifugal force compensating cylinder, the compensating piston of which is designed as a centrifugal weight and is radially movably guided in the chuck body. The radially outer end of the compensating piston projects into the pressure chamber. So that the system is effective independent of the level of the working pressure, the radially inner end of the compensating piston projects into a relief chamber which is directly connected, i.e. by-passing the check valve, with the source of pressure medium via a short-circuit line.