| 摘要 |
An electric motor, particularly for an actuating device for displacing a control device, such as a valve, a gate valve, a blow-out preventer or the like, for use in oil or gas production includes a stator and a rotor assigned to a motor shaft, and a position holding device for exerting a holding torque on the motor shaft. To improve an electric motor of this type such that said motor is of a compact structure, includes less additional parts for a corresponding position holding device and, particularly in case of failure of an external power supply, reliably prevents a situation where the motor shaft is moved out of the attained position upon corresponding pressure application e.g. by the control device, the position holding device comprises a plurality of permanent magnets, the permanent magnets being arranged in radial direction relative to the rotor and the motor shaft, respectively.
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