An electromechanical actuator comprising: a threaded output ram connectable to a mechanical component, the output ram having a longitudinal central axis; two or more electrical motor modules (24, 30, 34) configured to controllably translate the output ram along the longitudinal central axis of the output ram to impart movement to the mechanical component, wherein, for a given speed of the motor modules (24, 30, 34), a linear translation speed of the output ram is determined by a thread pitch of the output ram; and a torque sensing adaptive control system configured to monitor torque within the motor modules (24, 30, 34) and determine whether each motor module torque is outside an allowable motor module torque range; characterised in that each motor module (24, 30, 34) comprises: a stator; a roller nut that acts as an armature of the motor module (24, 30, 34) such that the roller nut is configured to rotate in response to magnetic fields created about the armature by the stator, the roller nut being laterally fixed with respect to the output ram, the roller nut including bearing caps at opposing ends that radially separate a plurality of threaded rollers engageable with the output ram, each bearing cap including a ramp and lock mechanism, the roller nut comprising one or more biasing devices to bias the threaded rollers radially inward and into contact with threads of the output ram; a disengaging cam (40, 116) configured to disengage the threaded rollers from the output ram; and a disengagement actuation device configured to move the disengaging cam (40, 116) longitudinally along the longitudinal central axis of the output ram so as to disengage the threaded rollers from the output ram by moving tapers of the ramp and lock mechanisms under corresponding taper sections of the threaded rollers to lift the threaded rollers away from the output ram when the torque sensing adaptive control system determines the motor module torque is outside the allowable motor module torque range. a threaded output ram connectable to a mechanical component, the output ram having a longitudinal central axis; two or more electrical motor modules (24, 30, 34) configured to controllably translate the output ram along the longitudinal central axis of the output ram to impart movement to the mechanical component, wherein, for a given speed of the motor modules (24, 30, 34), a linear translation speed of the output ram is determined by a thread pitch of the output ram; and a torque sensing adaptive control system configured to monitor torque within the motor modules (24, 30, 34) and determine whether each motor module torque is outside an allowable motor module torque range; characterised in that each motor module (24, 30, 34) comprises: a stator; a roller nut that acts as an armature of the motor module (24, 30, 34) such that the roller nut is configured to rotate in response to magnetic fields created about the armature by the stator, the roller nut being laterally fixed with respect to the output ram, the roller nut including bearing caps at opposing ends that radially separate a plurality of threaded rollers engageable with the output ram, each bearing cap including a ramp and lock mechanism, the roller nut comprising one or more biasing devices to bias the threaded rollers radially inward and into contact with threads of the output ram; a disengaging cam (40, 116) configured to disengage the threaded rollers from the output ram; and a disengagement actuation device configured to move the disengaging cam (40, 116) longitudinally along the longitudinal central axis of the output ram so as to disengage the threaded rollers from the output ram by moving tapers of the ramp and lock mechanisms under corresponding taper sections of the threaded rollers to lift the threaded rollers away from the output ram when the torque sensing adaptive control system determines the motor module torque is outside the allowable motor module torque range. a stator; a roller nut that acts as an armature of the motor module (24, 30, 34) such that the roller nut is configured to rotate in response to magnetic fields created about the armature by the stator, the roller nut being laterally fixed with respect to the output ram, the roller nut including bearing caps at opposing ends that radially separate a plurality of threaded rollers engageable with the output ram, each bearing cap including a ramp and lock mechanism, the roller nut comprising one or more biasing devices to bias the threaded rollers radially inward and into contact with threads of the output ram; a disengaging cam (40, 116) configured to disengage the threaded rollers from the output ram; and a disengagement actuation device configured to move the disengaging cam (40, 116) longitudinally along the longitudinal central axis of the output ram so as to disengage the threaded rollers from the output ram by moving tapers of the ramp and lock mechanisms under corresponding taper sections of the threaded rollers to lift the threaded rollers away from the output ram when the torque sensing adaptive control system determines the motor module torque is outside the allowable motor module torque range.