An electrical actuator comprises two or more electrical motors to drive a threaded screw ram. Each motor has an armature that drives a threaded roller screw that is engaged to the threaded screw ram. Each armature of each motor is independently engageable and/or dis-engageable with the ram. The motor armatures are engageable and disengageable by way of threaded roller screws, the ends of which are tapered to enable them to be lifted away from or lowered into engagement with the threaded ram.
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