A high speed, fail-safe device for an electric actuator that can be independently triggered in the event of an emergency shutdown is provided. An electromagnetic brake is attached to the roller nut of the screw actuator. When actuated, the brake prevents rotation of the roller nut, and therefore enables linear movement of the roller nut upon rotation of the lead screw to linearly move an output shaft to actuate the valve. During actuation a return spring is compressed to enable retraction of the output shaft upon system failure. During such failure, the electric break is de-energized, which allows the roller nut to rotate and linearly move under force of the return spring to retract the output shaft to its fail-safe condition. A soft-stop/over-travel system is provided to limit the impact loads on the lead screw.

An electric fail-safe actuator includes a speed reducer/gear assembly housing arranged between one or more electric motors, and a rotation to linear transformer including a roller or ball nut and a screw, or a nut and a roller or ball screw. The speed reducer/gear assembly housing is connected to an actuator housing via a counter hold release mechanism, allowing the speed reducer/gear assembly housing to co-rotate with a rotational side of the rotation to linear transformer when the counter hold release mechanism is released.