An actuator. In one embodiment, the actuator comprises a reversible electric motor having a stator having a housing, a rotor housed in the housing of the stator, and a shaft having a forward portion and a rearward portion extending oppositely and coaxially from the rotor, respectively; a fan member coaxially attached to the forward portion or the rearward portion of the motor shaft such that the fan member is operable simultaneously with the rotor of the reversible electric motor; and an electromagnetic brake movable between a first position and a second position, positioned in relation to the fan member such that when the electromagnetic brake is in the first position, the fan member is rotatable with the rotor of the reversible electric motor, and when the electromagnetic brake is in the second position, the fan member stops rotating firmly, thereby causing the motor stops instantly.