Electric screw jack is well known as a motorized screw jack, a gearmotor screw jack, a motor operated screw jack. This motorized jack includes a worm gear screw jack and an electric motor. The screw jack can be self locking MACHINE screw jack, or high efficiency BALL screw jack. The motor types can be high precision servo motor, stepper motor, gear motor, worm gear reducer, 3-phase motor and 12v 24v DC motor and dc gearmotor etc.