... screw jack can be directly connected with electric motor,or gear reducer. electric screw lifts Detailed Informations:For easy installation, ... mounts come with necessary hardware and coupling keys. All standard electric motors are 3 phase, 380VAC, 50 Hz, 1440 rpm ... control of motor speed is necessary. Electric motor drive revolutions are not exceed 1800 RPM.electric screw lifts Lifting Speed Formulas: V ...