Screw Jack selection calculation
(1) V=RPM*P/I
V(mm/min): Lifting speed     RPM(r/min): Motor input speed
P(mm): Screw Jack Pitch     I: Screw Jack Gear Ratio
(2) P=G*V/6120*f 
P(KW): Input Power          G(KG): Lifting Load
V=Lifting Speed              f: Transmission efficiency(15%-18%)
(3)  T=P*9550/RPM
T(N.m):Lifting Torque:   P(KW):Input Power  RPM(r/min): Motor input speed
Note: We usually change the RPM to change the lifting speed, we also can change the pitch and gear ratio according to the customer request.