Usually , a jack system does not continue to be operated so frequently . So people do not care about a loss in electricity expenses by selecting a large motor , and tend to select a motor with a larger capacity than calculated value , considering that it would be better than an insufficient one .
However , motors have the rotor inertia (J) , and this value increases along with an increase in the motor capacity .
Screw jacks are intended for performing a linear movement within a limited distance , so if the inertia is smaller , the overrun will be less .
Furthermore , if an obstacle gets stuck , the maximum torque of the motor will be imposed on the system , and it may damage the device . In contrast as the motor’s torque characteristics , it is deigned in a way that the start torque is 1.5 times larger than the rated torque , so it will sufficiently endure for a short time . Therefore , it is recommended to select a minimal motor .
