Quote Originally Posted by artmin View Post
Just my ignorance! I assumed that when stationary, the motors would be maxxed out to prevent any movement .
When stationary is the only time the motors will deliver their rated torque, so 1.5Nm. To calculate the holding force you need to know the pitch of the ballscrew and the diameter. For example if it's a standard 16mm ballscrew with 5mm pitch and direct drive gives holding force of about 1880N with your motor, plenty!
(Formula is F=2*T*pi/p where T is torque and p is pitch if anyone's interested)