I am attempting to size a linear actuator (check that the rated torque will be enough to open a damper). My damper is a circular plate that has a mass of 20kg. It will pivot about one side of the plate (not through the vertical centreline of the plate). The actuator is rated for 500 N.m.
I know:
T = F * r and F = ma
So the force required to pivot the damper can be determined from F = ma, giving me my required force. And If I know the radius/distance from my pivot location I can calculate the torque. Completing these calculations (assuming 0.3m from pivot axis):
F = 20 * 10 = 200 N
T = 200 * 0.3 = 60N
This doesn't make sense to me, as I increase the distance from the pivot axis, the required torque increases? I thought it would make sense for the required torque to decrease? If anyone has suggestions on how to properly check whether the rated actuator can open the damper of 20kg mass that would be greatly appreciated. Also if the applied motion of the linear actuator is not perpendicular to the axis of rotation, I assume I would just need to add in sin(theta) into the torque calculation.
Cheers