Hi,

I have a solar panel weighing 20 kgs mounted to a frame which resembles a see-saw. The panel is mounted to frame using ball bearings, so friction loss is minimum. A gear is connected to centre of frame which can turn the panel. I am using a stepper motor. What is the torque required?

Panel weight : 20kgs
Panel length : 1.5 meter
Gear ratio 28:1

Is the center of gravity of the panel perfectly balanced on the bearings - in other words does it balance in all orientatins all by itself? Also, to determine the torque you must estimate the friction force of the bearings - you say it's "minimal" but what we need a value. How hard do you have to lift or push in order to rotate the panel at the desired speed?