# Torque required to rotate panel on one axis

I am working on a project that requires solar panel to rotate around its axis, but I am struck with deciding the specs of the Servo Motor that is capable of doing this. Though, the panel hangs on its axis with help of two axle rods on each side attached almost in the mid of the length, and the servo is to be attached on one of the sides.

The specification of the panel is LBH - 1665 x 1000 x 50 mm and weighs around 24kgs.

I suppose it should not require that much toruqe to rotate the same, but can someone help me deciding the minimum torque needed to do that. Please consider providing an equation so that I can use it for deciding on panels of different dimensions.

• You should start with calculating the moment of inertia around the rotation axis. This will tell you how hard is it to rotate the panel. Then you should think how fast you want to rotate it - the way I see it, you could rotate it with any toy motor, provided that the gear ratio is high enough, but it would be very slow. – gigacyan Mar 20 '14 at 7:28
• Speed does not matter a lot. I was looking to do that with help of gears but I don't think normal toy motor will be able to do that in my case as I would be controlling the motor with some micro-controller board. I think a servo motor is capable in getting my job done. – Cyberpks Mar 20 '14 at 9:47

As mentioned in the comment $M=J\dot{\omega} [Nm]$. However I think you should lay the focus on things like friction and especially wind forces, as they are more likely to exert significant forces on your panel.