How do I calculate the amount of torque required to rotate a 35 pound object parallel to the ground?

Question

I need to also calculate the gearings needed to require this torque, in order to use less amperage.

I forgot that I would like to have a final RPM of around 2 - 4

A motor is attached to a gear box which drives a 5" spur gear that is directly attached to a round, ball bearing swivel. The load ontop of the swivel is around 35 pounds. And I would like the swivel to move at around 3 RPMs

Answer 1

We are distressed to visualize what you want to do. Are you rolling a barrel shaped object on the ground?
Is a 35 lb object on a cart with round wheels that you are trying to turn?
Or some other scenario..?

If something is rolling on the ground, the torque will be heavily influenced by the diameter of the round object and the softness of the ground. You give us none of that information. The only accurate way to predict this is to perform an experiment using the exact object and type of ground you have in mind.

The gearing will then depend on the torque available at the motor shaft.

Answer 2

The required torque only depends on the bearing/bushing losses and aerodynamic losses. For the ideal loss less bearing (ignoring air friction) you would need zero torque once the object had reached its final angular velocity.

If on the other hand you needed the torque to accelerate your object to the given final angular velocity in a given time, then the torque required would depend on the rotational inertia of the object.