# How to calculate holding and operating torque at the base?

Could anyone please help me with the formula to calculate the operating torque and holding torque at the base to rotate the structure on top of it as shown in image with white arrows?

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Oct 27, 2021 at 20:31

Without measuring friction coefficients and weights and such, there is no way to compute a number. But you asked instead about a formula.

The operating torque will be the sum of

• static friction (getting it unstuck so it will start moving)
• rolling/sliding friction (joints and bearings)
• accelerating the moment of inertia
• overcoming whatever externally might be trying to move it or constrain it (who knows, wind blowing on the operator's cage? bashing into the building?)

For holding torque (no motion) we see no rolling friction and no inertia. Furthermore, the static friction helps it stay in one position. So holding torque would be the "overcoming" torque (as above) minus static friction. Of course that can't really go negative -- like if there's no wind and the brake is on.