28/07/2026
𝐎𝐧𝐞 𝐜𝐚𝐧𝐧𝐨𝐭 𝐚𝐥𝐰𝐚𝐲𝐬 𝐩𝐮𝐭 𝐚 𝐬𝐭𝐫𝐚𝐢𝐧 𝐠𝐚𝐮𝐠𝐞 𝐨𝐧 𝐚 𝐬𝐡𝐚𝐟𝐭 𝐭𝐡𝐚𝐭'𝐬 𝐢𝐧 𝐩𝐫𝐨𝐝𝐮𝐜𝐭𝐢𝐨𝐧. 𝐒𝐭𝐨𝐩𝐩𝐢𝐧𝐠 𝐭𝐡𝐞 𝐥𝐢𝐧𝐞 𝐜𝐨𝐬𝐭𝐬 𝐦𝐨𝐧𝐞𝐲, 𝐰𝐡𝐢𝐥𝐞 𝐢𝐧𝐬𝐭𝐫𝐮𝐦𝐞𝐧𝐭𝐢𝐧𝐠 𝐢𝐬 𝐢𝐧𝐬𝐭𝐫𝐮𝐬𝐢𝐯𝐞.
Still, you need to know what torque passes through it - to size, understand a failure, and choose a component.
Indirect estimation is the approach. For the useful torque, start with the electrical power the motor draws and the line speed - power divided by angular velocity gives the torque.
For a looping friction torque, you start from the clamping force and the friction coefficient. Each path gives a grounded value, from quantities measured or know, without touching the shaft.
Of course it is not as exact or calibrated as a strain gauge, but it is enough to decide with a basis, without relegating to guessing. This is the clear differentiation between engineering and a random shot.
