Torque Requirements

Calculating Torque Requirements for Kinetic Sculptures

Experimental Evidence: 40 lb Video - Disabled

Experimental Evidence: Videos of Other Experiments - Disabled

Experimental Evidence: Data and Charts

Data from the experiments shown in the videos was collected. The video was recorded at 30 frames per second. This fact provided the measure of time. The number of frames per 1/5th revolution are counted - QuickTime provided that capability. (Note: after analyzing the data recorded at 30 frames per second it became clear that the fins on the sculpture are not exactly the same distance apart. Consequently, velocity calculated between each fin as the sculpture rotates is quite volatile. To account for this, my calculations below are based on the same fin-to-fin comparison, that is, the time it take to make six full revolutions, not 1/5th of a revolution. ) The data is available here. Regression analysis is used to estimate a log-log specification as shown in Table 1. Note: This specification may not directly conform to standard physics formulas, i.e., V = Vf*(1-exp(-kt)). I will be looking into this further; comments and suggestions would be helpful here. Nonetheless, the log-log specification gives a good prediction as shown in Figure 1 below. Based on these predicted results velocity in terms of RPM can be computed as shown in Figure 2.

Table 1
Figure 1
Figure 2

Torque Formulas

Motors, Drive Wheels and Power Supplies


Problems and Applications

External References