Figure 4.

Simulated trajectories are shown for motors with (a) one and (b) seven engaged stators, with ${\zeta }_L=0.005$ pN-nm-s-rad⁻¹. Horizontal black lines denote the distance between “perfect” steps ($\ell =\left(2\pi /26\right)$ rad). Colored bars at the bottom of the plots mark the duration of individual stator steps (in the shown trace, steps for three out of the seven engaged stators are shown). In the multistator motor trajectory (b), steps for each stator are differently colored. In accordance with published temporal resolutions (47, 48), we consider two steps distinguishable if the end of the first step and the start of the second step are separated by 10 μs. These are shaded in blue; for multistator motors, steps may overlap or be too close together to be observed. (c) Motor speed at low loads increases with the number of stators. An experimentally measured speed distribution at low loads is shown in the inset (data from (28)). Gaussian fits to the major peaks give mean speeds (blue squares) in good agreement with simulation predictions (open red circles). To see this figure in color, go online.