Let look in this deeper. A single drive would it be idlers of belt transmitting moment to platter has errors (slips, bends, elasticity… etc). Those errors make a platter to reset microscopic backlash in bearing. The minute deviation of speed is not truly a problem but the platter rocking back in force while it clears the micro freedoms between mating element of bearing is a problem.
Now we presume that let say 3 idlers or belts driver the platter at 120 degree and they create more uniform rotation. Yes, the errors of each idler or belt is less critical and now it transmits 1/3 of moment. However, why we are under a presumption that idlers or belts errors have random character. What will happen if idlers or belts errors took place in near same time? We just have no control over it as the idlers and belts are not synchronized. Now, let see how a single idler or belt work. The force of the moment from ONLY side permanently offset the backlash of the bearing, creating a mechanical biasing of the bearing errors. So, the theoretical conclusion is that a single drive is better. |
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