Fkeib. I agree, 100% torque conversion is not possible.
That is why I listed this assumption..."TDs motor only provides enough torque to maintain original speed before stylus is lowered, after it is lowered."
I have assumed that the motor plays no part in dealing with stylus drag. It is only delivering enough torque to overcome windage and bearing friction.
Any additional friction in the form of stylus drag is resisted by the stored energy in the rotating platter. That is why I needed to calculate its moment of inertia.
This makes my calcs conservative, since there will be some restorative torque from the motor. Since we don't know how much, it was considered best to ignore this parameter.
The info I did find online relating to calculating stylus drag used a free wheeling platter, running at rated speed. Timed to stop without and then with the stylus lowered. My calcs are a derivative of that method.
I don't think that Maynard and I would agree on very much at all!
That is why I listed this assumption..."TDs motor only provides enough torque to maintain original speed before stylus is lowered, after it is lowered."
I have assumed that the motor plays no part in dealing with stylus drag. It is only delivering enough torque to overcome windage and bearing friction.
Any additional friction in the form of stylus drag is resisted by the stored energy in the rotating platter. That is why I needed to calculate its moment of inertia.
This makes my calcs conservative, since there will be some restorative torque from the motor. Since we don't know how much, it was considered best to ignore this parameter.
The info I did find online relating to calculating stylus drag used a free wheeling platter, running at rated speed. Timed to stop without and then with the stylus lowered. My calcs are a derivative of that method.
I don't think that Maynard and I would agree on very much at all!