[Lizard]

Cool, nice to have you here Dr. T.

Not sure about magnet strength and drag and how it affects torque.

But what I've read is, that Lehner motors have very little magnet drag. They don't have iron cores (not sure what that is in english, it's called "Luftspule" in German, direct translation would be "air-coil"), so that thing about the iron core causing this seems to make sense.

With the TP5670 I can turn the shaft by hand, but it's a lot harder than with the 1717.