I dunno the detail, but this is on the Teknatool website re the Nova lathe;
'The DVR Motor works by pure magnetic attraction. When a magnet is switched on, an intense magnetic field is
created and pulls the tooth to line up with the magnet, and then the next magnet switched on, which forces the
spindle to rotate. A feedback loop senses the motors surroundings to actively
monitor conditions and performance.
This is unlike a ‘dumb’ AC or DC motor where there is no active management of conditions and the motors performance. The actions of the DVR motor are controlled by a computer chip. It constantly analyses (at 400 times per second for example, when running at 2000rpm) both the spindle position and the power required to maintain a given speed.'
If that makes any sense to you, then my work here is done! #-o
Greg