toolbreaker wrote:



If cogging is real important one might try a 3 phase induction motor
and a motor controller. We have project that uses this aproach will
good results. It wont be snappy but it will be smooth
Actually, typical induction motors tend to cog a fair amount if run
at very low speeds, as the induced rotor poles slip from one set
of rotor bars to the next. There are special motors built for servo
use that have many much thinner shorting bars, and put a helical twist
to them.

Jon