That's an excellent point. One of the sprockets would need some sort of clutch that could be disengaged without using tools, but I don't see that in this scheme.

Yes, they can eventually burn out, as my old Stanley opener did today. It was installed around 1990, so it lasted nearly 30 years. The wisps of smoke coming from the motor housing told me it was "toast".

@@Milosz_Ostrow often thats just the capacitor when see smoke they dont last ever but can be got at granger for like 10 bucks. They are super simple replace but some times boards do get burn spots then yeah its trash. Honestly form what ive seen 15 years the avg. 30 years damm good motor.