These german models seem to have the perfect gh motors in them for smooth power & long term use, but there's never any marking on them so I don't know where they're sourcing them from.
And I'm not going to ask them as it's their trade secret.
My 850 is using MFA ComoDrill motors. This is what's powering each track now (minus the right angle drive) with the 516:1 planetary head. Can't stall them.
http://www.mfacomodrills.com/gearbox...ra_series.html