if you could spare a couple amps and a couple bucks for an AC clutch then you could disengage the electric motor when not used or in danger of overspeed. I wish I knew a simple/common manual clutch you could use instead of constantly wasting electricity on the clutch. Some sort of sliding in-out(engaged-disengaged) coupling w/a rev match could work too, electric motors can rev match all the way down to 0 rpm
