[jdchmiel]

If the electric motor has very good bearings, wouldn't spinning it at a continious RPM really not eat up very much efficiency? Like on a purely cost basis, if the only significant benefit to adding an overrun clutch is to save brush life, how long do the brushes last, and how much do they cost, and how difficult is it to service the motor? How does that level of time, effort, and money compare to custom building an overrun pulley system?

Contrasting opinion side note, Ford Crown vic police alternators are 200 amp units that I think are 5 or 6 groove wide pulleys with a built in overrun. I bought two of them off ebay for around $100 total to use to build a tig welder. I do not know what kind of power they would handle continiously, but they must be rated for intermittant ~3.7 hp based on 14v @ 200 amps output..

And another fun thought - a timing belt transmits a lot more power on a continious basis.. If you can get rid of all of your other accessory belts, you can add a second crank timing pulley in place of the main crank pulley for a drive belt, and adapt another geared pulley to your motor. You can get that pulley from a timing belt + idler kit from many motors. for instance, my subaru flat 4 had 3 if I recall that were about the same diameter as the crank pulley for a close to 1:1 drive, and the cam gears obviosly are always a 1:2 ratio on all engines. Garages just throw many of these out all the time for each timing belt job they do!