I am designing anenergy regeneration system using a pulley attached to the wire rope of a track elevator using a 3:1 sprocket ratio I am getting around 670 RPM`s I am using two 6 volt lead acid batteries in series match to a 12 volt pure sine wave inverter I am trying to figure out what alternator/ generator should I use that will charge my system and knowing the 670 RPM what output can I expect
670 rpm is about half the minimum an alternator needs.
If you look on a car the alt pulley diameter is about 1/3 of the crank pulley diameter.
This means that when the car engine is idling the alternator can cover the demand.
But at max engine speed the alt must not exceed its max rpm - usually about 10000 rpm so the pulley ratios must be checked.
Have seen an alternator seized due to excess speed (not bearings but rotor welded to stator) - owner did a conversion on a v6 motor and did not check the pulley sizes...