The alternator requires voltage to activate regulator, it's designed to
recharge a battery. You need a generator to operate alone. An alternator
running at 500 rpm can produce 12 volts. Hope this helps..

"E. Walter Le Roy" wrote in message
link.net...
We have a 7 foot water wheel in a mountain stream and would like to hook
up an alternator, and light up the fish pond. Can anyone tell me what RPM
it needs to turn to run one headlamp?
Thanks
Walt