Of Generators and Alternators

[Toby Erkson <Toby_Erkson@ccm2.hf.intel.com>]

Okay you techies, here's one for ya'll...

I some solid answers (i.e. no guesses, please) on the rpm ratio between the 
generator and the crank.  I also would like to know at what rpm does the 
generator begin to produce current.  I believe at an idle the stock 
generator isn't rotating fast enough to charge the system -- is this true?

I talked to a custom alternator/starter shop and the owner was very helpful 
in educating me on the differences between the alternator and generator, 
beyond the obvious.  I didn't know that if a generator isn't rotating fast 
enough that it will stop producing current and it could even turn into a 
motor, thus *using* current from the battery instead of charging it (so 
keep that idle up)!

Another item that would be helpful, since I have a mechanical engineer that 
I work with, is the diameter of the crank pulley and the generator pulley.  
She could help with the ratio if no one knows it.

Thanks volks,
     Toby Erkson
     air_cooled_nut@pobox.com
     '72 VW Squareback 1.6L modified to 2.0L
     '75 Porsche 914 stock 1.8L