[Shop-talk] Alternator terminals

[Randall]

> If you look a this chart,
> 
> 
> 
> 	http://dasko.co.nz/articles/alternator-terminals-explained
> 
> 
> It looks like all I would need to hook up to would be the "B" 
> terminal and the ground and I can ignore the rest.  
> 
> Do I have this right?  

You can try that, but I suspect the Ex terminal needs to get current through the warning lamp (which provides excitation when the
alternator first starts turning), and the S terminal needs to get battery voltage (The 'sense' input to the voltage regulator).  You
can use a resistor instead of the lamp, if you want, but you'll still need an external source of 12v to get it working (and a switch
to stop it from drawing current all the time).  Just jumper the S terminal to the B terminal, though.

> On an automotive alternator how fast does it normally have to 
> spin to put out 12V?  

They'll usually put out something with the engine idling, maybe 1000-1200 rpm at the alternator.  Full output requires more, though,
generally something like 5000-7000 at the alternator.

Randall