Correct. If your alt has a field wire then putting it on a relay will allow you to manually (de)activate it. On the other hand, if your alternator's field is self-exciting, then it won't be easy. In that case you can either re-do the internal circuits (
AXMonster tried, but didn't get it working, iirc), or you can try A/C clutch pulley, which I don't recall anyone actually doing.
There's quite a bit about alternator killing here, but you can start here and then search for more:
Deceleration Alternator
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e·co·mod·ding: the art of turning vehicles into what they should be
What matters is
where you're going, not
how fast.
"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell
[Old] Piwoslaw's Peugeot 307sw modding thread